A comprehensive toxicological safety assessment of an extract of Ageratum conyzoides.

A battery of toxicological studies was conducted to aid in the safety assessment of an ethanolic extract of Ageratum conyzoides for use as an ingredient in food. In accordance with internationally accepted standards, a bacterial reverse mutation test, an in vitro mammalian chromosomal aberration test, an in vivo mammalian micronucleus test, and a 90-day repeated-dose oral toxicity study in rats were performed. In the first three applied test systems, no evidence of mutagenicity, clastogenicity or genotoxicity was revealed. Ageratum conyzoides did not cause mortality or toxic changes in Hsd.Han Wistar rats in the 90-day repeated dose oral (gavage) toxicity study at doses of 500, 1000 and 2000 mg/kg bw/d. The NOAEL was determined to be 2000 mg/kg bw/d for both male and female rats, the highest dose tested.