Drug-Lead Anti-tuberculosis Phytochemicals: A Systematic Review.

Today, the occurrence and recurrence of multidrug-resistant tuberculosis (MDR-TB) strains and TB-comorbidity incidence are the main reasons for long-term morbidity and mortality from tuberculosis (TB) caused by the nasty acid-fast pathogen, Mycobacterium tuberculosis, globally. Therefore, discovering and developing well-tolerated and non-toxic anti-TB regimens are directly needed to defend the gruesome MDR-TB strains and support WHO's 'END-TB' campaign. Alternatively, phytochemicals from various common and medicinal plants have always been vital therapeutic agents since the primitive era. Thus, to promote phytochemical-based anti-TB drug development, scientific documentation of biological activities, structural-cum-drug chemistry analyses are essential. In the present review, we have used some specific keywords such as 'antituberculosis phytochemicals', 'antituberculosis phytochemicals from plant source', 'natural products against tuberculosis' in Google, PubMed, ScienceDirect sites to get more appropriate research reports/ publications. Further, based on lower minimum inhibitory concentration (MIC) within 50 µg/mL, a total of two-hundred-twenty-one bioactive anti-TB phytochemicals were selected for critical drug-chemistry and structural activity relationship (SAR) analyses to accelerate the anti-TB drug development with most drug lead anti-TB candidates. Among all, abietane, ethyl-p-methoxycinnamate, ergosterol peroxide, mono-O-methyl curcumin isoxazole, 7-methyljuglone, 12-demethylmulticaulin, 12-methyl-5-dehy droacetylhorminone, tryptanthrin, etc. are some of the potential anti-TB phytochemicals display at the minimum concentration ≤ 1 µg/mL. Remarkably, existing and clinical drug pipelines for TB contain more than one phytochemical scaffold/ pharmacophores illustrated from the SAR analysis. Thus, updated experimental documentation and critical drug-chemistry analysis on isolated phytochemicals are more beneficial for drug developers, R & D centres and pharmaceutical companies to accelerate the anti-TB drug development.