title: Thymol, a monoterpene phenolic derivative of cymene, abrogates mercury-induced oxidative stress resultant cytotoxicity and genotoxicity in hepatocarcinoma cells.
abstract: Thymol (TOH) was investigated for its ability to protect against mercuric chloride (HgCl2 )-induced cytotoxicity and genotoxicity using human hepatocarcinoma (HepG2) cell line. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay confirmed the efficacy of TOH pretreatment in attenuating HgCl2 -induced cytotoxicity. Pretreatment with TOH inhibited HgCl2 -induced genotoxicity, depolarization of mitochondrial membrane, oxidative stress, and mitochondrial superoxide levels. Interestingly, TOH (100 µM) alone elevated the intracellular basal glutathione S-transferase (GST) levels and TOH pretreatment abrogated the decrease in glutathione, GST, superoxide dismutase, and catalase levels even after HgCl2 intoxication. Furthermore, TOH was also capable of inhibiting HgCl2 -induced apoptotic as well as necrotic cell death analyzed by flowcytometric analysis of cells dual stained with Annexin-FITC/propidium iodide. The present findings clearly indicate the cytoprotective potential of TOH against HgCl2 -induced toxicity, which may be attributed to its free radical scavenging ability which facilitated in reducing oxidative stress and mitochondrial damage thereby inhibiting cell death.
authors.affiliation: Department of Biotechnology, School of Life Sciences, Manipal University, Manipal, Karnataka, 576 104, India.
authors.forename: Nishan B
authors.initials: NB
authors.lastname: Shettigar
authors.affiliation: Division of Radiobiology and Toxicology, School of Life Sciences, Manipal University, Manipal, Karnataka, 576 104, India.
authors.forename: Shubhankar
authors.initials: S
authors.lastname: Das
authors.affiliation: Division of Radiobiology and Toxicology, School of Life Sciences, Manipal University, Manipal, Karnataka, 576 104, India.
authors.forename: Nageshwar B
authors.initials: NB
authors.lastname: Rao
authors.affiliation: Division of Radiobiology and Toxicology, School of Life Sciences, Manipal University, Manipal, Karnataka, 576 104, India.
authors.forename: Satish B S
authors.initials: SB
authors.lastname: Rao
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D002374:Catalase / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects*; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008627:Mercuric Chloride / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D051336:Mitochondrial Membranes / Q000187:drug effects; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D009336:Necrosis; D018384:Oxidative Stress / Q000187:drug effects*; D020011:Protective Agents / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism; D013943:Thymol / Q000494:pharmacology*
chemical_list: D009153:Mutagens; D020011:Protective Agents; D013481:Superoxides; D013943:Thymol; D008627:Mercuric Chloride; D002374:Catalase; D005982:Glutathione Transferase
keywords: apoptosis; genotoxicity; mercury; thymol