Ceramides

Physiology of skin aging.

Skin is the most voluminous organ of the body. It assumes several important physiological functions and represents also a "social interface" between an individual and other members of society. This is the main reason its age-dependent modifications are in the forefront of dermatological research and of the "anti-aging" cosmetic industry. Here we concentrate on some aspects only of skin aging, as far as the cellular and extracellular matrix components of skin are concerned. Most well studied mechanisms of skin aging can be situated at the postgenetic level, both epigenetic and post-translational mechanisms being involved. Some of these mechanisms will be reviewed as well as the capacity of fucose- and rhamnose-rich oligo- and polysaccharides (FROP and RROP) to counteract several of the mechanisms involved in skin aging.

Pathol Biol (Paris). 2009 Jun;57(4):336-41

Skin aging and dry skin.

Skin aging appears to be the result of both scheduled and continuous "wear and tear" processes that damage cellular DNA and proteins. Two types of aging, chronological skin aging and photoaging, have distinct clinical and histological features. Chronological skin aging is a universal and inevitable process characterized primarily by physiologic alterations in skin function. In this case, keratinocytes are unable to properly terminally differentiate to form a functional stratum corneum, and the rate of formation of neutral lipids that contribute to the barrier function slows, causing dry, pale skin with fine wrinkles. In contrast, photoaging results from the UVR of sunlight and the damage thus becomes apparent in sun-exposed skin. Characteristics of this aging type are dry and sallow skin displaying fine wrinkles as well as deep furrows, resulting from the disorganization of epidermal and dermal components associated with elastosis and heliodermatitis. Understanding of the functions of the skin and the basic principles of moisturizer use and application is important for the prevention of skin aging. Successful treatment of dry skin with appropriate skin care products gives the impression of eternal youth.

J Dermatol. 2004 Aug;31(8):603-9

Age-related changes in cellular protection, purification, and inflammation-related gene expression: role of dietary phytonutrients.

Oxidative injury and inflammation are intimately involved in the aging process and the development of age-related diseases. To date, most nutritional antiaging strategies have focused solely on the delivery of exogenous antioxidants to combat the negative effects of aging. A promising new strategy is to identify nutrients and phytochemicals that can directly target intrinsic cytoprotective mechanisms, including modulation of the expression of (1) genes involved in the detoxification of xenobiotics, (2) genes involved in the synthesis and regulation of intrinsic antioxidants and antioxidant enzymes, (3) genes involved in the regulation of inflammation, and (4) vitagenes. The purpose of this review is to provide an overview of the age-related changes in gene expression related to oxidative stress, detoxification, and inflammatory processes, and to discuss natural compounds with the potential to oppose age-related changes in gene expression related to these processes, which therefore may be suitable for use in human antiaging research.

Ann N Y Acad Sci. 2012 Jul;1259:112-20

Interaction between elastin and elastases and its role in the aging of the arterial wall, skin and other connective tissues. A review.

Elastic fibers are progressively lysed during maturation and aging and in an accelerated fashion in several aging diseases such as diabetes, arteriosclerosis, emphysema and several skin diseases. Several enzymes (elastase-type proteases) were isolated in recent years in our laboratory which appear to be involved in these processes. A cell membrane bound serine protease was isolated from arterial smooth muscle cells and was shown to increase with in vitro aging of the cells. A metallo-protease was isolated from skin fibroblasts and was shown to be capable of attacking the constituents of elastic fibers, mainly the microfibrillar glycoproteins and also the desmosine cross linked elastin in vivo. This partially purified fibroblast enzyme was shown to attack these elastic fibers when injected into the dermis. A new selective staining procedure was used to visualise and quantitate, by computerized image analysis, the skin elastic fibers in normal and pathological human or animal skin biopsies. This method, combined with the injection of elastase in rabbit skins, alone or together with inhibitors, enables the ex vivo/in vivo study of elastase action (and of its inhibition).

Mech Ageing Dev. 1984 Dec;28(2-3):155-66

Ultraviolet radiation and skin aging: roles of reactive oxygen species, inflammation and protease activation, and strategies for prevention of inflammation-induced matrix degradation - a review.

Inflammation and the resulting accumulation of reactive oxygen species (ROS) play an important role in the intrinsic and photoaging of human skin in vivo. Environmental insults such as ultraviolet (UV) rays from sun, cigarette smoke exposure and pollutants, and the natural process of aging contribute to the generation of free radicals and ROS that stimulate the inflammatory process in the skin. UV irradiation initiates and activates a complex cascade of biochemical reactions in human skin. In short, UV causes depletion of cellular antioxidants and antioxidant enzymes (SOD, catalase), initiates DNA damage leading to the formation of thymidine dimmers, activates the neuroendocrine system leading to immunosuppression and release of neuroendocrine mediators, and causes increased synthesis and release of pro-inflammatory mediators from a variety of skin cells. The pro-inflammatory mediators increase the permeability of capillaries leading to infiltration and activation of neutrophils and other phagocytic cells into the skin. The net result of all these effects is inflammation and free radical generation (both reactive oxygen and nitrogen species). Furthermore, elastsases and other proteases (cathepsin G) released from neutrophils cause further inflammation, and activation of matrix metalloproteases. The inflammation further activates the transcription of various matrixes degrading metalloproteases, leading to abnormal matrix degradation and accumulation of non-functional matrix components. In addition, the inflammation and ROS cause oxidative damage to cellular proteins, lipids and carbohydrates, which accumulates in the dermal and epidermal compartments, contributing to the aetiology of photoaging. Strategies to prevent photodamage caused by this cascade of reactions initiated by UV include: prevention of UV penetration into skin by physical and chemical sunscreens, prevention/reduction of inflammation using anti-inflammatory compounds (e.g. cyclooxygenase inhibitors, inhibitors of cytokine generation); scavenging and quenching of ROS by antioxidants; inhibition of neutrophil elastase activity to prevent extracellular matrix damage and activation of matrix metalloproteases (MMPs), and inhibition of MMP expression (e.g. by retinoids) and activity (e.g. by natural and synthetic inhibitors).

Int J Cosmet Sci. 2005 Feb;27(1):17-34

Recent advances in characterizing biological mechanisms underlying UV-induced wrinkles: a pivotal role of fibrobrast-derived elastase.

In clinical studies, the formation of facial wrinkles has been closely linked to the loss of elastic properties of the skin. Cumulative irradiation with ultraviolet (UV) B at suberythemal doses significantly reduces the elastic properties of the skin, resulting in the formation of wrinkles. In in vitro studies, we identified a paracrine pathway between keratinocytes and fibroblasts, which leads to wrinkle formation via the up-regulation of fibroblast elastases that degrade elastic fibers. UVB irradiation stimulates the activity of fibroblast elastases in animal skin. Scanning electron microscopy revealed that cumulative UVB irradiation elicits a marked alteration in the three-dimensional structure of elastic fibers, which is closely associated with the subsequent reduction in the elastic properties of the skin, resulting in wrinkle formation. Studies using anti-wrinkle treatments suggest a close relationship between the recovery of wrinkles and an improvement in the linearity of elastic fibers. Those studies also suggest a close correlation between the recovery in the linearity of elastic fibers and the improvement in skin elasticity. In a study using ovariectomized animals, we characterized the important role of elastase in their high vulnerability to UV-induced wrinkle formation. A synthetic inhibitor specific for fibroblast elastases significantly prevents wrinkle formation without reducing the elastic properties of the skin, accompanied by minor damage in elastic fibers. Finally, we identified an effective extract of Zingiber officinale (L.) Rose from a screen of many herb extracts, which has a safe and potent inhibitory activity against fibroblast elastases. Animal studies using the L. Rose extract revealed that it has significant preventive effects against UVB-induced wrinkle formation, which occur in concert with beneficial effects on skin elasticity. A 1-year clinical study on human facial skin to determine the efficacy of the L. Rose extract demonstrated that it inhibits the UV-induced decrease in skin elasticity and prevents or improves wrinkle formation in skin around the corner of the eye without changing the water content of the stratum corneum. Our long-term studies support our hypothesis for a mechanism of wrinkle formation in which cytokine expression is activated by UV irradiation and triggers dermal fibroblasts to increase the expression of elastase. That increase in elastase results in the deterioration of the three-dimensional architecture of elastic fibers, reducing skin elasticity and finally leading to the formation of wrinkles.

Arch Dermatol Res. 2008 Apr;300 Suppl 1:S7-20

Mechanism of UVB-induced wrinkling of the skin: paracrine cytokine linkage between keratinocytes and fibroblasts leading to the stimulation of elastase.

In clinical studies, the formation of facial wrinkles has been closely linked to the loss of elastic properties of the skin. Repetitive irradiation of animal skin with UVB radiation at suberythemal doses significantly reduces its elastic properties, resulting in the formation of wrinkles. Repetitive UVB irradiation elicits a marked alteration in the three-dimensional structure of elastic fibers, which is closely associated with a subsequent reduction in the elastic properties of the skin. Although UVB irradiation stimulates the activity of fibroblast elastases in the dermis, a synthetic inhibitor specific for fibroblast elastases prevents wrinkle formation. The close interrelationships among wrinkle formation, elastic properties, and elastic fiber linearity are revealed by the effects of different concentrations of the elastase inhibitor (R(2)>0.9), suggesting that enhanced elastase activity by dermal fibroblasts plays a pivotal role in the UVB wrinkling mechanism. In in vitro studies we identified a paracrine linkage between keratinocytes and fibroblasts that leads to wrinkle formation through the upregulation of fibroblast elastases. These studies support our hypothesis for a mechanism of wrinkle formation by which cytokine expression is activated in epidermal keratinocytes by UVB radiation and triggers dermal fibroblasts to increase their expression of elastase.

J Investig Dermatol Symp Proc. 2009 Aug;14(1):36-43

Effect of moisturizers on epidermal barrier function.

A daily moisturizing routine is a vital part of the management of patients with atopic dermatitis and other dry skin conditions. The composition of the moisturizer determines whether the treatment strengthens or deteriorates the skin barrier function, which may have consequences for the outcome of the dermatitis. One might expect that a patient's impaired skin barrier function should improve in association with a reduction in the clinical signs of dryness. Despite visible relief of the dryness symptoms, however, the abnormal transepidermal water loss has been reported to remain high, or even to increase under certain regimens, whereas other moisturizers improve skin barrier function. Differing outcomes have also been reported in healthy skin: some moisturizers produce deterioration in skin barrier function and others improve the skin. Possible targets for barrier-influencing moisturizing creams include the intercellular lipid bilayers, where the fraction of lipids forming a fluid phase might be changed due to compositional or organizational changes. Other targets are the projected size of the corneocytes or the thickness of the stratum corneum. Moisturizers with barrier-improving properties may delay relapse of dermatitis in patients with atopic dermatitis. In a worst-case scenario, treatment with moisturizing creams could increase the risks of dermatitis and asthma.

Clin Dermatol. 2012 May-Jun;30(3):286-96

The moisturizing effect of a wheat extract food supplement on women's skin: a randomized, double-blind placebo- controlled trial.

Ceramides, specific lipid components of the skin, represent 35-40% of the intercellular cement binding cells together and contributing to skin hydration. A wheat extract rich in ceramides and digalactosyl-diglycerides was developed by Hitex in two forms: wheat extract oil (WEO) and wheat extract powder (WEP). In vitro tests and two clinical studies demonstrated promising efficacy results with WEP on skin hydration. To confirm these early results, a double-blind, randomized, placebo-controlled study was carried out on 51 women aged 20-63 years with dry to very dry skin who received either 350 mg of WEO or placebo for 3 months. Evaluation of skin hydration on legs, arms and face, assessed at baseline (D0) and at study end (D84) was performed by the dermatologist using dermatological scores (dryness, roughness, erythema), skin hydration measurement (corneometry) and self-assessment scores (Visual Analogue Scale: VAS). Perceived efficacy was noted by participants throughout the study; tolerability and overall acceptability of the study products were evaluated by the dermatologist and the participants at the end of study. Skin hydration was significantly increased between D0 and D84 on the arms (P < 0.001) and legs (P = 0.012) in the WEO group compared with placebo. Even if no significant statistical differences between groups were observed for the dermatological evaluation, skin dryness and redness tended to be reduced in the WEO group. Moreover, from D0 to D84, the VAS index had a tendency to increase in favour of WEO for the overall skin hydration (P = 0.084) indicating that participants perceived an improvement. The WEO capsules were perceived by participants as being more effective than placebo on all skin dryness signs. In conclusion, WEO capsules were well tolerated and appreciated. After 3 months' treatment, a significant increase in skin hydration and an improvement in associated clinical signs were observed in women with dry skin.

Int J Cosmet Sci. 2011 Apr;33(2):138-43

The skin barrier in healthy and diseased state.

The primary function of the skin is to protect the body for unwanted influences from the environment. The main barrier of the skin is located in the outermost layer of the skin, the stratum corneum. The stratum corneum consists of corneocytes surrounded by lipid regions. As most drugs applied onto the skin permeate along the lipid domains, the lipid organization is considered to be very important for the skin barrier function. It is for this reason that the lipid organization has been investigated quite extensively. Due to the exceptional stratum corneum lipid composition, with long chain ceramides, free fatty acids and cholesterol as main lipid classes, the lipid organization is different from that of other biological membranes. In stratum corneum, two lamellar phases are present with repeat distances of approximately 6 and 13 nm. Moreover the lipids in the lamellar phases form predominantly crystalline lateral phases, but most probably a subpopulation of lipids forms a liquid phase. Diseased skin is often characterized by a reduced barrier function and an altered lipid composition and organization. In order to understand the aberrant lipid organization in diseased skin, information on the relation between lipid composition and organization is crucial. However, due to its complexity and inter-individual variability, the use of native stratum corneum does not allow detailed systematic studies. To circumvent this problem, mixtures prepared with stratum corneum lipids can be used. In this paper first the lipid organization in stratum corneum of normal and diseased skin is described. Then the role the various lipid classes play in stratum corneum lipid organization and barrier function has been discussed. Finally, the information on the role various lipid classes play in lipid phase behavior has been used to interpret the changes in lipid organization and barrier properties of diseased skin.

Biochim Biophys Acta. 2006 Dec;1758(12):2080-95

Dietary phytochemicals and cancer prevention: Nrf2 signaling, epigenetics, and cell death mechanisms in blocking cancer initiation and progression.

Reactive metabolites from carcinogens and oxidative stress can drive genetic mutations, genomic instability, neoplastic transformation, and ultimately carcinogenesis. Numerous dietary phytochemicals in vegetables/fruits have been shown to possess cancer chemopreventive effects in both preclinical animal models and human epidemiological studies. These phytochemicals could prevent the initiation of carcinogenesis via either direct scavenging of reactive oxygen species/reactive nitrogen species (ROS/RNS) or, more importantly, the induction of cellular defense detoxifying/antioxidant enzymes. These defense enzymes mediated by Nrf2-antioxidative stress and anti-inflammatory signaling pathways can contribute to cellular protection against ROS/RNS and reactive metabolites of carcinogens. In addition, these compounds would kill initiated/transformed cancer cells in vitro and in in vivo xenografts via diverse anti-cancer mechanisms. These mechanisms include the activation of signaling kinases (e.g., JNK), caspases and the mitochondria damage/cytochrome c pathways. Phytochemicals may also have anti-cancer effects by inhibiting the IKK/NF-κB pathway, inhibiting STAT3, and causing cell cycle arrest. In addition, other mechanisms may include epigenetic alterations (e.g., inhibition of HDACs, miRNAs, and the modification of the CpG methylation of cancer-related genes). In this review, we will discuss: the current advances in the study of Nrf2 signaling; Nrf2-deficient tumor mouse models; the epigenetic control of Nrf2 in tumorigenesis and chemoprevention; Nrf2-mediated cancer chemoprevention by naturally occurring dietary phytochemicals; and the mutation or hyper-expression of the Nrf2-Keap1 signaling pathway in advanced tumor cells. The future development of dietary phytochemicals for chemoprevention must integrate in vitro signaling mechanisms, relevant biomarkers of human diseases, and combinations of different phytochemicals and/or non-toxic therapeutic drugs, including NSAIDs.

Pharmacol Ther. 2012 Oct 3. pii: S0163-7258(12)00210-0

Selective depletion of mutant p53 by cancer chemopreventive isothiocyanates and their structure-activity relationships.

Isothiocyanates (ITCs) derived from cruciferous vegetables induce apoptosis in cancer cells. We demonstrate that certain naturally occurring ITCs selectively deplete mutant p53 but not the wild-type and do so via a transcription-independent mechanism. Direct p53 binding followed by conformational changes appears to be a mechanism by which mutant p53 is depleted. Structure-activity relationship studies (SARs) using naturally occurring and synthetic ITCs show that depletion is influenced by the ITC side-chain moiety. Furthermore, we show that cells with p53 mutations are more sensitive to cytotoxicity induced by phenethyl isothiocyanate (PEITC) than those with the wild-type protein. 2,2-Diphenylethyl ITC, a synthetic ITC, is one of the most potent depletors of mutant p53 studies and induces apoptosis to the greatest extent in mutant p53 breast cancer cells. Collectively, this study shows that mutant p53 depletion may be an important novel target for cancer chemoprevention and therapy by natural and synthetic ITCs

J Med Chem. 2011 Feb 10;54(3):809-16

Potent induction of phase 2 enzymes in human prostate cells by sulforaphane.

Two population-based, case-control studies have documented reduced risk of prostate cancer in men who consume cruciferous vegetables. Cruciferae contain high levels of the isothiocyanate sulforaphane. Sulforaphane is known to bolster the defenses of cells against carcinogens through up-regulation of enzymes of carcinogen defense (phase 2 enzymes). Prostate cancer is characterized by an early and near universal loss of expression of the phase 2 enzyme glutathione S-transferase (GST)-pi. We tested whether sulforaphane may act in prostatic cells by increasing phase 2 enzyme expression. The human prostate cancer cell lines LNCaP, MDA PCa 2a, MDA PCa 2b, PC-3, and TSU-Pr1 were treated with 0.1-15 microM sulforaphane in vitro. LNCaP was also treated with an aqueous extract of broccoli sprouts. Quinone reductase enzymatic activity, a surrogate of global phase 2 enzyme activity, was assayed by the menadione-coupled reduction of tetrazolium dye. Expression of NQO-1, GST-alpha, gamma-glutamylcysteine synthetase-heavy and -light chains, and microsomal GST was assessed by Northern blot analysis. Sulforaphane and broccoli sprout extract potently induce quinone reductase activity in cultured prostate cells, and this induction appears to be mediated by increased transcription of the NQO-1 gene. Sulforaphane also induces expression of gamma-glutamylcysteine synthetase light subunit but not the heavy subunit, and this induction is associated with moderate increases in intracellular glutathione levels. Microsomal and alpha-class glutathione transferases were also induced transcriptionally. Sulforaphane induces phase 2 enzyme expression and activity significantly in human prostatic cells. This induction is accompanied by, but not because of, increased intracellular glutathione synthesis. Our findings may help explain the observed inverse correlation between consumption of cruciferae and prostate cancer risk.

Cancer Epidemiol Biomarkers Prev. 2001 Sep;10(9):949-54

Cruciferous Vegetables

Prospective study of fruit and vegetable consumption and risk of lung cancer among men and women.

BACKGROUND: Diets high in fruits and vegetables have been shown to be associated with a lower risk of lung cancer. beta-carotene was hypothesized to be largely responsible for the apparent protective effect, but this hypothesis was not supported by clinical trials. METHODS: We examined the association between lung cancer risk and fruit and vegetable consumption in 77,283 women in the Nurses' Health Study and 47,778 men in the Health Professionals' Follow-up Study. Diet was assessed with the use of a food-frequency questionnaire that included 15 fruits and 23 vegetables. We used logistic regression models to estimate relative risks (RRs) of lung cancer within each cohort. All statistical tests were two-sided. RESULTS: We documented 519 lung cancer cases among the women and 274 among the men. Total fruit and vegetable consumption was associated with a modestly lower risk of lung cancer among the women but not among the men. The RR for the highest versus lowest quintile of intake was 0.79 (95% confidence interval [CI] = 0.59-1.06) among the women and 1.12 (95% CI = 0.74-1.69) among the men after adjustment for smoking status, quantity of cigarettes smoked per day, time since quitting smoking, and age at initiation of smoking. However, total fruit and vegetable consumption was associated with a lower risk of lung cancer among never smokers in the combined cohorts, although the reduction was not statistically significant (RR = 0.63; 95% CI = 0.35-1.12 in the highest tertile). CONCLUSION: Higher fruit and vegetable intakes were associated with lower risks of lung cancer in women but not in men. It is possible that the inverse association among the women remained confounded by unmeasured smoking characteristics, although fruits and vegetables were protective in both men and women who never smoked.

J Natl Cancer Inst. 2000 Nov 15;92(22):1812-23

Cruciferous vegetables and cancer risk in a network of case-control studies.

BACKGROUND: Cruciferous vegetables have been suggested to protect against various cancers, though the issue is open to discussion. To further understand their role, we analyzed data from a network of case-control studies conducted in Italy and Switzerland. PATIENTS AND METHODS: The studies included a total of 1468 cancers of the oral cavity/pharynx, 505 of the esophagus, 230 of the stomach, 2,390 of the colorectum, 185 of the liver, 326 of the pancreas, 852 of the larynx, 3,034 of the breast, 367 of the endometrium, 1031 of the ovary, 1,294 of the prostate, 767 of the kidney, and 11,492 controls. All cancers were incident, histologically confirmed; controls were subjects admitted to the same network of hospitals as cases for a wide spectrum of acute nonneoplastic conditions. RESULTS: The multivariate odds ratio (OR) for consumption of cruciferous vegetables at least once a week as compared with no/occasional consumption was significantly reduced for cancer of the oral cavity/pharynx (OR=0.83), esophagus (OR=0.72), colorectum (OR=0.83), breast (OR=0.83), and kidney (OR=0.68). The OR was below unity, but not significant, for stomach (OR=0.90), liver (OR=0.72), pancreatic (OR=0.90), laryngeal (OR=0.84), endometrial (OR=0.93), ovarian (OR=0.91), and prostate (OR=0.87) cancer. CONCLUSION: This large series of studies provides additional evidence of a favorable effect of cruciferous vegetables on several common cancers.

Ann Oncol. 2012 Aug;23(8):2198-203

Cruciferous vegetable consumption is associated with a reduced risk of total and cardiovascular disease mortality.

BACKGROUND: Asian populations habitually consume a large amount of cruciferous vegetables and other plant-based foods. Few epidemiologic investigations have evaluated the potential health effects of these foods in Asian populations. OBJECTIVE: We aimed to examine the associations of cruciferous vegetables, noncruciferous vegetables, total vegetables, and total fruit intake with risk of all-cause and cause-specific mortality. DESIGN: The analysis included 134,796 Chinese adults who participated in 2 population-based, prospective cohort studies: the Shanghai Women's Health Study and the Shanghai Men's Health Study. Dietary intakes were assessed at baseline through in-person interviews by using validated food-frequency questionnaires. Deaths were ascertained by biennial home visits and linkage with vital statistics registries. RESULTS: We identified 3,442 deaths among women during a mean follow-up of 10.2 y and 1,951 deaths among men during a mean follow-up of 4.6 y. Overall, fruit and vegetable intake was inversely associated with risk of total mortality in both women and men, and a dose-response pattern was particularly evident for cruciferous vegetable intake. The pooled multivariate hazard ratios (95% CIs) for total mortality across increasing quintiles of intake were 1 (reference), 0.91 (0.84, 0.98), 0.88 (0.77, 1.00), 0.85 (0.76, 0.96), and 0.78 (0.71, 0.85) for cruciferous vegetables (P < 0.0001 for trend) and 0.88 (0.79, 0.97), 0.88 (0.79, 0.98), 0.76 (0.62, 0.92), and 0.84 (0.69, 1.00) for total vegetables (P = 0.03 for trend). The inverse associations were primarily related to cardiovascular disease mortality but not to cancer mortality. CONCLUSION: Our findings support recommendations to increase consumption of vegetables, particularly cruciferous vegetables, and fruit to promote cardiovascular health and overall longevity.

Am J Clin Nutr. 2011 Jul;94(1):240-6

Cruciferous indole-3-carbinol inhibits apolipoprotein B secretion in HepG2 cells.

The cardioprotective effect of consuming cruciferous vegetables may be attributed to a number of unique indole-based compounds. We investigated the potential role and mechanism of action of an indole-based compound, indole-3-carbinol (I3C), on apolipoprotein B-100 (apoB) production using HepG2 cells. I3C reduced apoB secretion into the media dose dependently by 56% at 100 micromol/L. Relative to the untreated control cells, no change in the density of the secreted lipoproteins was noted. Significant decreases in cellular lipid synthesis, including triglycerides (TG) and cholesterol esters (CE), were observed in cells treated with I3C, indicating that limited lipid availability is a major factor in the regulation of apoB secretion. The decrease in TG synthesis was associated with significantly decreased diacylglycerol acyltransferase-1 and -2 activity and reduced fatty acid synthase (FASN) gene expression. The decreased CE synthesis was associated with significantly decreased acyl CoA:cholesterol acyltransferase gene expression and activity. The effect on FASN was shown to be mediated by sterol regulatory element binding protein-1, an important transcription factor involved in fatty acid synthesis. Further investigative work revealed that LDL uptake and fatty acid oxidation were not involved in the I3C-mediated reduction of apoB secretion. The results indicate that plant indoles have beneficial effects on lipid synthesis that could contribute to their potential cardioprotective effect.

J Nutr. 2007 Oct;137(10):2185-9

Antiplatelet and antithrombotic activity of indole-3-carbinol in vitro and in vivo.

Indole-3-carbinol, a natural compound found in cruciferous vegetables, is known to have anticancer activity. In the present study, the antiplatelet and antithrombotic activities of indole-3-carbinol were investigated in vitro and in vivo. Indole-3-carbinol significantly inhibited collagen-induced platelet aggregation in human platelet rich plasma (PRP) in a concentration-dependent manner. Indole-3-carbinol significantly inhibited fibrinogen binding to the platelet surface glycoprotein IIb/IIIa (GP IIb/IIIa) receptor by flow cytometric analysis. In addition, the levels of thromboxane B2 (TXB2) and prostaglandin E2 (PGE2) in collagen stimulated PRP were significantly inhibited in a concentration-dependent manner by indole-3-carbinol. Furthermore, indole-3-carbinol dose-dependently suppressed the death of mice with pulmonary thrombosis induced by intravenous injection of collagen and epinephrine. These results suggest that indole-3-carbinol can be a potent antithrombotic agent with antiplatelet activity through the inhibition of GP IIb/IIIa receptor and thromboxane B2 formation.

Phytother Res. 2008 Jan;22(1):58-64

Plasma vitamin C level, fruit and vegetable consumption, and the risk of new-onset type 2 diabetes mellitus: the European prospective investigation of cancer-- Norfolk prospective study.

BACKGROUND: Epidemiologic studies suggest that greater consumption of fruit and vegetables may decrease the risk of diabetes mellitus, but the evidence is limited and inconclusive. Plasma vitamin C level is a good biomarker of fruit and vegetable intake, but, to our knowledge, no prospective studies have examined its association with diabetes risk. This study aims to examine whether fruit and vegetable intake and plasma vitamin C level are associated with the risk of incident type II diabetes. METHODS: We administered a semiquantitative food frequency questionnaire to men and women from a population-based prospective cohort (European Prospective Investigation of Cancer-Norfolk) study who were aged 40 to 75 years at baseline (1993-1997) when plasma vitamin C level was determined and habitual intake of fruit and vegetables was assessed. During 12 years of follow-up between February 1993 and the end of December 2005, 735 clinically incident cases of diabetes were identified among 21,831 healthy individuals. We report the odds ratios of diabetes associated with sex-specific quintiles of fruit and vegetable intake and of plasma vitamin C levels. RESULTS: A strong inverse association was found between plasma vitamin C level and diabetes risk. The odds ratio of diabetes in the top quintile of plasma vitamin C was 0.38 (95% confidence interval, 0.28-0.52) in a model adjusted for demographic, lifestyle, and anthropometric variables. In a similarly adjusted model, the odds ratio of diabetes in the top quintile of fruit and vegetable consumption was 0.78 (95% confidence interval, 0.60-1.00). CONCLUSIONS: Higher plasma vitamin C level and, to a lesser degree, fruit and vegetable intake were associated with a substantially decreased risk of diabetes. Our findings highlight a potentially important public health message on the benefits of a diet rich in fruit and vegetables for the prevention of diabetes.

Arch Intern Med. 2008 Jul 28;168(14):1493-9

Serum and dietary potassium and risk of incident type 2 diabetes mellitus: The Atherosclerosis Risk in Communities (ARIC) study.

BACKGROUND: Serum potassium levels affect insulin secretion by pancreatic β-cells, and hypokalemia associated with diuretic use has been associated with dysglycemia. We hypothesized that adults with lower serum potassium levels and lower dietary potassium intake are at higher risk for incident diabetes mellitus (DM), independent of diuretic use. METHODS: We analyzed data from 12,209 participants from the Atherosclerosis Risk in Communities (ARIC) Study, an ongoing prospective cohort study, beginning in 1986, with 9 years of in-person follow-up and 17 years of telephone follow-up. Using multivariate Cox proportional hazard models, we estimated the hazard ratio (HR) of incident DM associated with baseline serum potassium levels. RESULTS: During 9 years of in-person follow-up, 1475 participants developed incident DM. In multivariate analyses, we found an inverse association between serum potassium and risk of incident DM. Compared with those with a high-normal serum potassium level (5.0-5.5 mEq/L), adults with serum potassium levels lower than 4.0 mEq/L, 4.0 to lower than 4.5 mEq/L, and 4.5 to lower than 5.0 mEq/L had an adjusted HR (95% confidence interval [CI]) of incident DM of 1.64 (95% CI, 1.29-2.08), 1.64 (95% CI, 1.34-2.01), and 1.39 (95% CI, 1.14-1.71), respectively. An increased risk persisted during an additional 8 years of telephone follow-up based on self-report with HRs of 1.2 to 1.3 for those with a serum potassium level lower than 5.0 mEq/L. Dietary potassium intake was significantly associated with risk of incident DM in unadjusted models but not in multivariate models. CONCLUSIONS: Serum potassium level is an independent predictor of incident DM in this cohort. Further study is needed to determine if modification of serum potassium could reduce the subsequent risk of DM.

Arch Intern Med. 2010 Oct 25;170(19):1745-51

COQ10

Clinical aspects of coenzyme Q10: an update.

The fundamental role of coenzyme Q(10) (CoQ(10)) in mitochondrial bioenergetics and its well-acknowledged antioxidant properties constitute the basis for its clinical applications, although some of its effects may be related to a gene induction mechanism. Cardiovascular disease is still the main field of study and the latest findings confirm a role of CoQ(10) in improving endothelial function. The possible relation between CoQ(10) deficiency and statin side effects is highly debated, particularly the key issue of whether CoQ(10) supplementation counteracts statin myalgias. Furthermore, in cardiac patients, plasma CoQ(10) was found to be an independent predictor of mortality. Studies on CoQ(10) and physical exercise have confirmed its effect in improving subjective fatigue sensation and physical performance and in opposing exercise-related damage. In the field of mitochondrial myopathies, primary CoQ(10) deficiencies have been identified, involving different genes of the CoQ(10) biosynthetic pathway; some of these conditions were found to be highly responsive to CoQ(10) administration. The initial observations of CoQ(10) effects in Parkinson's and Huntington's diseases have been extended to Friedreich's ataxia, where CoQ(10) and other quinones have been tested. CoQ(10) is presently being used in a large phase III trial in Parkinson's disease. CoQ(10) has been found to improve sperm count and motility on asthenozoospermia. Moreover, for the first time CoQ(10) was found to decrease the incidence of preeclampsia in pregnancy. The ability of CoQ(10) to mitigate headache symptoms in adults was also verified in pediatric and adolescent populations.

Nutrition. 2010 Mar;26(3):250-4

The reduced form of coenzyme Q10 improves glycemic control in patients with type II diabetes: An open label pilot study.

Coenzyme Q10 (CoQ10) provides the energy for vital cellular functions and is known to act as an antioxidant. We conducted an open label study to examine the clinical effects of supplementation of the reduced form of CoQ10, ubiquinol, in addition to conventional glucose-lowering agents in patients with type II diabetes. Nine subjects (3 males and 6 females) with type II diabetes and receiving conventional medication were recruited. The subjects were assigned to receive an oral dose of 200 mg ubiquinol daily for 12 weeks. The effect of ubiquinol on blood pressure, lipid profile, glycemic control, oxidative stress, and inflammation were examined before and after ubiquinol supplementation. In addition, five healthy volunteers were also assigned to receive an oral dose of 200 mg ubiquinol daily for 4 weeks to examine the effects of ubiquinol on insulin secretion. In patients with diabetes, there were no differences with respect to blood pressure, lipid profile, oxidative stress marker, and inflammatory markers. However, there were significant improvements in glycosylated hemoglobin (53.0 ± 4.3 to 50.5 ± 3.7 mmol/mol, P = 0.01) (7.1 ± 0.4 to 6.8 ± 0.4%, P = 0.03). In healthy volunteers, the insulinogenic index (0.65 ± 0.29 to 1.23 ± 0.56, P = 0.02) and the ratio of proinsulin to insulin were significantly improved (3.4 ± 1.8 to 2.1 ± 0.6, P = 0.03). The results of our study are consistent with the suggestion that the supplementation of ubiquinol in subjects with type 2 diabetes, in addition to conventional antihyperglycemic medications, improves glycemic control by improving insulin secretion without any adverse effects.

Biofactors. 2012 Aug 8. doi: 10.1002/biof.1038

The reduced form of coenzyme Q10 decreases the expression of lipopolysaccharide-sensitive genes in human THP-1 cells.

Monocytes are key players in inflammatory processes that are triggered by lipopolysaccharide (LPS), the major outer membrane component of Gram-negative bacteria. The present study in human monocytic THP-1 cells was designed in order to identify LPS-inducible genes that are down-regulated by the reduced form of coenzyme Q(10) (ubiquinol, Q(10)H(2)). For this purpose, THP-1 cells were incubated with 10 µM Q(10)H(2) for 24 hours. Subsequently, cells were stimulated for 4 hours with 1 µg/mL LPS, and the resulting gene expression levels were determined using microarrays. Fourteen LPS-inducible genes were identified to be significantly (P ≤ .05) down-regulated by Q(10)H(2) pretreatment between a factor of 1.32 and 1.65. The strongest effect of Q(10)H(2) incubation was found for the nuclear receptor coactivator 2 gene (NCOA2). Gene ontology terms revealed for the Q(10)H(2)-sensitive genes an involvement in, e.g., signal transduction processes (centaurin, delta 1; NCOA2; pleckstrin and Sec7 domain containing 3; protein phosphatase 2, regulatory subunit B [B56], γ isoform), transcriptional regulation (NCOA2; POU domain, class 2, transcription factor 1; ETS variant gene 3), and cell proliferation pathways (hypothetical protein FLJ36090, epidermal growth factor receptor pathway substrate 15). In conclusion, we provide evidence in THP-1 cells that Q(10)H(2) modulates LPS-induced gene expression.

J Med Food. 2011 Apr;14(4):391-7

Coenzyme Q10 protects against amyloid beta-induced neuronal cell death by inhibiting oxidative stress and activating the P13K pathway.

Oxidative stress plays critical roles in the pathogenic mechanisms of several neurodegenerative disorders including Alzheimer's disease (AD), thus much research effort has focused on antioxidants as potential treatment agents for AD. Coenzyme Q10 (CoQ10) is known to have powerful antioxidant effects. We investigated the neuroprotective effects of CoQ10 against Amyloid beta(25-35) (Aβ(25-35))-induced neurotoxicity in rat cortical neurons. To evaluate the neuroprotective effects of CoQ10 on Aβ(25-35)-injured neurons, primary cultured cortical neurons were treated with several concentrations of CoQ10 and/or Aβ(25-35) for 48h. CoQ10 protected neuronal cells against Aβ(25-35)-induced neurotoxicity in a concentration-dependent manner. These neuroprotective effects of CoQ10 were blocked by LY294002 (10µM), a phosphatidylinositol 3-kinase (PI3K) inhibitor. Aβ(25-35) concentration-dependent increased free radical levels in rat cortical neurons, while combined treatment with CoQ10 reduced these free radical levels in a dose-dependent manner. Meanwhile, CoQ10 treatment of Aβ(25-35)-injured primary cultured cortical neurons increased the expression levels of p85aPI3K, phosphorylated Akt, phosphorylated glycogen synthase kinase-3β, and heat shock transcription factor, which are proteins related to neuronal cell survival, and decreased the levels of cytosolic cytochrome c and cleaved caspase-3, which are associated with neuronal cell death. Together, these results suggest that the neuroprotective effects of CoQ10 on Aβ(25-35) neurotoxicity are mediated by inhibition of oxidative stress together with activation of the PI3-K/Akt pathway.

Neurotoxicology. 2012 Jan;33(1):85-90

Parkinson's disease: mitochondrial molecular pathology, inflammation, statins, and therapeutic neuroprotective nutrition.

Pathological hallmarks of Parkinson's disease are destruction of dopaminergic neurons in the basal ganglia, especially the substantia nigra, and the presence of Lewy bodies within nerve cells. Environmental toxins are associated with the disease and, in a minority of cases, genetic factors have been identified. Inflammation-with activation of phagocytic microglia, release of cytokines, invasion by T cells, and complement activation-plays a role in damaging these neurons. Excessive production of reactive oxygen species, mitochondrial dysfunction leading to apoptosis, accumulation and oligomerization of the protein alpha-synuclein, and defective protein disposal by the ubiquitin proteasome system are involved in the complex web of events mediating nigral cell demise. Two agents of current interest, coenzyme Q10 and creatine, may be disease modifying, and large studies are in progress. Related mechanisms of other substances, including omega-3 fatty acids and vitamin D, are included in this review. The association with serum cholesterol levels and the effects of statin drugs are uncertain but important.

Nutr Clin Pract. 2010 Aug;25(4):371-89

Cellular and molecular mechanisms of antioxidants in Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative movement disorder characterized by the degeneration and progressive loss of dopaminergic neurons in the substantia nigra pars compacta. It has been suggested that oxidative stress plays a role in the etiology and progression of PD. For instance, low levels of endogenous antioxidants, increased reactive species, augmented dopamine oxidation, and high iron levels have been found in brains from PD patients. In vitro and in vivo studies of Parkinson models evaluating natural and endogenous antioxidants such as polyphenols, coenzyme Q10, and vitamins A, C, and E have shown protective effects against oxidative-induced neuronal death. In this paper, we will review the mechanisms by which polyphenols and endogenous antioxidants can produce protection. Some of the mechanisms reviewed include: scavenging nitrogen and oxygen reactive species, regulation of signaling pathways associated with cell survival and inflammation, and inhibition of synphilin-1 and alpha-synuclein aggregation.

Nutr Neurosci. 2012 May;15(3):120-6

Nutraceuticals and their preventive or potential therapeutic value in Parkinson's disease.

Parkinson's disease (PD) is the second most common aging-related disorder in the world, after Alzheimer's disease. It is characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta and other parts of the brain, leading to motor impairment, cognitive impairment, and dementia. Current treatment methods, such as L-dopa therapy, are focused only on relieving symptoms and delaying progression of the disease. To date, there is no known cure for PD, making prevention of PD as important as ever. More than a decade of research has revealed a number of major risk factors, including oxidative stress and mitochondrial dysfunction. Moreover, numerous nutraceuticals have been found to target and attenuate these risk factors, thereby preventing or delaying the progression of PD. These nutraceuticals include vitamins C, D, E, coenzyme Q10, creatine, unsaturated fatty acids, sulfur-containing compounds, polyphenols, stilbenes, and phytoestrogens. This review examines the role of nutraceuticals in the prevention or delay of PD as well as the mechanisms of action of nutraceuticals and their potential applications as therapeutic agents, either alone or in combination with current treatment methods.

Nutr Rev. 2012 Jul;70(7):373-86

A review on the oxidative and nitrosative stress (O&NS) pathways in major depression and their possible contribution to the (neuro)degenerative processes in that illness.

This paper reviews the body of evidence that major depression is accompanied by a decreased antioxidant status and by induction of oxidative and nitrosative (IO&NS) pathways. Major depression is characterized by significantly lower plasma concentrations of a number of key antioxidants, such as vitamin E, zinc and coenzyme Q10, and a lowered total antioxidant status. Lowered antioxidant enzyme activity, e.g. glutathione peroxidase (GPX), is another hallmark of depression. The abovementioned lowered antioxidant capacity may impair protection against reactive oxygen species (ROS), causing damage to fatty acids, proteins and DNA by oxidative and nitrosative stress (O&NS). Increased ROS in depression is demonstrated by increased levels of plasma peroxides and xanthine oxidase. Damage caused by O&NS is shown by increased levels of malondialdehyde (MDA), a by-product of polyunsaturated fatty acid peroxidation and arachidonic acid; and increased 8-hydroxy-2-deoxyguanosine, indicating oxidative DNA damage. There is also evidence in major depression, that O&NS may have changed inactive autoepitopes to neoantigens, which have acquired immunogenicity and serve as triggers to bypass immunological tolerance, causing (auto)immune responses. Thus, depression is accompanied by increased levels of plasma IgG antibodies against oxidized LDL; and increased IgM-mediated immune responses against membrane fatty acids, like phosphatidyl inositol (Pi); oleic, palmitic, and myristic acid; and NO modified amino-acids, e.g. NO-tyrosine, NO-tryptophan and NO-arginine; and NO-albumin. There is a significant association between depression and polymorphisms in O&NS genes, like manganese superoxide dismutase, catalase, and myeloperoxidase. Animal models of depression very consistently show lowered antioxidant defences and activated O&NS pathways in the peripheral blood and the brain. In animal models of depression, antidepressants consistently increase lowered antioxidant levels and normalize the damage caused by O&NS processes. Antioxidants, such as N-acetyl-cysteine, compounds that mimic GPX activity, and zinc exhibit antidepressive effects. This paper reviews the pathways by which lowered antioxidants and O&NS may contribute to depression, and the (neuro)degenerative processes that accompany that illness. It is concluded that aberrations in O&NS pathways are—together with the inflammatory processes—key components of depression. All in all, the results suggest that depression belongs to the spectrum of (neuro)degenerative disorders.

Prog Neuropsychopharmacol Biol Psychiatry. 2011 Apr 29;35(3):676-92

Mitochondrial modulators for bipolar disorder: A pathophysiologically informed paradigm for new drug development.

Objectives: Bipolar patients frequently relapse within 12 months of their previous mood episode, even in the context of adequate treatment, suggesting that better continuation and maintenance treatments are needed. Based on recent research of the pathophysiology of bipolar disorder, we review the evidence for mitochondrial dysregulation and selected mitochondrial modulators (MM) as potential treatments.Methods: We reviewed the literature about mitochondrial dysfunction and potential MMs worthy of study that could improve the course of bipolar disorder, reduce subsyndromal symptoms, and prevent subsequent mood episodes.Results: MM treatment targets mitochondrial dysfunction, oxidative stress, altered brain energy metabolism and the dysregulation of multiple mitochondrial genes in patients with bipolar disorder. Several tolerable and readily available candidates include N-acetyl-cysteine (NAC), acetyl-L-carnitine (ALCAR), S-adenosylmethionine (SAMe), coenzyme Q(10) (CoQ10), alpha-lipoic acid (ALA), creatine monohydrate (CM), and melatonin. The specific metabolic pathways by which these MMs may improve the symptoms of bipolar disorder are discussed and combinations of selected MMs could be of interest as well.Conclusions: Convergent data implicate mitochondrial dysfunction as an important component of the pathophysiology of bipolar disorder. Clinical trials of individual MMs as well as combinations are warranted

Aust N Z J Psychiatry. 2012 Jun 18

Coenzyme Q10, copper, zinc, and lipid peroxidation levels in serum of patients with chronic obstructive pulmonary disease.

Severity of chronic obstructive pulmonary disease (COPD) exacerbation is associated with increased level of copper (Cu), zinc (Zn), and lipid peroxidation (malodialdehyde, MDA). The aim of this study was to investigate the levels of lipid peroxidation, Coenzyme Q10 (CoQ10), Zn, and Cu in the COPD exacerbations. Forty-five patients with COPD acute exacerbation and 45 healthy smokers as control group were used in the study. Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were lower in exacerbation group than in control. C- reactive protein levels, white blood cell count, and sedimentation rate were significantly (p<0.001) higher in patients than in control. CoQ10 level and Cu/Zn ratio was significantly (p<0.05) lower in patients than in control, although MDA, Cu, and Zn levels were significantly (p<0.05) higher in patients than in control. Negative correlations were found among MDA, Cu, Zn, FEV1, and FVC values in exacerbation and control subjects (p<0.05). In conclusion, we observed that oxidative stress in the exacerbation period of COPD patients was increased. The decrease in CoQ10 level and Cu/Zn ratio and elevation in Cu and Zn levels observed in the patients probably result from the defense response of organism and are mediated by inflammatory-like substances.

Biol Trace Elem Res. 2011 Nov;143(2):659-67

Black Cumin

Protective effect of black seed oil from Nigella sativa against murine cytomegalovirus infection.

In this study, antiviral effect of black seed oil (BSO) from Nigella sativa was investigated using murine cytomegalovirus (MCMV) as a model. The viral load and innate immunity mediated by NK cells and Mφ during early stage of the infection were analyzed. Intraperitoneal (i.p.) administration of BSO to BALB/c mice, a susceptible strain of MCMV infection, strikingly inhibited the virus titers in spleen and liver on day 3 of infection with 1x10(5) PFU MCMV. This effect coincided with an increase in serum level of IFN-gamma. Although BSO treatment decreased both number and cytolytic function of NK cells on day 3 of infection, it increased numbers of Mφ and CD4(+) T cells. On day 10 of infection, the virus titer was undetectable in spleen and liver of BSO-treated mice, while it was detectable in control mice. Although spleen of both control and BSO-treated mice showed similar CTL activities on day 10 after infection, serum level of IFN-gamma in BSO-treated mice was higher. Furthermore, BSO treatment upregulated suppressor function of Mφ in spleen. These results show that BSO exhibited a striking antiviral effect against MCMV infection which may be mediated by increasing of Mφ number and function, and IFN-gamma production.

Int J Immunopharmacol. 2000 Sep;22(9):729-40

Thymoquinone, the active ingredient of Nigella sativa seeds, enhances survival and activity of antigen-specific CD8-positive T cells in vitro.

Recent preclinical and clinical studies provide evidence that adoptive transfer of in vitro activated T cells can results in significant antitumour responses in vivo upon acquisition of certain survival and homing properties during in vitro activation. Based on recent studies showing in vivo antioxidant effects of thymoquinone (TQ), the active ingredient of Nigella sativa seeds, this study aims to determine whether or not TQ can increase survival and sustain the expression of the homing receptor CD62L in antigen-specific T cells in vitro. The results showed that stimulation of OT-1 (transgenic CD+) T cells with OVA antigen resulted in activation, as shown by a decrease in the surface expression of CD62L which coincided with significant apoptosis measured three and five days after antigen stimulation. Addition of low concentrations of TQ during CD85+ T-cell activation resulted in enhanced survival of the activated T cells and sustained expression of CD62L. These effects coincided with enhancement in the capability of CD8+ T cells to produce the effector cytokine interferon-gamma (IFNgamma). These results suggest that TQ has a beneficial effect in conditioning T cells in vitro for adoptive T-cell therapy against cancer and infectious disease.

Br J Biomed Sci. 2011;68(3):131-7

Immunomodulatory and therapeutic properties of the Nigella sativa L. seed.

A larger number of medicinal plants and their purified constituents have been shown beneficial therapeutic potentials. Seeds of Nigella sativa, a dicotyledon of the Ranunculaceae family, have been employed for thousands of years as a spice and food preservative. The oil and seed constituents, in particular thymoquinine (TQ), have shown potential medicinal properties in traditional medicine. In view of the recent literature, this article lists and discusses different immunomodulatory and immunotherapeutic potentials for the crude oil of N. sativa seeds and its active ingredients. The published findings provide clear evidence that both the oil and its active ingredients, in particular TQ, possess reproducible anti-oxidant effects through enhancing the oxidant scavenger system, which as a consequence lead to antitoxic effects induced by several insults. The oil and TQ have shown also potent anti-inflammatory effects on several inflammation-based models including experimental encephalomyelitis, colitis, peritonitis, oedama, and arthritis through suppression of the inflammatory mediators prostaglandins and leukotriens. The oil and certain active ingredients showed beneficial immunomodulatory properties, augmenting the T cell- and natural killer cell-mediated immune responses. Most importantly, both the oil and its active ingredients expressed anti-microbial and anti-tumor properties toward different microbes and cancers. Coupling these beneficial effects with its use in folk medicine, N. sativa seed is a promising source for active ingredients that would be with potential therapeutic modalities in different clinical settings. The efficacy of the active ingredients, however, should be measured by the nature of the disease. Given their potent immunomodulatory effects, further studies are urgently required to explore bystander effects of TQ on the professional antigen presenting cells, including macrophages and dendritic cells, as well as its modulatory effects upon Th1- and Th2-mediated inflammatory immune diseases. Ultimately, results emerging from such studies will substantially improve the immunotherapeutic application of TQ in clinical settings.

Int Immunopharmacol. 2005 Dec;5(13-14):1749-70

Modulation of the oxidative stress and inflammatory cytokine response by thymoquinone in the collagen induced arthritis in Wistar rats.

Thymoquinone (TQ) is the major active compound derived from Nigella sativa. Our aim of this work was to evaluate the antioxidant and antiarthritic activity of TQ in Wistar rat by collagen induced arthritis (CIA). TQ was administered at a dose of 5mgkg(-1) body weight once daily for 21days. The effects of treatment in the rats were assessed by biochemical (articular elastase, MPO, LPO, GSH, catalase, SOD and NO), inflammatory mediators (IL-1β, IL-6, TNF-α, IL-10, IFN-γ and PGE(2)) and histological studies in joints. TQ was effective in bringing significant changes on all the parameters (articular elastase, MPO, LPO, GSH, catalase, SOD and NO) studied. Oral administration of TQ resulted in significantly reduced the levels of pro-inflammatory mediators (IL-1β, IL-6, TNF-α, IFN-γ and PGE(2)) and increased level of IL-10. The protective effects of TQ against RA were also evident from the decrease in arthritis scoring and bone histology. In conclusion, the fact that TQ abolished a number of factors known to be involved in RA pathogenesis indicates that the administration of thymoquinone may have potential value in the treatment of inflammatory disease.

Chem Biol Interact. 2012 Apr 15;197(1):40-6

Protective effects of black cumin (Nigella sativa) oil on TNBS-induced experimental colitis in rats.

BACKGROUND: The pathogenesis and treatment of ulcerative colitis remain poorly understood. The aim of the present study is to investigate the effects of black cumin (Nigella sativa) oil on rats with colitis. METHODS: Experimental colitis was induced with 1 mL trinitrobenzene sulfonic acid (TNBS) in 40% ethanol by intracolonic administration with 8-cm-long cannula under ether anesthesia to rats in colitis group and colitis + black cumin oil group. Rats in the control group were given saline at the same volume by intracolonic administration. Black cumin oil (BCO, Origo "100% natural Black Cumin Seed Oil," Turkey) was given to colitis + black cumin oil group by oral administration during 3 days, 5 min after colitis induction. Saline was given to control and colitis groups at the same volume by oral administration. At the end of the experiment, macroscopic lesions were scored and the degree of oxidant damage was evaluated by colonic total protein, sialic acid, malondialdehyde, and glutathione levels, collagen content, and tissue factor, superoxide dismutase, and myeloperoxidase activities. Tissues were also examined by histological and cytological analysis. Proinflammatory cytokines [tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, and IL-6], lactate dehydrogenase activity, and triglyceride and cholesterol levels were analyzed in blood samples. RESULTS: We found that black cumin oil decreased the proinflammatory cytokines, lactate dehydrogenase, triglyceride, and cholesterol, which were increased in colitis. CONCLUSIONS: BCO, by preventing inflammatory status in the blood, partly protected colonic tissue against experimental ulcerative colitis.

Dig Dis Sci. 2011 Mar;56(3):721-30

Gastroprotective activity of Nigella sativa L oil and its constituent, thymoquinone against acute alcohol-induced gastric mucosal injury in rats.

AIM: To evaluate the role of reactive oxygen species in the pathogenesis of acute ethanol-induced gastric mucosal lesions and the effect of Nigella sativa L oil (NS) and its constituent thymoquinone (TQ) in an experimental model. METHODS: Male Wistar albino rats were assigned into 4 groups. Control group was given physiologic saline orally (10 mL/kg body weight) as the vehicle (gavage); ethanol group was administrated 1 mL (per rat) absolute alcohol by gavage; the third and fourth groups were given NS (10 mL/kg body weight) and TQ (10 mg/kg body weight p.o) respectively 1 h prior to alcohol intake. One hour after ethanol administration, stomach tissues were excised for macroscopic examination and biochemical analysis. RESULTS: NS and TQ could protect gastric mucosa against the injurious effect of absolute alcohol and promote ulcer healing as evidenced from the ulcer index (UI) values. NS prevented alcohol-induced increase in thiobarbituric acid-reactive substances (TBARS), an index of lipid peroxidation. NS also increased gastric glutathione content (GSH), enzymatic activities of gastric superoxide dismutase (SOD) and glutathione-S-transferase (GST). Likewise, TQ protected against the ulcerating effect of alcohol and mitigated most of the biochemical adverse effects induced by alcohol in gastric mucosa, but to a lesser extent than NS. Neither NS nor TQ affected catalase activity in gastric tissue. CONCLUSION: Both NS and TQ, particularly NS can partly protect gastric mucosa from acute alcohol-induced mucosal injury, and these gastroprotective effects might be induced, at least partly by their radical scavenging activity.

World J Gastroenterol. 2005 Nov 14;11(42):6662-6

Thymoquinone: potential cure for inflammatory disorders and cancer.

Thymoquinone is an active ingredient isolated from Nigella sativa and has been investigated for its anti-oxidant, anti-inflammatory and anticancer activities in both in vitro and in vivo models since its first extraction in 1960s. Its anti-oxidant/anti-inflammatory effect has been reported in various disease models, including encephalomyelitis, diabetes, asthma and carcinogenesis. Moreover, thymoquinone could act as a free radical and superoxide radical scavenger, as well as preserving the activity of various anti-oxidant enzymes such as catalase, glutathione peroxidase and glutathione-S-transferase. The anticancer effect(s) of thymoquinone are mediated through different modes of action, including anti-proliferation, apoptosis induction, cell cycle arrest, ROS generation and anti-metastasis/anti-angiogenesis. In addition, this quinone was found to exhibit anticancer activity through the modulation of multiple molecular targets, including p53, p73, PTEN, STAT3, PPAR-γ, activation of caspases and generation of ROS. The anti-tumor effects of thymoquinone have also been investigated in tumor xenograft mice models for colon, prostate, pancreatic and lung cancer. The combination of thymoquinone and conventional chemotherapeutic drugs could produce greater therapeutic effect as well as reduce the toxicity of the latter. In this review, we summarize the anti-oxidant/anti-inflammatory and anticancer effects of thymoquinone with a focus on its molecular targets, and its possible role in the treatment of inflammatory diseases and cancer.

Biochem Pharmacol. 2012 Feb 15;83(4):443-51

Contrasting actions of diesel exhaust particles on the pulmonary and cardiovascular systems and the effects of thymoquinone.

BACKGROUND AND PURPOSE: Acute exposure to particulate air pollution has been linked to acute cardiopulmonary events, but the underlying mechanisms are uncertain. EXPERIMENTAL APPROACH We investigated the acute (at 4 and 18 h) effects of diesel exhaust particles (DEP) on cardiopulmonary parameters in mice and the protective effect of thymoquinone, a constituent of Nigella sativa. Mice were given, intratracheally, either saline (control) or DEP (30 µg•per mouse). KEY RESULTS At 18 h (but not 4 h) after giving DEP, there was lung inflammation and loss of lung function. At both 4 and 18 h, DEP caused systemic inflammation characterized by leucocytosis, increased IL-6 concentrations and reduced systolic blood pressure (SBP). Superoxide dismutase (SOD) activity was decreased only at 18 h. DEP reduced platelet numbers and aggravated in vivo thrombosis in pial arterioles. In vitro, addition of DEP (0.1-1 µg•mL(-1)) to untreated blood-induced platelet aggregation. Pretreatment of mice with thymoquinone prevented DEP-induced decrease of SBP and leucocytosis, increased IL-6 concentration and decreased plasma SOD activity. Thymoquinone also prevented the decrease in platelet numbers and the prothrombotic events but not platelet aggregation in vitro. CONCLUSIONS AND IMPLICATIONS: At 4 h after DEP exposure, the cardiovascular changes did not appear to result from pulmonary inflammation but possibly from the entry of DEP and/or their associated components into blood. However, at 18 h, DEP induced significant changes in pulmonary and cardiovascular functions along with lung inflammation. Pretreatment with thymoquinone prevented DEP-induced cardiovascular changes.

Br J Pharmacol. 2011 Dec;164(7):1871-82

Protective effects of propolis and thymoquinone on development of atherosclerosis in cholesterol-fed rabbits.

Hypercholesterolemia, cholesterol-enriched diet and oxidative stress have been shown to increase serum total cholesterol (TC) and low density lipoprotein-cholesterol (LDL-C) levels resulting in development of atherosclerosis. Antioxidants play an important role in inhibiting and scavenging free radicals, thus providing protection to humans against infectious and degenerative diseases. The present study was undertaken to examine the possible protective effects of propolis (a resinous hive product collected by honeybees from various plant sources) and thymoquinone (TQ, active constituent of Nigella. Sativa seeds oil) on serum lipid levels and early atherosclerotic lesions in hypercholestrolemic rabbits. New Zealand rabbits were fed on either standard chow or atherogenic diet during four weeks and concomitantly received either propolis or TQ. At the end of experiment period, serum samples were collected to determine lipid profile, kidney functions and antioxidant status. Tissues from aorta, pulmonary artery and kidney were taken for histopathological examination. The cholesterol-enriched diet induced a significant increase in serum TC, triglycerides, LDL-C, thiobarbituric acid-reactive substances concentrations and a significant decrease in high density lipoprotein-cholesterol and in reduced glutathione levels compared to control group. Administration of propolis or TQ with cholesterol-enriched diet significantly (p < 0.05) reduced TC, LDL-C, triglycerides and thiobarbituric acid-reactive substances concentrations, while increased high density lipoprotein-cholesterol concentration, as well as glutathione content compared to high cholesterol (HC) control group. Kidney function parameters were significantly affected by cholesterol diet and both propolis and TQ counterregulated the cholesterol-induced changes. Histopathologically, early atherosclerotic changes were observed in HC control group represented by endothelial damage and thickened foam cells while propolis or TQ provided protection against the HC-induced damage. In conclusion, the present study suggests the potential beneficial effects of both propolis and TQ in diminishing the risk of atherosclerosis via antioxidant mechanism.

Arch Pharm Res. 2010 Apr;33(4):637-43

Nigella sativa oil, nigellone and derived thymoquinone inhibit synthesis of 5-lipoxygenase products in polymorphonuclear leukocytes from rats.

In the present study, Nigella sativa oil (NSO), nigellone (polythymoquinone) and derived thymoquinone were studied to evaluate their effect on the formation of 5-lipoxygenase (5-LO) products from polymorphonuclear leukocytes (PMNL).NSO produced a concentration dependent inhibition of 5-LO products and 5-hydroxy-eicosa-tetra-enoic acid (5-HETE) production with half maximal effects (IC(50)) at 25+/-1 micro g/ml, respectively 24+/-1 micro g/ml. Nigellone caused a concentration-related inhibition of 5-HETE production (IC(50): 11.9+/-0.3 micro g/ml). Moreover thymoquinone, the active principle of NSO inhibited the production of 5-LO products (IC(50): 0.26+/-0.02 micro g/ml) and 5-HETE production (IC(50): 0.36+/-0.02 micro g/ml) in a similar way. The effects are probably due to an antioxidative action. The data may in part explain the effect of the oil, its derived thymoquinone and nigellone in ameliorating inflammatory diseases.

J Ethnopharmacol. 2002 Jul;81(2):161-4