Inhibition of gut proteases and development of dengue vector, Aedes aegypti by Allium sativum protease inhibitor

Abstract

The paper describes the bio efficacy of a protease inhibitor; isolated from Allium sativum ‘garlic’ (ASPI); against Aedes aegypti mosquito, a well-known transmitter of dengue and Chikungunya. The purification of protease inhibitor from Allium sativum ‘garlic’ (ASPI) was carried out by ammonium sulfate precipitation followed by Fast Protein Liquid Chromatography using akta DEAE-Cellulose column. The protein fraction demonstrating trypsin inhibitory activity was further evaluated for its insecticidal activity using gut protease inhibition assay and larvicidal assay. ASPI is an inhibitor of porcine trypsin (IC50 of 650.726 μg/mL) and has molecular weight of ~15 kDa determined by SDS PAGE similar to other inhibitors of the Kunitz-type family (14–26 kDa). ASPI demonstrated 50% reduced activity of Ae. aegypti midgut proteases and showed a dose-dependent acute toxicity on Ae. aegypti 3rd instars exhibiting LC50 value of ~50.827 μg/mL. After ten days of larval exposure ASPI resulted in a 24-h delay of larval development and ~72% mortality at 61.5 μg/mL. These results suggest that ASPI may serve as potent insecticidal agent and hence opens a new gateway in the field of phyto-remediation.