Inhibition of sphingosine-1-phosphate- and vascular endothelial growth factor-induced endothelial cell chemotaxis by red grape skin polyphenols correlates with a decrease in early platelet-activating factor synthesis.
Free Radical Biology and Medicine. 2006 Feb 15;40(4):581-90
The production of vascular endothelial growth factor and the enzyme sphingosine-1-phosphate contribute to angiogenesis. The study showed that red grape skin polyphenolic extract prevents and inhibits angiogenesis, decreases the basal motility of endothelial and cancer cells and inhibit the production of vascular endothelial growth factor and the enzyme sphingosine-1-phosphate. The study concluded that grape skin extract could help to prevent the development of diseases associated with angiogenesis dysregulation, including cancer and glioblastoma (malignant brain tumors).
Polyphenol contents in grape seed extracts correlate with antipica effects in cisplatin-treated rats.
Journal of Alternative and Complementary Medicine. 2005 December;11(6):1059-65
Grape seed extract is a widely used supplement with antioxidant activity. The aim of this study was to investigate the effect of 3 commercial grape seed extracts on adverse effects of the chemotherapeutic drug cisplatin. The study was carried out on rats which were supplemented with the extract. The effect on kaolin consumption, a side effect of cisplatin, was used as measure. The grape seed extract contained mainly following phytochemicals: gallic acid, catechin, epicatechi, procyanidin B2, and epicatechin gallate. The polyphenol levels differed a lot between the extracts: from 27 mg/g to 194 mg/g. The researchers found that all grape seed extract reduced kaolin consumption from 45% to 66%. The study concluded that grape seed extract has therapeutic value in treating cisplatin-induced emesis. The study further stressed that there is a need for standardization of herbal extracts.
Grape seed and skin extracts inhibit platelet function and release of reactive oxygen intermediates.
Journal of Cardiovascular Pharmacology. 2005 October;46(4):445-51
Grapes and especially red wine and dark coloured grape juice are rich in flavonoids with antioxidant properties. Flavonoids protect against heart disease but the high alcohol of red wine and high sugar content of grape juice have limited their use for medicinal purposes. Heart disease is related with increased inflammation and thrombosis. The aim of this study was to investigate the anti-inflammatory effect of grape skin extract and grape seed extract and to determine their effect on the release of reactive oxygen intermediates by platelets. When the platelets were first incubated with the grape extracts the platelet aggregation and their release of superoxide decreased significantly. The grape extracts also resulted in a significant increase in radical-scavenging activity and decrease in reactive oxygen species. The study concluded that grape skin extract and grape seed extract inhibit platelet function and inflammatory responses.