A comprehensive in vitro biological investigation of metal complexes of tolfenamic acid

Abstract

Objective: The inquisitive objective of the study was to observe the antimicrobial, cytotoxicity, and antioxidant activities of some newly synthesized metal complexes of tolfenamic acid.

Methods: While antimicrobial activity was studied by disk diffusion method, cytotoxicity was studied by performing brine shrimp lethality bioassay. Moreover, DPPH radical scavenging potential was observed to determine the antioxidant property of the complexes.

Results: From the disk diffusion antimicrobial screening of tolfenamic acid and its metal complexes, it was found out that considerable antimicrobial activity in terms of zone of inhibition against the tested organisms had been demonstrated by Cu and Zn complex of tolfenamic acid. In addition, the brine shrimp lethality bioassay corroborated that tolfenamic acid and Cu, Co, Zn complexes of the parent NSAID exhibited cytotoxicity with LC₅₀ values 1.23 ± 0.91 lg/ml, 1.12 ± 0.12 lg/ml, 1.17 ± 0.56 lg/ml, 1.35 ± 0.24 lg/ ml respectively, compared to the vincristine sulfate had LC₅₀ value of 0.82 ± 0.09 lg/ml. Furthermore, 1,1- diphenyl-2-picrylhydrazyl assay revealed that in comparison with standard BHT had IC₅₀ of 11.84 ± 0.65, Cu and Co complex of tolfenamic acid exhibited significant antioxidant or radical-scavenging properties with IC₅₀ values 13.61 ± 0.58 lg/ml and 15.38 ± 0.09 lg/ml, respectively.

Conclusion: It can be postulated that metal complexes of tolfenamic acid have auspicious pharmacological effects: antimicrobial, cytotoxicity, and antioxidant potency. Hence, these complexes might have better therapeutic responses in future; notwithstanding, it needs further detailed analysis in other pharmacological perspectives.

Keywords: Tolfenamic acid, Metal complex, Antimicrobial screening, Cytotoxicity, Antioxidant activity