title: Anti-osmotic and antioxidant activities of gigantol from Dendrobium aurantiacum var. denneanum against cataractogenesis in galactosemic rats.
abstract: BACKGROUND
  Dendrobium aurantiacum var. denneanumis widespread in southern China, locally known as "Shihu", "Huangcao" or "Fengdou", has long been used in traditional Chinese medicine for antipyretic, immunomodulatory, anti-aging effects and eye benefiting.
  
  
  OBJECTIVE
  To investigate the effects of gigantol extracted from the stem of D. aurantiacum var. denneanum on the formation of galactose-induced cataractogenesis and the potential mechanisms underlying these effects.
  
  
  METHODS
  Cataract lens models were induced by d-galactose both in vitro and in vivo. The transparency of the rat lenses in vitro and in vivo was observed with an anatomical microscope and a slit lamp microscope. The differential protein and action targets of gigantol were determined and compared among the control group, model group, and gigantol group using two-dimensional electrophoresis and mass spectrometry (MS). Enzyme kinetics was used to show the ability of gigantol to respress aldose reductase (AR) and inducible nitric oxide synthase (iNOS). Quantitative real-time PCR (RT-qPCR). was used to detect repression of the expression of AR and iNOS genes. Molecular docking and dynamic simulation were used to predict the interaction points and combination patterns between gigantol, AR, and iNOS.
  
  
  RESULTS
  Gigantol was found to prevent galactose-induced damage to the rat lenses both in vitro and in vivo, to delay lens turbidity, and to keep the lenses transparent. Differential proteomes, MS, and RT-qPCR showed AR and iNOS to be the target proteins of gigantol. Gigantol reduced the galactose-induced AR and iNOS mRNA expression by 51.2% and 60.9%, respectively. The IC50 of gigantol for inhibition of AR and iNOS activities were 65.67 μg/mL and 8.768 μg/mL, respectively. Gigantol-AR binding sites were Trp111, His110, Tyr48, and Trp20, and gigantol-iNOS binding sites were Ile195 and Gln257. The main forms of interaction were hydrophobic forces, hydrogen bonds, and van der Waals forces.
  
  
  CONCLUSIONS
  Gigantol extracted from D. aurantiacum var. denneanum was found to inhibit galactose-induced formation of cataracts through repression of the gene expression and activity of AR and iNOS.
authors.affiliation: School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China.
authors.forename: Hua
authors.initials: H
authors.lastname: Fang
authors.affiliation: School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Hu
authors.affiliation: School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China.
authors.forename: Meiling
authors.initials: M
authors.lastname: Wang
authors.affiliation: School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China.
authors.forename: Wencheng
authors.initials: W
authors.lastname: Wan
authors.affiliation: School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China.
authors.forename: Qiaohong
authors.initials: Q
authors.lastname: Yang
authors.affiliation: School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China.
authors.forename: Xiaosheng
authors.initials: X
authors.lastname: Sun
authors.affiliation: Institute of Drug Synthesis and Pharmaceutical Processing, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510275, PR China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Gu
authors.affiliation: School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Gao
authors.affiliation: Shanghai R&D Center for Standardization of Chinese Medicines, Institute of Chinese Materia Medica of Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China.
authors.forename: Zhengtao
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Institute of Drug Synthesis and Pharmaceutical Processing, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510275, PR China.
authors.forename: Lianquan
authors.initials: L
authors.lastname: Gu
authors.affiliation: Antioxidants Research Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA.
authors.forename: C-Y
authors.initials: CY
authors.lastname: Oliver Chen
authors.affiliation: School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China; Antioxidants Research Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA. Electronic address: jidewowxy@163.com.
authors.forename: Xiaoyong
authors.initials: X
authors.lastname: Wei
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000302:isolation & purification / Q000494:pharmacology*; D001632:Bibenzyls / Q000302:isolation & purification / Q000494:pharmacology*; D002386:Cataract / Q000209:etiology / Q000517:prevention & control*; D031667:Dendrobium / Q000737:chemistry*; D004365:Drugs, Chinese Herbal; D005693:Galactosemias / Q000150:complications; D006139:Guaiacol / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D007908:Lens, Crystalline / Q000187:drug effects / Q000473:pathology; D008516:Medicine, Chinese Traditional; D062105:Molecular Docking Simulation; D009997:Osmotic Pressure / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D000975:Antioxidants; D001632:Bibenzyls; D004365:Drugs, Chinese Herbal; C478099:gigantol; D006139:Guaiacol
keywords: Aldose reductase (AR); Ammonium acetate (PubChem CID: 517165); Butyl alcohol (PubChem CID: 263); Cataract; D-galactose (PubChem CID: 86278404); DL-glyceraldehyde (PubChem CID: 24895192).; Dendrobii; Dichloromethane (PubChem CID: 6344); Dimethyl sulfoxide (PubChem CID: 679); Ethanol (PubChem CID: 702); Ethyl acetate (PubChem CID: 8857); Gigantol; Gigantol (PubChem CID: 10221179); Inducible nitric oxide synthase (iNOS); L-arginine (PubChem CID: 6322); Mechanisms; Methanol (PubChem CID: 887); NADPH (PubChem CID: 52945042); Pencillin G (PubChem CID: 5904); Pirenoxine sodium (PubChem CID: 23695982); Streptomycin (PubChem CID: 19649); Tetrahydrobiopterin (PubChem CID: 1125); Trifluoroacetic acid (PubChem CID: 6422)