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The microbiological transformation of the triterpene nigranoic acid (3,4-secocycloarta-4(28),24(Z)-diene-3,26-dioic acid) (1) to 3,4-secocycloarta-4(28),17(20),24(Z)-triene-7β-hydroxy-16β,26-lactone-3-oic acid (2) and 3,4-secocycloarta-4(28),17(20)(Z),24(Z)-triene-7β-hydroxy-16β-methoxy-3,26-dioic acid (3) by the freshwater fungus Dictyosporium heptasporum YMF1.01213 has been demonstrated. The structures of the biotransformation products were determined by spectroscopic and MS analyses. Compound 2, characterized by the presence of a formed C-16/C-26 ester bridge, provided a novel nine-membered lactone ring structural skeleton for 3,4-secocycloartane triterpenoid derivatives. In addition, Compounds 1–3 exhibited weak anti-HIV activity in vitro. Compounds 2 and 3 were reported for the first time as natural product derivatives. [ABSTRACT FROM AUTHOR]

Abstract: Two new metabolites, (3S*,4S*,5S*,6R*)-4,5,6-trihydroxy-3-methyl-3,4,6,7-tetrahydro-1H-isochromen-8 (5H)-one (1) and (3R*,4S*)-7-ethyl-3,4,6,8-tetrahydroxy-3,4-dihydronaphthalen-1 (2H)-one (2), were isolated from the culture broth of the aquatic fungus Delitschia corticola YMF 1.01111, together with four known ones, 6-ethyl-7-hydroxyl-2-methoxyjuglone (3), 6-ethyl-2,7-dimethoxyjuglone (4), 6-(1-hydroxyethyl)-2,7-dimethoxyjuglone (5) and sporidesmin A (6). Structures of these compounds were elucidated mainly by NMR spectroscopic and mass spectroscopic methods. Furthermore, the antimicrobial activities of compounds 1–6 were evaluated against a panel of bacteria and fungi. [Copyright &y& Elsevier]

Abstract: Four new cycloartane triterpenoids, angustific acid A (1), angustific acid B (2), angustifodilactone A (3) and angustifodilactone B (4) were isolated from the branches of Kadsura angustifolia together with six known compounds, micranoic acid B (5), nigranoic acid (6), schisandrin (7), schisantherin D (8), interiotherin B (9), schisantherin B (10). Their structures were established on the basis of extensive spectroscopic data analyses and comparison with spectroscopic data reported. Compound 1, characterized by the presence of a C-16/C-17, C-20/C-21 conjugated diene and a C-1/C-7 ester bridge formed in rings A and B, provided a novel structural skeleton for 3,4-secocycloartane triterpenoid derivatives. In addition, the anti-HIV activities of these compounds were determined in infected C8166 cells, and it was found that angustific acid A (1) exhibited the most potent anti-HIV activity with an EC50 value of 6.1μg/mL and a therapeutic index of more than 32.8. [ABSTRACT FROM AUTHOR]