Acute skin irritation, acute and sub-acute oral toxicity studies of Rosmarinus officinalis essential oils in mice and rabbit

Abstract

In Ankober, Northern Ethiopia, Rosmarinus officinalis has been commonly used for flavoring foods as a condiment; moreover, the plant has also been widely used for different medicinal purposes. The current study was undertaken to provide data on acute and subacute toxicity in mice as well as skin irritation of R. officinalis essential oil in rabbit. Acute dermal and oral toxicity tests were conducted using limited dose of 2000 mg/kg. In sub-acute study, 1000 mg/kg were given by gavage to mice for 28 consecutive days. The mice were weighed and various observations like mortality, behavior, injury, or any signs of illness were conducted once daily during the study period. At the end of each study, biochemical parameters were evaluated and kidney and liver were taken after sacrifice for gross findings and histological analyses. For dermal toxicity, 10% ointment formulation of oils was applied on the rabbit skin to evaluate whether the animals sustained significant skin damage. The LD 50 of R. officinalis essential oil for both dermal and oral administration is greater than 2000 mg/kg. There was no significant difference (p > 0.05) observed in the body weights, biochemical parameters, and gross abnormalities, as compared to the control in subacute study. No mortality was recorded. Pathological studies showed that there were no any macroscopic changes in kidneys and liver and all of them have normal appearance. The data of acute skin irritation test demonstrated that 10% R. officinalis oils ointment formulation did not induce acute toxicity in the skin of the animals. Overall, the findings of this study indicate that R. officinalis essential oil is non-toxic.