Study of Total Phenolic and Flavonoid Content, Antioxidant Activity and Antimicrobial Properties of Medicinal Plants

The anti-oxidant activity and total phenolic content of alcoholic extracts from seven medicinal plants (Asparagus racemosus, Ocimum sanctum, Cassia fistula, Piper betel, Citrus aurantifolia, Catharanthus roseus, and Polyalthia longifolia) were evaluated by using a model system consisting of β-carotene, DPPH free radical and Folin-Ciocalteu method. The total Phenolic content of the extracts was determined spectrophotometrically according to the Folin-Ciocalteu procedure and ranged from 366mg/100g to 212 mg/100g on fresh weight basis. The total flavanoid content of extracts determined by Aluminium chloride colorimetric assay and ranged from 39.84mg/100g to 15.94mg/100g of fresh weight. The highest antioxidant activity was demonstrated by Citrus auantifolia (87.05%) followed by Ocimum sanctum (81.80%) and Catharanthus roseus (71.4%). The highest tannin content was found to be in Catharanthus roseus (7.14%) while in case of anthocyanin content the highest value was found to be in Polyalthia longifolia (0.65mg/l). As far as antimicrobial activity is concerned, Ocimum sanctum and Citrus aurantifolia were found to be most potent against Escherichia coli and Staphylococcus aureus whereas Piper betel showed no effect. Except Piper betel all the extracts were able to inhibit the two bacterial strains and the zone of inhibitions ranged from 19.6 mm to 13.5 mm. The minimum inhibitory concentration against E. coli in case of Ocimum sanctum is 10% and against S. aureus it is 20% while in case of Citrus aurantifolia extracts were active even at 10% concentration for E. coli and 15% for S. aureus.