Embriotoxic and antioxidant effects of Cymbopogon citratus leaf volatile oil on zebrafish

Abstract

This study aimed to characterize the phytochemical composition and in vivo embryotoxic potential of Cymbopogon citratus Stapf, Poaceae, volatile oil in zebrafish (Danio rerio) embryos. Volatile oil was obtained by steam distillation and analysed using gas chromatography-mass spectrometry. Embryotoxicity was assessed using eight concentrations (50, 25, 12.5, 6.25, 3.12, 1.56, 0.78, and 0.39 μg/ml) of volatile oil, diluted in 0.5% dimethyl sulfoxide, and their teratogenic effects were examined in 20 embryos until 120 h post-fertilization. The activity of the antioxidant enzymes superoxide dismutase, catalase, and glutathione S-transferase was analysed in 60 larvae per treatment group at 96 post-fertilization. Cell apoptosis and reactive oxygen species levels were analysed using acridine orange staining and a fluorescence assay, respectively. The major constituents of volatile oil, geranial, neral, and myrcene, were determined by GC–MS analysis. Embryotoxicity was observed to be concentration and time-dependent, with an LC50 value of 9.02 μg/ml. Teratogenic effects, such as pericardial and yolk sac edema, tail deformity, and lordosis, were evident at a concentration of 6.25 μg/ml. Superoxide dismutase activity was significantly reduced at concentrations above 0.78 µg/ml, and catalase activity was markedly decreased at concentrations exceeding 1.56 µg/ml. All volatile oil concentrations induced a significant increase in reactive oxygen species production, with cell apoptosis notably elevated at 1.56 and 3.12 μg/ml. We conclude that high concentrations of C. citratus volatile oil exhibited toxic and teratogenic effects on zebrafish embryos and larvae, while lower concentrations were non-toxic.