Acute oral toxicity test and assessment of rhynchophylline in mice

As the main alkaloid constituent of Uncaria species, rhynchophylline has drawn extensive attention in recent years for its antihypertensive and neuroprotective activities. However, toxicity study of the rhynchophylline is still lacking. In the present study, oral acute toxicity of rhynchophylline was conducted in Kunming mice. The mice were orally treated with 520.00, 442.00, 375.70, 319.34 and 271.44 mg/kg of rhynchophylline for 14 d. The general behavior, body weight changes, toxic reaction, and death were recorded, and histopathological analyses were performed. The acute toxicity was evaluated by the assessment of the median lethal dose (LD₅₀). The acute toxicity study showed that no significant difference was found in the body weight of the mice in the control group and those in the drug group. However, the mice treated with rhynchophylline showed obvious abnormal symptoms and mortality. The median lethal dose (LD₅₀) of orally administered rhynchophylline was 308.08 mg/kg. The histopathological results showed that the mice in the high-dose rhynchophylline group displayed toxic effects in the brain, liver, lung, and kidney. The results of the current study indicated that rhynchophylline could not be taken at a high dose. Collectively, our current findings provided a strong basis for further clinical investigation.