| dc.description.abstract | The stems of Aloe secundiflora was exhaustively extracted by percolation in CH2Ch-MeOH
(1: 1) at room temperature. The extract showed significant antiplasmodial activity against the
chloroquine-resistant (W2) strain of Plasmodium falciparum with an ICso value of
2.09±0.43 ug/rnl. The extract was subjected to chromatographic separations (Column
chromatography and preparative thin layer chromatography) and crystallization which led to
isolation of seven compounds.
By the use of spectroscopic methods including IR, UV, MS and NMR CH, l3C, DEPT,
COSY, HMQC and HMBC) and direct TLC comparison with authentic samples in some
cases, these compounds were identified as the monomeric anthraquinones chrysophanol (1),
aloesaponarin II (2), aloesaponarin I (3), laccaic acid D-methyl ester (4), emodin (5); thepre-anthraquinone aloesaponol I (6); and the naphthoquinone derivative 8-hydroxy-2,7-
dimethoxy-3-methylnaphthalene-l,4-dione (7). Of these, the naphthaquinone derivative (7)
is a new compound. More over this is the first report on the occurrence of a naphthaquinone
in the genus Aloe.
The isolated compounds from Aloe secundiflora were tested for antiplasmodial activity and
aloesaponarin I (3), aloesaponarin II (2), aloesaponol I (6) and the naphthoquinone
derivative (7) showed significant activities. Amongst these, aloesaponarin I (3) was the most
active with an ICso value of O.92±O.071lg/ml against the chloroquine-resistant (W2) strain.
This investigation has shown the potential of the aloesaponarin I (3) as a lead structure for
the development of antimalarial drugs.
Antibacterial and antifungal tests were also carried out for some of the isolated compounds
against three bacterial strains viz. Staphylococcus aureus, Escherichia coli, Pseudomonas
eruginosa and four fungal strains viz. Candida albicans, Cryptococcus neoformans,
Trichophyton mentagrophytes and Microsporum gypsum. Amongst those tested,
aloesaponarin II (2) was the most active showing activity against Staphylococcus aureus and
Cryptococcus neoformans with an MIe value of 18.8 ug/disc for both organisms. No
significant activity was observed for any of the isolated compounds against Gram-negative
bacteria, Escherichia coli and Pseudomonas eruginosa.......... | en |
