Free Radical Scavenging Activity of Some Therapeutic Plants and Protection of Radiation-induced DNA Damage by Zingiber montanum Extract

Abstract

Free radical scavenging activities of rhizome extracts of Acorus calamus, Curcuma longa, Paris polyphylla, and Zingiber montanum were established in vitro Z. montanum in 60% methanol showed a significant radical scavenging activity with IC₅₀ values of 0.34 ± 0.06 mg.mL⁻¹ and 0.68 ± 0.08 mg.mL⁻¹ in DPPH and superoxide free radical assays. It also provided optimal protection of curcumin from thiyl free radicals generated by γ-radiolysis of glutathione. All the four species showed free radical scavenging properties, and the highest was observed with Z. montanum. Supplementation of Plasmid pBR322 DNA with 40μg Z. montanum extract showed a high DNA protection rate of 81.87% when exposed to100 Gy. The efficacy of Z. montanum in free radical scavenging and protection of DNA from radiation-induced damage suggests that it could be useful in radioprotection.

Keywords:

• Radioprotection
• thiyl radicals
• superoxide radicals
• pBR322
• phenolics
• flavonoids

Acknowledgments

The authors are thankful to the Indian Council of Medical Research, Government of India, New Delhi for financial support (Grant No. 4/2-1/2003/CAR/BMS/TRM).