Phenolic compounds from Baseonema acuminatum leaves: isolation and antimicrobial activity

Three new phenolic compounds, 1-galloyl-beta-D-glucopyranosyl(1-->4)-beta-D-galactopyranoside (1), 2-methoxy-5-(1',2',3' -trihydroxypropyl)-phenyl-1-O-(6"-galloyl)-beta-D-glucopyranoside (2), and 2-methoxy-5-hydroxymethyl-phenyl-1-O-(6 "-galloyl)-beta-D-glucopyranoside (3), together with the known compounds benzyl 6'-O-galloyl-beta-D-glucopyranoside (4), 1,6-di-O-galloyl-beta-D-glucopyranose (5), myrciaphenone B (6), kaempferol 3-O-(6' galloyl)-beta-D-glucopyranoside (7), quercetin 3-O-(6"-galloyl)-beta-D-glucopyranoside (8), vornifoliol 9-O-beta-D-apiofuianosyl-(1-->6)-beta-D-glucopyranoside, 2,3-dihydrobenzofuran-2-(4'-hydroxy-3'-methoxyphenyl)-3-alpha-L-rhamnopyranosyloxymethyl-7-methoxy-5-propanol, and benzyol-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside were isolated from the leaves of Baseonema acuminatum P. Choux (Asclepiadaceae). The antimicrobial activity of all compounds was evaluated in vitro against various bacteria and three strains of Candida albicans. The new compounds 2 and 3, together with the known compound 4, showed antifungal activity against two clinically isolated Candida albicans strains and against C. albicans ATCC 2091. Compound 5 was active against the two clinically isolated strains of C. albicans. Compounds 1, 6, 7, and 8 inhibited only one strain of C. albicans at the maximum concentration used. None of the phenolic compounds tested was active against the bacteria studied.