DNA-DAMAGING STEROIDAL ALKALOIDS FROM ECLIPTA-ALBA FROM THE SURINAM RAIN-FOREST

Bioassay-guided fractionation of the MeOH extract of Eclipta alba usin g three yeast strains (1138, 1140, and 1353) resulted in the isolation of eight bioactive steroidal alkaloids (1-8), six of which are report ed for the first time from nature. The major alkaloid was identified a s (20S)(25S)-22,26-imino-cholesta-5,22(N)-dien-3 beta-ol (verazine, 3) , while the new alkaloids were identified as -3-dehydroxy-3-oxo-5,6-di hydro-4,5-dehydroverazine (1), ecliptalbine [(20R)-20-pyridyl-cholesta -5-ene-3 beta,23-diol] (4), (20R)-4 beta-hydroxyverazine (5), 4 beta-h ydroxyverazine (6), (20R)-25 beta-hydroxyverazine (7), and 25 beta-hyd roxyverazine (8). Ecliptalbine (4), in which the 22,26-imino ring of v erazine was replaced by a 3-hydroxypyridine moiety, had comparable bio activity to verazine in these assays, while a second alkaloid (8) show ed good activity against Candida albicans. All the alkaloids showed we ak cytotoxicity against the M-109 cell line.