Characterization of Ruta chalepensis L. extract and evaluation of its larvicidal activity against Culex pipiens L. larvae

The global threat posed by Culex pipiens is a major concern in many regions. This investigation was carried out to assess the larvicidal properties of Ruta chalepensis extract against Cx. pipiens. Methanolic extract from R. chalepensis was prepared and tested on Cx. pipiens larvae. Results displayed that the methanolic extract of R. chalepensis had larvicidal activity against Cx. pipiens with LC90 and LC95 values of 4.94 and 5.18 µg/mL, respectively, 24 h post application. The total phenolic (TP) and flavonoid (TF) contents of R. chalepensis were 97.70 ± 2.22 µg GAE/mg and 5.64 ± 0.052µg QE/mg, respectively. Histopathological study of treated larvae showed histological alterations in the digestive system, such as collapsed brush border, broken membranes, and cytoplasmic masses. The two major bioactive compounds found in the methanolic extracts were 2-(2-Hydroxyethoxy) phenol (14.8%) and oleic acid (14.7%). Future research is encouraged to evaluate the effectiveness of controlling Cx. pipiens in small-scale field tests using ecologically safe, botanical insecticides.