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Antiplasmodial hirsutinolides from Vernonia staehelinoides and their utilization towards a simplified pharmacophore
Bioassay-guided fractionation of the dichloromethane extract of the leaves of Vernonia staehelinoides led to the isolation of two structurally-related hirsutinolides, displaying in vitro antiplasmodial activity. The compounds lacked selectivity (cytotoxicity vs. bioactivity) but the results led to t...
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Published in: | Phytochemistry (Oxford) 2007-04, Vol.68 (8), p.1200-1205 |
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Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Bioassay-guided fractionation of the dichloromethane extract of the leaves of
Vernonia staehelinoides led to the isolation of two structurally-related hirsutinolides, displaying
in vitro antiplasmodial activity. The compounds lacked selectivity (cytotoxicity
vs. bioactivity) but the results led to the identification of mucochloric and mucobromic acids as privileged 2(5
H)-furanone substructures.
The dichloromethane extract of the leaves of
Vernonia staehelinoides Harv. (
Asteraceae) showed
in vitro activity (IC
50
∼
3
μg/ml) against the chloroquine-sensitive (D10) and the chloroquine-resistant (K1) strains of
Plasmodium falciparum. Through conventional chromatographic techniques and bioassay-guided fractionation two structurally-related hirsutinolides displaying
in vitro antiplasmodial activity (IC
50
∼
0.2
μg/ml against D10) were isolated and identified by spectroscopic data. Compounds
1, 8α-(2-methylacryloyloxy)-3-oxo-1-desoxy-1,2-dehydrohirsutinolide-13-
O-acetate, and
2, 8α-(5′-acetoxysenecioyloxy)-3-oxo-1-desoxy-1,2-dehydrohirsutinolide-13-
O-acetate were found to be cytotoxic to mammalian Chinese Hamster Ovarian (CHO) cells at similar concentrations but proved to be attractive scaffolds for structure–activity relationship studies. Two main privileged substructures, a 2(5
H)-furanone unit and a dihydrofuran-4-one unit, were identified as potential pharmacophores which may be responsible for the observed biological activity. Mucochloric and mucobromic acids were selected as appropriate 2(5
H)-furanone substructures and these were shown to have comparable activity against the D10 and superior activity against the K1 strains relative to the hirsutinolide natural product. Mucochloric and mucobromic acids also show selective cytotoxicity to the malaria parasites compared to mammalian (CHO) cells
in vitro. The antiplasmodial data obtained in respect of these two acids suggests that the 2(5
H)-furanone substructure is a key pharmacophore in the observed antiplasmodial activity. |
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ISSN: | 0031-9422 1873-3700 |
DOI: | 10.1016/j.phytochem.2007.02.019 |