Leishmanicidal cycloartane-type triterpene glycosides from Astragalus oleifolius.
Two new cycloartane-type glycosides oleifoliosides A (1) and B (2) were isolated from the lower stem parts of Astragalus oleifolius. Their structures were identified as 3-O-[beta-xylopyranosyl-(1 --> 2)-alpha-arabinopyranosyl]-6-O-beta-xylopyranosyl-3beta,6alpha,16beta,24(S),25-pentahydroxycycloartane and 3-O-[beta-xylopyranosyl-(1 --> 2)-alpha-arabinopyranosyl]-6-O-beta-glucopyranosyl-3beta,6alpha,16beta,24(S),25-pentahydroxycycloartane, respectively, by means of spectroscopic methods (IR, 1D and 2D NMR, ESI-MS). Three known cycloartane glycosides cyclocanthoside E (3), astragaloside II (4) and astragaloside IV (5) were also isolated and characterized. All five compounds were evaluated for in vitro trypanocidal, leishmanicidal and antiplasmodial activities as well as their cytotoxic potential on primary mammalian (L6) cells. Except for the compound 5, all compounds showed notable growth inhibitory activity against Leishmania donovani with IC50 values ranging from 13.2 to 21.3 microg/ml. Only weak activity against Trypanosoma brucei rhodesiense was observed with the known compounds astragaloside II (4, IC50 66.6 microg/ml) and cyclocanthoside E (3, IC50 85.2 microg/ml), while all compounds were inactive against Trypanosoma cruzi and Plasmodium falciparum. None of the compounds were toxic to mammalian cells (IC50's > 90 microg/ml). This is the first report of leishmanicidal and trypanocidal activity of cycloartane-type triterpene glycosides.
Ozipek
Meltem
M
Department of Pharmacognosy, Faculty of Pharmacy, Hacettepe University, Ankara, Turkey. meltemozipek@yahoo.com
Dönmez
Ali A
AA
Caliş
Ihsan
I
Brun
Reto
R
Rüedi
Peter
P
Tasdemir
Deniz
D
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D000981:Antiprotozoal Agents / Q000737:chemistry* / Q000494:pharmacology*; D027883:Astragalus Plant / Q000737:chemistry*; D002460:Cell Line; D007893:Leishmania donovani / Q000187:drug effects*; D024301:Plant Bark / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D010963:Plasmodium falciparum / Q000187:drug effects; D014315:Triterpenes / Q000737:chemistry* / Q000494:pharmacology*; D016833:Trypanosoma brucei rhodesiense / Q000187:drug effects; D014349:Trypanosoma cruzi / Q000187:drug effects
D000972:Antineoplastic Agents, Phytogenic; D000981:Antiprotozoal Agents; D014315:Triterpenes