ON donor tethered copper (II) and vanadium (V) complexes as efficacious anti-TB and anti-fungal agents with spectroscopic approached HSA interactions

Antimicrobial drug resistance poses a significant threat worldwide, hence triggering an urgent situation for developing feasible drugs. 3D-transition metal coordination complexes being multifaceted, offer tremendous potency as drug candidates. However, there are fewer reports on non-toxic and safe transition metal complexes; therefore, we hereby attempted to develop novel copper and vanadium-based therapeutic agents. We have synthesised six metal complexes viz. , [V V O 2 (Quibal-INH)] (1) , [Cu II (Quibal-INH) 2 ] (2) , [V V O(Quibal-INH) (cat)] (3) , [Cu II (Quibal-INH) (cat)] (4) , [V V O(Quibal-INH) (bha)] (5) and [Cu II (Quibal-INH) (bha)] (6) . Quibal-INH (L) is an ON bidentate donor ligand synthesized from Schiff base reaction between 4-(2-(7-chloroquinolin-3-yl)vinyl)benzaldehyde (Quibal) and Isoniazid (INH). The synthesized compounds were characterized using analytical techniques involving ATR-IR, UV-Vis, EPR, 1 H NMR, 13 C NMR, and 51 V NMR. Ligand (L) and compound 3 exhibited moderate growth inhibitory activity towards Candida albicans and Cryptococcus neoformans fungal species. Compound 6 has been identified as active against the above fungal species with no toxicity and hemolysis activity on the healthy cells. Compound 5 exhibited significant activity against the Mycobacterium tuberculosis H 37 R v strain. Further, compounds 4 , 5 and 6 exhibited excellent free radical scavenging activity. All the developed compounds were found to exhibit stability over a wide range of pH conditions. The complexes were additionally studied for their interaction with human serum albumin (HSA) with the UV-vis spectroscopic technique.