Essential oil extracted from ginger (GEO) was evaluated for its mutagenicity to Salmonella typhimurium TA 98, TA 100, TA 102, and TA 1535 strains with and without microsomal activation. GEO was found to be non-mutagenic up to a concentration of 3 mg/plate. It was also assessed for antimutagenic potential against direct acting mutagens such as sodium azide, 4-nitro-o-phenylenediamine, N-methyl-N'-nitro-N-nitrosoguanidine, tobacco extract, and 2-acetamidoflourene, which needs microsomal activation. GEO significantly inhibited (p < 0.001) the mutagenicity induced by these agents in a concentration-dependent manner. The effect of GEO to modulate the action of phase I carcinogen-metabolizing enzymes was investigated by studying its effect on various isoforms of microsomal cytochrome P450 enzymes. Significant inhibition of CYP1A1, CYP1A2, and CYP2B1/2, aniline hydroxylase (an indicator of CYP2E1 activity), and aminopyrine-N-demethylase (indicator of CYP1A, 2A, 2B, 2D, and 3A activity) was shown by GEO both in vitro and in vivo. GEO gave an IC50 value of 30, 57.5, and 40 µg for CYP1A1, CYP1A2, and CYP2B1/2, respectively, 55 µg for aniline hydroxylase, and 37.5 µg for aminopyrene-N-demethylase. GEO also significantly increased the levels of phase II carcinogen-metabolizing enzymes uridine 5'-diphospho-glucuronyl transferase and glutathione-S-transferase in vivo indicating the use of GEO as an antimutagen and as a potential chemopreventive agent.

Radioprotective effects of ginger essential oil (GEO) on mortality, body weight alteration, hematological parameters, antioxidant status and chromosomal damage were studied in irradiated mice. Regression analysis of survival data in mice exposed to radiation yielded LD50/30 as 7.12 and 10.14 Gy for control (irradiation alone) and experimental (GEO-treated irradiated) mice, respectively, with a dose reduction factor (DRF) of 1.42. In mice exposed to whole-body gamma-irradiation (6 Gy), GEO pre-treatment at 100 and 500 mg/kg b.wt (orally) significantly ameliorated decreased hematological and immunological parameters. Radiation induced reduction in intestinal tissue antioxidant enzyme levels such as superoxide dismutase, catalase, glutathione peroxidase and glutathione was also reversed following administration of GEO. Tissue architecture of small intestine which was damaged following irradiation was improved upon administration of GEO. Anticlastogenic effects of GEO were studied by micronuclei assay, chromosomal aberration and alkaline gel electrophoresis assay. GEO significantly decreased the formation of micronuclei, increased the P/N ratio, inhibited the formation of chromosomal aberrations and protected agaisnt cellular DNA damage in bone marrow cells as revealed by comet assay. These results are supportive of use of GEO as a potential radioprotective compound.