DNA-damaging steroidal alkaloids from Eclipta alba from the suriname rainforest1.
Bioassay-guided fractionation of the MeOH extract of Eclipta alba using three yeast strains (1138, 1140, and 1353) resulted in the isolation of eight bioactive steroidal alkaloids (1-8), six of which are reported for the first time from nature. The major alkaloid was identified as (20S)(25S)-22,26-imino-cholesta-5,22(N)-dien-3beta-ol (verazine, 3), while the new alkaloids were identified as 20-epi-3-dehydroxy-3-oxo-5,6-dihydro-4,5-dehydroverazine (1), ecliptalbine [(20R)-20-pyridyl-cholesta-5-ene-3beta,23-diol] (4), (20R)-4beta-hydroxyverazine (5), 4beta-hydroxyverazine (6), (20R)-25beta-hydroxyverazine (7), and 25beta-hydroxyverazine (8). Ecliptalbine (4), in which the 22,26-imino ring of verazine was replaced by a 3-hydroxypyridine moiety, had comparable bioactivity to verazine in these assays, while a second alkaloid (8) showed good activity against Candida albicans. All the alkaloids showed weak cytotoxicity against the M-109 cell line.
Abdel-Kader
M S
MS
Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0212, USA.
Bahler
B D
BD
Malone
S
S
Werkhoven
M C
MC
van Troon
F
F
David
Wisse
J H
JH
Bursuker
I
I
Neddermann
K M
KM
Mamber
S W
SW
Kingston
D G
DG
D000470:Alkaloids / Q000302:isolation & purification / Q000494:pharmacology*; D019659:Asteraceae / Q000737:chemistry*; D002176:Candida albicans / Q000187:drug effects; D002460:Cell Line; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D007194:India; D009682:Magnetic Resonance Spectroscopy; D010840:Phytosterols / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000187:drug effects; D013532:Suriname
D000470:Alkaloids; D010840:Phytosterols; D004247:DNA