Anti-tubercular activities of Curcuma longa extract and fractions against Mycobacterium tuberculosis (H37Rv)

Abstract

Tuberculosis is one of the major human diseases primarily caused by Mycobacterium tuberculosis with other members of Mycobacterium complex. The disease is complicated due to the emergence of multi-drug resistant and extensively drug resistant strains of M. tuberculosis. The anti-tubercular activities of crude extract and fractions of Curcuma longa (turmeric) was evaluated against a clinical isolate of M. tuberculosis (H37Rv) using microbroth dilution method. The activity of the extract and fractions were comparable to Rifampicin (0.04 µg/ml). Qualitative phytochemical components were determined using standard methods. The Minimum Inhibitory Concentration (MIC) was determined by tetrazolium dye assay using a microbroth dilution technique. Cold maceration of powdered turmeric (rhizome) with 70% ethanol yielded a crude extract (E), successive and exhaustive partitioning of E with petroleum ether (Ep), ethyl acetate (Eea) yielded soluble fractions as well as residual fraction (Eaq). The crude extract and fractions inhibited the growth of M. tuberculosis at 5000 µg/mL. The MIC of crude ethanol (E), petroleum ether (Ep) and aqueous (Eaq) was at 39.06±0.58 µg/mL while ethyl acetate (Eea) was at 19.53±0.50 µg/mL. The extract and all the fractions were bactericidal on M. tuberculosis. The Minimum Bactericidal Concentration (MBC) of crude ethanol extract, petroleum ether and aqueous fractions was at 78.13±0.51 µg/mL while the MBC of ethyl acetate fraction was at 3 39.06±0.57 µg/mL. The crude extract and fractions contained alkaloids, flavonoids, tannins and saponins. The results obtained suggest that turmeric will be a good bio resource for anti-TB drug development.