Effect of Four Indigenous Medicinal Plants on Dengue Fever, Vector Aedes aegypti from Jeddah Saudi Arabia

Aedes aegypti is the vector mosquito of dengue fever, which is an endemic disease in Saudi Arabia, Jeddah. The use of conventional insecticides in water sources introduces risks to people and/or the environment. In this study, mosquitocidal activity and adult development inhibition were investigated using four medicinal plants (Rhazya stricta, Lantana camara, R. chalepensis, and Punica granatum) against Ae. aegypti under laboratory conditions. A laboratory bioassay was conducted to assess larvicidal activity of leaves and peels crude acetonic extract of L. camara, Ruta chalepensis, Rh. stricta and P. granatum. Under controlled laboratory conditions, late 3rd or early 4th instar larvae were exposed to various concentrations - ranging from 150ppm to 1000 ppm - of the extracts to obtain the median lethal concentration (LC50) values for each plant extract tested. Mortalities were observed to increase with the increase in concentrations. Acetone extract of Rh. Stricta revealed high activity against Ae. aegypti compared to the rest of the extracts. The larval mortality rates of mosquito larvae ranged from 25 to 97% for Rh. stricta, 23 to 94% for L. camara, 17 to 96% for R. chalepensis, and 10 to 72% for P. granatum. In terms of effects on adult emergence, the inhibition percentage of the mosquito ranged from 26 to 100% for Rh. stricta, 13 to 100% for L. camara, 10 to 100% for R. chalepensis, and 22 to 92% for P. granatum. The evaluated medicinal plants seemed to be a better alternative to synthetic insecticides for controlling Ae. aegypti.