In-vitro anti-Mycobacterium tuberculosis effect of essential oil of Ocimum sanctum L. (Tulsi/Basil) leaves

Background/Objectives Mycobacterium tuberculosis, the causative agent of tuberculosis has developed resistance to most of the available antimicrobials. Consequently, it is difficult to cure all the patients with tuberculosis and in future, the incidence of tuberculosis by drug resistant M. tuberculosis is likely to increase, worldwide. Therefore detection and development of new antimicrobials against M. tuberculosis is needed urgently. Methods Essential oil from the leaves of Ocimum sanctum L (Tulsi/Basil) was obtained by hydro distillation. The anti-mycobacterial effect of essential oil was evaluated against H37Rv and nine clinical isolates of M. tuberculosis in the BD BACTEC MGIT instrument using different volumes of essential oil. Results The essential oil inhibited the growth of H37Rv and all the nine clinical isolates of M. tuberculosis. The minimal inhibitory concentration of H37Rv was 3 μl (2.931 μg) and those of the clinical isolates of M. tuberculosis ranged from 1.5 μl (1.4655 μg) to 6 μl (5.862 μg). Conclusion The Essential oil from the leaves of O. sanctum L.(Tulsi/Basil) has anti-M. tuberculosis effect in the in-vitro BD BACTEC MGIT method.