Mosquito larvicidal and silver nanoparticles synthesis potential of plant latex

Abstract

Silver nanoparticles (AgNPs) were synthesized from the latex of the medicinally important plants <em>Euphorbia milii</em>, <em>Euphorbia hirta</em>, <em>Ficus</em> <em>racemosa</em> and <em>Jatropha</em> <em>curcas</em>. Synthesized AgNPs were characterized by UV-Vis spectrophotometry, scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, Fourier transformed infrared spectroscopy, particle size, and zeta potential analysis. Potency of latex and latex-synthesized AgNPs was evaluated against the 2<sup>nd</sup> and 4<sup>th</sup> instar larvae of <em>Aedes</em> <em>aegypti</em> and <em>Anopheles stephensi</em>. The lowest lethal concentration 50 (LC<sub>50</sub>) value among the different types of plant latex studied was observed for latex of <em>E. milii</em> (281.28±23.30 and 178.97±37.82 ppm, respectively) against 2<sup>nd</sup> instar larvae of <em>Ae. aegypti</em> and <em>An. stephensi. E. milii</em> latex-synthesised AgNPs showed a high reduction in LC<sub>50</sub> compared with its latex; <em>i.e.</em>, 8.76±0.46 and 8.67±0.47 ppm, respectively, for 2<sup>nd</sup> instars of <em>Ae. aegypti</em> and <em>An. stephensi</em>. LC<sub>50</sub> values of AgNPs synthesized using the latex of <em>E. hirta</em>, <em>F. racemosa</em> and <em>J. curcas</em> were lower than those of the latex of the respective plants; <em>i.e.</em>, 10.77±0.53, 9.81±0.52, 12.06±0.60 and 8.79±0.51, 9.83±0.52, 9.60±0.51 ppm, respectively, for 2<sup>nd</sup> instars of <em>An. stephensi</em> and <em>Ae. aegypti</em>. Similarly, as compared with the plant latex, lower LC<sub>50</sub> values were reported for latex-synthesized AgNPs against 4<sup>th</sup> instars of <em>Ae. aegypt</em> and <em>An. stephensi.</em> Results showed that all the types of plant latex investigated have the potential to convert silver nitrate into AgNPs showing a spectrum of potent mosquito larvicidal effects, indicating the possibility of further exploration of the bioefficacy of latex and latex-synthesized AgNPs against vectors of public health concerns.