Bioactive constituents from a Thai sponge, Reniera sp

Abstract

The antimicrobial assay-directed fractionation of the 90% methanolic extract from a Thai sponge, Reniera sp., led to the isolation of 2 new isoquinoline quinones, N-( 1"E-buten:-3"-onyl)-1,2-dihydrorenierone (47) and renierine B (55), and 4 known isoquinoline quinones, mimosamycin (16), renierone (17), N-formyl-1,2-dihydrorenierone (19), and 1,6-dimethyl-7- methoxy-5,8-dihydroisoquinoline-5,8-dione (21). The identification and structure elucidation of the isolated compounds were executed by the analyses of the uv, ir ms, 1-D nmr, and 2-D nmr spectral data, as well as the comparison with other known compounds. The antimicrobial activity of the isolated compounds was determined to reveal the good to moderate activity against S. aureus and B. suhtilis of compounds 16, 17, 19, 21 and 47. On the other hand, renierine B (55) is not active at the concentration of 0.1 mg/disc. The structure-activity relationship of renierine B (55) is suggested.