Komal Kalani, Vineeta Chaturvedi, Sudeep Tondon and Santosh Kumar Srivastava*
Tuberculosis (TB) is one of the leading causes of mortality worldwide. Resistance against the frontline anti-tubercular drugs has worsened the already alarming situation, which requires intensive drug discovery to develop new, more effective, affordable and accessible anti-tubercular agents possessing novel modes of action. Dihydroartemisinin, a metabolite of artemisinin was semi-synthesized into 8 acyl (DHA-2 – DHA-9) derivatives and were evaluated for anti-tubercular potential against H37Rv virulent strain of Mycobacterium tuberculosis by agar-based proportion assay. Results show that all the derivatives were active but out of eight, 12-O-m-anisoyl DHA-5 and 12-O-p-anisoyl DHA-6 (MIC 25.0 µg/mL) showed promising activities. Further, the synergistic activity was studied between DHA-5 and front-line anti-TB drugs, Isoniazid (INH) and Rifampicin (RFM), which showed reduction in MIC to with the derivative (by 1/8th, i.e. 3.12 µg/mL and that of RFM by ¼th, i.e. 0.05 µg/mL). The sum -fractional inhibitory concentration (Σ FIC) was 0.375. These results suggest a synergistic effect of the DHA-5 with RFM. Therefore, these compounds have potential for anti-tubercular drug development from an in-expensive and non-toxic natural product. To the best of our knowledge this is the first ever report on the anti-tubercular potential of DHA and its derivatives.
Dihydroartemisinin, semi-synthetic derivatives, anti-tubercular activity, synergistic effect.
Medicinal Chemistry Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, Microbiology Division, Central Drug Research Institute, Lucknow, Process Chemistry & Chemical Engineering Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, Medicinal Chemistry Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow