title: Autoxidation of gallic acid induces ROS-dependent death in human prostate cancer LNCaP cells.
abstract: BACKGROUND
  Prostate cancer is the second most common cause of mortality. Gallic acid (GA) is a natural polyphenol, and we tested its in-vitro cytotoxicity after 24 h in prostate cancer LNCaP cells.
  
  
  METHODS
  GA autoxidation was measured fluorimetrically for H(2)O(2), and O(2)(•-) radicals by chemiluminescence. Intracellular reactive oxygen species (ROS) levels were detected with 2',7'-dichlorodihydrofluorescein diacetate. Cytotoxicity was evaluated by crystal-violet, while apoptosis and mitochondrial membrane potential were determined by flow cytometry. Cytochrome c release was detected by enzyme-linked immunosorbent assay, and caspase-8, -9 and -3 activities were measured calorimetrically.
  
  
  RESULTS
  GA autoxidation produced significant levels of H(2)O(2) and O2.-. Increased intracellular ROS levels with GA were reduced by N-acetyl-L-cysteine (NAC) and L-glutathione (GSH). Cells were protected against GA cytotoxicity when pretreated with increasing levels of superoxide dismutase/catalase mixture, NAC, or GSH for 3 h. The number of apoptotic cells increased with GA dose. GA caused mitochondrial potential loss, cytochrome c release, and activation of caspases 3, 8 and 9.
  
  
  CONCLUSIONS
  The ROS-dependent apoptotic mechanism of GA kills malignant cells effectively; it is likely that GA could be a good anticancer agent.
authors.affiliation: Neuropharmacology Section, College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA.
authors.forename: Larry H
authors.initials: LH
authors.lastname: Russell
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Mazzio
authors.forename: Ramesh B
authors.initials: RB
authors.lastname: Badisa
authors.forename: Zhi-Ping
authors.initials: ZP
authors.lastname: Zhu
authors.forename: Maryam
authors.initials: M
authors.lastname: Agharahimi
authors.forename: Ebenezer T
authors.initials: ET
authors.lastname: Oriaku
authors.forename: Carl B
authors.initials: CB
authors.lastname: Goodman
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D005707:Gallic Acid / Q000737:chemistry / Q000494:pharmacology*; D005978:Glutathione / Q000494:pharmacology; D006801:Humans; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D010084:Oxidation-Reduction; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D005707:Gallic Acid; D045304:Cytochromes c; D020169:Caspases; D005978:Glutathione; D000111:Acetylcysteine