Chemical Composition, Cytotoxicity and Larvicidal Activity of Essential Oils of Three Medicinal Plants of Ethiopian Flora Against Anisakis L3 Larvae

Uvaria scheffleri Diels (Annonaceae), Zanthoxylum chalybeum Engl. (Rutaceae), and Vepris dainelli (Pichi-Serm.) Kokwaro (Rutaceae) are medicinal plants traditionally used in Ethiopia against pathogenic infections. In the present study, the chemical composition, larvicidal activity, and cytotoxic effect of essential oils were investigated.

Hydrodistillation technique was used to extract essential oils. In vitro larvicidal activity against Anisakis L3 larvae was tested in marinated solutions. MTT assay was used to assess the cytotoxicity.

The yields (v/w) of essential oils obtained from U. scheffleri roots, Z. chalybeum, and V. dainelli fruits were 0.5, 2.7, and 2.0 %, respectively. Gas chromatography-mass spectrometry analysis of essential oils revealed a total of 58, 18, and 20 chemical constituents, representing 97.6, 99.6, and 98.8 % of the oil contents, respectively. Tricyclo [5.3.0.0(3, 9)] decane was identified to be the principal constituent in the essential oils of Z. chalybeum (82.8%) and V. dainelli (69.8%), reported herein for the first time. Essential oils of Z. chalybeum, U. scheffleri, and V. dainelli displayed a dose-dependent larvicidal activity with LT100 values of 3 h, 5 h, and 5 h for 5% concentrations, respectively. The cytotoxicity study of essential oils on VERO cells showed moderate toxicity with IC50 values of 65.46 µg/mL, 83.88 µg/mL, and 96.82 µg/mL, respectively.

The results obtained revealed that the studied essential oils could serve as larvicidal agents in treating human anisakidosis. The observed weak cytotoxicity at low concentrations points out the possibility of developing effective and safe botanical larvicides.