Toxicological evaluation of a tea from leaves of Vernonia condensata

Teas of Vernonia condensata Baker (Asteraceae) are widely used in Brazil for gastro-intestinal disorders and to treat several other diseases. In this study, we evaluated the acute toxicity, embryotoxicity and mutagenicity of a lyophilized aqueous extract (LAE) from V. condensata leaves. Single doses of LAE, up to 5000 mg/kg body weight, were given orally or intraperitoneally to male and female Swiss albino mice. No toxicity was observed after oral administration. The "Approximate Lethal Dose" after intraperitoneal injections was 3400 mg/kg for males and 5000 mg/kg for females. Embryotoxicity was investigated in Han:NMRI mice. LAE (0, 500 and 2000 mg/kg/day) was given by gavage on days 10, 11 and 12, and dams were submitted to caesarean sections on day 18 of pregnancy. Fetuses were weighed, examined for externally visible malformations, and evaluated for skeletal anomalies. Except for a slight reduction of fetal body weight accompanied by signs of delayed ossification at the highest dose, no other embryotoxic effect was noted in the exposed offspring. LAE-induced mutagenicity was evaluated in the Salmonella/microsome assay without and with S9 mixture. LAE, tested up to 5000 microg/plate, was not mutagenic to tester strains TA97a, TA98 and TA100. Results therefore suggest that V. condensata aqueous extracts present low acute toxicity and pose neither teratogenic nor mutagenic risks.