Panax ginseng C.A. Meyer has been extensively used in the traditional oriental medicine as a restorative, tonic and prophylatic agent. Petroleum ether extract of panax ginseng C.A. Meyer (GPE) and its several fractions (P1-P5) were tested for the evaluation of antigenotoxicity against N-methyl-N-nitrosourea (MNU) and benzo(a)pyrene [B(a)P]-induced micronucleated reticulocytes in mouse peripheral blood. GPE and P2 showed more significant anticlastogenicity than other fractions did. To elucidate the anticlastogenic action mechanism of GPE and P2 against B(a)P, the alteration of B(a)P metabolism was studied. GPE and P2 inhibited B(a)P metabolism in the presence of S-9 mix and decreased B(a)P-DNA binding in calf thymus DNA with S-9 mix. They also decreased [3H] MNU induced DNA binding and methylation to 7-methyl guanine and O^5-methyl guanine adducts in calf thymus DNA by HPLC analysis. These results suggest that the anticlastogenicity of GPE and P2 on the B(a)P or MNU-induced clastogenicity is due to decrease of DNA binding with B(a)P or MNU, the inhibition of metabolism with B(a)P and the inhibition of methylation in DNA. Therefore, GPE and P2 may be useful chemopreventive agents of alkylating agent like MNU and secondary carcinogen like B(a)P.

Panax ginseng C.A. Meyer has been extensively used in the traditional oriental medicine as a restorative, tonic and prophylatac agent. This study was devised to develop a chemopreventive agent from panax ginseng to be able to suppress the genotoxicity and oxidative damage by reactive oxygen species, which are involved with cancer or aging. Ginseng petroleum ether extract (GPE) and one of its fraction, P2, showed an antioxidative effect on the lipid peroxidation of ethyl linoleate with Fenton's reagents and free radical scavenging effect to 1,1-diphenyl-2-picryl hydrazil (DPPH) radical generation. They also showed the suppressive effect of H₂O₂ or KO₂ induced DNA damage by single cell gel electrophoresis (SCGE). Results from our study indicate that GPE and P2 are capable of protecting lipid peroxidation, and oxidative DNA damage. Therefore, GPE and P2 may be useful chemopreventive agents which are involved with cancer and aging.