Biochemical and toxicological effects of Citrullus colocynthis (L.) seed oil (extracted by three different methods) on the Potato tuber moth, Phthorimaea operculella (Zeller).

Background Citrullus colocynthis (L.) is a plant of the Cucurbitaceae family, traditionally known for its medicinal properties. Recently, its seed oil has gained attention as a natural insecticidal agent. Objective This study aimed to compare three extraction methods : maceration, Soxhlet, and ultrasound-assisted solvent extraction for obtaining seed oil from C. colocynthis, and to evaluate the oils’ physicochemical properties and their toxicological and biochemical effects on Phthorimaea operculella. Materials and methods Seeds were extracted using hexane via the three methods. The oils were analyzed for yield, acid value, peroxide value, iodine value, and saponification value, and fatty acid composition. FTIR spectroscopy was used to identify functional groups. Toxicity (LC₅₀) was tested against P. operculella larvae and adults. Enzyme activities (AChE, GST, SOD) and total protein content were assessed in treated insects and compared with those of the control group. Results and conclusion Ultrasound-assisted extraction gave the highest oil yield. The extracted oils differed slightly in physicochemical properties. FTIR analysis showed consistent functional groups, with macerated oil displaying more absorption bands. Toxicity tests revealed that ultrasound oil had the strongest insecticidal effect. Enzyme assays showed significant inhibition in treated insects. These findings support the potential of C. colocynthis seed oil as an eco-friendly insecticide.