Assessment of total polyphenols, antioxidants and antimicrobial properties of aonla varieties

Phenolic content, antioxidant activities and antimicrobial activities of methanolic, ethanolic and ethyl acetate extracts of five different varieties of aonla (Emblica officinalis) fruits as well their powders were evaluated. Total polyphenolic content in fresh aonla fruit extracts varied from 70.6 to 159.4 mg GAE/g and their EC 50 (effective concentration) values for antioxidant activity ranged from 46.72 to 359.7 µg/ml. Significant varietal difference were observed in antioxidant activity of the extracts of fresh aonla fruit and powder. Among the variety analyzed, Desi variety exhibited significantly higher TPC (total polyphenol content) and antioxidant activity in fresh as well as dried form in all the extracts. Methanolic extracts of various varieties had maximum TPC and antioxidant activity. Variety NA-7 showed high TPC and antioxidant activity. Almost, similar trend was observed among the extracts of aonla powders for TPC and AOA (antioxidant activity). A high positive correlation coefficient existed between TPC and AOA of different aonla extracts. All the extracts analyzed, exhibited a strong antimicrobial potential against E. coli, Salmonella typhi, Staphylococcus aureus and Candida albicans. This study suggests aonla as potential natural source of antioxidants and antimicrobial agents.