The developing resistance of mosquitoes against chemical insecticides gave rise to a worldwide increase in mosquito borne viral diseases and deaths. Most of these diseases were vectored by the same type of mosquito, the Aedes aegypti. The present study made use of Cracker plant leaf extract and solution of 1mM AgNO3 in the green synthesis of silver nanoparticles (AgNPs) to be tested as larvicidal agents. The increase solubility and penetrability of AgNPs make it a promising delivery system. Green synthesis was initially detected after 5 minutes but has eventually stabilized after 12h, its optimum reaction time. This was evident when a spectral wavelength shift at 420nm was seen through a UV-Vis. The reduction was carried through by phytochemicals in the cracker plant extract which served as capping and stabilizing agents. The synthesized AgNps were then characterized as spherical and oval with sizes ranging from 28-50nm using UV-Vis and Scanning Electron Microscopy (SEM), respectively. The Infra-Red Spectroscopy (IR) revealed bioactive compounds that capped the AgNps may be luteolin, lupeol and betulin. Larvicidal activity was assessed for 24h against IIIrd and IVth instar larvae of A.aegypti with varying concentrations of AgNPs. The recorded 90% lethal concentration (LC90) was found to be 105.42 ppm. Bioassay was done using OL pellets and de-ionized water as positive and negative control. Results obtained from this study present green-synthesized AgNps as larvicidal agent and could be used along with traditional insecticides as an alternative for mosquito larvae control in the Philippines.
Philippine E-Journals
