494QUANTITATIVE DETERMINATION OF TANNIN CONTENT AND EVALUATION OF ANTIBACTERIAL ACTIVITY OF AMARANTHUS TRICOLOR (L)The present study is designed to determine the tannin content and evaluate antibacterial activity of crude extracts of Amaranths tricolor (L) leaf against few pathogens. The leaf powder was extracted by successive solvent extraction using petroleum ether, chloroform, ethyl acetate and methanol. The extracts were analyzed for presence of phytoconstituents, tannin content and antibacterial screening. The preliminary phytochemical analysis revealed the presence of steroids, alkaloids, glycosides, flavonoids and tannins. The extracts contained appreciable levels of tannin content (2.6 to 7.2 mg of GAE/gm extract). Antibacterial activity of Amaranthus tricolor (L) extracts were studied using agar well diffusion method which showed better activity against E.coli (24.66±0.57) by methanolic extract. In this study different extracts exhibited varying susceptibility pattern to the growth of the tested microorganisms. It was observed that methanolic extract exhibited prominent activity and ethyl acetate extract moderate activity followed by chloroform and petroleum ether extracts. The results were compared with commercial antibiotic ciprofloxacinsowjypulipati@gmail.comResearch572014Amaranthus tricolor (L), Tannin content, Antibacterial activitySowjanya Pulipati,P. Srinivasa Babu,M. Lakshmi NarasuVignan Pharmacy College, Vadlamudi- 522 213, Guntur (Dt), Andhra Pradesh, India,Vignan Pharmacy College, Vadlamudi- 522 213, Guntur (Dt), Andhra Pradesh, India,Department of Biotechnology, Jawaharlal Nehru Technology University-Hyderabad, Telangana (Dt), India.