The present study was carried out to evaluate the antimicrobial properties of Azadirachta indica leaves against certain bacterial strains causing dental carries using cup plate method and disc diffusion method. The leaf extracts of Azadirachta indica were prepared using different solvents like methanol, chloroform and petroleum ether and are screened for its anti-microbial activity. The best suitable extract was further optimized from the results of anti-microbial studies. The phytochemical screening of the leaf extracts was performed. The strains of four human pathogenic bacteria causing dental caries are Micrococcus albus, Staphylococcus aureus, Proteus vulgaris and Pseudomonas aerogenosa. The anti-microbial activities of petroleum ether extract, chloroform extract, methanol extract of neem leaves are checked by disc diffusion method. All the leaf extracts exhibited significant inhibition.Comparative study of the results obtained from both the methods indicates that the Chloroform Extract shows better antimicrobial activity against desired strains. All the extracts showed concentration dependent activity comparable with the reference Drug Streptomycin.
