Abdullah D. Alanazi

Background. This investigation was designed to evaluate the insecticidal, antiplasmodial, anti-leishmanial, and cytotoxic effects of Capparis spinosa essential oil (CSEO) and its main components, methyl isothiocyanate, hexadecanoic acid, and limonene. Methods. Insecticidal activity of CSEO and its main components, methyl isothiocyanate, hexadecanoic acid, and limonene, was determined against Aedes aegypti 4th-instar larvae at 25 ± 2°C. Antiplasmodial and anti-leishmanial effects of CSEO and its main components were carried out against chloroquine-resistant Plasmodium falciparum K1 strain and Leishmania major amastigotes based on the Malstat method and the macrophage model, respectively. We also performed the cytotoxic activity of CZEO and its main components against J774A1 macrophage cells using the colorimetric MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. In addition, the plasma membrane permeability and caspase-3-like activity CSEO and its main components were evaluated against L. major. Results. CSEO and its main components showed considerable ( p < 0.001 ) larvicidal activity against Ae. aegypti larva. The 50% lethal concentration values for CSEO, methyl isothiocyanate, hexadecanoic acid, and limonene were 21.6, 30.9, 41.6, and 35.3 μg/mL, respectively. By antiplasmodial effects, the 50% inhibitory concentration (IC50) values for CSEO, methyl isothiocyanate, hexadecanoic acid, and limonene were 7.4, 14.5, 19.6, and 21.3 μg/mL, respectively, while these values for their anti-leishmanial effects were 9.1, 20.7, 23.3, and 18.6 μg/mL, respectively. The 50% cytotoxic concentration values for CSEO, methyl isothiocyanate, hexadecanoic acid, and limonene were 93.7, 216.2, 199.4, and 221.3 μg/mL, respectively. Different concentrations of CSEO and its main components significantly ( p < 0.05 ) increased the plasma membrane permeability and caspase-3-like activity against L. major promastigote level as dose-dependent response. Conclusion. Based on the obtained results, C. spinosa essential oil and its main components, methyl isothiocyanate, hexadecanoic acid, and limonene, displayed insecticidal, antiplasmodial, and anti-leishmanial activity against healthy 4th-instar larvae of A. aegypti, chloroquine-resistant P. falciparum K1 strain, and L. major amastigotes, respectively. However, further surveys are required to display the mechanisms of action mode of tested drugs and their efficacy in animal model and clinical settings.