Bioefficacy of ?-amylase inhibitors from the seeds of macrotyloma uniflorum and vigna unguiculata against sitophilus oryzae

Laxmi Gupta, Sudhakar Deshpande, Sheeja George3 and Sushma Sabharwal

In the present study the bioefficacy of the α­amylase inhibitor from the seeds of Macrotyloma uniflorum and Vigna unguiculata against Sitophilus oryzae larvae has been studied. M. uniflorum α­amylase inhibitor (MUAI) was purified using ion exchange chromatography on a CMC column while V. unguiculata α­amylase inhibitor (VUAI) was purified on a Poros HS- 50 column. Both amylase inhibitors were tested against the fourth instar larvae for their insecticidal activity at different concentrations. Both MUAI and VUAI inhibited the S. oryzae α­amylase in a non-competitive manner, with a Ki value of 2.2 and 1.17 µM respectively. Significant mortality was observed only at higher concentration of the inhibitors.