FREE RADICAL SCAVENGING AND ANTIMICROBIAL POTENTIAL OF MIXTURE OF SELECTIVE MEDICINAL PLANTS

Abstract

Objectives: Even though pharmacological industries have produced a number of new antibiotics in the last three decades, resistance to these drugs by microorganisms has increased. The present study was aimed to evaluate antioxidant, antimicrobial activity and phytochemical screening of the mixture of plants extracts.

Method: The antimicrobial activity of the mixture was tested by agar well diffusion assay and antioxidant or free radical scavenging activity of the mixture was assessed against 1, 1- diphenyl-2-picrylhydazyl (DPPH) and ferric reducing agent. Total phenolic content and phytochemical screening was also determined to assess their corresponding effect on the antioxidant activity of the plants mixture.

Result: Among all the four extracts (viz. methanol, ethanol, ethyl acetate and benzene) of mixture, methanol and ethanol extract exhibited maximum activity against L. acidophilus and S. aureus, respectively. Benzene and ethyl acetate extracts of mixture was found to be significantly effective against all fungal strains tested with the inhibition zone ranging from 26.0 ± 1.41 to 11.0 ± 0.43 mm. Ethyl acetate and benzene extract of mixture  were highly effective against A. terrus (20.5 ± 0.71 mm) and A. niger (26 ± 1.41 mm) respectively. The superoxide radical scavenging activity (as evaluated by DPPH assay) of ethanol extract of mixture at concentration of 100 μg/ml was found to be 74.54 % followed by methanol i.e. 72.10 % where as maximum metal chelating activity was observed in ethyl acetate (76.82 %) followed by methanol extract (72.91 %) and ethanol extract (62.11 %) respectively. The IC₅₀ value of the ethanol extract of the mixture was more than that of L-ascorbic acid showing the maximum inhibitory effect followed by methanol extract as evaluated by DPPH assay while the same was higher in ethyl acetate extract as evaluated by ferric reducing agents.

Conclusion: These finding provides evidence that plant mixture has strong antimicrobial and antioxidant effect and hence may be used as a source of natural antibiotics for the treatment of the diseases caused by the above pathogenic micro-organisms.

Keywords: Plants mixture extracts, antimicrobial activity, antioxidant activity, minimum inhibitory concentration, phytochemical screening