title: Thymol, a naturally occurring monocyclic dietary phenolic compound protects Chinese hamster lung fibroblasts from radiation-induced cytotoxicity.
abstract: The effect of thymol (TOH), a dietary compound was investigated for its ability to protect against radiation-induced cytotoxicity in Chinese hamster lung fibroblast (V79) cells growing in vitro. Treatment of V79 cells with 25 microg/ml of TOH prior to 10 Gy gamma radiation resulted increase in the cell viability than that of radiation alone as evaluated by MTT assay. Similarly, there was a significant increase in the surviving fraction observed with 25 microg/ml of TOH administered 1h prior to graded doses of gamma radiation. Further, 25 microg/ml TOH treatment before irradiation significantly decreased the percentage of radiation-induced apoptotic cells (sub-G(1) population) analyzed by flow cytometry as well as DNA ladder assay. TOH was found to inhibit various free radicals generated in vitro, viz., DPPH, O(2), ABTS(+) and OH in a concentration dependent manner. TOH also inhibited the radiation-induced decrease in intracellular glutathione, superoxide dismutase and catalase enzyme levels in V79 cells accompanied by the reduction in lipid peroxides. Our study demonstrated antagonistic potential of TOH against radiation-induced oxidative stress, lipid peroxidation resulting in increased cell viability.
authors.affiliation: Division of Radiobiology & Toxicology, Manipal Life Sciences Centre, Manipal University, Manipal 576104, Karnataka, India.
authors.forename: P R
authors.initials: PR
authors.lastname: Archana
authors.forename: B
authors.initials: B
authors.lastname: Nageshwar Rao
authors.forename: Mamatha
authors.initials: M
authors.lastname: Ballal
authors.forename: B S
authors.initials: BS
authors.lastname: Satish Rao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002374:Catalase / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002999:Clone Cells / Q000187:drug effects / Q000528:radiation effects; D003114:Colony-Forming Units Assay / Q000379:methods; D006224:Cricetinae; D004249:DNA Damage / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D005562:Formazans / Q000378:metabolism; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005720:Gamma Rays / Q000009:adverse effects*; D005978:Glutathione / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects / Q000528:radiation effects; D018384:Oxidative Stress / Q000187:drug effects; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000378:metabolism; D013778:Tetrazolium Salts / Q000378:metabolism; D013943:Thymol / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D005562:Formazans; D016166:Free Radical Scavengers; D011837:Radiation-Protective Agents; D013778:Tetrazolium Salts; C079782:MTT formazan; D013943:Thymol; D002374:Catalase; D013482:Superoxide Dismutase; D005978:Glutathione