Antimicrobial and Antioxidant Activities of Careya arborea Roxb. Stem Bark

The present study was carried out to evaluate the antimicrobial and antioxidant activities of methanol ex-tract of Careya arborea (MECA) stem barks (Myrtaceae) in various in-vitro systems. Antimicrobial activi-ties of MECA were carried out using disc diffusion methods with Gram positive and Gram negative bacte-ria and some fungal species. MECA showed broad-spectrum antimicrobial activity against all tested mi-croorganisms. Antioxidant and free radical scavenging activities of MECA was assessed by using 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH), superoxide anion radical, nitric oxide radical and hydroxyl radi-cal scavenging assays. The antioxidant activity of MECA increased in a concentration dependent manner. In DPPH radical scavenging assay the IC50 value of the extract was found to be 132.25 g/mL. MECA was found to inhibit the nitric oxide radicals generated from sodium nitroprusside. The IC50 value was found to be 72.54 g/mL, whereas the IC50 value of curcumin was 20.4 g/mL. Moreover, the MECA was found to scavenge the superoxide generated by phenazine methosulphate (PMS) / nicotinamide adenine dinucleotide (NADH)-nitroblue tetrazolium (NBT) system. MECA was also found to inhibit the hydroxyl radical generated by Fenton’s reaction, where the IC50 value of MECA was found to be more than 1000 g/mL and for catechin the IC50 value was found to be 5 g/mL. The results obtained in the present study indicate that the MECA can be a potential source of natural antimicrobial and antioxidant agents.