10.22376/ijpbs.2019.10.1.p1-12 Volume 7 Issue 4 2016 (October - December) Throughout the history of drug development, natural products have provided a fundamental source of drugs for fighting infections. In this study, the phytochemical constituents present in the leaf extract of lessThan i greaterThan Phyllanthus niruri lessThan /i greaterThan (Keela Nelli) were screened and their antibacterial properties in vitro were determined using the agar diffusion plate method on selected human pathogens, namely lessThan i greaterThan Vibrio cholera lessThan /i greaterThan 01 lessThan i greaterThan ogawa, V. cholera lessThan /i greaterThan 0139, lessThan i greaterThan V. parahaemolyticus lessThan /i greaterThan VP81; O3:K6, lessThan i greaterThan Vibrio fluvialis, Salmonella enteritidis lessThan /i greaterThan -A11, lessThan i greaterThan Shigella dysenteriae lessThan /i greaterThan type 5, lessThan i greaterThan Enterotoxigenic E. coli, Bacillus cereus and Pseudomonas sp. lessThan /i greaterThan The solvent extracts revealed a good concentration dependent antibacterial activity against the test organisms similar to that of the standard antibiotic discs, such as Penicillin, Streptomycin, Kanamycin, Ampicillin, Amoxycillin and Rifampicin. The antioxidant activity was evaluated by free radical scavenging power against 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical. The IC lessThan sub greaterThan 50 lessThan /sub greaterThan values of the methanolic extract of lessThan i greaterThan P. niruri lessThan /i greaterThan was 49.2 μg/ml and that of control i.e. ascorbic acid was 39.1 μg/ml. Results of phytochemical components of the leaf extracts of lessThan i greaterThan Phyllanthus niruri lessThan /i greaterThan were rich in the alkaloids, terpenoids, tannins, flavonoids and saponins, which might be responsible for its various bioactivities. Qualitative estimation was also done by FT-IR and GCMS analyses for the determination of major functional groups. The outcome of this study could therefore justify the ethno medicinal uses of lessThan i greaterThan P. niruri lessThan /i greaterThan and the antibacterial and antioxidant activities of lessThan i greaterThan P. niruri lessThan /i greaterThan against human pathogens. RAJAM CHIDAMBARAMC AND ASUMA JANEENA Phyllanthus, Pathogenic bacteria, clinical isolates, antibacterial, plant extract, phytochemical. 354-363