title: Radiation protection of HepG2 cells by Podophyllum hexandrum Royale.
abstract: Radioprotection by an aqueous extract of Podophyllum hexandrum (RP-1) was investigated in HepG2 cells by evaluating colony forming efficacy (CFE), redox status of mitochondria, reactive oxygen species (ROS), generation of nitric oxide (NO), peroxidation of lipids and intracellular glutathione. Lower concentrations of RP-1 (0.1 and 1 microg/ml) rendered maximum radioprotection when administered 1 or 2 h before irradiation. Higher concentrations (5 and 10 microg/ml) however were less effective when administered 1 or 2 h before irradiation, but were more effective with increased time intervals (4 or 8 h) between RP-1 administration and irradiation. RP-1 pre-treatment also significantly inhibited radiation-induced MTT reduction in a concentration and time-dependent manner by decreasing gamma radiation-induced leakage of electrons from electron transport chain. Pre-irradiation administration of RP-1 significantly reduced both ROS and NO generation and enhanced glutathione levels, thereby inhibiting lipid peroxidation.
authors.affiliation: Radiation Biology Division, Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organization (DRDO), Delhi, India.
authors.forename: Damodar
authors.initials: D
authors.lastname: Gupta
authors.forename: Rajesh
authors.initials: R
authors.lastname: Arora
authors.forename: Amar Prakash
authors.initials: AP
authors.lastname: Garg
authors.forename: Harish Chandra
authors.initials: HC
authors.lastname: Goel
mesh_terms: D002453:Cell Cycle / Q000528:radiation effects; D002460:Cell Line; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004579:Electron Transport; D016195:G2 Phase / Q000528:radiation effects; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D050356:Lipid Metabolism; D015227:Lipid Peroxidation; D008564:Membrane Potentials; D008938:Mitosis / Q000528:radiation effects; D009569:Nitric Oxide / Q000378:metabolism; D010084:Oxidation-Reduction; D011035:Podophyllum / Q000378:metabolism*; D011835:Radiation Protection; D011837:Radiation-Protective Agents; D017382:Reactive Oxygen Species; D013778:Tetrazolium Salts / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D013997:Time Factors
chemical_list: D011837:Radiation-Protective Agents; D017382:Reactive Oxygen Species; D013778:Tetrazolium Salts; D013844:Thiazoles; D009569:Nitric Oxide; C022616:thiazolyl blue; D005978:Glutathione