Free radical scavenging and metal chelation by Tinospora cordifolia, a possible role in radioprotection.
Aqueous extract of T. cordifolia inhibited Fenton (FeSO4) reaction and radiation mediated 2-deoxyribose degradation in a dose dependent fashion with an IC50 value of 700 microg/ml for both Fenton and radiation mediated 2-DR degradation. Similarly, it showed a moderate but dose dependent inhibition of chemically generated superoxide anion at 500 microg/ml concentration and above with an IC50 value of 2000 microg/ml. Aqueous extract inhibited the formation of Fe2+-bipiridyl complex and formation of comet tail by chelating Fe2+ ions in a dose dependent manner with an IC50 value of 150 microg/ml for Fe2+-bipirydyl formation and maximally 200 microg/ml for comet tail formation, respectively. The extract inhibited ferrous sulphate mediated lipid peroxidation in a dose-dependent manner with an IC50 value of 1300 microg/ml and maximally (70%) at 2000 microg/ml. The results reveal that the direct and indirect antioxidant actions of T. cordifolia probably act in corroboration to manifest the overall radioprotective effects.
Goel
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Department of Radiation Biology, Institute of Nuclear Medicine and Allied sciences, Brig SK Majumdar Marg, Delhi 110 054. radbiol@nda.vsnl.net.in
Prem Kumar
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Rana
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D015082:2,2'-Dipyridyl / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002084:Butylated Hydroxytoluene / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology; D020552:Comet Assay; D003300:Copper; D004249:DNA Damage / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers / Q000494:pharmacology*; D007502:Iron Chelating Agents / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008099:Liver / Q000187:drug effects* / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D018384:Oxidative Stress; D010618:Phenanthrolines / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D013950:Thymus Gland / Q000187:drug effects* / Q000528:radiation effects*; D031610:Tinospora / Q000737:chemistry*; D014916:Whole-Body Irradiation
D000975:Antioxidants; D002614:Chelating Agents; D016166:Free Radical Scavengers; D007502:Iron Chelating Agents; D010618:Phenanthrolines; D010936:Plant Extracts; D011837:Radiation-Protective Agents; D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; D002084:Butylated Hydroxytoluene; D015082:2,2'-Dipyridyl; D003300:Copper; C025205:1,10-phenanthroline