10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 2 2015 (April - June) Biofilm formation in micro-organisms is one of the significant factors for pathogenicity of lessThan i greaterThan S. pyogenes. lessThan /i greaterThan Medicinal plants have been used for treatment against many infections. Our study gives an insight into the anti-biofilm property of lessThan i greaterThan Vitex negundo lessThan /i greaterThan (VN) and lessThan i greaterThan Leucas aspera lessThan /i greaterThan (LA) solvent extracts against lessThan i greaterThan S. pyogenes lessThan /i greaterThan isolated from pharyngitis patients. A total of five strains were isolated and identified as lessThan i greaterThan S. pyogenes lessThan /i greaterThan from the throat swab samples collected from pharyngitis patients. All the isolated strains were treated with different solvent extracts (Methanol, Ethyl Acetate, Petroleum Ether and Hexane) of lessThan i greaterThan V. negundo lessThan /i greaterThan and lessThan i greaterThan L. aspera lessThan /i greaterThan at various concentrations (0.0625 – 8 mg/ml MIC) using MTP assay. Phytochemical analysis of plant extracts revealed the presence of various phyto constituents. The anti-bacterial potential of these solvent extracts were analyzed using agar disc diffusion assay and growth curve analysis. Moreover, the anti-biofilm property of the solvent extracts has been tested with BIC assay and Light microscopic analysis. Among the four solvent extracts tested, the methanol and ethyl acetate extracts of lessThan i greaterThan V. negundo lessThan /i greaterThan and lessThan i greaterThan L. aspera lessThan /i greaterThan showed significant biofilm inhibition percentage against the isolates. In addition, the light microscopic analysis validated the potential concentration of methanol and ethyl acetate extracts against the biofilm of five isolates. Our results showed that the inhibitory effect of the methanol and ethyl acetate extracts on lessThan i greaterThan S. pyogenes lessThan /i greaterThan biofilm formation was concentration dependent. lessThan i greaterThan V. negundo lessThan /i greaterThan and lessThan i greaterThan L. aspera lessThan /i greaterThan at proper dosage can be effective against lessThan i greaterThan S. pyogenes lessThan /i greaterThan and lower concentrations may prevent the bacteria forming barriers against the antibiotics. Our report suggests that the methanol and ethyl acetate extract of VN and LA could be developed as an alternative for the inhibition of lessThan i greaterThan S. pyogenes lessThan /i greaterThan biofilms. J. DINESHBABU, P. SRINIVASAN, K. MANIMEKALAI, G. GUNA AND D. TEEPICA PRIYA DARSINI Biofilms, Streptococcus pyogenes, V. negundo, L. aspera, Minimal inhibitory concentration. 464-479