Mutagenic and teratogenic toxicity evaluation of Forsythia suspensa leaves aqueous extract

Forsythia suspensa leaves (FSL), rich in phillyrin, forsythiaside A, phillygenin, rutin, and other compounds, is a known traditional Chinese medicine (TCM). It has been effective in heat retreat and detoxification. In this study, we performed the mutagenic and teratogenic toxicity evaluation of FSL aqueous extract (FSLAE) using the bacterial reverse mutation assay (Ames test), mouse bone marrow micronucleus assay, spermatocyte chromosomal aberration assay in mice. Kunming mice and SD rats were used were for the mutagenic and the teratogenic studies, respectively. We found that FSLAE was not mutagenic and did not induce unfavorable chromosomal events. Additionally, the Ames test revealed FSLAE was not genotoxic and showed no mutagenic activity in histidine dependent strains of Salmonella typhimurium at concentrations up to 5000 μg/plate. Likewise, in vivo test revealed no induced micronucleus of mouse bone marrow or chromosome aberration in spermatocytes up to the dose of 10.00 g/kg BW. For the teratogenic evaluations, pregnant rats were treated with 1.04, 2.08, and 4.17 g/kg FSL, and fetuses were examined on the 6-15 day of pregnancy. We observed no maternal toxicity and embryotoxicity related to the treatment. Based on these in vitro and in vivo studies, we concluded the genotoxic and teratogenic safety of FSL.