Potential of bio fabricated Annona glabra - silver nanoparticles to control Aedes aegypti and Aedes albopictus

Abstract

Bio synthesized silver nanoparticles using Annona glabra leaf extract (An-AgNPs) as the reducing and stabrlizing agent were assessed as a novel larvicide against dengue vector mosquito larvae. The fresh leaves of A. glabra were crushed well and heated with distilled water under 70 0C for I hour. The supernatant was mixed (10% and 20% v/v of total volume) with 5 mM AgNO, to synthesize AnAgNPs. Formation ofAn-AgNPs were confirmed bythe color change and by appearance ofSPR peak in the Uv-vis spectrum and characterized by Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared spectroscopy (FTIR). lhe larvicidal activity of An-AgNPs was assessed against the third instar larvae of Ae. aegypti ^nd, Ae. albopictus, under the laboratory conditions (2 -10 mg/L). The change ofsolution color from yellow to dark brown/black and the SPR band at 435 nm confirmed the formation of An-AgNPs. According to SEM; An-AgNPs were spherical in morphology. FTIR analysis detected that An-AgNPs are capped and stabilized with biomolecules of A. glabraleaf ltZl9 (C=O stretching), 1366 (CH2 bending) and 3500-3200 (N-H and O-H stretching) and l2l7 cm-' (C-O stretching)i. The LCro of An-AgNPs (10%) and An-AgNPs (20%)againstthethirdinstarslarvaeofAe.aeglptiafter24hourswere5.2gand2.43mglland of Ae. albopictus were 3.02 and 2.51 mg/L respectively. The LC* of An-AgNPs (I0%) and An-AgNPs (20%)againstthethirdinstarslarvaeof Ae.aegyptiafter48hourswerel.5l andl.lT mg/Landof Ae. albopictus were 1.14 and 2.i0 mg/L respectively. The LC,n ofleafcrude plant extract against the third instars larvae of Ae. aegTpti after 24 and 48 hours were 5.9455 and 3.5485 mg/L and for the third instars iaruae of Ae. albopictus were 5.0040 arrd2.7346 mg/L respectivdy. This study shows that AnAgNPs is efficient in controlling mosquito larvae.