Hispidin in the Medicinal Fungus Protects Dopaminergic Neurons from JNK Activation-Regulated Mitochondrial-Dependent Apoptosis in an MPP+-Induced In Vitro Model of Parkinson's Disease.

Degenerative diseases of the brain include Parkinson's disease (PD), which is associated with moveable signs and is still incurable. Hispidin belongs to polyphenol and originates primarily from the medicinal fungi Inonotus and Phellinus, with distinct biological effects. In the study, MES23.5 cells were induced by 1-methyl-4-phenylpyridinium (MPP+) to build a cell model of PD in order to detect the protective effect of hispdin and to specify the underlying mechanism. Pretreatment of MES23.5 cells with 1 h of hispdin at appropriate concentrations, followed by incubation of 24 h with 2 µmol/L MPP+ to induce cell damage. MPP+ resulted in reactive oxygen species production that diminished cell viability and dopamine content. Mitochondrial dysfunction in MS23.5 cells exposed to MPP+ was observed, indicated by inhibition of activity in the mitochondrial respiratory chain complex I, the collapse of potential in mitochondrial transmembrane, and the liberation of mitochondrial cytochrome c. Enabling C-Jun N-terminal kinase (JNK), reducing Bcl-2/Bax, and enhancing caspase-9/caspase-3/PARP cleavage were also seen by MPP+ induction associated with increased DNA fragmentation. All of the events mentioned above associated with MPP+-mediated mitochondrial-dependent caspases cascades were attenuated under cells pretreatment with hispidin (20 µmol/L); similar results were obtained during cell pretreatment with pan-JNK inhibitor JNK-IN-8 (1 µmol/L) or JNK3 inhibitor SR3576 (25 µmol/L). The findings show that hispidin has neuroprotection against MPP+-induced mitochondrial dysfunction and cellular apoptosis and suggest that hispidin can be seen as an assist in preventing PD.

p-Hydroxybenzyl Alcohol Antagonized the ROS-Dependent JNK/Jun/Caspase-3 Pathway to Produce Neuroprotection in a Cellular Model of Parkinson's Disease.

Parkinson's disease (PD) is a progressive disorder that affects brain nerve cells responsible for body motion and remains incurable. p-Hydroxybenzyl alcohol (HBA) is the primary phenolic compound in Gastrodiae Rhizoma, known for its therapeutic benefits against neurodegeneration. However, the protective effect of HBA against Parkinson's disease (PD) remains unclear. The objective of this study was to evaluate the neuroprotective effects of HBA in vitro 6-hydroxydopamine (6-OHDA)-induced PD model in SH-SY5Y cells. SH-SY5Y cells were pretreated with various concentrations of HBA for 1 h and incubated with 100 µmol/L 6-OHDA for 24 h to induce cellular lesions. 2,5-Diphenyl-2H-tetrazolium bromide was used to detect cellular viability. 2',7'-dichlorofluorescin oxidation detects reactive oxygen species (ROS). The enzyme-linked immunosorbent assay was used to determine the activities of superoxide dismutase, catalase, and glutathione peroxidase. The cellular mitochondrial function was identified through the collapse of the mitochondrial membrane potential, the release of cytochrome c, and the synthesis of mitochondrial ATP. Expression of pro-and anti-apoptotic factors was measured by Western blot. HBA enhanced cell viability, blocked ROS overproduction, and reduced antioxidant activities induced by 6-OHDA. HBA also reduced mitochondrial dysfunction and cell death caused by 6-OHDA. Moreover, HBA reversed the 6-OHDA-mediated activation of c-Jun N-terminal kinase, the downregulation of the Bcl-2/Bax ratio, the Apaf-1 upregulation and the induction of caspase-9, caspase-3, and PARP cleavage. This study shows that the protective effects of HBA against 6-OHDA-induced cell injury provide the potential preventive effects of HBA, making it a promising preventive agent for PD.

Diosmetin Targeted at Peroxisome Proliferator-Activated Receptor Gamma Alleviates Advanced Glycation End Products Induced Neuronal Injury.

The present study aimed to evaluate the role of diosmetin in alleviating advanced glycation end products (AGEs)-induced Alzheimer's disease (AD)-like pathology and to clarify the action mechanisms. Before stimulation with AGEs (200 µg/mL), SH-SY5Y cells were treated with diosmetin (10 µmol/L), increasing cell viability. The induction of AGEs on the reactive oxygen species overproduction and downregulation of antioxidant enzyme activities, including superoxide dismutase, glutathione peroxidase, and catalase, were ameliorated by diosmetin. Amyloid precursor protein upregulation, accompanied by increased production of amyloid-ß, caused by AGEs, was reversed by diosmetin. In the presence of diosmetin, not only ß-site amyloid precursor protein cleaving enzyme1 expression was lowered, but the protein levels of insulin-degrading enzyme and neprilysin were elevated. Diosmetin protects SH-SY5Y cells from endoplasmic reticulum (ER) stress response to AGEs by suppressing ER stress-induced glucose regulated protein 78, thereby downregulating protein kinase R-like endoplasmic reticulum kinase, eukaryotic initiation factor 2 α, activating transcription factor 4, and C/EBP homologous protein. Diosmetin-pretreated cells had a lower degree of apoptotic DNA fragmentation; this effect may be associated with B-cell lymphoma (Bcl) 2 protein upregulation, Bcl-2-associated X protein downregulation, and decreased activities of caspase-12/-9/-3. The reversion of diosmetin on the AGEs-induced harmful effects was similar to that produced by pioglitazone. The peroxisome proliferator-activated receptor (PPAR)γ antagonist T0070907 (5 µmol/L) abolished the beneficial effects of diosmetin on AGEs-treated SH-SY5Y cells, indicating the involvement of PPARγ. We conclude that diosmetin protects neuroblastoma cells against AGEs-induced ER injury via multiple mechanisms and may be a potential option for AD.

The Citrus Flavonoid Hesperetin Encounters Diabetes-Mediated Alzheimer-Type Neuropathologic Changes through Relieving Advanced Glycation End-Products Inducing Endoplasmic Reticulum Stress.

The present study investigates whether hesperetin, a citrus flavonoid, can encounter advanced glycation end-product (AGE)-induced Alzheimer's disease-like pathophysiological changes with the underlying mechanisms. SH-SY5Y cells pretreated with hesperetin before stimulation with AGEs (200 µg/mL) were assessed in the following experiments. Hesperetin (40 µmol/L) elevated the reduced cell viability induced by AGEs. Hesperetin ameliorated reactive oxygen species overproduction and the downregulation of superoxide dismutase, glutathione peroxidase, and catalase, triggered by AGEs. Amyloid precursor protein upregulation, accompanied by the increased production of Aß, caused by AGEs, was reversed by hesperetin. However, hesperetin lowered ß-site APP-cleaving enzyme 1 expression, inducing insulin-degrading and neprilysin expression. In addition, hesperetin downregulated the expressions of the AGEs-induced endoplasmic reticulum (ER) stress proteins, including 78-kDa glucose-regulated protein and C/EBP homologous protein, and lowered the phosphorylation of protein kinase R-like ER kinase and activating transcription factor 4. Hesperetin-pretreated cells had a minor apoptotic DNA fragmentation. Hesperetin is able to upregulate Bcl-2 protein expression, downregulate Bax expression, and decrease caspase-12/-9/-3 activity as well, indicating that it inhibits ER stress-mediated neuronal apoptosis. There is a similar effect between hesperetin and positive rosiglitazone control against Aß aggravation of SH-SY5Y cell injury induced by AGEs. Thus, hesperetin might be a potential agent for treating glycation-induced Aß neurotoxicity.

A Bibenzyl Component Moscatilin Mitigates Glycation-Mediated Damages in an SH-SY5Y Cell Model of Neurodegenerative Diseases through AMPK Activation and RAGE/NF-κB Pathway Suppression.

Moscatilin can protect rat pheochromocytoma cells against methylglyoxal-induced damage. Elimination of the effect of advanced glycation end-products (AGEs) but activation of AMP-activated protein kinase (AMPK) are the potential therapeutic targets for the neurodegenerative diseases. Our study aimed to clarify AMPK signaling's role in the beneficial effects of moscatilin on the diabetic/hyperglycemia-associated neurodegenerative disorders. AGEs-induced injury in SH-SY5Y cells was used as an in vitro neurodegenerative model. AGEs stimulation resulted in cellular viability loss and reactive oxygen species production, and mitochondrial membrane potential collapse. It was observed that the cleaved forms of caspase-9, caspase-3, and poly (ADP-ribose) polymerase increased in SH-SY5Y cells following AGEs exposure. AGEs decreased Bcl-2 but increased Bax and p53 expression and nuclear factor kappa-B activation in SH-SY5Y cells. AGEs also attenuated the phosphorylation level of AMPK. These AGEs-induced detrimental effects were ameliorated by moscatilin, which was similar to the actions of metformin. Compound C, an inhibitor of AMPK, abolished the beneficial effects of moscatilin on the regulation of SH-SY5Y cells' function, indicating the involvement of AMPK. In conclusion, moscatilin offers a promising therapeutic strategy to reduce the neurotoxicity or AMPK dysfunction of AGEs. It provides a potential beneficial effect with AGEs-related neurodegenerative diseases.

The protective effects of moscatilin against methylglyoxal-induced neurotoxicity via the regulation of p38/JNK MAPK pathways in PC12 neuron-like cells.

Methylglyoxal (MGO) is an endogenous toxic compound that plays a vital role in diabetic complications such as diabetic neuropathy. Moscatilin is a bibenzyl component from Dendrobium species, has been shown to possess a wide range of pharmacological activities. To clarify whether moscatilin prevents rat pheochromocytoma cells (PC12 cells) from damage induced by MGO, cells were pre-treated with moscatilin and then stimulated with MGO. Moscatilin inhibited MGO associated cytotoxicity in a concentration (0.1, 0.5, or 1.0 µmol/L)-dependent manner and downregulated the formation of advanced glycation end products and reactive oxygen species. Moscatilin attenuated MGO-induced mitochondrial dysfunction involving the loss of mitochondrial membrane potential and depletion of adenosine triphosphate. MGO induced cell apoptosis via the upregulation of p53, caspases 3 and poly(ADP-ribose)polymerase, enhancement of cytochrome c release, and interruption of the Bax/Bcl-2 balance; these detrimental effects were ameliorated by moscatilin. Furthermore, moscatilin inhibited MGO-induced activation of MAP kinase (MAPK) superfamily, including p38 and c-Jun N-terminal kinases (JNKs). In conclusion, we found that the neuroprotective effect of moscatilin is due to a reduction of MGO-induced damage to mitochondria function through modulating the p38 and JNK stress-activated MAPK cascades pathway. Thus, it might be a potent compound for preventing/counteracting diabetic neuropathy.

Erianin protects against high glucose-induced oxidative injury in renal tubular epithelial cells.

Erianin is the major bibenzyl compound found in Dendrobium chrysotoxum Lindl. The current study was designed to investigate the protective effects of erianin on high glucose-induced injury in cultured renal tubular epithelial cells (NRK-52E cells) and determine the possible mechanisms for its effects. NRK-52E cells were pretreated with erianin (5, 10, 25 or 50 nmol/L) for 1 h followed by further exposure to high glucose (30 mmol/L, HG) for 48 h. Erianin concentration dependently enhanced cell viability followed by HG treatment in NRK-52E cells. HG induced reactive oxygen species (ROS) generation, malondialdehyde production, and glutathione deficiency were recovered in NRK-52E cells pretreated with erianin. HG triggered cell apoptosis via the loss of mitochondrial membrane potential, depletion of adenosine triphosphate, upregulation of caspases 9 and 3, enhancement of cytochrome c release, and subsequent interruption of the Bax/Bcl-2 balance. These detrimental effects were ameliorated by erianin. HG also induced activation of p53, JNK, p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) in NRK-52E cells, which were blocked by erianin. The results suggest that treatment NRK-52E cells with erianin halts HG-induced renal dysfunction through the suppression of the ROS/MAPK/NF-κB signaling pathways. Our findings provide novel therapeutic targets for diabetic nephropathy.

Gigantol has Protective Effects against High Glucose-Evoked Nephrotoxicity in Mouse Glomerulus Mesangial Cells by Suppressing ROS/MAPK/NF-κB Signaling Pathways.

Gigantol is a bibenzyl compound derived from several medicinal orchids. This biologically active compound has shown promising therapeutic potential against diabetic cataracts, but whether this compound exerts beneficial effects on the other diabetic microvascular complications remains unclear. This study was carried out to examine effects of gigantol on high glucose-induced renal cell injury in cultured mouse kidney mesangial cells (MES-13). MES-13 cells were pretreated with gigantol (1, 5, 10 or 20 µmol/L) for 1 h followed by further exposure to high (33.3 mmol/L) glucose for 48 h. Gigantol concentration dependently enhanced cell viability followed by high glucose treatment in MES-13 cells. High glucose induced reactive oxygen species (ROS) generation, malondialdehyde production and glutathione deficiency were recoved in MES-13 cells pretreated with gigantol. High glucose triggered cell apoptosis via the the loss of mitochondrial membrane potential, depletion of adenosine triphosphate, upregulation of caspases 9 and 3, enhancement of cytochrome c release, and subsequent interruption of the Bax/Bcl-2 balance. These detrimental effects were ameliorated by gigantol. High glucose also induced activation of JNK, p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) in MES-13 cells, which were blocked by gigantol. The results suggest that treatment MES-13 cells with gigantol halts high glucose-induced renal dysfunction through the suppression of the ROS/MAPK/NF-κB signaling pathways. Our data are of value to the understanding the mechanism for gigantol, and would benefit the study of drug development or food supplement for diabetes and nephropathy.

Hesperidin Prevents High Glucose-Induced Damage of Retinal Pigment Epithelial Cells.

The present study aimed to determine whether hesperidin, a plant-based active flavanone found in citrus fruits, can prevent high glucose-induced retinal pigment epithelial (RPE) cell impairment. Cultured human RPE cells (ARPE-19) were exposed to a normal glucose concentration (5.5 mM) for 4 d and then soaked in either normal (5.5 mM) or high (33.3 mM) concentrations of D-glucose with or without different concentrations of hesperidin (10, 20, or 40 µM) for another 48 h. The survival rates of the cells were measured using a 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide reduction assay. With the help of a fluorescent probe, the intracellular production of reactive oxygen species (ROS) was evaluated. Colorimetric assay kits were used to assess the antioxidant enzyme activities, and western blotting was used to measure the expression of apoptosis-related protein. Hesperidin was effective in inhibiting high glucose-induced ROS production, preventing loss of cell viability, and promoting the endogenous antioxidant defense components, including glutathione peroxidase, superoxide dismutase, catalase, and glutathione, in a concentration-dependent manner. Furthermore, high glucose triggered cell apoptosis via the upregulation of caspase-9/3, enhancement of cytochrome c release into the cytosol, and subsequent interruption of the Bax/Bcl-2 balance. These detrimental effects were ameliorated by hesperidin in a concentration-dependent manner. We conclude that through the scavenging of ROS and modulation of the mitochondria-mediated apoptotic pathway, hesperidin may protect RPE cells from high glucose-induced injury and thus may be a candidate in preventing the visual impairment caused by diabetic retinopathy.

The Benefits of the Citrus Flavonoid Diosmin on Human Retinal Pigment Epithelial Cells under High-Glucose Conditions.

We investigate diosmin for its effect on the ARPE-19 human retinal pigment epithelial cells exposed to high glucose, a model of diabetic retinopathy (DR). After incubation for 4 days with a normal (5 mmol/L) concentration of D-glucose, ARPE-19 cells were exposed separately to normal or high concentrations of D-glucose (30 mmol/L) with or without diosmin at different concentrations (0.1, 1, 10 µg/mL) for another 48 h. Next, we assessed cell viability, reactive oxygen species (ROS) generation and antioxidant enzyme activities. In order to examine the underlying molecular mechanisms, we meanwhile analyzed the expressions of Bax, Bcl-2, total and phosphorylated JNK and p38 mitogen-activated protein kinase (MAPK). Diosmin dose dependently enhanced cell viability following high glucose treatment in ARPE-19 cells. The activities of superoxide dismutase and glutathione peroxidase, as well as the levels of reduced glutathione were decreased, while it was observed that levels of ROS in high glucose cultured ARPE-19 cells increased. High glucose also disturbed Bax and Bcl-2 expression, interrupted Bcl-2/Bax balance, and triggered subsequent cytochrome c release into the cytosol and activation of caspase-3. These detrimental effects were ameliorated dose dependently by diosmin. Furthermore, diosmin could abrogate high glucose-induced apoptosis as well as JNK and P38 MAPK phosphorylation in ARPE-19 cells. Our results suggest that treatment ARPE-19 cells with diosmin halts hyperglycemia-mediated oxidative damage and thus this compound may be a candidate for preventing the visual impairment caused by DR.

Protective Effects of Hesperidin (Citrus Flavonone) on High Glucose Induced Oxidative Stress and Apoptosis in a Cellular Model for Diabetic Retinopathy.

The aim of this study was to investigate the protective effects and mechanisms of hesperidin, a plant based active flavanone found in citrus fruits, under the oxidative stress and apoptosis induced by high levels of glucose in retinal ganglial cells (RGCs). RGC-5 cells were pretreated with hesperidin (12.5, 25, or 50 µmol/L) for 6 h followed by exposure to high (33.3 mmol/L) d-glucose for 48 h. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was adopted to evaluate cell viability. Mitochondrial function was estimated by measuring the mitochondrial membrane potential (ΔΨm). A fluorescent probe was employed to evaluate the intercellular production of reactive oxygen species (ROS). Colorimetric assay kits were used to evaluate lipid peroxidation, antioxidant enzyme activities, and protein carbonyls formation. The expression of apoptosis-related proteins and mitogen-activated protein kinase (MAPK) were measured with Western blotting. Hesperidin inhibited high glucose-mediated cell loss and restored mitochondrial function including a reversion of ΔΨm loss and cytochrome c release. Treated with hesperidin, high glucose-induced increase in ROS, malondialdehyde, and protein carbonyl levels were blocked in RGC-5 cells. Hesperidin was found to elevate the activities of superoxide dismutase, catalase, glutathione peroxidase, and to recover glutathione levels. Hesperidin inhibited high glucose-induced cell apoptosis by attenuating the downregulation of caspase-9, caspase-3, and Bax/Bcl-2. Furthermore, the phosphorylation of c-Jun N-terminal kinases (JNK) and p38 MAPK triggered by high glucose were attenuated in RGC-5 cells after their incubation with hesperdin. We concluded that hesperidin may protect RGC-5 cells from high glucose-induced injury since it owns the properties of antioxidant action and blocks mitochondria-mediated apoptosis.

Antioxidant-Rich Extract from Plantaginis Semen Ameliorates Diabetic Retinal Injury in a Streptozotocin-Induced Diabetic Rat Model.

Plantaginis semen, the dried ripe seed of Plantago asiatica L. or Plantago depressa Willd. (Plantaginaceae), has been traditionally used to treat blurred vision in Asia. The aim of this work was to investigate the effect of plantaginis semen ethanol extract (PSEE) on the amelioration of diabetic retinopathy (DR) in streptozotocin (STZ)-diabetic rats. PSEE has abundant polyphenols with strong antioxidant activity. PSEE (100, 200 or 300 mg/kg) was oral administrated to the diabetic rats once daily consecutively for 8 weeks. Oral administration of PSEE resulted in significant reduction of hyperglycemia, the diameter of the retinal vessels, and retinal vascular permeability and leukostasis in diabetic rats. In addition, PSEE administration increased the activities of superoxidase dismutase (SOD) and catalase (CAT), and glutathione peroxidase (GSH) level in diabetic retinae. PSEE treatment inhibited the expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α) and the phosphorylation of Akt without altering the Akt protein expression in diabetic retinae. PSEE not only down-regulated the gene expression of hypoxia-inducible factor-1α (TNF-α) and interleukin-1ß (IL-1ß), but also reduced ICAM-1 and VCAM-1 expression in diabetic retinae. Moreover, PSEE reduced the nuclear factor-κB (NF-κB) activation and corrected imbalance between histone deacetylases (HDAC) and histone acetyltransferases (HAT) activities in diabetic retinae. In conclusion, phenolic antioxidants extract from plantaginis semen has potential benefits in the prevention and/or progression of DR.

Tetranortriterpenes and Limonoids from the Roots of Aphanamixis polystachya.

Phytochemical investigation of the acetone extract from the roots of Aphanamixis polystachya resulted in isolation of four new tetranortriterpenes (1-4) in addition to one protolimonoid (methyl-1ξ,7R-diacetoxy-23R,25-dihydroxy-20S,24R-21,24-epoxy-3,4-seco-apotirucall-4(28),14(15)-diene-3-oate (5)), five known limonoids (rohituka 3 (6), rohituka 7 (7), nymania 1 (8), rubrin G (9), prieurianin (10)) and a steroid (2,3-dihydroxy-5-pregnan-16-one (11)). Their structures were determined by spectroscopic analyses, including 2D-NMR (COSY, HMQC, HMBC, and NOESY) and high-resolution electrospray ionization mass spectrometry (HRESIMS). Cytotoxic and anti-inflammatory activities of these compounds were evaluated. Compounds 4 and 5 showed significant inhibition against superoxide generation and elastase release by human neutrophils in response to (formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B) (FMLP/CB).

Zerumbone, a Phytochemical of Subtropical Ginger, Protects against Hyperglycemia-Induced Retinal Damage in Experimental Diabetic Rats.

Diabetic retinopathy (DR), the most ordinary and specific microvascular complication of diabetes, is a disease of the retina. Zerumbone (ZER) is a monocyclic sesquiterpene compound, and based on reports, it is the predominant bioactive compound from the rhizomes of Zingiber zerumbet. The aim of the current study is to evaluate the protective effect of zerumbone against DR in streptozotocin (STZ)-induced diabetic rats. STZ-diabetic rats were treated with ZER (40 mg/kg) once a day orally for 8 weeks. ZER administration significantly (p < 0.05) lowered the levels of plasma glucose (32.5% ± 5.7% lower) and glycosylated hemoglobin (29.2% ± 3.4% lower) in STZ-diabetic rats. Retinal histopathological observations indicated that disarrangement and reduction in thickness of retinal layers were reversed in ZER-treated diabetic rats. ZER downregulated both the elevated levels of advanced glycosylated end products (AGEs) and the higher levels of the receptors for AGEs (RAGE) in retinas of diabetic rats. What's more, ZER significantly (p < 0.05) ameliorated diabetes-induced upregulation of tumor necrosis factor-α, interleukin (IL)-1 and IL-6. ZER also attenuated overexpression of vascular endothelial growth factor and intercellular adhesion molecule-1, and suppressed activation of nuclear factor (NF)-κB and apoptosis in the retinas of STZ-diabetic rats. Our results suggest ZER possesses retinal protective effects, which might be associated with the blockade of the AGEs/RAGE/NF-κB pathway and its anti-inflammatory activity.

The ethanol extract of Zingiber zerumbet rhizomes mitigates vascular lesions in the diabetic retina.

Diabetic retinopathy (DR) is a common diabetic eye disease which is well-known as the result of microvascular retinal changes. Although the ethanol extract from Zingiber zerumbet (L.) Smith rhizome (EEZZR) has been indicated to ameliorate hyperglycemia in diabetes, its protective effect on DR remains unclear. The aim of this study was to determine the effects of EEZZR on DR in streptozotocin (STZ) diabetic rats. Diabetic rats were treated orally with EEZZR (200, 300 mg/kg per day) or calcium dobesilate (CD; 500 mg/kg per day) for 12 weeks. EEZZR displayed similar characteristics to CD in reducing blood-retinal barrier permeability in diabetic rats. Retinal histopathological observation showed that retinal vessels were decreased in EEZZR-treated diabetic rats. EEZZR decreased the increased retinal expression of vascular endothelial growth factor (VEGF) and upregulate the expressions of renal pigment epithelium-derived factor (PEDF) in diabetic rats. Retinal mRNA expression of tumor necrosis factor-α, interleukin (IL)-1, IL-6, monocyte chemotactic proteins-1, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 were all decreased in EEZZR-treated diabetic rats. Moreover, EEZZR could attenuate phosphorylation of nuclear factor Kappa B (NF-κB) p65 and extracellular signal-regulated kinase (ERK)1/2 as well as inhibit the nuclear translocation of pNF-κB p65 induced by diabetes. In conclusion, restoring the balance between stimulators and inhibitors of angiogenesis may be associated with the protective effect of EEZZR on DR. In addition, EEZZR can ameliorate retinal inflammation via transrepression of NF-κB and inhibition of ERK1/2 signaling pathway.

The Ethanol Extract from Lonicera japonica Thunb. Regresses Nonalcoholic Steatohepatitis in a Methionine- and Choline-Deficient Diet-Fed Animal Model.

Nonalcoholic steatohepatitis (NASH) is characterized as fat accumulation in the hepatic tissue associated with various degrees of inflammation and progressive fibrosis. The potent anti-inflammatory and ethnopharmacological properties of Lonicera japonica Thunb. (Caprifoliaceae) make it an excellent source of novel medicinal targets for the treatment of NASH. The aim of the study was to investigate the effects of L. japonica ethanol extract (LJEE) on NASH in mice. C57BL/6J mice were fed with methionine-choline-deficient diet (MCDD) for eight weeks to promote the development of NASH. After development of the model, the mice were administered LJEE once daily via oral gavage at doses of 100, 200, or 300 mg/kg for another four weeks. Simultaneous treatments with LJEE (300 mg/kg/day) resulted in pronounced improvements in liver steatosis, ballooning degeneration, and inflammation. LJEE prevented MCDD-induced plasma level increases in aspartate aminotransferase and alanine aminotransferase. LJEE significantly reduced hepatic malondialdehyde level and ameliorated hepatic inflammation and fibrosis in MCDD-fed mice, which were associated with down-regulation of cytochrome P450 2E1 suppression of multiple proinflammatory and profibrotic genes. LJEE can prevent hepatic steatosis by reducing hepatic peroxisome acyl-CoA:diacylglycerol acyltransferase 2 expression, as well as by inducing proliferator-activated receptor α expression. In addition, the LJEE treatments caused significant reduction in the phosphorylated form of Jun N-terminal kinase along with an increase in the phosphorylated level of extra cellular signal-regulated kinase 1/2. Our study demonstrated the protective role of LJEE in ameliorating nutritional steatohepatitis.

Consumption of Polyphenol-Rich Zingiber Zerumbet Rhizome Extracts Protects against the Breakdown of the Blood-Retinal Barrier and Retinal Inflammation Induced by Diabetes.

The present study investigates the amelioration of diabetic retinopathy (DR) by Zingiber zerumbet rhizome ethanol extracts (ZZRext) in streptozotocin-induced diabetic rats (STZ-diabetic rats). ZZRext contains high phenolic and flavonoid contents. STZ-diabetic rats were treated orally with ZZRext (200, 300 mg/kg per day) for three months. Blood-retinal barrier (BRB) breakdown and increased vascular permeability were found in diabetic rats, with downregulation of occludin, and claudin-5. ZZRext treatment effectively preserved the expression of occludin, and claudin-5, leading to less BRB breakdown and less vascular permeability. Retinal histopathological observation showed that the disarrangement and reduction in thickness of retinal layers were reversed in ZZRext-treated diabetic rats. Retinal gene expression of tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, vascular endothelial growth factor, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 were all decreased in ZZRext-treated diabetic rats. Moreover, ZZRext treatment not only inhibited the nuclear factor κB (NF-κB) activation, but also downregulated the protein expression of p38 mitogen-activated protein kinase (MAPK) in diabetic retina. In conclusion, the results suggest that the retinal protective effects of ZZRext occur through improved retinal structural change and inhibiting retinal inflammation. The antiretinopathy property of ZZRext might be related to the downregulation of p38 MAPK and NF-κB signal transduction induced by diabetes.

[6]-gingerol dampens hepatic steatosis and inflammation in experimental nonalcoholic steatohepatitis.

The aim of the study was to investigate the effects of [6]-gingerol ((S)-5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-3-decanone) in experimental models of non-alcoholic steatohepatitis. HepG2 cells were exposed to 500 µmol/l oleic acid (OA) for 24 h and preincubated for an additional 24 h with [6]-gingerol (25, 50 or 100 µmol/l). [6]-Gingerol (100 µmol/l) inhibited OA-induced triglyceride and inflammatory marker accumulation in HepG2 cells. After being fed a high-fat diet (HFD) for 2 weeks, male golden hamsters were dosed orally with [6]-gingerol (25, 50 or 100 mg/kg/day) once daily for 8 weeks while maintained on HFD. [6]-Gingerol (100 mg/kg/day) alleviated liver steatosis, inflammation, and reversed plasma markers of metabolic syndrome in HFD-fed hamsters. The expression of inflammatory cytokine genes and nuclear transcription factor-κB (NF-κB) were increased in the HFD group; these effects were attenuated by [6]-gingerol. The hepatic mRNA expression of lipogenic genes such as liver X receptor-α, sterol regulating element binding protein-1c and its target genes including acetyl-CoA carboxylase, fatty acid synthase, stearoyl-CoA desaturase 1, and acyl-CoA:diacylglycerol acyltransferase 2 in HFD-fed hamsters was also blocked by [6]-gingerol. [6]-Gingerol may attenuate HFD-induced steatohepatitis by downregulating NF-κB-mediated inflammatory responses and reducing hepatic lipogenic gene expression.

6-gingerol protects against nutritional steatohepatitis by regulating key genes related to inflammation and lipid metabolism.

Non-alcoholic fatty liver disease, including non-alcoholic steatohepatitis (NASH), appears to be increasingly common worldwide. The aim of the study was to investigate the effects of 6-gingerol ((S)-5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-3-decanone), a bioactive ingredient of plants belonging to the Zingiberaceae family, on experimental models of NASH. In HepG2 cells, 6-gingerol (100 µmol/L) treatment inhibited free fatty acids mixture (0.33 mmol/L palmitate and 0.66 mmol/L oleate)-induced triglyceride and inflammatory marker accumulations. Male C57BL/6 mice were fed with a methionine and choline-deficient (MCD) diet to induce steatohepatitis. After four weeks of MCD diet feeding, the mice were dosed orally with 6-gingerol (25, 50 or 100 mg/kg/day) once daily for another four weeks. 6-Gingerol (100 mg/kg/day) attenuated liver steatosis and necro-inflammation in MCD diet-fed mice. The expressions of inflammatory cytokine genes, including those for monocyte chemoattractant protein-1, tumor necrosis factor-α, and interleukin-6, and nuclear transcription factor (NF-κB), which were increased in the livers of MCD diet-fed mice, were attenuated by 6-gingerol. 6-Gingerol possesses a repressive property on hepatic steatosis, which is associated with induction of peroxisome proliferator-activated receptor α. Our study demonstrated the protective role of 6-gingerol in ameliorating nutritional steatohepatitis. The effect was mediated through regulating key genes related to lipid metabolism and inflammation.

Ruscogenin ameliorates experimental nonalcoholic steatohepatitis via suppressing lipogenesis and inflammatory pathway.

The aim of the study was to investigate the protective effects of ruscogenin, a major steroid sapogenin in Ophiopogon japonicus, on experimental models of nonalcoholic steatohepatitis. HepG2 cells were exposed to 300 µmol/l palmitic acid (PA) for 24 h with the preincubation of ruscogenin for another 24 h. Ruscogenin (10.0 µmol/l) had inhibitory effects on PA-induced triglyceride accumulation and inflammatory markers in HepG2 cells. Male golden hamsters were randomly divided into five groups fed a normal diet, a high-fat diet (HFD), or a HFD supplemented with ruscogenin (0.3, 1.0, or 3.0 mg/kg/day) by gavage once daily for 8 weeks. Ruscogenin alleviated dyslipidemia, liver steatosis, and necroinflammation and reversed plasma markers of metabolic syndrome in HFD-fed hamsters. Hepatic mRNA levels involved in fatty acid oxidation were increased in ruscogenin-treated HFD-fed hamsters. Conversely, ruscogenin decreased expression of genes involved in hepatic lipogenesis. Gene expression of inflammatory cytokines, chemoattractive mediator, nuclear transcription factor-(NF-) κB, and α-smooth muscle actin were increased in the HFD group, which were attenuated by ruscogenin. Ruscogenin may attenuate HFD-induced steatohepatitis through downregulation of NF-κB-mediated inflammatory responses, reducing hepatic lipogenic gene expression, and upregulating proteins in ß-oxidation pathway.