title: Attenuation of Oxidative Stress in HEK 293 Cells by the TCM Constituents Schisanhenol, Baicalein, Resveratrol or Crocetin and Two Defined Mixtures.
abstract: OBJECTIVE
  Our working hypothesis is that single bioactive phytochemicals with antioxidant properties that are important constituents of Traditional Chinese Medicine (TCM) and their defined mixtures have potential as chemoprotective agents for chronic conditions characterized by oxidative and nitrosative stress, including Alzheimer's. Here we evaluate the ability of baicalein, crocetin, trans-resveratrol or schisanhenol and two defined mixtures of these TCM phytochemicals to attenuate the toxicity resulting from exposure to cell permeant t-butyl hydroperoxide (tBPH) in wild-type and bioengineered (to express choline acetyltransferase) HEK 293 cells.
  
  
  METHODS
  Endpoints of tBHP-initiated oxidative and nitrosative stress in both types of HEK 293 cells and its attenuation by TCM constituents and mixtures included cytotoxicity (LDH release); depletion of intracellular glutathione (GSH); formation of S-glutathionylated proteins; oxidative changes to the disulfide proteome; and real-time changes in intracellular redox status.
  
  
  RESULTS
  At low µM concentrations, each of the TCM constituents and mixtures effectively attenuated intracellular toxicity due to exposure of HEK 293 cells to 50 or 250 µM tBHP for 30 min to 3 h. Confocal microscopy of HEK 293 cells transfected with mutated green fluorescent protein (roGFP2) showed effective attenuation of tBHP oxidation by baicalein in real time. Three redox-regulated proteins prominent in the disulfide proteome of HEK 293 cells were identified by MALDI-TOF mass spectrometry.
  
  
  CONCLUSIONS
  We conclude that single TCM chemicals and their simple mixtures have potential for use in adjunct chemoprotective therapy. Advantages of mixtures compared to single TCM constituents include the ability to combine compounds with varying molecular mechanisms of cytoprotection for enhanced biological activity; and to combine chemicals with complementary pharmacokinetic properties to increase half-life and prolong activity in vivo. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.
authors.affiliation: Department of Pathology and Laboratory Medicine, Schulich School of Medicine & Dentistry, Siebens-Drake Medical Research Institute, Western University, London ON. Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, Western University.
authors.forename: John Richard
authors.initials: JR
authors.lastname: Bend
authors.forename: Xue Yan
authors.initials: XY
authors.lastname: Xia
authors.forename: Daofeng
authors.initials: D
authors.lastname: Chen
authors.forename: Abudi
authors.initials: A
authors.lastname: Awaysheh
authors.forename: Andrea
authors.initials: A
authors.lastname: Lo
authors.forename: Michael John
authors.initials: MJ
authors.lastname: Rieder
authors.forename: Rebecca Jane
authors.initials: RJ
authors.lastname: Rylett
mesh_terms: D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D002338:Carotenoids / Q000008:administration & dosage / Q000494:pharmacology; D034242:Cyclooctanes / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage / Q000494:pharmacology*; D044950:Flavanones / Q000008:administration & dosage / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D008516:Medicine, Chinese Traditional; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D011083:Polycyclic Compounds / Q000008:administration & dosage / Q000494:pharmacology; D000077185:Resveratrol; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013267:Stilbenes / Q000008:administration & dosage / Q000494:pharmacology; D014801:Vitamin A / Q000031:analogs & derivatives; D020122:tert-Butylhydroperoxide / Q000008:administration & dosage / Q000633:toxicity
chemical_list: D000975:Antioxidants; D034242:Cyclooctanes; D004365:Drugs, Chinese Herbal; D044950:Flavanones; D011083:Polycyclic Compounds; D013267:Stilbenes; C487773:trans-sodium crocetinate; D014801:Vitamin A; D002338:Carotenoids; C006680:baicalein; C045309:schisanhenol; D020122:tert-Butylhydroperoxide; D000077185:Resveratrol