Safety assessment of Cymbopogon shoenanthus (L.) Spreng. (Poaceae) essential oils: Oral toxicity, dermal and eye irritancy investigations

Abstract

The side effects prediction is a regulatory requirement prior the effective use of a new product as drug or pesticide constituent is allowed. The handling hazards of Cymbopogon schoenanthus essential oils (CSEO) were determined by investigating their acute and subacute toxicities as well as irritancy potential for eye and skin in compliance with the Organization for Economic Cooperation and Development guidelines. In mice, the essential oils did not induce mortality at the limit single dose of 2000 mg/kg b.w., meaning that the test product estimated LD50 is 5000 mg/kg b.w. In the 28 days sub-acute oral toxicity study in rats, there was no mortality observed for all tested doses in both sex. Furthermore, besides body weight gain that slightly dropped, there was no significant difference observed in food and water consumption, relative organs weight, and blood biochemical profile in test animals, compared to the control. No eye irritant reaction was shown in the rabbits exposed to CSEO. To assess dermal irritation, rabbits were dermally exposed to CSEO for 4 h. The results showed that no adverse reactions such as erythema and edema were observed throughout the test. Based on these findings, CSEO do not cause either oral toxicity up to 28 days in repeated administration, nor dermal and eye irritation, and seems to be safe for animal in the study conditions. These results constitute a new scientific support for the safe use of C. scheonanthus essential oils as alternatives to synthetic pesticides. However, for further clinical relevance of the results and complete toxicological profile elucidation, toxicity studies must be extended to long term toxicity test as subchronic and chronic toxicities, reprotoxicity, carcinogenicity, teratogenicity, and mutagenicity investigations. Key words: Cymbopogon schoenanthus, Wistar rat, essential oils, sub-acute toxicity, blood chemistry, naturel insecticide.