Inhibitory effect of aqueous bean extract, Phaseolus vulgaris (fabaceae), on α-amylase of the cabbage aphid, Brevicoryne brassicae

Brevicoryne brassicae is one of the most important pests of wide range of cruciferous host plants. In this study, the inhibitory effects of aqueous extracts of five cultivars of common bean (Phaseolus vulgarisL.), that includes white beans, pinto, red, cowpea and keshavarzi on the activity of the alpha-amylase enzyme ofB. brassicaewas studied. Aphids were reared under laboratory conditions with 25 +/- 1 degrees C, 60 +/- 5% RH and 16 L:8D h photoperiods. According to obtained results, the cytotoxic effect of extracts of the highest concentration of 0.05 mg ml(-1)and within 72 hours had the best performance and mortality. Also, all bean extracts had an inhibitory effect on insect alpha-amylase enzyme and red bean had the highest inhibitory effect (IC50 = 0.223). The effects of the bean inhibitor on alpha-amylase ofB. brassicaeshowed a dose-dependent manner of inhibition, e.g., less inhibition of enzyme activity (around 10%) with a lower dose (0.25 mg protein) and high inhibition of enzyme activity (around 90%) when a high dose of inhibitor was used (1 mg protein). Based on the data presented in this study, it could be said that the bean extract has good inhibitory activity onB. brassicae alpha-amylase.

Automated summary

The study demonstrated that the aqueous extracts of common bean cultivars had inhibitory effects on the alpha-amylase enzyme activity of Brevicoryne brassicae. Among the bean extracts tested, red bean showed the highest inhibitory effect. The inhibition of the enzyme activity showed a dose-dependent pattern, with higher doses of inhibitor leading to greater inhibition of the enzyme.