OBJECTIVETo optimize the hydrolysis process of linarin by response surface methodology, and to use the model of aldose reductase to study the acacetin's activity of aldose reductase inhibitory.

METHODThe model of acacetin enzyme in vitro was established by the determination of fluorescence absorption of NADPH, the inhibition rate of acacetin aldose reductase was calculated, and then the IC50 of hydrolysis was obtained. The hydrolysis process of linarin hydrolysis condition was optimized by using response surface method.

RESULTThe results indicated that the IC50 of acacetin (2.74 mg x L(-1)) was less than the IC50 of linarin (3.53 mg x L(-1)). Hydrolyzation time of 7.4 h, sulphuric acid concentration of 0.54 mol x L(-1) and the ratio of material to liquid of 3 : 1 were the optimum conditions.

CONCLUSIONHydrolyzate acacetin has preferable inhibitory activity of aldose reductase. The optimized hydrolysis condition of linarin is convenient to use with good predictability.

Aldehyde Reductase ; antagonists & inhibitors ; metabolism ; Animals ; Diabetic Retinopathy ; enzymology ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Enzyme Inhibitors ; chemistry ; pharmacology ; Flavones ; chemistry ; Glycosides ; chemistry ; pharmacology ; Glycosylation ; Humans ; Hydrolysis ; Male ; Rats ; Rats, Wistar ; Retina ; enzymology

OBJECTIVETo investigate the chemical compounds from the ethanol extract with inhibitory effects against aldose reductase from Thunbergia.

METHODGuided by anti-aldose reductase assay, compounds from the bioactive fraction (ethyl acetate extract) were separated and purified by various chromatographic methods including silica gel, Sephadex LH-20, and reversed-phase HPLC. Their structures were indentified based on analysis of the spectroscopic data including 1D and 2D NMR data.

RESULTEight compounds were obtained and identified as 8-hydroxy-8-methyl-9-methene-cyclopentane [7,11] -1,4, 6-trihydroxy-tetrahydronaphthalene-12-one, named as thunbergia A (1), 3,4-dihydro-4,5,8-trihydroxy-2-(3-methyl-2-butenyl) naphtha[2,3-b] oxiren-1(2H)-one (2), 8-(beta-gluco pyranosyloxy)-3,4-dihydro-2-(3-methyl-2-butenyl)naphtha [2,3-b] oxiren-1(2H)-one (3), galangin (4), quercetin (5), luteolin (6), 5,6,3',4'-tetrahydroxy -3,7-dimethoxy-flavone (7) and upeol (8).

CONCLUSIONThunbergia A was a new derivative of tetrahydronaphthalene, and compounds 2 and 3 were separated from the genus Thunbergia for the first time.

Acanthaceae ; chemistry ; Aldehyde Reductase ; antagonists & inhibitors ; Animals ; Nuclear Magnetic Resonance, Biomolecular ; Plant Extracts ; chemistry ; isolation & purification ; pharmacology ; Plant Roots ; chemistry ; Rats

OBJECTIVEIsoliquiritigenin (ISL), a licorice chalconoid, is considered to be a bioactive agent with chemopreventive potential. This study investigates the mechanisms involved in ISL-induced apoptosis in human cervical carcinoma HeLa cells.

METHODSCell viability was evaluated using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) assay. Apoptosis was determined by flow cytometry using an Annexin V-FITC Apoptosis Detection Kit. The intracellular ROS levels were assessed using a 2, 7-dichlorofluorescein probe assay. The mitochondrial membrane potential was measured with the dual-emission potential-sensitive probe 5, 5', 6, 6'-tetra-chloro-1, 1', 3, 3'-tetraethyl-imidacarbocyanine iodide (JC-1). The degradation of poly-ADP-ribose polymerase (PARP) protein, the phosphorylation of PKR-like ER kinase (PERK), the phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α), the expression of the 78 kD glucose-regulated protein (GRP 78), and the activation of caspase-12 were analyzed via western blot analysis.

RESULTSISL significantly inhibited the proliferation, the increase in ROS levels and apoptotic rates of HeLa cells in a concentration-dependent manner. Moreover, ISL induced mitochondrial dysfunction, caspase activation, and PARP cleavage, which displayed features of mitochondria dependent on apoptotic signals. Besides, exposure of HeLa cells to ISL triggered endoplasmic reticulum (ER) stress, as indicated by the increase in p-eIF2α and GRP78 expression, ER stress-dependent apoptosis is caused by the activation of ER-specific caspase-12.

CONCLUSIONThe findings from our study suggest that ISL-induced oxidative stress causes HeLa cell apoptosis via the mitochondrion-dependent and the ER stress-triggered signaling pathways.

Aldehyde Reductase ; antagonists & inhibitors ; Apoptosis ; drug effects ; Cell Survival ; drug effects ; Chalcones ; pharmacology ; therapeutic use ; Chemoprevention ; Drug Screening Assays, Antitumor ; Endoplasmic Reticulum Stress ; drug effects ; HeLa Cells ; Humans ; Mitochondria ; drug effects ; Neoplasms ; prevention & control ; Reactive Oxygen Species ; metabolism

OBJECTIVETo study the protective effect of epalrestat against endothelial cell injuries induced by high glucose.

METHODSHuman umbilical vein endothelial cells were pretreated with epalrestat (0.1 µmol/L) for 30 min followed by exposure to high glucose for 8 h. NO concentration in the cell culture supernatant was assayed using chemiluminescence method following the exposure. Real-time PCR and Western blotting were used to detect eNOS mRNA and protein expression levels and the protein expressions of AR gene (the target gene of epalrestat) and NOX4 (the upstream gene of NO).

RESULTSCompared with mannitol treatment, an 8-h exposure to high glucose caused significantly decreased NO levels and eNOS mRNA and protein expression in the vascular endothelial cells (P<0.05). Pretreatment with epalrestat prior to high glucose exposure resulted in elevated eNOS mRNA and protein expression levels and NO up-regulation in the cell culture as compared with the glucose exposure alone group (P<0.05), causing also decreased expression of AR and NOX4 in the cells.

CONCLUSIONSHigh glucose can induce endothelial cell damage characterized by a lowered level of NO secretion. Epalrestat can protect the endothelial cells against high glucose-induced injury by inhibiting the expression of AR and NOX4.

Aldehyde Reductase ; antagonists & inhibitors ; Cells, Cultured ; Endothelium, Vascular ; drug effects ; metabolism ; Enzyme Inhibitors ; pharmacology ; Glucose ; adverse effects ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; Humans ; NADPH Oxidase 4 ; NADPH Oxidases ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; RNA, Messenger ; genetics ; Rhodanine ; analogs & derivatives ; pharmacology ; Thiazolidines ; pharmacology

OBJECTIVETo study the anti-cataract effect of gigantol combined with syringic acid and their action mechanism.

METHODH202-induced lens oxidative injury in vitro rat model was establish to observe the impact of gigantol combined with syringic acid on lens transparency under a dissecting microscope. D-galactose-induced cataract rat model was established to observe the impact of gigantol combined with syringic acid on lens transparency under a slit-lamp. UV spectrophotometry was adopted to detect the inhibitory activity of gigantol combined with syringic acid against AR. Molecular docking method was used to detect binding sites, binding types and pharmacophores of gigantol combined with syringic acid in prohibiting aldose reductase.

RESULTBoth in vitro and in vivo experiments showed a good anti-sugar cataract activity in the combination of gigantol and syringic acid and a better collaborative effect than single component-gigantol and syringic acid and positive control drug Catalin. Molecular docking and dynamic simulation showed their collaborative AR-inhibiting amino acid residue was Asn160 and the major acting force was Van der Waals' force, which formed common pharmacophores.

CONCLUSIONGigantol combined with syringic acid shows good anti-cataract, their action mechanism is reflected in their good collaborative inhibitory effect on AR.

Aldehyde Reductase ; antagonists & inhibitors ; Animals ; Bibenzyls ; Cataract ; drug therapy ; enzymology ; Drug Synergism ; Female ; Gallic Acid ; analogs & derivatives ; pharmacology ; Guaiacol ; analogs & derivatives ; pharmacology ; Humans ; In Vitro Techniques ; Lens, Crystalline ; drug effects ; enzymology ; Male ; Rats ; Rats, Wistar

OBJECTIVETo evaluate the aldose reductase inhibitory (ARI) activity of different fractions of Hybanthus enneaspermus for potential use in diabetic cataract.

METHODSTotal phenol and flavonoid content of different fractions was determined. ARI activity of different fractions in rat lens was investigated in vitro.

RESULTSThe results showed significant level of phenolic and flavonoid content in ethyl acetate fraction [total phenol (212.15±0.79 mg/g), total flavonoid (39.11±2.27 mg/g)] and aqueous fraction [total phenol (140.62±0.57 mg/g), total flavonoid (26.07±1.49 mg/g)] as compared with the chloroform fraction [total phenol (68.56±0.51 mg/g), total flavonoid (13.41±0.82 mg/g)] and petrolium ether fraction [total phenol (36.68±0.43 mg/g), total flavonoid (11.55±1.06 mg/g)]. There was a significant difference in the ARI activity of each fraction, and it was found to be the highest in ethyl acetate fraction [IC50 (49.26±1.76 µg/mL)] followed by aqueous extract [IC50 (70.83±2.82 µg/mL)] and it was least in the petroleum ether fraction [IC50 (118.89±0.71 µg/mL)]. Chloroform fraction showed moderate activity [IC50 (98.52±1.80 µg/mL)].

CONCLUSIONSDifferent fractions showed significanct amount of ARI activity, where in ethyl acetate fraction it was found to be maximum which may be due to its high phenolic and flavonoid content. The extract after further evaluation may be used in the treatment of diabetic cataract.

Aldehyde Reductase ; antagonists & inhibitors ; Animals ; Cataract ; drug therapy ; prevention & control ; Diabetes Complications ; drug therapy ; prevention & control ; Diabetes Mellitus ; pathology ; Flavonoids ; analysis ; Lens, Crystalline ; enzymology ; Phenols ; analysis ; Plant Extracts ; pharmacology ; Rats ; Rats, Wistar ; Violaceae ; metabolism

PURPOSE: The vascular endothelial growth factor (VEGF) expression of podocyte is one of the well-known major factors in development of diabetic nephropathy. In this study, we investigated the effects of aldose reductase inhibitor, fidarestat on diabetic nephropathy, and renal VEGF expression in a type 1 diabetic rat model. MATERIALS AND METHODS: Twenty four Sprague-Dawley male rats which were performed intraperitoneal injection of streptozotocin and normal six rats were divided into four groups including a normal control group, untreated diabetic control group, aldose reductase (AR) inhibitor (fidarestat, 16 mg.kg(-1).day(-1)) treated diabetic group, and angiotensin receptor blocker (losartan, 20 mg.kg(-1).day(-1)) treated diabetic group. We checked body weights and blood glucose levels monthly and measured urine albumin-creatinine ratio (ACR) at 8 and 32 weeks. We extracted the kidney to examine the renal morphology and VEGF expressions. RESULTS: The ACR decreased in fidarestat and losartan treated diabetic rat groups than in untreated diabetic group (24.79 +/- 11.12, 16.11 +/- 9.95, and 84.85 +/- 91.19, p < 0.05). The renal VEGF messenger RNA (mRNA) and protein expression were significantly decreased in the fidarestat and losartan treated diabetic rat groups than in the diabetic control group. CONCLUSION: We suggested that aldose reductase inhibitor may have preventive effect on diabetic nephropathy by reducing renal VEGF overexpression.
Aldehyde Reductase/*antagonists & inhibitors ; Animals ; Antihypertensive Agents/therapeutic use ; Diabetes Mellitus, Experimental/*drug therapy/*metabolism ; Diabetic Nephropathies/prevention & control ; Imidazolidines/*therapeutic use ; Kidney/*drug effects/*metabolism/pathology ; Losartan/therapeutic use ; Male ; Rats ; Rats, Sprague-Dawley ; Receptors, Angiotensin/*antagonists & inhibitors ; Vascular Endothelial Growth Factor A

OBJECTIVETo study the effect of PKC signalling pathway and aldose reductase (AR) on the expression of fibronectin (FN) induced by transforming growth factor-β1 (TGF-β1).

METHODSHuman mesangial cells (HMCs) were cultured and transfected with pcDNA3-AR, and subject to AR gene silencing with small interfering RNA (siRNA) and then the cell was treated with recombinant human TGF-β1. The AR mRNA expression in the HMCs was examined using real time RT-PCR and protein expression of AR and FN was detected by Western blotting.

RESULTSThe cultured HMC treated with TGF-β1 showed increased expression of AR and FN, the normal HMC showed not reduced expression of FN after incubation with single inhibitors of AR.Pre-incubation of cells with inhibitors of AR and PKC, then the different groups of cells were treated with TGF-β1, and the induction effect on FN expression was suppressed (34%) in HMC. HMCs transfected with AR showed a strong protein expression of FN, which was increased by 3.6-fold after treatment with TGF-β1 (P < 0.05), and the induction effect on FN expression was suppressed by GÖ6983 (42%) in HMCs (P < 0.05). The HMC with AR gene knock-down by siRNA showed a decreased expression of AR and 90% decrease of FN protein in HMCs (P < 0.01), and TGF-β1-induced up-regulation of FN was significantly suppressed by siRNA (12%) in HMCs (P < 0.01).

CONCLUSIONSAR is capable of regulating FN expression only in the presence of TGF-β1, and this reaction is possibly accomplished through the activation of PKC signalling pathway.

Aldehyde Reductase ; antagonists & inhibitors ; biosynthesis ; genetics ; Benzothiazoles ; pharmacology ; Carbazoles ; pharmacology ; Cells, Cultured ; Fibronectins ; metabolism ; Gene Knockdown Techniques ; Humans ; Indoles ; Maleimides ; Mesangial Cells ; cytology ; metabolism ; Phthalazines ; pharmacology ; Protein Kinase C ; antagonists & inhibitors ; metabolism ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; genetics ; Signal Transduction ; Transfection ; Transforming Growth Factor beta1 ; pharmacology ; Up-Regulation

Aldose reductase is a member of aldehyde-keto reductase superfamily widely existing in the kidney, adrenal gland, lens, retina, nerve, heart, placenta, brain, skeletal muscle, testis, blood vessels, lung, liver, et al. It is a reduced nicotinamide-adenine dinucleotide phosphate (NADPH)-dependent enzyme catalyzing the reduction of various aldehydes and ketones to the corresponding alcohol. It is involved in many oxidative stress diseases, cell signal transduction and cell proliferation process as well as diabetes complications. In recent years, some progress has been made in research of the activity and gene regulation of aldose reductase and the relation with many common diseases.
Aldehyde Reductase ; antagonists & inhibitors ; metabolism ; physiology ; Animals ; Cell Proliferation ; Diabetes Complications ; drug therapy ; enzymology ; Enzyme Inhibitors ; therapeutic use ; Humans ; Oxidative Stress ; Rhodanine ; analogs & derivatives ; therapeutic use ; Signal Transduction ; Thiazolidines ; therapeutic use

Epalrestat is the unique aldose reductase inhibitor on the market, which was mainly used for the diabetic neuropathy. Lenses osmotic expansion could be induced by galactose to mimic the pathological process of diabetic cataract in vitro. In present study, we mainly investigated whether epalrestat possesses inhibitory effect on the lens osmotic expansion. The results indicated that epalrestat could not only markedly inhibit rat lens osmotic expansion in vitro, but also significantly reduced the high expression of the osmotic expansion-related genes such as AR and AQP1 in mRNA and protein levels. The findings may provide an important reference to epalrestat in the clinical application for the treatment of diabetic cataract.
Aldehyde Reductase ; antagonists & inhibitors ; biosynthesis ; genetics ; Animals ; Aquaporin 1 ; genetics ; metabolism ; Cataract ; etiology ; metabolism ; pathology ; Diabetes Mellitus, Experimental ; complications ; Enzyme Inhibitors ; pharmacology ; Galactose ; antagonists & inhibitors ; Lens, Crystalline ; drug effects ; metabolism ; pathology ; Male ; Osmosis ; drug effects ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley ; Rhodanine ; analogs & derivatives ; pharmacology ; Thiazolidines ; pharmacology