title: Effect of Hedyotis diffusa water extract on protecting human hepatocyte cells (LO2) from H2O2-induced cytotoxicity.
abstract: BACKGROUND
  Natural products are good sources of natural dietary antioxidants that are believed to protect the body against hepatotoxic effect induced by oxidative stress. Hedyotis diffusa Willd (Rubiaceae) (HDW) is a traditional Chinese medicinal herb that has been shown to possess a variety of antioxidant properties.
  
  
  OBJECTIVE
  The present study examines and explains the cell protective property of HDW water extract (WEHDW).
  
  
  METHODS
  2,2-Diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) assay was used to measure the free radical scavenging property of WEHDW (0.001-10 mg/mL). The protective effect of WEHDW (0.3-10 mg/mL 2 h pretreatment) against hydrogen peroxide (H2O2, 200 μM for 6 h) induced cytotoxicity in human hepatic cells, LO2, was evaluated using cell viability assay and nuclear staining. The molecular pathway of WEHDW's effect was investigated by using Western blot assay.
  
  
  RESULTS
  WEHDW had a 50% scavenging concentration (SC50) at 0.153 mg/mL in the DPPH assay. Exposure of LO2 cells to H2O2 resulted in apoptosis which could be markedly attenuated by pre-treating WEHDW in a concentration-dependent manner (0.5, 1, 3, 5, or 10 mg/mL) (all with p < 0.001, versus control). Moreover, Hoechst (nuclear) staining showed that 1 mg/mL WEHDW could protect LO2 cells by attenuating apoptotic cell death mediated by H2O2. It was found that WEHDW reversed H2O2-induced activation of MEK/ERK pathway and H2O2-induced inhibition of P13-K/AKT/GSK3β pathway in LO2 cells.
  
  
  CONCLUSIONS
  WEHDW may help to improve the antioxidant defense system, resulting in prevention of oxidative stress-related fatty liver diseases.
authors.affiliation: a Food Safety and Technology Research Centre, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University , Hong Kong , China .|b School of Biological Sciences, The University of Hong Kong , Hong Kong , China .
authors.forename: Xin
authors.initials: X
authors.lastname: Gao
authors.affiliation: a Food Safety and Technology Research Centre, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University , Hong Kong , China .|b School of Biological Sciences, The University of Hong Kong , Hong Kong , China .
authors.forename: Chang
authors.initials: C
authors.lastname: Li
authors.affiliation: a Food Safety and Technology Research Centre, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University , Hong Kong , China .
authors.forename: Yee-Ling
authors.initials: YL
authors.lastname: Tang
authors.affiliation: a Food Safety and Technology Research Centre, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University , Hong Kong , China .|c State Key Laboratory of Chinese Medicine and Molecular Pharmacology , Shenzhen , China , and.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: a Food Safety and Technology Research Centre, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University , Hong Kong , China .|c State Key Laboratory of Chinese Medicine and Molecular Pharmacology , Shenzhen , China , and.|d Faculty of Science and Technology , Technological and Higher Education Institute of Hong Kong , Hong Kong , China.
authors.forename: Shun-Wan
authors.initials: SW
authors.lastname: Chan
mesh_terms: D000975:Antioxidants / Q000302:isolation & purification / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019610:Cytoprotection; D004305:Dose-Response Relationship, Drug; D032064:Hedyotis / Q000737:chemistry; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D006861:Hydrogen Peroxide / Q000633:toxicity*; D008517:Phytotherapy; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D015398:Signal Transduction / Q000187:drug effects; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D012997:Solvents; D014867:Water; D006861:Hydrogen Peroxide
keywords: Apoptosis; liver disease; reactive oxygen species; traditional Chinese medicinal herb