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

ABSTRACT

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 vulgaris L.), that includes white beans, pinto, red, cowpea and keshavarzi on the activity of the α-amylase enzyme of B. brassicae was studied. Aphids were reared under laboratory conditions with 25 ± 1°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 α-amylase enzyme and red bean had the highest inhibitory effect (IC₅₀ = 0.223). The effects of the bean inhibitor on α-amylase of B. brassicae showed 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 on B. brassicae α-amylase.

KEYWORDS:

• α-amylase
• Brevicoryne brassicae
• Phaseolus vulgaris
• proteinaceous inhibitor

Acknowledgements

The work received financial support from the Postgraduate Education Bureau of Shahed University, Iran, which is greatly appreciated.

Disclosure statement

No potential conflict of interest was reported by the authors.