Comparative antioxidant and antimycobacterial activities of Opuntia ficus-indica fruit extracts from summer and rainy seasons

摘要

The antioxidant and antimycobacterial activities of Opuntia ficus-indica (OFI) fruit extracts were evaluated according to seasonal cultivation. The antioxidant activities of OFI extracts were assessed by different in vitro methods and the total phenolic and flavonoid contents were also examined. The antimycobacterial activity was measured against Mycobacterium tuberculosis strain H37Rv (ATCC 27294) by the microplate alamar blue assay method. In the antioxidant assay, methanol extracts of OFI in summer showed the highest antioxidant activity of all tested methods, and the lowest IC50 was observed in the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. Pearson's correlation coefficient was evaluated and the results from the extracts of summer and rainy season OFI were significantly correlated with the total phenolic and flavonoid contents. The methanol extracts of OFI in summer showed a high level of antimycobacterial activity against M. tuberculosis H37Rv, with a minimum inhibitory concentration of 50 mu g ml(-1). The results of this study suggest that OFI could be an important source of antioxidants as well as antimycobacterials against M. tuberculosis.