Antigenotoxic effect of genistein against 7,12-dimethylbenz[a]anthracene induced genotoxicity in bone marrow cells of female Wistar rats.

Carcinogen induced mutation in somatic cells leads to genetic instability, which is considered as an important facet of carcinogenesis. Agents that inhibit DNA adduct formation, stimulate DNA repair mechanisms, and possess antioxidant functions are considered as antigenotoxic agents. Genistein, the major isoflavone of soy products, protects animals against experimentally induced mammary and prostate cancers. 7,12-Dimethylbenz[a]anthracene (DMBA), a potent site-specific carcinogen, induce mutations in DNA through its active metabolite, dihydrodiol epoxide, what is a crucial step in cancer initiation. The antigenotoxic effect of genistein against DMBA-induced genotoxicity has been investigated in the present study by analyzing the frequency of micronucleated polychromatic erythrocytes (MnPCEs) and chromosomal aberrations as cytogenetic end-points. The status of lipid peroxidation, antioxidants and detoxication agents were used as biochemical end-points to assess the antigenotoxic effect of genistein. Elevated MnPCEs frequency, marked chromosomal aberrations and enhanced status of lipid peroxidation, antioxidants and detoxication agents were observed in DMBA-treated animals. Oral pretreatment of genistein (20 mg/kg b.w.) for 5 days to DMBA-treated animals significantly reduced the frequency of micronucleus formation and chromosomal abnormalities as well as reversed the status of biochemical variables. Our results suggest that genistein has potent antigenotoxic effect against DMBA-induced genotoxicity.

Protective role of withaferin-A on 7,12-dimethylbenz(a)anthracene-induced genotoxicity in bone marrow of Syrian golden hamsters.

The present study has investigated the antigenotoxic effect of withaferin-A, a steroidal lactone obtained from the roots and leaves of Withania somnifera, in 7,12-dimethylbenz(a)anthracene (DMBA)-induced genotoxicity. Measurement of the frequency of micronucleated polychromatic erythrocytes (MnPCEs) and chromosomal aberrations is used as cytogenetic endpoints. A single intraperitoneal injection of DMBA (30 mg/kg b.w.) to golden Syrian hamsters resulted in marked elevation in the frequency of MnPCEs and aberrations in the chromosomal structure. Hamsters pretreated with withaferin-A intraperitonealy 2 h before the injection of DMBA, significantly reduced the frequency of MnPCEs and chromosomal aberrations such as chromosomal break, gap, minute, and fragment. Our results thus demonstrated the antigenotoxic effect of withaferin-A in DMBA-induced genotoxicity in the bone marrow of golden Syrian hamsters.

Protective effect of Withaferin-A on micronucleus frequency and detoxication agents during experimental oral carcinogenesis.

Our aim was to investigate the effect of Withaferin-A on bone marrow micronucleus frequency and buccal mucosa detoxication agents during 7, 12-dimethylbenz[a]anthracene (DMBA) induced hamster buccal pouch carcinogenesis. Oral squamous cell carcinoma was developed in hamsters' buccal pouches by painting 0.5% DMBA in liquid paraffin, three times per week for 14 weeks. We observed 100% tumor formation in DMBA painted hamsters. Elevated frequency of bone marrow micronucleated polychromatic erythrocytes (MnPCEs) and decrease in buccal mucosa phase II detoxication agents were noticed in tumor bearing hamsters. Oral administration of Withaferin-A significantly reduced the micronucleus frequency and brought back the status of phase II detoxication agents in DMBA painted hamsters. Our study thus demonstrated the protective effect of Withaferin-A on DMBA-induced micronucleus frequency in the bone marrow of golden Syrian hamsters. Also, Withaferin-A maintained the status of buccal mucosa detoxication agents during DMBA-induced hamster buccal pouch carcinogenesis.