Anti-mycobacterial and phytochemical analysis of medicinal plants used in Magu district, Tanzania.

Introduction: Tuberculosis remains a global health threat, further complicated by the rise of multi-drug-resistant of the available antimycobacterial drugs. Some secondary metabolites of plants have demonstrated potential antimycobacterial activity against different mycobacterium stains. This study aimed at investigating antimycobacterial activities and secondary metabolites of medicinal plants claimed to manage tuberculosis in Magu District, Mwanza – Tanzania. Materials and methods: Medicinal plant were selected from the community. Both 80% ethanol and water extracts (prepared according to traditional methods) were tested against two non-pathogenic mycobacterial strains: Mycobacterium indicus pranii and Mycobacterium madagascariense, using the broth microdilution method. The Phytochemical screening of the most active extracts was conducted using standard chemical tests. Results: Among the 17 plants, 11 (64.7%) 80% ethanolic extracts showed antimycobacterial activity, with minimum inhibitory concentrations (MICs) ranging from 19 μg/mL to 1250 μg/mL. Notably, the 80% ethanolic extract of Zanha africana (Radlk.) Exell (stem bark and roots) showed the strongest activity, with MICs of 19 μg/mL and 39 μg/mL against M. indicus pranii and M. madagascariense, respectively. The Harrisonia abyssinica Oliv. extracts also displayed good activity with MICs of 39 μg/mL. Lanna fulva (Engl.) Engl, and Dichrostachys cinerea (L) Wight&Arn. showed average activity at 78 μg/mL. In contrast, decoction extracts prepared using traditional methods showed little to no activity, except for Z. africana stem bark, which had weak activity (417±147 μg/mL). Conclusion: The presence of secondary metabolites in the selected medicinal plants support the reliability of traditional knowledge. This suggests isolation of active antimycobacterial compounds of Z. africana, H. abyssinica, L. fulva, and D. cinerea warrant.