Rhubarb extract having antiradical, antioxidant and estrogenic action, used in medicaments, cosmetics or foods, contains synergistic combination of specific hydroxystilbene compounds

摘要

Rhubarb extract (A), obtained from the rhizomes of Rheum rhaponticum, comprises at least 50% hydroxystilbenes (I). At least 50% of (I) are formed from rhaponticoside (Ia) (3,5,3'-trihydroxy-4'-methoxystilbene-3beta-D-glucopyranoside), deoxyrhaponticoside (Ib) (3,5-dihydroxy-4'-methoxystilbene-3beta-D-glucopyranoside), astrangin (Ic) (3,5,4'-trihydroxystilbene-3'beta-D-glucopyranoside) and piceatannol (Id) (3,3',4',5-tetrahydroxy-trans-stilbene). Independent claims are also included for: (1) compositions (B) obtained from (A) by replacing the majority of the phenolic and alcoholic OH groups of (I) (especially (Ia)-(Id)) with ester groups of formula O-CO-R or the majority of at least the phenolic OH groups (preferably the majority of both the phenolic and alcoholic OH groups) of (I) (especially (Ia)-(Id)) with silyl ether groups of formula O-SiR1R2R3; (2) compositions (C) obtained by mixing (A) or (B) with a hop extract with high prenyl-flavonoid content, and (3) preparation of (A). R = optionally unsaturated 1-25C alkyl, aryl or aralkyl (preferably the residue of a saturated or unsaturated fatty acid having at least 6C), and R1-R3 = optionally unsaturated 1-20C alkyl, aryl or aralkyl, bonded to Si by a non-hydrolyzable Si-C bond. (A), (B) or (C) is optionally encapsulated in liposomes or microcapsules.