Scientific Name: Vitis vinifera L. ssp. vinifera; synonym V. vinifera ssp. sativa. 1 Common Names: Common grape vine, grapevine, muskat.
Grape seed proanthocyanidins refer to procyanidin mixtures. These are derived from the flavan-3-o1 class of flavonoids, which includes (+)-catechin and (-)-epicatechin. Procyanidins are dimers and oligomers of catechin and epicatechin and their gallic acid esters.
Procyanidins are found in grape seeds, cocoa, chocolate, apples, peanuts, almonds, cranberries, and blueberries, in the bark of pines and in other plant sources.
The procyanidin dimers and oligomers of grape seed are also known as oligomeric procyanidins (OPCs), procyanidolic oligomers (PCOs) and condensed tannins.
The proanthocyanidins of grape seed comprise approximately 60 to 70% of the polyphenol content of grapes and are colorless in their pure state.
The pharmacokinetics of grape seed proanthocyanidins in humans are still not fully appreciated. It appears that the proanthocyanidins are partially absorbed, but the extent of the absorption varies widely among subjects and various products.
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Animal and in vitro studies have shown that grape seed proanthocyanidins may have the following activities:
- Antioxidant
- Anti-inflammatory
- Anticarcinogenic
- Antiatherogenic
- Anti-ulcer
- Capillary-reinforcing
- Cardioprotective
- Free-radical-scavenging
Medical literature contains no reports of significant adverse reactions, although its toxicity has not been extensively examined.
Pregnant and lactating women should avoid grape seed proanthocyanidin supplementation.
Contraindication:
Since some procynidin oligomers have been found to possess platelet antiaggregatory activity comparable to aspirin 3 , persons taking anticoagulant medication would we advised to refrain from consuming GSE as also those preparing for surgery.
Antioxidant/Anticholesterol/Antiatherosclerosis:Flavonoids occurring in grape seed and red wine may have potent antioxidant activity and protect low-density lipoprotein (LDL) against oxidation . Some researchers speculate that this might have beneficial effects on coronary artery disease.
Researchers gave rats 250 mg/kg of body weight of proanthocyanidin-rich extract from grape seeds by intragastric intubation. Plasma analysis showed that metabolites of proanthocyanidin occurred at 15 minutes after administration, and indicated a significant increase in antioxidant potential in GSE-treated rats as compared to rats administered only water. Three peaks of metabolites were identifies as gallic acid, (+)-catechin, and (-)-epicatechin. The difference was diminished after 2h but even after 8h the plasma from the GSE group continued to show a higher resistance to oxidation as compared to that of control rat plasma, even though the difference was not statistically significant. 4
A study involving 40 hypercholesterolemic subjects with total serum cholesterol concentrations between 210-300 mg/dL received either placebo, chromium polynicotinate 200 mcg, grape seed extract 100 mg, or a combination of chromium and grape seed extract twice a day for two months. Average percentage change in the total serum cholesterol concentration from baseline was placebo –3.5% grape seed extract –2.5% chromium –10% and combination –16.5%. The combination of chromium and grape seed extract also significantly decreased serum LDL concentrations when compared to placebo. The authors concluded that a combination of chromium and grape seed extract could decrease total serum cholesterol and LDL concentrations significantly. 1
A study of 38 rabbits looked at the effects of cholesterol and proanthocyanidin extract from grape seeds or probucol for 8 weeks. Rabbits were divided into 5 groups: control, cholesterol-fed, 1% proanthocyanidin-rich extract and 1% cholesterol, 0.1% proanthocyanidin-rich extract and 1% cholesterol, and 1% probucol and 1% cholesterol group. Feeding proanthocyanidin-rich extracts to rabbits significantly reduced severe atherosclerosis in the aorta and decreased the number of oxidized LDL-positive macrophage-derived foam cells in atherosclerotic lesions in the aorta. The results suggested that proanthocyanidins might inhibit LDL oxidation and exhibit antiatherosclerotic activity. 2
Nuttall et al. 7 conducted a single-blind, randomized placebo-controlled study in 20 healthy nonsmoking subjects, aged 19-31 years, to assess the antioxidant potential of a proprietary GSE, standardized to contain 150mg of grape procyanidins per capsule, at a daily dosage of 2 capsules for 5 days. Following a washout period of two weeks, the verum and placebo groups had their treatments switched. The mean total antioxidant capacity of serum from those on GSE increased significantly compared to baseline, while no significant change was observed in the placebo group. The authors of the study noted that the results were comparable to those found in a similar study in which the active treatment was red wine (5.7ml/kg).
Free radical scavenging/Antitoxic/Anticancer: During chemotherapy, stem cells are often damaged and significant damage to normal and healthy organs and tissues may occur. Therefore, development of new and effective strategies to diminish normal tissue toxicity is essential. Grape seed proanthocyanidin extract might be useful to serve as a free radical scavenger, chemoprotective and cytotoxic agent, as seen in both in vitro and in vivo models.
A review on grape seed proanthocyanidin extract evaluated the beneficial effects of grape seed on human health and disease prevention. The review assessed the concentration or dose-dependent free radical scavenging ability of a novel IH636 grape seed proanthocyanidin extract (GSPE) in both in vitro and in vivo models and compared the free radical scavenging ability of GSPE with vitamins C, E and beta-carotene. The GSPE demonstrated cytotoxicity towards human breast, lung and gastric adenocarcinoma cells, and enhanced growth and viability of normal human gastric mucosal cells. Overall, these researchers concluded that GSPE is a safe, novel, highly potent and bioavailable free radical scavenger and antioxidant possessing a broad spectrum of health benefits.8
Researchers assessed the ability of a novel IH636 grape seed proanthocyanidin extract to ameliorate chemotherapy induced toxic effects, in cultured Chang epithelial cells. Cells were treated and grown in vitro with 30 nM of idarubicin (Ida) or 1 mcg/ml of 4 –hydroxyperoxycyclophosphamide (4HC), with or without 25 mcg/ml of GSPE. Results showed that GSPE decreased growth inhibitory and cytotoxic effects of Ida as well as 4HC on Chang epithelial cells in vitro. The results indicated that GSPE could be a potential candidate for reducing toxic effects associated with chemotherapeutic agents. 9
A study looked at the effects of IH636 grape seed proanthocyanidin extract (GSPE) on MCF-7 human breast cancer cells, A-427 human lung cancer cells, CRL-1739 human gastric adenocarcinoma cells, and K562 chronic myelogenous leukemic cells for 0 to 72 hours. The study also looked at the effects on normal human gastric mucosal cells and normal J774A.1murine macrophage cells. Following incubation of the MCF-7 cells with GSPE, there were inhibitions in cell growth observed at 24, 48 and 72 hours, with similar results in the A-427 and gastric adenocarcinoma cells. The study showed that GSPE exhibits cytotoxicity toward some cancer cells, and enhances the growth and viability of the normal cells examined. 10
Anti-Ulcer Activity: Grape seed extracts may have anti-ulcer activity on gastric mucosal lesions. This anti-ulcer activity may be due to the longer oligomers of procyanidin contained in extracts.
Researchers gave grape seed extract with low flavanol content, grape seed extract with high flavanol content and procyanidins to rats. In each, a dose of 200 mg/kg strongly inhibited stomach mucosal injury induced by 60% ethanol containing 150 mM hydrochloride, which may be dependent on the content of procyanidin oligomers. Procyanidin oligomers (dimers to hexamers) were prepared and studied. Oligomers, longer than tetramers showed a strong protective effect against gastric mucosal damage. In this study, grape seed extracts exhibited a protective effect on acute gastric lesions in rats. 11
Microcurculatory Disorders/Venous Insufficiency:
A randomized placebo-controlled double-
blind study with 20 patients diagnosed with
capillary hyperpermeability and hepatic
cirrhosis showed significant improvements in
the capillary fragility index, compared to
placebo, in patients receiving 2x150mg
procyanidins daily from a GSE for 8 weeks. 12
A double-blind placebo-controlled study of 92
patients aged 24-62 years, with peripheral
venous insufficiency administered the
equivalent of 300mg/day of procyanidns for 28
days; 71 subjects completed the full course of
treatment. Functional measures such as
paresthesias, nocturnal cramps and edema were
improved by more than 50% in roughly 75% of
patients, resulting in a 41% increase in venous
function over the placebo group. 13
A placebo-controlled study with 30 patients
aged 26-55 years, without varicose veins,
assessed the relative effects of daily GSE
(150mg procyanidins), the semisynthetic
flavonoid, diosmin (450mg), and placebo over a
30 day period. The GSE-treated group
experienced significantly fewer indications of
functional problems, suggesting a potential for
GSE as a varicose vein prophylactic. 14
In another double-blind study comparing GSE
and diosmin in 50 female patients, aged 20-60,
similar treatments were administered to two
groups of subjects, most with preganancy –
related chronic venous insufficiency, over 30
days, following a 30-day placebo period. Both
treatments were effective in reducing symptoms
of peripheral venous insufficiency, but GSE was
superior in terms of rapidity of action and
duration of activity. Only 45% of the diosmin
group became symptom free, as compared to
65% of the GSE group. In addition, a significant
decrease in varicose veins, compared to baseline,
was observed only in the GSE group. 15
Royer and Schmidt observed improved venous
tone from a single dose of 150mg procyanidins, as
measured by gas plethysmography, in patients
with widespread varicose veins. 13
Retinopathies
A double-blind placebo-controlled study with 75
patients who had suffered ocular stress from a
visual display found significant improvement in
contrast sensitivity in those treated with the
equivalent of 300mg procyanidins daily for 60
days, as compared to the relatively unresponsive
control group. A global improvement of
subjective symptoms was also reported for the
active treatment group. 17
Twenty-six patients with diabetic retinopathy
experienced favourable effects from treatment
with a daily dose of 100mg procyanidins for an
average of 51 days. Notable improvements were
observed respecting microaneurisms and exudates.
In addition 30 retinopathy patients, suffering from
microaneurisms, hemorrhage, and
neovascularization after capillary hypoxia found
these retinopathic lesions stabilized when treated
with 50mg procyanidins thrice daily. 18
In a double-blind placebo-controlled study
involving 30 patients with atheroxclerotic
retinopathy, treatment with the equivalent of
100mg procyanidins daily for one year showed
improved visual acuity or remained stable in 29
cases. 19
Some data suggest that grape seed proanthocyanidins may have anticancer activity.
May protect against some forms of lipid peroxidation and may be cardioprotective, hepatoprotective and capillary protective.
May have antiinflammatory activity.
There is anecdotal testimony that they are useful in the treatment of arthritis, varicose viens, diabetic retinopathy and some allergies, but there are few clinical trials to support these applications.
Caution with pregnancy or nursing. Consult physician before using.
Information on the relationship between substances and disease is provided for general information, in order to convey a balanced review of the scientific literature. In many cases the relationship between a substance and a disease is tentative and additional research is needed to confirm such a relationship.
The dietary supplement information contained on this site has been compiled from published sources thought to be reliable, but it cannot be guaranteed. Efforts have been made to assure this information is accurate and current. However, some of this information may be purported or outdated due to ongoing research or discoveries. The authors, editors and publishers cannot accept responsibility for errors or omissions or for any consequences from applications of the information in this site and make no warranty, expressed or implied, with respect to the contents herein.
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