Study on the Relative Toxicity of Certain Encapsulated Nanoparticles of Plant Origin Against Selected Mosquito Larvae

Abstract

The present work mainly focuses on the synthesis of encapsulated nanoparticles by novel modes of polymers for controlling malaria vectors. The study majorly insight the toxic potential of different extracts and seed oils of Citrullus colocynthis and a highly effective product was used to form the polymeric nanoformulations against the target mosquito larvae, Anopheles culicifacies and Anopheles stephensi and also assessed their risk assessment on aquatic non-target organisms and cyto-compatibility to mammalian cell lines if any. The seed oil exhibited the best results in terms of larvicidal efficacy against both the malaria vectors. The different nanoformulations of seed oil were prepared by using different polymers, chitosan (CH), gum acacia (GA) and polyethylene glycol 6000 (PEG). The nanoformulations CH 1:2, GA 6% and PEG 8% indicated potent larvicidal efficacy, therefore, further proceeded for their characterization. SEM characterization results depicted that the nanoparticles of CH1:2 were spherical in nature and ranged 50 nm in size whereas nanoparticles of GA 6% and PEG 8% showed the hydrodynamic size of 168 and 140 nm with amorphous nature. PEG 8% nanoparticles are observed stable upto 20 days and show the residual toxicity against An. culicifacies and An. stephensi with a % loading capacity of 91.70% followed by CH 1:2 (16 days ) and GA 6% (11days), respectively. The LC50 values for CH1:2, GA 6% and PEG 8% nanoparticles from 14.24 and 15.76ppm , 51.76 and 61.49 ppm and 18.02 and 22.24 ppm against An. culicifacies and An. stephensi respectively. All these nanoformulations proceeded for histopathological studies and remarkable alterations in the tegument and midgut of An culicifacies and An. stephensi were observed. In morphological assessment, deformities observed in larval-pupal intermediate, larval abdominal distortion and feeding brushes alteration was also monitored with CHI: 2, GA 6% and PEG 8% at all lethal concentrations after 24hrs exposure. The nanoparticles were further tested for their impact revealing their non-toxic nature on aquatic non-target organisms (Daphnia magna and Gambusia affinis) and human cell line (HEK293T). newline