10.22376/ijpbs.2019.10.1.p1-12 Volume 2 Issue 2 2011 (April - June) The present investigations evaluate the antimicrobial efficacy of six different solvent extracts and isolated constituents of lessThan i greaterThan Samanea saman lessThan /i greaterThan (Jacq.) Merr. against 21 microorganisms. Our result revealed that, the methanol extract showed a highest antibacterial activity with zone of inhibition ranging from 11.0mm to 30.5mm at 1mg/ml concentration. The MIC value of the methanol extract for the tested bacteria ranged between 15µg/ml to 500µg/ml. The most susceptible organism in the present investigation was lessThan i greaterThan Streptococcus faecalis lessThan /i greaterThan (MIC 15µg/ml) followed by lessThan i greaterThan Staphylococcus aureus lessThan /i greaterThan (MIC 62µg/ml), while the most resistant was lessThan i greaterThan Proteus vulgaris lessThan /i greaterThan (MIC 500µg/ml). The highly significant antifungal activity against all the fungi was observed in methanol extract with percentage of inhibition ranging from 20.4% to 81.6% depending upon fungal species at 1mg/ml concentration. The IC lessThan sub greaterThan 50 lessThan /sub greaterThan value of the methanol extract ranged from 0.3mg/ml to 5mg/ml. Among the tested fungi, lessThan i greaterThan Fusarium moniliforme lessThan /i greaterThan (IC lessThan sub greaterThan 50 lessThan /sub greaterThan 0.3mg/ml) was highly sensitive and lessThan i greaterThan Aspergillus tamari lessThan /i greaterThan (IC lessThan sub greaterThan 50 lessThan /sub greaterThan 5mg/ml) was least sensitive. Thippeswamy S.,Praveen P.,Mohana D. C. And Manjunath K. Samanea saman, antimicrobial activity, human pathogenic bacteria, seed-borne fungi, active fraction. 443-451