مشخصات پژوهش

In this study inhibitory activity of seed and foliage extracts of Ageratum houstonianum and Xanthium strumarium on Potato tuber moth (PTM) α-amylase activity investigated. Insects were reared in controlled condition on potato tubers. Enzyme extraction carried out from different developmental stages of PTM, including: first larval instars, 10 day old larvae, adults, and pre-pupa using phosphate buffer pH 7. Seeds and fresh leaves of plants, collected, washed with distilled water, after air dry, inhibitors extracted by liquid nitrogen using mortar and pestle. The extractions heated for 5 minutes in 70°C then centrifuged 10 minutes in 12000 RPM, the supernatants was precipitated by 3 different concentrations of ammonium sulfate (0-20, 20-40 and 40-60%). α-amylase assays carried out using 1% starch as substrate and dinitrosalicylic acid (DNS) reagent. For inhibitory activity assays, enzyme and inhibitors preincubated for 10 minutes in 35°C. The results revealed that α-amylase activity in 10 days old larva of PTM was significantly more than other studied stages. Crude extracts of seed and fresh leaf of A. houstonianum and X. strumarium inhibited PTM α-amylase activity by 26.24, 37.72 and 23.83, 37.18% respectively. Protein fractions precipitated with ammonium sulfate showed notable inhibitory activity of 53.62 and 53.58% in 20-40 and 40-60% fractions of X. strumarium leaves. And 44.32% inhibition was obtained from 40-60% fraction of A. houstonianum seed extract. High potential of α-amylase inhibitory activity of leaves extracts was the interesting results of this study.