亚洲传统医药

Abstract: The crude extracts from the leaves (VGL), stem barks (VGB) and roots (VGR) of Vismia guineensis were purified by column chromatography to afford 3-geranyloxy-6-methyl-1, 8-dihydroxyanthraquinone (1), vismiaquinone (2), vismiaquinone B (3), and betulinic acid (4) from the roots; compound 3, caloxanthone J (5), O¹-demethyl-3′, 4′-deoxypsorospermin-3′, 4′-diol (6), 6-deoxyisojacareubin (7), and 1, 7-dihydroxyxanthone (8) from the stem barks and friedelin (9), 1, 8-dihydroxy-6-methoxy-3-methylanthraquinone (10), and kaempferol (11) from the leaves. The antimicrobial activity of these compounds and the crude extracts were tested against Gram-positive and Gram-negative bacteria, mycobacteria, and fungi. The disc diffusion assay was used to determine the sensitivity of the microorganisms against the samples tested. The micro-dilution method was used for the determination of both the Minimal Inhibitory Concentration (MIC) and Minimal Microbicidal Concentration (MMC). The radiometric respiratory technique using the BACTEC 460 system was used for susceptibility testing against M. tuberculosis. Results showed that the crude extracts from all parts of V. guineensis were able to prevent the growth of all the tested Gram-positive and -negative bacteria, fungi as well as Mycobacterium smegmatis. VGR was particularly active against M. smegmatis. In addition, some of the tested compounds were very active. The lowest MIC value (0.61 μg/ml) was recorded for compound 6 on M. smegmatis. The antimicrobial activity of this plant as well as that of vismiaquinone B (3) and caloxanthone J (5) is being reported for the first time. The overall results provided evidence that the studied plant extracts and some of the compounds could be potential sources of new antimicrobial drugs.

Key words: Vismia guineensis, anthraquinons, xanthones, flavonoids, Mycobacterium tuberculosis, antimicrobial activity