The desert wormwood (Artemisia herba-alba) - From Arabian folk medicine to a source of green and effective nanoinsecticides against mosquito vectors.

The development of eco-friendly and effective insecticides is crucial for public health worldwide. Herein, we focused on the desert wormwood (Artemisia herba-alba), a plant widely used in Arabian traditional medicine, as a source of green nanoinsecticides against mosquito vectors, as well as growth inhibitors to be employed against microbial pathogens. Ag nanoparticles (AgNPs) fabricated with the A. herba-alba extract were tested on Indian and Saudi Arabian strains of Anopheles, Aedes and Culex mosquitoes. The chemical profile of the A. herba-alba extract was determined by LC-DAD-MS and 1H NMR studies. Then, AgNPs were studied using UV-vis spectroscopy, XRD, FTIR spectroscopy, TEM, and EDX analyses. Artemisia herba-alba-synthesized AgNPs showed high larvicidal toxicity against mosquitoes from both Indian and Saudi Arabian strains. LC50 of AgNPs against Indian strains was 9.76 µg/ml for An. stephensi, 10.70 µg/ml for Ae. aegypti and 11.43 µg/ml for Cx. quinquefasciatus, whereas against Saudi Arabian strains it was 33.58 µg/ml for Ae. aegypti and 38.06 µg/ml for Cx. pipiens. In adulticidal experiments, A. herba-alba extract showed LC50 ranging from 293.02 to 450 µg/ml, while AgNP LC50 ranged from 8.22 to 27.39 µg/ml. Further, low doses of the AgNPs inhibited the growth of selected microbial pathogens. Overall, A. herba-alba can be further considered as a source of phytochemicals, with special reference to saponins, for effective and prompt fabrication of AgNPs with relevant insecticidal and bactericidal activity against species of high public health importance.