title: Honokiol induces reactive oxygen species-mediated apoptosis in Candida albicans through mitochondrial dysfunction.
abstract: OBJECTIVE
  To investigate the effects of honokiol on induction of reactive oxygen species (ROS), antioxidant defense systems, mitochondrial dysfunction, and apoptosis in Candida albicans.
  
  
  METHODS
  To measure ROS accumulation, 2',7'-dichlorofluorescein diacetate fluorescence was used. Lipid peroxidation was assessed using both fluorescence staining and a thiobarbituric acid reactive substances (TBARS) assay. Protein oxidation was determined using dinitrophenylhydrazine derivatization. Antioxidant enzymatic activities were measured using commercially available detection kits. Superoxide dismutase (SOD) genes expression was measured using real time RT-PCR. To assess its antifungal abilities and effectiveness on ROS accumulation, honokiol and the SOD inhibitor N,N'-diethyldithiocarbamate (DDC) were used simultaneously. Mitochondrial dysfunction was assessed by measuring the mitochondrial membrane potential (mtΔψ). Honokiol-induced apoptosis was assessed using an Annexin V-FITC apoptosis detection kit.
  
  
  RESULTS
  ROS, lipid peroxidation, and protein oxidation occurred in a dose-dependent manner in C. albicans after honokiol treatment. Honokiol caused an increase in antioxidant enzymatic activity. In addition, honokiol treatment induced SOD genes expression in C. albicans cells. Moreover, addition of DDC resulted in increased endogenous ROS levels and potentiated the antifungal activity of honokiol. Mitochondrial dysfunction was confirmed by measured changes to mtΔψ. The level of apoptosis increased in a dose-dependent manner after honokiol treatment.
  
  
  CONCLUSIONS
  Collectively, these results indicate that honokiol acts as a pro-oxidant in C. albicans. Furthermore, the SOD inhibitor DDC can be used to potentiate the activity of honokiol against C. albicans.
authors.affiliation: Department of Pharmacology, Medical School of Southeast University, Nanjing, China.
authors.forename: Lingmei
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Pathology and Pathophysiology, Medical School of Southeast University, Nanjing, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Liao
authors.affiliation: Department of Pharmacology, Medical School of Southeast University, Nanjing, China.
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Hang
authors.affiliation: Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Medical School of Southeast University, Nanjing, China.
authors.forename: Dayong
authors.initials: D
authors.lastname: Wang
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001713:Biphenyl Compounds / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D004050:Ditiocarb / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D017705:Lignans / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D010084:Oxidation-Reduction / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000498:Allyl Compounds; D010636:Phenols
chemical_list: D000890:Anti-Infective Agents; D001713:Biphenyl Compounds; D004050:Ditiocarb; D017705:Lignans; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase; C005499:honokiol; D000498:Allyl Compounds; D010636:Phenols