Vitamin E

Treatment of vascular retinopathies with Pycnogenol. 

The aim of our study was to investigate the effects of Pycnogenol on the progression of diabetic retinopathy and other vascular retinal disorders. The study consisted of a double-blind phase in which 20 patients were recruited and randomly treated with placebo or Pycnogenol (50 mg x 3/day for 2 months) and an open phase in which another 20 patients were treated with Pycnogenol at the same dose schedule. In total, 40 patients with diabetes, atherosclerosis and other vascular diseases involving the retina were enrolled; 30 of them were treated with Pycnogenol and 10 with placebo. The results demonstrated a beneficial effect of Pycnogenol on the progression of retinopathy. Without any treatment (placebo) the retinopathy progressively worsened during the trial and the visual acuity significantly decreased; on the contrary, the Pycnogenol-treated patients showed no deterioration of retinal function and a significant recovery of visual acuity was also obtained. The fluorangiography showed an improvement of retinal vascularization and a reduced endothelial permeability and leakage in the Pycnogenol, but not in the placebo-treated, patients. The ophthalmoscopy and the electroretinogram (ERG) also confirmed the beneficial effects of Pycnogenol. The mechanism of action of Pycnogenol may be related to its free radical (FR) scavenging, anti-inflammatory and capillary protective activities. It has been suggested that Pycnogenol may bind to the blood vessel wall proteins and mucopolysaccharides and produce a capillary 'sealing' effect, leading to a reduced capillary permeability and oedema formation.

Phytother Res. 2001 May;15(3):219-23

Improvement of diabetic microangiopathy with Pycnogenol: A prospective, controlled study.

The aim of this study was to investigate the clinical efficacy of oral Pycnogenol (Horphag Research Ltd, United Kingdom) in patients with diabetic microangiopathy. Patients without a history of diabetic ulcerations were treated with Pycnogenol. Patients received oral Pycnogenol (50 mg capsules, 3 times daily for a total of 150 mg daily for 4 weeks). A group of 30 patients was included (severe microangiopathy); 30 comparable patients were observed as controls (no treatment during the observation period). All patients (age, 59 years; range, 55-68 years; male:female = 18:12) included in the treatment group completed the 4-week study. Also, all controls completed the follow-up period. There were no drop-outs. All included subjects had signs and symptoms of diabetic microangiopathy. The duration of diabetes-from the first signs/symptoms--was on average 7.5 years (SD = 3). After 4 weeks, microcirculatory and clinical evaluations showed a progressive decrease in skin flux at rest in the foot (indicating an improvement in the level of microangiopathy), a significant decrease in capillary filtration, and a significant improvement in the venoarteriolar response in all treated subjects. There were no visible effects in controls except a slight reduction in skin flux at rest in the foot. Treatment was well tolerated in both groups. In conclusion, this study confirms the clinical efficacy of Pycnogenol in patients with diabetic microangiopathy. The study indicates the clinical role of Pycnogenol in the management, treatment, and control of this common clinical problem. The treatment may be also useful to prevent diabetic ulcerations by controlling the level of microangiopathy.

Angiology. 2006 Aug-Sep;57(4):431-6

Pycnogenol protects vascular endothelial cells from beta-amyloid-induced injury.

The neuropathological hallmarks of Alzheimer's disease (AD) are senile plaques, cerebrovascular beta-amyloidosis, neurofibrillary tangles, and selective neuronal loss. Beta-amyloid (Abeta) has been shown to cause vascular damage mediated by generation of reactive oxygen species and this damage is considered an early event in the development of AD. In this study, we determined the effect of pyenogenol, a potent antioxidant phytochemical, on Abeta-induced cellular injury. Pulmonary artery endothelial cells (PAEC) were exposed to Abeta for 24 h. Cell injury was assessed by measuring cell viability with methylthiazol tetrazolium (MTT) assay, and by determining the release of intracellular lactate dehydrogenase (LDH). Lipid peroxidation products of PAEC were determined by measuring thiobarbituric acid-reactive substances (TBARS). Exposure of PAEC to Abeta resulted in a decrease in cell viability, an increase of LDH release indicating membrane damage, and an elevated level of TBARS. Preincubation of PAEC with pycnogenol significantly minimized these changes. This study demonstrated that pycnogenol can protect vascular endothelial cells from Abeta-induced injury. The data suggest that pycnogenol may be useful for the prevention and/or treatment of vascular or neurodegenerative diseases associated with Abeta toxicity.

Biol Pharm Bull. 2000 Jun;23(6):735-7

Pycnogenol protects neurons from amyloid-beta peptide-induced apoptosis.

Neuronal apoptosis is one of the pathological features of Alzheimer's disease (AD). Morphological pathology reveals that neuronal apoptosis is associated with senile plaques containing amyloid-beta peptide (Abeta) in AD brains. Reactive oxygen species (ROS) has been proposed to be involved in the apoptotic mechanism of Abeta-mediated neurotoxicity. In the present study, using a rat pheochromocytoma (PC12) cell line, we investigated the effect of Pycnogenol (PYC), a potent antioxidant and ROS scavenger, on Abeta(25-35)-induced apoptosis and ROS generation. We used vitamin E, a known antioxidant agent, to verify the effect of PYC. Abeta(25-35)-induced apoptosis in PC12 cells was demonstrated by: (1) a dose-dependent loss of cell viability; (2) a time- and dose-dependent increase in the apoptotic cells; (3) an induction of DNA fragmentation; and (4) an increase in caspase-3 activity and cleavage of poly (ADP-ribose) polymerase (PARP). Our data showed that a significant increase in ROS formation preceded apoptotic events after PC12 cells were exposed to Abeta(25-35). We further found that PYC not only suppressed the generation of ROS but also attenuated caspase-3 activation, DNA fragmentation, PARP cleavage, and eventually protected against Abeta-induced apoptosis. Vitamin E also suppressed cell death and caspase-3 activation induced by Abeta(25-35). Taken together, these results suggest that ROS may be involved in Abeta-induced apoptosis in PC12 cells. They further suggest that PYC can reduce apoptosis, possibly by decreasing free radical generation in PC12 cells.

Brain Res Mol Brain Res. 2002 Jul 15;104(1):55-65

An examination of the effects of the antioxidant Pycnogenol on cognitive performance, serum lipid profile, endocrinological and oxidative stress biomarkers in an elderly population.

The study examines the effects of the antioxidant flavonoid Pycnogenol on a range of cognitive and biochemical measures in healthy elderly individuals. The study used a double-blind, placebo-controlled, matched-pair design, with 101 elderly participants (60-85 years) consuming a daily dose of 150 mg of Pycnogenol for a three-month treatment period. Participants were assessed at baseline, then at 1, 2, and 3 months of the treatment. The control (placebo) and Pycnogenol groups were matched by age, sex, body mass index, micronutrient intake, and intelligence. The cognitive tasks comprised measures of attention, working memory, episodic memory, and psychomotor performance. The biological measures comprised levels of clinical hepatic enzymes, serum lipid profile, human growth hormone, and lipid peroxidation products. Statistically significant interactions were found for memory-based cognitive variables and lipid peroxidation products, with the Pycnogenol group displaying improved working memory and decreased concentrations of F2-isoprostanes relative to the control group.

J Psychopharmacol. 2008 Jul;22(5):553-62

Pycnogenol attenuates the inflammatory and nitrosative stress on joint inflammation induced by urate crystals.

Acute gouty arthritis results from monosodium urate (MSU) crystal deposition in joint tissues. Deposited MSU crystals induce an acute inflammatory response which leads to damage of joint tissue. Pycnogenol (PYC), an extract from the bark of Pinus maritime, has documented antiinflammatory and antioxidant properties. The present study aimed to investigate whether PYC had protective effects on MSU-induced inflammatory and nitrosative stress in joint tissues both in vitro and in vivo. MSU crystals upregulated cyclooxygenase 2 (COX-2), interleukin 8 (IL-8) and inducible nitric oxide synthase (iNOS) gene expression in human articular chondrocytes, but only COX-2 and IL-8 in synovial fibroblasts. PYC inhibited the up-regulation of COX-2, and IL-8 in both articular chondrocytes and synovial fibroblasts. PYC attenuated MSU crystal induced iNOS gene expression and NO production in chondrocytes. Activation of NF-κB and SAPK/JNK, ERK1/2 and p38 MAP kinases by MSU crystals in articular chondrocytes and synovial fibroblasts in vitro was attenuated by treatment with PYC. The acute inflammatory cell infiltration and increased expression of COX-2 and iNOS in synovial tissue and articular cartilage following intra-articular injection of MSU crystals in a rat model was inhibited by coadministration of PYC. Collectively, this study demonstrates that PYC may be of value in treatment of MSU crystal-induced arthritis through its anti-inflammatory and anti-nitrosative activities.

Free Radic Biol Med. 2012 Feb 15;52(4):765-74

Variations in C-reactive protein, plasma free radicals and fibrinogen values in patients with osteoarthritis treated with Pycnogenol.

In a previous, double-blind, placebo-controlled study we evaluated the efficacy of a 3-month treatment with Pycnogenol for 156 patients with osteoarthritis of the knee. Pycnogenol significantly decreased joint pain and improved joint function as evaluated using the WOMAC score and walking performance of patients on a treadmill. In this study, we further investigated the anti-inflammatory and antioxidant activity of Pycnogenol in a subset of the osteoarthritis patients presenting with elevated C-reactive protein (CRP) and plasma-free radicals. Elevated CRP levels have been suggested to be associated with disease progression in osteoarthritis. In our study, 29 subjects of the Pycnogenol group and 26 patients in the placebo group showed CRP levels higher than 3 mg/l at baseline. Comparison of blood specimens drawn at baseline and after 3-month treatment showed that Pycnogenol significantly decreased plasma free radicals to 70.1% of baseline values. Plasma CRP levels decreased from baseline 3.9 mg/l to 1.1 mg/l in the Pycnogenol group whereas the control group had initial values of 3.9 mg/l which decreased to 3.6 mg/l. The CRP decrease in the Pycnogenol was statistical significant as compared to the control group (P < 0.05). Fibrinogen levels were found to be lowered to 62.8% of initial values (P < 0.05) in response to Pycnogenol. No significant changes for plasma free radicals, CRP and fibrinogen were found in the placebo-treated group. The decrease of systemic inflammatory markers suggests that Pycnogenol may exert anti-inflammatory activity in osteoarthritic joints and patients did not present with other ailments or infections. The nature of the anti-inflammatory effects of Pycnogenol with regard to CRP warrants further investigation.

Redox Rep. 2008;13(6):271-6

Treatment of melasma with Pycnogenol.

Melasma (or chloasma) is a common disorder of cutaneous hyperpigmentation predominantly affecting sun-exposed areas in women. The pathogenesis of melasma is not fully understood and treatments are frequently disappointing and often associated with side effects. Pycnogenol is a standardized extract of the bark of the French maritime pine (Pinus pinaster), a well-known, potent antioxidant. Studies in vitro show that Pycnogenol is several times more powerful than vitamin E and vitamin C. In addition, it recycles vitamin C, regenerates vitamin E and increases the endogenous antioxidant enzyme system. Pycnogenol protects against ultraviolet (UV) radiation. Therefore its efficacy in the treatment of melasma was investigated. Thirty women with melasma completed a 30-day clinical trial in which they took one 25 mg tablet of Pycnogenol with meals three times daily, i.e. 75 mg Pycnogenol per day. These patients were evaluated clinically by parameters such as the melasma area index, pigmentary intensity index and by routine blood and urine tests. After a 30-day treatment, the average melasma area of the patients decreased by 25.86 +/- 20.39 mm(2) (p < 0.001) and the average pigmentary intensity decreased by 0.47 +/- 0.51 unit (p < 0.001). The general effective rate was 80%. No side effect was observed. The results of the blood and urine test parameters at baseline and at day 30 were within the normal range. Moreover, several other associated symptoms such as fatigue, constipation, pains in the body and anxiety were also improved. To conclude, Pycnogenol was shown to be therapeutically effective and safe in patients suffering from melasma.

Phytother Res. 2002 Sep;16(6):567-71

Reduction of cardiovascular risk factors in subjects with type 2 diabetes by Pycnogenol supplementation.

Patients with type 2 diabetes are at considerable risk of excessive morbidity and mortality from cardiovascular disease (CVD). We investigated the clinical effectiveness of Pycnogenol, a flavonoid-rich dietary supplement, in reducing antihypertensive medication use and CVD risk factors in subjects with type 2 diabetes. Forty-eight individuals were enrolled in a randomized, double-blind, placebo-controlled trial with parallel-group design. Patients were diagnosed with both type 2 diabetes and mild to moderate hypertension and were undergoing treatment with angiotensin-converting enzyme (ACE) inhibitors. Subjects were randomly assigned to receive either Pycnogenol pill (125 mg daily) or matched placebo for 12 weeks. According to the values of blood pressure (BP) measured at 2-week intervals, the pretrial ACE inhibitor dosage was left unchanged, reduced by 50%, or brought back to the pretrial dosage until a stable BP was obtained. Fasting plasma glucose, low-density lipoprotein (LDL) cholesterol, glycosylated hemoglobin (HbA1c), serum endothelin-1, and urinary albumin were evaluated monthly. Pycnogenol treatment achieved BP control in 58.3% of subjects at the end of the 12 weeks with 50% reduction in individual pretrial dose of ACE-inhibitors (P <.05). Plasma endothelin-1 decreased by 3.9 pg/mL in Pycnogenol-treated group vs 0.5 pg/mL increase in control group (P < .001). Mean HbA1c dropped by 0.8% in Pycnogenol-treated group (P < .05), whereas it decreased by 0.1% in control group. Fasting plasma glucose declined by 23.7 mg/dL in Pycnogenol-treated group vs 5.7 mg/dL in control group (P < .0001). Low-density lipoprotein cholesterol improved significantly in Pycnogenol-treated group, declining by 12.7 mg/dL (P < .001). A significant decrease in urinary albumin level was observed at week 8 compared with the control group (P < .05). However, this reduction was not significant at 12th week. After 12 weeks of supplementation, Pycnogenol resulted in improved diabetes control, lowered CVD risk factors, and reduced antihypertensive medicine use vs controls.

Nutr Res. 2008 May;28(5):315-20

Prevention of venous thrombosis and thrombophlebitis in long-haul flights with Pycnogenol.

The aim of this study was to evaluate the occurrence of deep venous thrombosis (DVT) and superficial vein thrombosis (SVT) and its prophylaxis with an oral anti-edema and antithrombotic agent (Pycnogenol, Horphag, Research Management SA, Geneva, Switzerland) in long-haul flights, in subjects at moderate to high-risk of DVT and SVT. The study pre-included 244 pre-selected subjects; 211 were included (33 were excluded for several reasons due to logistic problems) and 198 completed the study; 13 subjects were lost for follow-up at the end of the flight, all for non-medical problems (i.e., for difficult connections). All subjects were scanned within 90 minutes before the flight and within 2 hours after disembarking. Subjects were supplemented with 100 mg Pycnogenol per capsule. Treatment subjects received two capsules between 2 and 3 hours before flights with 250 mL of water; two capsules were taken 6 hours later with 250 mL of water and one capsule the next day. The control group received comparable placebo at the same intervals. The flight duration was on average 8 hours and 15 minutes (SD 55 min) (range, 7.45-12.33). In the control group there were five thrombotic events (one DVT and four superficial thromboses) while only nonthrombotic, localized phlebitis was observed in the Pycnogenol group (5.15% vs. no events; p<0.025). The ITT (intention to treat) analysis detects 13 failures in the control group (eight lost to follow up + five thrombotic events) of 105 subjects (12.4%) vs. five failures (4.7%; all lost, no thrombotic events) in the treatment group (p<0.025). No unwanted effects were observed. In conclusion, this study indicates that Pycnogenol treatment was effective in decreasing the number of thrombotic events (DVT and SVT) in moderate-to-high risk subjects, during long-haul flights.

Clin Appl Thromb Hemost. 2004 Oct;10(4):373-7

Satiereal, a Crocus sativus L extract, reduces snacking and increases satiety in a randomized placebo-controlled study of mildly overweight, healthy women. 

Snacking is an uncontrolled eating behavior, predisposing weight gain and obesity. It primarily affects the female population and is frequently associated with stress. We hypothesized that oral supplementation with Satiereal (Inoreal Ltd, Plerin, France), a novel extract of saffron stigma, may reduce snacking and enhance satiety through its suggested mood-improving effect, and thus contribute to weight loss. Healthy, mildly overweight women (N = 60) participated in this randomized, placebo-controlled, double-blind study that evaluated the efficacy of Satiereal supplementation on body weight changes over an 8-week period. Snacking frequency, the main secondary variable, was assessed by daily self-recording of episodes by the subjects in a nutrition diary. Twice a day, enrolled subjects consumed 1 capsule of Satiereal (176.5 mg extract per day (n = 31) or a matching placebo (n = 29). Caloric intake was left unrestricted during the study. At baseline, both groups were homogeneous for age, body weight, and snacking frequency. Satiereal caused a significantly greater body weight reduction than placebo after 8 weeks (P < .01). The mean snacking frequency was significantly decreased in the Satiereal group as compared with the placebo group (P < .05). Other anthropometric dimensions and vital signs remained almost unchanged in both groups. No subject withdrawal attributable to a product effect was reported throughout the trial, suggesting a good tolerability to Satiereal. Our results indicate that Satiereal consumption produces a reduction of snacking and creates a satiating effect that could contribute to body weight loss. The combination of an adequate diet with Satiereal supplementation might help subjects engaged in a weight loss program in achieving their objective.

Nutr Res. 2010 May;30(5):305-13

Crocus sativus L. in the treatment of mild to moderate depression: a double-blind, randomized and placebo-controlled trial.

Depression is a serious disorder in today's society, with estimates of lifetime prevalence as high as 21% of the general population in some developed countries. As a therapeutic plant, saffron is considered excellent for stomach ailments and as an antispasmodic, to help digestion and to increase appetite. It is also used for depression in Persian traditional medicine. Our objective was to assess the efficacy of the stigmas of Crocus sativus (saffron) in the treatment of mild to moderate depression in a 6-week double-blind, placebo-controlled and randomized trial. Forty adult outpatients who met the Diagnostic and Statistical Manual of Mental Disorders, 4th edition for major depression based on the structured clinical interview for DSM IV participated in the trial. Patients had a baseline Hamilton rating scale for depression score of at least 18. In this double-blind, placebo-controlled, single-centre and randomized trial, patients were randomly assigned to receive a capsule of saffron 30 mg[sol ]day (BD) (Group 1) or a capsule of placebo (BD) (Group 2) for a 6-week study. At 6 weeks, Crocus sativus produced a significantly better outcome on the Hamilton depression rating scale than the placebo (d.f. = 1, F = 18.89, p < 0.001). There were no significant differences in the two groups in terms of the observed side effects. The results of this study indicate the efficacy of Crocus sativus in the treatment of mild to moderate depression. A large-scale trial is justified.

Phytother Res. 2005 Feb;19(2):148-51

Anxiolytic and hypnotic effect of Crocus sativus aqueous extract and its constituents, crocin and safranal, in mice.

Saffron stigma (Crocus sativus L.) is used for insomnia and anxiety in traditional medicine. In this study, the anxiolytic and hypnotic effects of saffron aqueous extract and its constituents, crocin and safranal, were studied in mice. Agents were administered intraperitoneally in mice before the experiments for the evaluation of hypnotic activity (induced by sodium pentobarbital, 30 mg/kg, i.p.), anxiolytic activity (elevated plus maze test), locomotor activity (open field test) and motor coordination (Rotarod test). The aqueous extract reduced the locomotor activity dose dependently. At low doses, saffron showed a significant increase in the time on the open arms of the maze. When using the Rotarod method, the aqueous extract showed considerable effect on motor coordination of the mice. In the hypnotic test, only a dose of 0.56 g/kg of saffron increased the total sleep. Crocin showed no anxiolytic, hypnotic or myorelaxation effects. Safranal, in higher doses, 0.15 and 0.35 mL/kg, showed anxiolytic effects. Safranal increased the total sleep time dose dependently. This constituent at lower doses (0.05 and 0.15 mL/kg) decreased some locomotion activity parameters. Safranal demonstrated no effects on motor coordination. The results showed that saffron aqueous extract and safranal have anxiolytic and hypnotic effects.

Phytother Res. 2009 Jun;23(6):768-74

Crocin, safranal and picrocrocin from saffron (Crocus sativus L.) inhibit the growth of human cancer cells in vitro.

Extracts of saffron (Crocus sativus L.) have been reported to inhibit cell growth of human tumor cells. In order to study the cytotoxic effect of the characteristic compounds of saffron spice, we have isolated crocin, crocetin, picrocrocin and safranal. Doses inducing 50% cell growth inhibition (LD50) on HeLa cells were 2.3 mg/ml for an ethanolic extract of saffron dry stigmas, 3 mM for crocin, 0.8 mM for safranal and 3 mM for picrocrocin. Crocetin did not show cytotoxic effect. Cells treated with crocin exhibited wide cytoplasmic vacuole-like areas, reduced cytoplasm, cell shrinkage and pyknotic nuclei, suggesting apoptosis induction. Considering its water-solubility and high inhibitory growth effect, crocin is the more promising saffron compound to be assayed as a cancer therapeutic agent.

Cancer Lett. 1996 Feb 27;100(1-2):23-30

Inhibition of breast cancer cell proliferation by style constituents of different Crocus species.

Among the different species of Crocus, only C. sativus has been extensively studied for the composition and the biological properties of its styles, since these constitute the well-known spice saffron, which is widely used in the Mediterranean, Indian and Chinese diet. With high performance liquid chromatography (HPLC) and UV/vis spectroscopy, the presence of hydrophilic carotenoids in the styles of three other Crocus taxa, endemic in Greece, C. boryi ssp. tournefortii, C. boryi ssp. boryi and C. niveus, is reported for the first time. Incubation of MCF-7 and MDA-MB-231 breast cancer cells for 48 h with different concentrations of all four Crocus style extracts showed a dose-dependent inhibitory effect on cell proliferation measured by the MTT assay. The antiproliferative effect was not related to the presence of estrogen receptors. Studies on the effect of trans-crocin-4 (the main carotenoid constituent of C. sativus styles, digentibiosylester of crocetin), crocetin and safranal showed that the antiproliferative effect is attributed to the constituent crocins irrespective of the degree of glycosylation. These results show that the styles of the various Crocus taxa merit further investigation of their composition and mechanisms of action of their carotenoid constituents in order to establish if they could be used as chemopreventive or anticancer agents.

Anticancer Res. 2007 Jan-Feb;27(1A):357-62

Cancer chemopreventive and tumoricidal properties of saffron (Crocus sativus L.).

Since cancer is the most common cause of death in the world population, the possibility that readily available natural substances from plants, vegetables, herbs, and spices may be beneficial in the prevention of cancer warrants closer examination. Saffron in filaments is the dried, dark red stigmata of Crocus sativus L. flowers and it is used as a spice, food colorant, and a drug in medicine. A growing body of research has demonstrated that saffron extract itself and its main constituents, the carotenoids, possess chemopreventive properties against cancer. This review discusses recent literature data and our results on the cancer chemopreventive activities of saffron and its main ingredients.

Exp Biol Med (Maywood). 2002 Jan;227(1):20-5

Radical scavenging activity of Crocus sativus L. extract and its bioactive constituents.

Radical scavenging activity is involved in aging processes, antiinflammatory, anticancer and wound healing activity. Hence, in the present study the DPPH radical scavenging activity of a natural product that possesses biological properties, an extract of Crocus sativus L. (saffron), grown in Crocos, Kozani (Greece), and some of its bioactive constituents (crocin, safranal) was studied. It was shown that a methanol extract of Crocus sativus exhibited high antioxidant activity, although it contains several active and inactive constituents. In trying to approximate a structure-activity relationship, two bioactive constituents of saffron extract were tested, namely crocin and safranal. Crocin showed high radical scavenging activity (50% and 65% for 500 and 1,000 ppm solution in methanol, respectively), followed by safranal (34% for 500 ppm solution). All the tested samples showed high radical scavenging activity, probably due to the ability to donate a hydrogen atom to the DPPH radical.Thus, saffron grown in Greece can be used promisingly in functional foods, drinks with antioxidant activity, in pharmaceutical and cosmetic preparations for their antioxidant activity and probably for their antiaging activity. Saffron can also be used internally in the form of powder or other pharmacotechnical formulae as a food supplement with antioxidant properties.

Phytother Res. 2005 Nov;19(11):997-1000

Crocetin prevents retinal degeneration induced by oxidative and endoplasmic reticulum stresses via inhibition of caspase activity.

Crocetin is a carotenoid that is the aglicone of crocin, which are found in saffron stigmas (Crocus sativus L.) and gardenia fruit (Gardenia jasminoides Ellis). In this study, we investigated the effects of crocetin on retinal damage. To examine whether crocetin affects stress pathways, we investigated intracellular oxidation induced by reactive oxygen species, expression of endoplasmic reticulum (ER) stress-related proteins, disruption of the mitochondrial membrane potential ((m)), and caspases activation. In vitro, we employed cultured retinal ganglion cells (RGC-5, a mouse ganglion cell-line transformed using E1A virus). Cell damage was induced by tunicamycin or hydrogen peroxide (H(2)O(2)) exposure. Crocetin at a concentration of 3μM showed the inhibitory effect of 50-60% against tunicamycin- and H(2)O(2)-induced cell death and inhibited increase in caspase-3 and -9 activity. Moreover, crocetin inhibited the enzymatic activity of caspase-9 in a cell-free system. In vivo, retinal damage in mice was induced by exposure to white light at 8000lx for 3h after dark adaptation. Photoreceptor damage was evaluated by measuring the outer nuclear layer thickness at 5days after light exposure and recording the electroretinogram (ERG). Retinal cell damage was also detected with Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining at 48h after light exposure. Crocetin at 100mg/kg, p.o. significantly inhibited photoreceptor degeneration and retinal dysfunction and halved the expression of TUNEL-positive cells. These results indicate that crocetin has protective effects against retinal damage in vitro and in vivo, suggesting that the mechanism may inhibit increase in caspase-3 and -9 activities after retinal damage.

Eur J Pharmacol. 2011 Jan 10;650(1):110-9

Antidepressant properties of bioactive fractions from the extract of Crocus sativus L.

The aim of this study was to investigate the antidepressant properties of stigmas and corms of Crocus sativus L. The aqueous ethanol extract of C. sativus corms was fractionated on the basis of polarity. Among the different fractions, the petroleum ether fraction and dichloromethane fraction at doses of 150, 300, and 600 mg/kg showed significant antidepressant-like activities in dose-dependent manners, by means of behavioral models of depression. The immobility time in the forced swimming test and tail suspending test was significantly reduced by the two fractions, without accompanying changes in ambulation when assessed in the open-field test. By means of a gas chromatography-mass spectrometry technique, twelve compounds of the petroleum ether fraction were identified. These data show that administration of C. sativus corms extract produces antidepressant-like effects. Aqueous stigmas extract also exerted antidepressive effects in the behavioral models. Crocin 1 and crocin 2 of the aqueous stigmas extract were identified by a reversed-phase HPLC analysis. In addition, the bioactive compound crocin 1 in this herb was quantitatively determined. The data indicate that antidepressant-like properties of aqueous stigma extracts may be due to crocin 1, giving support to the validity of the use of this plant in traditional medicine. All these results suggest that the low polarity parts of C. sativus corms should be considered as a new plant material for curing depression, which merit further studies regarding antidepressive-like activities of chemical compounds isolated from the two fractions and mechanism of action.

J Nat Med. 2010 Jan;64(1):24-30

Influence of saffron supplementation on retinal flicker sensitivity in early age-related macular degeneration.

PURPOSE: To evaluate the functional effect of short-term supplementation of saffron, a spice containing the antioxidant carotenoids crocin and crocetin, in early age-related macular degeneration (AMD). METHODS: Twenty-five patients with AMD were randomly assigned to oral saffron 20 mg/d or placebo supplementation over a 3-month period and then reverted to placebo or saffron for a further 3 months. Focal electroretinograms (fERGs) and clinical findings were recorded at baseline and after 3 months of saffron or placebo supplementation. fERGs were recorded in response to a sinusoidally modulated (41 Hz), uniform field presented to the macular region (18°) at different modulations between 16.5% and 93.5%. Main outcome measures were fERG amplitude (in microvolts), phase (in degrees), and modulation thresholds. RESULTS: After saffron, patients' fERGs were increased in amplitude, compared with either baseline or values found after placebo supplementation (mean change after saffron, 0.25 log μV; mean change after placebo, -0.003 log μV; P < 0.01). fERG thresholds were decreased after saffron supplementation but not placebo, compared with baseline (mean change after saffron, -0.26 log units; mean change after placebo, 0.0003 log units). CONCLUSIONS: The results indicate that short-term saffron supplementation improves retinal flicker sensitivity in early AMD. Although the results must be further replicated and the clinical significance is yet to be evaluated, they provide important clues that nutritional carotenoids may affect AMD in novel and unexpected ways, possibly beyond their antioxidant properties. (ClinicalTrials.gov number, NCT00951288.).

Invest Ophthalmol Vis Sci. 2010 Dec;51(12):6118-24

Curcumin Phase I dose escalation trial of docetaxel plus curcumin in patients with advanced and metastatic breast cancer.

BACKGROUND: Since the improvement of chemotherapy with safe molecules is needed for a better efficacy without supplementary toxicity, we investigated the feasibility and tolerability of the combination of docetaxel and curcumin, a polyphenolic derivative extracted from Curcuma longa root. RESULTS: Fourteen patients were accrued in this open-label phase I trial. At the last dose level of curcumin, three dose-limiting toxicities were observed and two out of three patients at this dose level refused to continue treatment, leading us to define the maximal tolerated dose of curcumin at 8,000 mg/d. Eight patients out of 14 had measurable lesions according to RECIST criteria, with five PR and three SD. Some improvements as biological and clinical responses were observed in most patients. PATIENTS AND METHODS: Patients with advanced or metastatic breast cancer were eligible. Docetaxel (100 mg/m(2)) was administered as a 1 h i.v. infusion every 3 w on d 1 for six cycles. Curcumin was orally given from 500 mg/d for seven consecutive d by cycle (from d-4 to d+2) and escalated until a dose-limiting toxicity should occur. The primary endpoint of this study was to determine the maximal tolerated dose of the combination of dose-escalating curcumin and standard dose of docetaxel chemotherapy in advanced and metastatic breast cancer patients. Secondary objectives included toxicity, safety, vascular endothelial growth factor and tumor markers measurements and assessment of objective and clinical responses to the combination therapy. CONCLUSION: The recommended dose of curcumin is 6,000 mg/d for seven consecutive d every 3 w in combination with a standard dose of docetaxel. From the encouraging efficacy results, a comparative phase II trial of this regimen plus docetaxel versus docetaxel alone is ongoing in advanced and metastatic breast cancer patients.

Cancer Biol Ther. 2010 Jan;9(1):8-14

Combined inhibitory effects of soy isoflavones and curcumin on the production of prostate-specific antigen.

BACKGROUND: Sustained chronic inflammation in the prostate promotes prostate carcinogenesis. Since an elevated level of prostate-specific antigen (PSA) per se reflects the presence of inflammation in the prostate, intervention to improve the PSA value might potentially have beneficial effects for the prevention of the development of prostate cancer. Isoflavones and curcumin have anti-inflammatory and anti-oxidant properties. We examined the biological effects of soy isoflavones and curcumin on LNCaP cells. After that, we conducted a clinical trial for men who received prostate biopsies, but were not found to have prostate cancer, to evaluate the effects of soy isoflavones and curcumin on serum PSA levels. METHODS: The expression of androgen receptor and PSA were examined in LNCaP cells before and after treatment of isoflavones and/or curcumin. Eighty-five participants were randomized to take a supplement containing isoflavones and curcumin or placebo daily in a double-blind study. Subjects were subdivided by the cut-off of their baseline PSA value at 10 microg/ml. We evaluated values of PSA before and 6 months after treatment. RESULTS: The production of PSA were markedly decreased by the combined treatment of isoflavones and curcumin in prostate cancer cell line, LNCaP. The expression of the androgen receptor was also suppressed by the treatment. In clinical trials, PSA levels decreased in the patients group with PSA >or= 10 treated with supplement containing isoflavones and curcumin (P = 0.01). CONCLUSIONS: Our results indicated that isoflavones and curcumin could modulate serum PSA levels. Curcumin presumably synergizes with isoflavones to suppress PSA production in prostate cells through the anti-androgen effects.

Prostate. 2010 Jul 1;70(10):1127-33

A randomized, pilot study to assess the efficacy and safety of curcumin in patients with active rheumatoid arthritis.

Curcumin is known to possess potent antiinflammatory and antiarthritic properties. This pilot clinical study evaluated the safety and effectiveness of curcumin alone, and in combination with diclofenac sodium in patients with active rheumatoid arthritis (RA). Forty-five patients diagnosed with RA were randomized into three groups with patients receiving curcumin (500 mg) and diclofenac sodium (50 mg) alone or their combination. The primary endpoints were reduction in Disease Activity Score (DAS) 28. The secondary endpoints included American College of Rheumatology (ACR) criteria for reduction in tenderness and swelling of joint scores. Patients in all three treatment groups showed statistically significant changes in their DAS scores. Interestingly, the curcumin group showed the highest percentage of improvement in overall DAS and ACR scores (ACR 20, 50 and 70) and these scores were significantly better than the patients in the diclofenac sodium group. More importantly, curcumin treatment was found to be safe and did not relate with any adverse events. Our study provides the first evidence for the safety and superiority of curcumin treatment in patients with active RA, and highlights the need for future large-scale trials to validate these findings in patients with RA and other arthritic conditions.

Phytother Res. 2012 Mar 9

Curcumin: the Indian solid gold.

Turmeric, derived from the plant Curcuma longa, is a gold-colored spice commonly used in the Indian subcontinent, not only for health care but also for the preservation of food and as a yellow dye for textiles. Curcumin, which gives the yellow color to turmeric, was first isolated almost two centuries ago, and its structure as diferuloylmethane was determined in 1910. Since the time of Ayurveda (1900 Bc) numerous therapeutic activities have been assigned to turmeric for a wide variety of diseases and conditions, including those of the skin, pulmonary, and gastrointestinal systems, aches, pains, wounds, sprains, and liver disorders. Extensive research within the last half century has proven that most of these activities, once associated with turmeric, are due to curcumin. Curcumin has been shown to exhibit antioxidant, anti-inflammatory, antiviral, antibacterial, antifungal, and anticancer activities and thus has a potential against various malignant diseases, diabetes, allergies, arthritis, Alzheimer's disease, and other chronic illnesses. These effects are mediated through the regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases, and other enzymes. Curcumin exhibits activities similar to recently discovered tumor necrosis factor blockers (e.g., HUMIRA, REMICADE, and ENBREL), a vascular endothelial cell growth factor blocker (e.g., AVASTIN), human epidermal growth factor receptor blockers (e.g., ERBITUX, ERLOTINIB, and GEFTINIB), and a HER2 blocker (e.g., HERCEPTIN). Considering the recent scientific bandwagon that multitargeted therapy is better than monotargeted therapy for most diseases, curcumin can be considered an ideal “Spice for Life.”

Adv Exp Med Biol. 2007;595:1-75

Synergistic chondroprotective effects of curcumin and resveratrol in human articular chondrocytes: inhibition of IL-1beta-induced NF-kappaB-mediated inflammation and apoptosis.

INTRODUCTION: Currently available treatments for osteoarthritis (OA) are restricted to nonsteroidal anti-inflammatory drugs, which exhibit numerous side effects and are only temporarily effective. Thus novel, safe and more efficacious anti-inflammatory agents are needed for OA. Naturally occurring polyphenolic compounds, such as curcumin and resveratrol, are potent agents for modulating inflammation. Both compounds mediate their effects by targeting the NF-kappaB signalling pathway. METHODS: We have recently demonstrated that in chondrocytes resveratrol modulates the NF-kappaB pathway by inhibiting the proteasome, while curcumin modulates the activation of NF-kappaB by inhibiting upstream kinases (Akt). However, the combinational effects of these compounds in chondrocytes has not been studied and/or compared with their individual effects. The aim of this study was to investigate the potential synergistic effects of curcumin and resveratrol on IL-1beta-stimulated human chondrocytes in vitro using immunoblotting and electron microscopy. RESULTS: Treatment with curcumin and resveratrol suppressed NF-kappaB-regulated gene products involved in inflammation (cyclooxygenase-2, matrix metalloproteinase (MMP)-3, MMP-9, vascular endothelial growth factor), inhibited apoptosis (Bcl-2, Bcl-xL, and TNF-alpha receptor-associated factor 1) and prevented activation of caspase-3. IL-1beta-induced NF-kappaB activation was suppressed directly by cocktails of curcumin and resveratrol through inhibition of Ikappakappa and proteasome activation, inhibition of IkappaBalpha phosphorylation and degradation, and inhibition of nuclear translocation of NF-kappaB. The modulatory effects of curcumin and resveratrol on IL-1beta-induced expression of cartilage specific matrix and proinflammatory enzymes were mediated in part by the cartilage-specific transcription factor Sox-9. CONCLUSIONS: We propose that combining these natural compounds may be a useful strategy in OA therapy as compared with separate treatment with each individual compound.

Arthritis Res Ther. 2009;11(6):R165

Dietary curcumin significantly improves obesity-associated inflammation and diabetes in mouse models of diabesity.

Obesity is a major risk factor for the development of type 2 diabetes, and both conditions are now recognized to possess significant inflammatory components underlying their pathophysiologies. We tested the hypothesis that the plant polyphenolic compound curcumin, which is known to exert potent antiinflammatory and antioxidant effects, would ameliorate diabetes and inflammation in murine models of insulin-resistant obesity. We found that dietary curcumin admixture ameliorated diabetes in high-fat diet-induced obese and leptin-deficient ob/ob male C57BL/6J mice as determined by glucose and insulin tolerance testing and hemoglobin A1c percentages. Curcumin treatment also significantly reduced macrophage infiltration of white adipose tissue, increased adipose tissue adiponectin production, and decreased hepatic nuclear factor-kappaB activity, hepatomegaly, and markers of hepatic inflammation. We therefore conclude that orally ingested curcumin reverses many of the inflammatory and metabolic derangements associated with obesity and improves glycemic control in mouse models of type 2 diabetes. This or related compounds warrant further investigation as novel adjunctive therapies for type 2 diabetes in man.

Endocrinology. 2008 Jul;149(7):3549-58

Curcumin protects human chondrocytes from IL-l1beta-induced inhibition of collagen type II and beta1-integrin expression and activation of caspase-3: an immunomorphological study.

Interleukin 1beta (IL-1beta) is a pleiotropic pro-inflammatory cytokine that plays a key role in mediating cartilage degradation in osteoarticular disorders such as osteoarthritis (OA) and rheumatoid arthritis (RA). At the cellular level, IL-1beta activates matrix degrading enzymes, down-regulates expression of matrix components and induces chondrocyte apoptosis. Curcumin (diferuloylmethane) is an anti-inflammatory phytochemical agent that has recently been shown to antagonize the pro-inflammatory effects of cytokines in chondrocytes and other cells. To test the hypothesis that curcumin also protects chondrocytes from morphological alterations induced by IL-1beta, we investigated its in vitro effects on apoptotic signalling proteins and key cartilage-specific matrix components in IL-1beta-stimulated chondrocytes. Human articular chondrocytes were pre-treated with 10 ng/mI IL-1beta alone for 30 min before being co-treated with IL-1beta and 50 microM curcumin for 5, 15 or 30 min, respectively. The ultrastructural morphology of chondrocytes was investigated by transmission electron microscopy. The production of collagen type II, the adhesion and signal transduction receptor beta1-integrin, the apoptosis marker activated caspase-3 was analysed by immunohistochemistry, immunoelectron microscopy and Western blotting. Transmission electron microscopy of chondrocytes stimulated with IL-1beta revealed early degenerative changes which were relieved by curcumin co-treatment. The suppression of collagen type II and beta1-integrin synthesis by IL-1beta was inhibited by curcumin. Additionally, curcumin antagonized IL-1beta-induced caspase-3 activation in a time-dependent manner. This study clearly demonstrates that curcumin exerts anti-apoptotic and anti-catabolic effects on IL-1beta-stimulated articular chondrocytes. Therefore curcumin may have novel therapeutic potential as an adjunct nutraceutical chondroprotective agent for treating OA and related osteoarticular disorders.

Ann Anat. 2005 Nov;187(5-6):487-97

A Pilot Cross-Over Study to Evaluate Human Oral Bioavailability of BCM-95CG (Biocurcumax), A Novel Bioenhanced Preparation of Curcumin.

Curcumin, the bioactive component of turmeric, Curcuma longa has an exceptionally wide spectrum of activities including antioxidant, anti-inflammatory and anti-cancer properties, and is currently under different phases of clinical trials for various types of soft tissue cancers. However, although in vitro and animal studies have shown anticancer activities of curcumin for virtually all types of human cancers, its poor bioavailability in the human body has severely limited its application to these diseases. Methods to increase its oral bioavailability are a subject of intense current research. Reconstituting curcumin with the non-curcuminoid components of turmeric has been found to increase the bioavailability substantially. In the present clinical study to determine the bioavailability of curcuminoids, a patented formulation, BCM-95((R))CG was tested on human volunteer group. Normal curcumin was used in the control group. Curcumin content in blood was estimated at periodical intervals. After a washout period of two weeks the control group and drug group were crossed over BCM-95((R))CG and curcumin, respectively. It was also compared with a combination of curcumin-lecithin-piperine which was earlier shown to provide enhanced bioavailability. The results of the study indicate that the relative bioavailability of BCM-95((R))CG (Biocurcumax) was about 6.93-fold compared to normal curcumin and about 6.3-fold compared to curcumin-lecithin-piperine formula. BCM-95((R))CG thus, has potential for widespread application for various chronic diseases.

Indian J Pharm Sci. 2008 Jul-Aug;70(4):445-9

Biological actions of curcumin on articular chondrocytes.

OBJECTIVES: Curcumin (diferuloylmethane) is the principal biochemical component of the spice turmeric and has been shown to possess potent anti-catabolic, anti-inflammatory and antioxidant, properties. This article aims to provide a summary of the actions of curcumin on articular chondrocytes from the available literature with the use of a text-mining tool. We highlight both the potential benefits and drawbacks of using this chemopreventive agent for treating osteoarthritis (OA). We also explore the recent literature on the molecular mechanisms of curcumin mediated alterations in gene expression mediated via activator protein 1 (AP-1)/nuclear factor-kappa B (NF-kappaB) signalling in chondrocytes, osteoblasts and synovial fibroblasts. METHODS: A computer-aided search of the PubMed/Medline database aided by a text-mining tool to interrogate the ResNet Mammalian database 6.0. RESULTS: Recent work has shown that curcumin protects human chondrocytes from the catabolic actions of interleukin-1 beta (IL-1beta) including matrix metalloproteinase (MMP)-3 up-regulation, inhibition of collagen type II and down-regulation of beta1-integrin expression. Curcumin blocks IL-1beta-induced proteoglycan degradation, AP-1/NF-kappaB signalling, chondrocyte apoptosis and activation of caspase-3. CONCLUSIONS: The available data from published in vitro and in vivo studies suggest that curcumin may be a beneficial complementary treatment for OA in humans and companion animals. Nevertheless, before initiating extensive clinical trials, more basic research is required to improve its solubility, absorption and bioavailability and gain additional information about its safety and efficacy in different species. Once these obstacles have been overcome, curcumin and structurally related biochemicals may become safer and more suitable nutraceutical alternatives to the non-steroidal anti-inflammatory drugs that are currently used for the treatment of OA.

Osteoarthritis Cartilage. 2010 Feb;18(2):141-9

Phase II trial of curcumin in patients with advanced pancreatic cancer.

PURPOSE: Pancreatic cancer is almost always lethal, and the only U.S. Food and Drug Administration-approved therapies for it, gemcitabine and erlotinib, produce objective responses in 18 months; interestingly, one additional patient had a brief, but marked, tumor regression (73%) accompanied by significant increases (4- to 35-fold) in serum cytokine levels (IL-6, IL-8, IL-10, and IL-1 receptor antagonists). No toxicities were observed. Curcumin down-regulated expression of NF-kappaB, cyclooxygenase-2, and phosphorylated signal transducer and activator of transcription 3 in peripheral blood mononuclear cells from patients (most of whom had baseline levels considerably higher than those found in healthy volunteers). Whereas there was considerable interpatient variation in plasma curcumin levels, drug levels peaked at 22 to 41 ng/mL and remained relatively constant over the first 4 weeks. CONCLUSIONS: Oral curcumin is well tolerated and, despite its limited absorption, has biological activity in some patients with pancreatic cancer.

Clin Cancer Res. 2008 Jul 15;14(14):4491-9

HPLC analysis of vitamin E isoforms in human epidermis: correlation with minimal erythema dose and free radical scavenging activity.

The content and composition of different vitamin E isoforms was analyzed in normal human skin. Interestingly the epidermis contained 1% alpha-tocotrienol, 3% gamma-tocotrienol, 87% alpha-tocopherol, and 9% gamma-tocopherol. Although the levels of tocotrienol in human epidermis appear to be considerably lower than reported in the hairless mouse, the presence of significant amounts of tocotrienol levels leads to speculation about the physiological function of tocotrienols in skin. Besides antioxidant activity and photoprotection, tocotrienols may have skin barrier and growth-modulating properties. A good correlation was found for epidermal alpha-tocopherol (r = 0.7909, p <.0003), gamma-tocopherol (r = "0.556," p <.025), and the total vitamin E content (r = "0.831," p <.0001) with the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging in epidermis, as assessed by electron paramagnetic resonance (EPR) spectroscopy. In human epidermis, alpha-tocopherol is quantitatively the most important vitamin E isoform present and comprises the bulk of first line free radical defense in the lipid compartment. Epidermal tocotrienol levels were not correlated with DPPH scavenging activity. The minimal erythema dose (MED), an individual measure for sun sensitivity and a crude indicator for skin cancer susceptibility, did not correlate with the epidermal content of the vitamin E isoforms. Hence it is concluded that vitamin E alone is not a determinant of individual photosensitivity in humans.

Free Radic Biol Med. 2003 Feb 1;34(3):330-6

Vitamin E and its function in membranes.

Vitamin E is a fat-soluble vitamin. It is comprised of a family of hydrocarbon compounds characterised by a chromanol ring with a phytol side chain referred to as tocopherols and tocotrienols. Tocopherols possess a saturated phytol side chain whereas the side chain of tocotrienols have three unsaturated residues. Isomers of these compounds are distinguished by the number and arrangement of methyl substituents attached to the chromanol ring. The predominant isomer found in the body is alpha-tocopherol, which has three methyl groups in addition to the hydroxyl group attached to the benzene ring. The diet of animals is comprised of different proportions of tocopherol isomers and specific alpha-tocopherol-binding proteins are responsible for retention of this isomer in the cells and tissues of the body. Because of the lipophilic properties of the vitamin it partitions into lipid storage organelles and cell membranes. It is, therefore, widely distributed in throughout the body. Subcellular distribution of alpha-tocopherol is not uniform with lysosomes being particularly enriched in the vitamin compared to other subcellular membranes. Vitamin E is believed to be involved in a variety of physiological and biochemical functions. The molecular mechanism of these functions is believed to be mediated by either the antioxidant action of the vitamin or by its action as a membrane stabiliser. alpha-Tocopherol is an efficient scavenger of lipid peroxyl radicals and, hence, it is able to break peroxyl chain propagation reactions. The unpaired electron of the tocopheroxyl radical thus formed tends to be delocalised rendering the radical more stable. The radical form may be converted back to alpha-tocopherol in redox cycle reactions involving coenzyme Q. The regeneration of alpha-tocopherol from its tocopheroxyloxyl radical greatly enhances the turnover efficiency of alpha-tocopherol in its role as a lipid antioxidant. Vitamin E forms complexes with the lysophospholipids and free fatty acids liberated by the action of membrane lipid hydrolysis. Both these products form 1:1 stoichiometric complexes with vitamin E and as a consequence the overall balance of hydrophobic:hydrophillic affinity within the membrane is restored. In this way, vitamin E is thought to negate the detergent-like properties of the hydrolytic products that would otherwise disrupt membrane stability. The location and arrangement of vitamin E in biological membranes is presently unknown. There is, however, a considerable body of information available from studies of model membrane systems consisting of phospholipids dispersed in aqueous systems. From such studies using a variety of biophysical methods, it has been shown that alpha-tocopherol intercalates into phospholipid bilayers with the long axis of the molecule oriented parallel to the lipid hydrocarbon chains. The molecule is able to rotate about its long axis and diffuse laterally within fluid lipid bilayers. The vitamin does not distribute randomly throughout phospholipid bilayers but forms complexes of defined stoichiometry which coexist with bilayers of pure phospholipid. alpha-Tocopherol preferentially forms complexes with phosphatidylethanolamines rather than phosphatidylcholines, and such complexes more readily form nonlamellar structures. The fact that alpha-tocopherol does not distribute randomly throughout bilayers of phospholipid and tends to form nonbilayer complexes with phosphatidylethanolamines would be expected to reduce the efficiency of the vitamin in its action as a lipid antioxidant and to destabilise rather than stabilise membranes. The apparent disparity between putative functions of vitamin E in biological membranes and the behaviour in model membranes will need to be reconciled.

Prog Lipid Res. 1999 Jul;38(4):309-36

The pecking order of free radicals and antioxidants: lipid peroxidation, alpha-tocopherol, and ascorbate.

Free radicals vary widely in their thermodynamic properties, ranging from very oxidizing to very reducing. These thermodynamic properties can be used to predict a pecking order, or hierarchy, for free radical reactions. Using one-electron reduction potentials, the predicted pecking order is in agreement with experimentally observed free radical electron (hydrogen atom) transfer reactions. These potentials are also in agreement with experimental data that suggest that vitamin E, the primary lipid soluble small molecule antioxidant, and vitamin C, the terminal water soluble small molecule antioxidant, cooperate to protect lipids and lipid structures against peroxidation. Although vitamin E is located in membranes and vitamin C is located in aqueous phases, vitamin C is able to recycle vitamin E; i.e., vitamin C repairs the tocopheroxyl (chromanoxyl) radical of vitamin E, thereby permitting vitamin E to function again as a free radical chain-breaking antioxidant. This review discusses: (i) the thermodynamics of free radical reactions that are of interest to the health sciences; (ii) the fundamental thermodynamic and kinetic properties that are associated with chain-breaking antioxidants; (iii) the unique interfacial nature of the apparent reaction of the tocopherol free radical (vitamin E radical) and vitamin C; and (iv) presents a hierarchy, or pecking order, for free radical electron (hydrogen atom) transfer reactions.

Arch Biochem Biophys. 1993 Feb 1;300(2):535-43

Alpha-Lipoic acid as a biological antioxidant.

alpha-Lipoic acid, which plays an essential role in mitochondrial dehydrogenase reactions, has recently gained considerable attention as an antioxidant. Lipoate, or its reduced form, dihydrolipoate, reacts with reactive oxygen species such as superoxide radicals, hydroxyl radicals, hypochlorous acid, peroxyl radicals, and singlet oxygen. It also protects membranes by interacting with vitamin C and glutathione, which may in turn recycle vitamin E. In addition to its antioxidant activities, dihydrolipoate may exert prooxidant actions through reduction of iron. alpha-Lipoic acid administration has been shown to be beneficial in a number of oxidative stress models such as ischemia-reperfusion injury, diabetes (both alpha-lipoic acid and dihydrolipoic acid exhibit hydrophobic binding to proteins such as albumin, which can prevent glycation reactions), cataract formation, HIV activation, neurodegeneration, and radiation injury. Furthermore, lipoate can function as a redox regulator of proteins such as myoglobin, prolactin, thioredoxin and NF-kappa B transcription factor. We review the properties of lipoate in terms of (1) reactions with reactive oxygen species; (2) interactions with other antioxidants; (3) beneficial effects in oxidative stress models or clinical conditions.

Free Radic Biol Med. 1995 Aug;19(2):227-50

Molecular aspects of alpha-tocotrienol antioxidant action and cell signalling.

Vitamin E, the most important lipid-soluble antioxidant, was discovered at the University of California at Berkeley in 1922 in the laboratory of Herbert M. Evans (Science 1922, 55: 650). At least eight vitamin E isoforms with biological activity have been isolated from plant sources. Since its discovery, mainly antioxidant and recently also cell signaling aspects of tocopherols and tocotrienols have been studied. Tocopherols and tocotrienols are part of an interlinking set of antioxidant cycles, which has been termed the antioxidant network. Although the antioxidant activity of tocotrienols is higher than that of tocopherols, tocotrienols have a lower bioavailability after oral ingestion. Tocotrienols penetrate rapidly through skin and efficiently combat oxidative stress induced by UV or ozone. Tocotrienols have beneficial effects in cardiovascular diseases both by inhibiting LDL oxidation and by down-regulating 3-hydroxyl-3-methylglutaryl-coenzyme A (HMG CoA) reductase, a key enzyme of the mevalonate pathway. Important novel antiproliferative and neuroprotective effects of tocotrienols, which may be independent of their antioxidant activity, have also been described.

J Nutr. 2001 Feb;131(2):369S-73S

Suppression of gamma- tocotrienol on UVB induced inflammation in HaCaT keratinocytes and HR-1 hairless mice via inflammatory mediators multiple signaling.

Tocopherol (Toc) such as alpha-Toc has been expected to act as photochemopreventive agent of skin, but the effect of the other vitamin E forms [tocotrienols (T3)] has not been fully understood. We evaluated the anti-inflammatory effect of T3 on UVB-induced inflammatory reaction using immortalized human keratinocytes and hairless mice. gamma-T3 suppressed UVB-induced PGE(2) production while similar alpha-Toc doses had no effect. The anti-inflammatory actions of gamma-T3 were explained by its ability to reduce UVB-induced inflammatory gene and protein expression [cyclooxgenase-2 (COX-2), interleukin (IL)-1beta, IL-6, and monocyte chemotactic protein-1]. Western blot analysis revealed gamma-T3 inhibited p38, extracellular signal-regulated kinase, and c-Jun N-terminal kinase/stress-activated protein kinase activation. In HR-1 hairless mice, oral T3 suppressed UVB-induced changes in skin thickness, COX-2 protein expression, and hyperplasia, but alpha-Toc did not. These results suggest T3 has potential use to protect against UVB-induced skin inflammation.

J Agric Food Chem. 2010 Jun 9;58(11):7013-20

Vitamin E: function and metabolism.

Although vitamin E has been known as an essential nutrient for reproduction since 1922, we are far from understanding the mechanisms of its physiological functions. Vitamin E is the term for a group of tocopherols and tocotrienols, of which alpha-tocopherol has the highest biological activity. Due to the potent antioxidant properties of tocopherols, the impact of alpha-tocopherol in the prevention of chronic diseases believed to be associated with oxidative stress has often been studied, and beneficial effects have been demonstrated. Recent observations that the alpha-tocopherol transfer protein in the liver specifically sorts out RRR-alpha-tocopherol from all incoming tocopherols for incorporation into plasma lipoproteins, and that alpha-tocopherol has signaling functions in vascular smooth muscle cells that cannot be exerted by other forms of tocopherol with similar antioxidative properties, have raised interest in the roles of vitamin E beyond its antioxidative function. Also, gamma-tocopherol might have functions apart from being an antioxidant. It is a nucleophile able to trap electrophilic mutagens in lipophilic compartments and generates a metabolite that facilitates natriuresis. The metabolism of vitamin E is equally unclear. Excess alpha-tocopherol is converted into alpha-CEHC and excreted in the urine. Other tocopherols, like gamma- and delta-tocopherol, are almost quantitatively degraded and excreted in the urine as the corresponding CEHCs. All rac alpha-tocopherol compared to RRR-alpha-tocopherol is preferentially degraded to alpha-CEHC. Thus, there must be a specific, molecular role of RRR-alpha-tocopherol that is regulated by a system that sorts, distributes, and degrades the different forms of vitamin E, but has not yet been identified. In this article we try to summarize current knowledge on the function of vitamin E, with emphasis on its antioxidant vs. other properties, the preference of the organism for RRR-alpha-tocopherol, and its metabolism to CEHCs.

FASEB J. 1999 Jul;13(10):1145-55

Vitamin E in human health and disease.

Vitamin E in nature is comprised of a family of tocopherols and tocotrienols. The most studied of these is alpha-tocopherol (alpha-TOH), because this form is retained within the body, and vitamin E deficiency is corrected with this supplement. alpha-TOH is a lipid-soluble antioxidant required for the preservation of cell membranes, and it potentially acts as a defense against oxidative stress. Many studies have investigated the metabolism, transport, and efficacy alpha-TOH in the prevention of sequelae associated with cardiovascular disease (CVD). Supplementation with vitamin E is considered to provide health benefits against CVD through its antioxidant activity, the prevention of lipoprotein oxidation, and the inhibition of platelet aggregation. However, the results from large prospective, randomized, placebo-controlled clinical trials with alpha-TOH have been largely negative. A recent meta-analysis suggests that alpha-TOH supplements may actually increase all-cause mortality; however, the mechanism for this increased risk is unknown. In vitro studies performed in human cell cultures and animal models suggest that vitamin E might increase the hepatic production of cytochrome P450s and MDR1. Induction of CYP3A4 or MDR1 by vitamin E could potentially lower the efficacy of any drug metabolized by CYP3A4 or MDR1. Other possibilities include an adverse effect of alpha-TOH on blood pressure in high-risk populations. Because of the wide popularity and use of vitamin E supplements, further research into potential adverse effects is clearly warranted.

Crit Rev Clin Lab Sci. 2008;45(5):417-50

Free radical recycling and intramembrane mobility in the antioxidant properties of alpha-tocopherol and alpha-tocotrienol.

d-Alpha-tocopherol (2R,4'R, 8'R-Alpha-tocopherol) and d-alpha- tocotrienol are two vitamin E constituents having the same aromatic chromanol “head” but differing in their hydrocarbon “tail”: tocopherol with a saturated and toctrienol with an unsaturated isoprenoid chain. d-Alpha-tocopherol has the highest vitamin E activity, while d-alpha-tocotrienol manifests only about 30% of this activity. Since vitamin E is considered to be physiologically the most important lipid-soluble chain-breaking antioxidant of membranes, we studied alpha-tocotrienol as compared to alpha-tocopherol under conditions which are important for their antioxidant function. d-Alpha-tocotrienol possesses 40-60 times higher antioxidant activity against (Fe2+ + ascorbate)- and (Fe2+ + NADPH)-induced lipid peroxidation in rat liver microsomal membranes and 6.5 times better protection of cytochrome P-450 against oxidative damage than d-alpha-tocopherol. To clarify the mechanisms responsible for the much higher antioxidant potency of d-alpha-tocotrienol compared to d-alpha-tocopherol, ESR studies were performed of recycling efficiency of the chromanols from their chromanoxyl radicals. 1H-NMR measurements of lipid molecular mobility in liposomes containing chromanols, and fluorescence measurements which reveal the uniformity of distribution (clusterizations) of chromanols in the lipid bilayer. From the results, we concluded that this higher antioxidant potency of d-alpha-tocotrienol is due to the combined effects of three properties exhibited by d-alpha-tocotrienol as compared to d-alpha-tocopherol: (i) its higher recycling efficiency from chromanoxyl radicals, (ii) its more uniform distribution in membrane bilayer, and (iii) its stronger disordering of membrane lipids which makes interaction of chromanols with lipid radicals more efficient. The data presented show that there is a considerable discrepancy between the relative in vitro antioxidant activity of d-alpha-tocopherol and d-alpha-tocotrienol with the conventional bioassays of their vitamin activity.

Free Radic Biol Med. 1991;10(5):263-75