Vitis coignetiae

Abstract: Phenolic compounds were extracted from European and Japanese grapevine species (Vitis vinifera and V. coignetiae) seeds using 80% methanol or 80% acetone. The total content of phenolic compounds was determined utilizing Folin-Ciocalteu's phenol reagent, while the content of tannins was assayed by the vanillin and BSA precipitation methods. Additionally, the DPPH free radical and ABTS cation radical scavenging activities and the reduction power of the extracts were measured. The HPLC method was applied to determine the phenolic compounds, such as phenolic acids and catechins. The seeds contained large amounts of tannins and gallic acid and observable quantities of catechins, p-coumaric, ferulic and caffeic acids. The dominant form of phenolic acids in the extracts was the ester-bound form. The content of total phenolics was higher in the European grape V. vinifera seeds, which also contained more tannins, catechins and phenolic acids, except for caffeic acid. Extracts from V. vinifera seeds showed better radical scavenger properties and stronger reducing power. The total contents of phenolic compounds and tannins in acetone extracts were higher than in methanolic extracts. Acetone extracts also exhibited stronger antiradical properties as well as stronger reducing power.

Abstract: The methanolic extract of one of the common Vitaceaeous plants, Vitis coignetiae, showed marked prevention against injuries of primary cultured rat liver cells induced by carbon tetrachloride and D-galactosamine. Activity-guided fractionation of the extract resulted in the isolation of not only an antihepatotoxic stilbene derivative, e-viniferin, but also novel oligostilbenes, vitisin A and its stereoisomer cis-vitisin A as a mixture. The structures of the oligostilbenes have been determined on the basis of spectroscopic evidence, especially by 2D NMR methods such as HMBC spectra of degradative products