In this study, the anti diabetic potential of column fractions of leaf ethanol extract of P.grandis was assessed by α-amylase inhibition assay. Acarbose (250μg/mL) used as a standard for reference showed 67% inhibition efficiency . The results of the study disclose the amylase inhibition potential of all fractions of P.grandis which can be correlated to anti diabetic potential. The isolated molecule pinitol (250 μg/mL ), the fraction PGL aq.1 obtained by liquid-liquid extraction of P.grandis leaves and the column fractionate PGL1% (both at a concentration of 20 μg/mL ) exhibited the highest inhibition of α-amylase. All other fractionates (at concentration of 20 μg/mL) also exhibited moderate inhibition of α-amylase. The promising use of P.grandis extracts in formulating anti diabetic agents is obvious from the results.