Structural study of isoflavonoids possessing antioxidant activity isolated from the fermentation broth of streptomyces SP

Abstract

Structures of three antioxidant isoflavonoids isolated from the cultured broth of Streptomyces sp. OH-1049 were shown to be 4′, 7, 8-trihydroxyisoflavone (1), 3′, 4′, 7-trihydroxyisoflavone (2) and 8-chloro-3′, 4′, 5, 7-tetrahydroxyisoflavone (3), respectively. Among them, 3 is a novel isoflavonoid possessing a chlorine atom in the molecule. Compound 1 was synthesized and its antitumor activities were tested against IMC carcinoma, SI80, P388 leukemia and P388/ADM leukemia in vivo. As a result, 1 showed 139% increase in life span (ILS) against S180 bearing mice whereas it showed slight or no ILS against IMC carcinoma, P388 leukemia and P388/ADM leukemia bearing mice. © 1989, JAPAN ANTIBIOTICS RESEARCH ASSOCIATION. All rights reserved.