Assessment of dermal safety of oil extracted from Periplaneta americana: acute dermal toxicity, irritation, and sensitization

Abstract Introduction The American cockroach (Periplaneta americana) is used in traditional Chinese medicine. Periplaneta americana (P. americana) is rich in oil that has shown potential antioxidant and antibacterial activities in vitro. Objective To evaluate the safety of oil extracted from P. americana by conducting acute dermal toxicity, irritation, and sensitization tests. Materials and methods In an acute dermal toxicity study, adult Sprague–Dawley rats were exposed to P. americana oil (2000 mg/kg body weight) for 24 h. Clinical observations were conducted to evaluate the toxicity, behaviour, and health of the animals every day after dermal exposure for 14 days. For the dermal irritation test, the oil was applied to rabbits in single and multiple doses. Multi-dose treatment was administered once per day for 14 days. Each rabbit served as its own left- and right-side control and the rabbits’ irritation reactions in local intact and damaged skin were recorded and scored. The skin sensitization study of guinea pigs with the oil was conducted for a period of 28 days. Results The acute dermal median lethal dose (LD50) of P. americana oil was > 2000 mg/kg body weight in adult rats. There was no significant difference in mean irritation scores between the negative control and oil groups. The oil caused very little or no irritation in the intact and damaged skin rabbits treated with either single or multiple doses and it was non-sensitizing to the skin of guinea pigs. Conclusions These results suggest that P. americana oil does not produce any significant acute toxic effects and is safe for use in animal models with almost no dermal irritation or sensitization. Therefore, it presents a low risk of provoking skin reactions in humans.