Isolation and characterization of antimutagenic components of against -methyl--nitrosourea.

Background: A powdered ethanolic extract of root exhibits antimutagenic activity against -methyl--nitrosourea (MNU) based on the Ames assay with TA1535. The aim of this study was to identify the antimutagenic components of the powdered ethanolic extract of root.

Results: The powdered ethanolic extract of root was sequentially suspended in -hexane, carbon tetrachloride, dichloromethane, ethyl acetate, and ethanol, and each solvent soluble fraction and the residue were assayed for antimutagenic activity against MNU in TA1535. The dichloromethane soluble fraction exhibited the highest antimutagenicity and was fractionated several times by silica gel chromatography. The fraction with the highest antimutagenic activity was further purified using HPLC, and the fractions were assayed for antimutagenicity against MNU in TA1535. Finally, five components with antimutagenic activity against MNU were identified as glyurallin A, glyasperin B, licoricidin, 1-methoxyphaseollin, and licoisoflavone B.

Conclusions: The five components were demonstrated to possess an antigenotoxic effect against carcinogenic MNU for the first time. It is important to prevent DNA damage by -nitrosamines for cancer chemoprevention.