INVESTIGATING THE EFFECT OF TODDA COMPOUND ON EXTENSIVELY DRUG RESISTANT MYCOBACTERIUM TUBERCULOSIS

Abstract

Tuberculosis (TB), a deadly disease caused by Mycobacterium tuberculosis (M. tb), posing a significant global health problem. The emergence of drug resistant strains, notably multidrug-resistant (MDR) and extensively drug-resistant (XDR) M. tb strains has drastically reduced treatment effectiveness and underscoring the urgent need for novel therapeutic strategies. DNA gyrase is an essential enzyme help in bacterial DNA replication is an attractive target for development of novel antibacterial drugs. This study has employed integrated computational and experimental approaches to evaluate the interaction and antibacterial activity of a novel compound TODDA (1R,4E,9E,11S)-4,12,12-trimethyl-8-oxobicyclo [9.1.0] dodeca-4,9-dien-2-yl acetate), targeting DNA gyrase protein.

Molecular docking studies were conducted to assess binding affinity between TODDA compound with DNA gyrase protein of M.tb. Discovery Studio visualizer and HDock serve results showed a strong binding affinity of TODDA compound with DNA gyrase protein, with key interactions at amino acid residues such as TYR276A (2.513), SER118A (2.558), GLY120A (2.529), and GLN277A (3.277), yielding a binding affinity of –142.71.

To validate these finding, in vitro experiments were conducted at the Provincial Tuberculosis Reference Laboratory (PTRL), Peshawar. Pulmonary and extrapulmonary samples from patient presenting TB symptom were processed through GeneXpert assay, microscopy and culturing to confirm M. tb positivity. XDR M. tb strains were confirmed using the 10-Color GeneXpert and drug susceptibility testing (DST). The MIC results indicated that the XDR-M. tb strain exhibited resistance to the TOODA compound across all tested concentrations (0.5 to 32 µg/ml). This suggests that TOODA may not effectively inhibit M. tb cellular mechanisms critical for bacterial survival or replication.

It is concluded that, while in silico analysis demonstrated that TODDA successfully bind to the DNA gyrase of M. tb at its binding pocket domain, while in vitro testing on drug resistant strains, particularly XDR-M. tb, showed that the compound fail to inhibit growth of M.tb. These findings emphasize the need to combine computational and experimental approaches in drug discovery and suggested that structural modifications or combination therapies may enhance TODDA’s potential against drug resistant M.tb.