Tarbiat Modares University Journal of Agricultural Science and Technology 1680-7073 13 7 2011 12 01 α-Amylase Activity of Stored Products Insects and Its Inhibition by Medicinal Plant Extracts 1173 1182 15067 EN M. Mehrabadi Department of Plant Protection, College of Agricultural and Natural Resources, University of Tehran, Karaj, Islamic Republic of Iran. A. R. Bandani Department of Plant Protection, College of Agricultural and Natural Resources, University of Tehran, Karaj, Islamic Republic of Iran. F. Saadati Department of Plant Protection, College of Agricultural and Natural Resources, University of Tehran, Karaj, Islamic Republic of Iran. M. Mahmudvand Department of Plant Protection, Faculty of Agriculture, Shahed University, Tehran, Islamic Republic of Iran. Journal Article The experiment was conducted to determine α-amylase activity and the effect of seven plant species extracts including Punica granatum L. (Punicaceae), Rheum officinale B. (Polygonaceae), Rhus coriaria L. (Anacardiaceae), Artemisia sieberi B. ( Compositae), Peganum harmala L. (Nitrariaceae) , Datura stramonium L. (Solanaceae) and Thymus vulgaris L. (Lamiaceae) on α-amylase activity of four stored insect pests including Callosobruchus maculatus F. (Coleoptera: Bruchidae), Rhyzopertha dominica F. (Coleoptera: Bostrichidae), Sitophilus granarius L. (Coleoptera: Curculionidae), and Trogoderma granarium E. (Coleoptera : Dermestidae). Also, gut pH and optimum temperature for α-amylase activity of these insects were determined. It was found that α -amylases midgut pH of all four insect species was acidic and optimum temperature was between 30 and 40 °C. Beyond these temperatures, the α-amylases activities sharply decreased. Plant extracts caused inhibitory activity on insect α-amylases varying from nearly 4% to 95% inhibition. D. stramonium and R. officinali extracts had the highest amylase inhibitory activity among the tested extracts, while methanolic extracts of P. harmala, and T. vulgaris (except for S. granaries α-amylase) showed the lowest inhibitory activity. Gel assays revealed that more than one isoform of α -amylase detected in midgut crude extracts of the four insect pests examined could be inhibited by the plant extracts. https://jast.modares.ac.ir/article_15067_6c2962f5fd32e7cf54968b00cb4ecea5.pdf