Abstract

Antimicrobial and antioxidant potency of aqueous and organic solvent extracts of five Indian medicinal plants (Prosopis cineraria, Capparis decidua, Tinospora cordifolia, Carissa carandas and Cordia dichotoma) was investigated. The acetone and ethanol extracts exhibited highest antimicrobial activity (60 to 80% and 40 to 60%, respectively) againstStaphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Aspergillus niger andCandida albicans. Acetone extracts showed inhibitory zones ranging from 11.2 - 19.8 mm whereas no inhibitory effect was observed for aqueous extracts. During NBT assay of acetone and ethanol extracts of all the plants, maximum antioxidant activity was noticed in C. carandas (63.5 and 61.0% for acetone and ethanol extracts, respectively). The inhibitory potential when compared with known antioxidant (L-ascorbic acid), it was observed that IC₅₀values of acetone extracts of C. carandas and T. cordifolia (93 and 97 µg/ml) were very close to L-ascorbic acid (81 µg/ml). The results suggest that C. carandas has promising antimicrobial and antioxidant activities.

Key words: Antimicrobial activity, antioxidant activity, microbial susceptibility index, NBT, medicinal plants.