Tropical Ginger Extract as Protectant in Radiation Countermeasures

Objective: The tropical ginger, Zingiber montanum (J. König) A. Dietr., has significant potential in scavenging free radicals and protection of chromosomes from radiationinduced aberrations. The present investigation aims at determining antioxidant activities and radioprotective potentials of the rhizome extract of tropical ginger. Method: Sulfur (thiyl) free radical, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide radical scavenging assays were carried out to assess the antioxidant activities. Radiationinduced DNA damage in pBR322 could be significantly reduced up to 71% (P<0.05) by treatment with 60% ethanol extract (20 μg) at 50 Gy γ-radiation exposure. The LD50 and maximum tolerated dose (MTD) of 60% ethanol extract of Z. montanum rhizome as determined through acute toxicity tests using albino rats (Rattus norvegicus, 2n=42) as experimental model and was found to be 2.9 g/kg and 1.3 g/kg respectively. Albino rats were administered intra-peritoneal injection of 0.5 g/kg rhizome extract in 60% ethanol and were subsequently exposed to 100, 300 and 500 cGy respectively. Single cell alkaline comet assay revealed significant reduction (P < 0.05) of comet tail DNA (68%) and length (61%) in rat bone marrow cells at a radiation dose of 500 cGy. Results and Conclusion: The results do demonstrate that tropical ginger has free radical scavenging properties and can protect rat bone marrow cells from radiation-induced DNA damage. Radioprotection assay using pBR322 plasmid obviously justify that the extract at low concentration can protect DNA from undergoing strand breakage due to gamma radiation exposure.