Determination of the Antimycobacterial Activity of the Ethyl Acetate Fractions and Isolated Compounds from the Roots of Allexis batangae and Allexis obanensis

Nganso Ditchou Yves Oscar, Ndo

Abstract

The ethyl acetate extracts (AcOEt) obtained from the fractionation of the methanol (MeOH) extract of Allexis obanensis, Allexis batangae and two compounds, 7-hydroxy-3-(3-hydroxy-4-methoxyphenyl)-5-methoxy-4H-chromen-4-one and 4,4’’’-dimethoxylophirone A, respectively isolated from these plants were tested against two species of Mycobacterium. The minimum inhibitory concentration (MIC) of the Allexis obanensis ethyl acetate fractions and Allexis batangae ranged from 0.78 to 1.3 mg/mL against a non-pathogenic strain of mycobacteria, M. smegmatis. Allexis batangae showed the best activity, with a MIC of 0.78 mg/mL and a minimal bactericidal concentration (MBC) of 1.560 mg/mL against M. smegmatis. A drug susceptible M. tuberculosis strain was found to be sensitive to Allexis obanensis extracts of Allexis batangae. (MIC 0.78 and 0.80 mg/mL respectively) when using the BACTEC rapid radiometric method. The MIC of 4,4 '''- dimethoxylophirone A against M. tuberculosis was 100 μg/mL, whereas 7-hydroxy-3-(3-hydroxy-4-methoxyphenyl)-5-methoxy-4H-chromen-4-one had a MIC of 50 μg/mL.