Assessment of the antiprotozoal activity of Galphimia glauca and the isolation of new nor-secofriedelanes and nor-friedelanes.
del Rayo Camacho, Maria;
Phillipson, J David;
Croft, Simon L;
Marley, Dereck;
Kirby, Geoffrey C;
Warhurst, David C;
(2002)
Assessment of the antiprotozoal activity of Galphimia glauca and the isolation of new nor-secofriedelanes and nor-friedelanes.
Journal of natural products, 65 (10).
pp. 1457-1461.
ISSN 0163-3864
DOI: https://doi.org/10.1021/np010419i
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Four new terpenoids, comprising three nor-secofriedelanes (1-3) and one nor-friedelane (4), were isolated from Galphimia glauca, together with the known flavonol quercetin and the sterols stigmasterol and sitosterol 3-O-beta-D-glucoside. The structure elucidation of the new isolates was conducted by 1D and 2D NMR techniques. Compounds 1-4 were given the trivial names galphin A, galphin B, galphin C, and galphimidin, respectively. All isolates were tested for in vitro antiprotozoal and cytotoxic activities. Quercetin was the only substance isolated that showed any antiprotozoal activity, and this was weak; the IC(50) values were 14 microM against Plasmodium falciparum K1, 13.2 microM against Trypanosoma brucei brucei, and 63.8 microM against Leishmania donovani. Quercetin was found to be inactive against KB cells (IC(50) = 295.8 microM).
