Formation and reduction of glutathione-protein mixed disulfides during oxidative stress. A study with isolated hepatocytes and menadione (2-methyl-1,4-naphthoquinone)

Glucosinolates Extracts from Brassica juncea Ameliorate HFD-Induced Non-Alcoholic Steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is mainly characterized by excessive fat accumulation in the liver. It spans a spectrum of diseases from hepatic steatosis to non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Brassica juncea is rich in glucosinolates and has been proven to possess many potential pharmacological properties, including hypoglycemic, anti-oxidation, anti-inflammatory, and anti-carcinogenic activities. This study aims to investigate whether whole-plant Brassica juncea (WBJ) and its glucosinolates extracts (BGE) have hepatoprotective effects against a high-fat diet (HFD)-induced NAFLD and further explore the mechanism underlying this process in vivo and in vitro. WBJ treatment significantly reduced body fat, dyslipidemia, hepatic steatosis, liver injury, and inflammation; WBJ treatment also reversed the antioxidant enzyme activity to attenuate oxidative stress in HFD-fed rat liver. Moreover, WBJ and BGE enhanced the activation of AMPK to reduce SREBPs, fatty acid synthase, and HMG-CoA reductase but increased the expression of CPT-I and PPARα to improve hepatic steatosis. In addition, WBJ and BGE could ameliorate NAFLD by inhibiting TNF-α and NF-κB. Based on the above results, this study demonstrates that WBJ and BGE ameliorate HFD-induced hepatic steatosis and liver injury. Therefore, these treatments could represent an unprecedented hope toward improved strategies for NAFLD.

Neuroprotective potential of plant derived parenchymal stem cells extract on environmental and genetic models of Parkinson disease through attenuation of oxidative stress and neuroinflammation

Parkinson's disease (PD) is a neurodegenerative disorder characterized by both motor and non-motor features. The current treatment regimen for PD are dopamine enhancers which have been reported to worsen the disease prognosis after long term treatment, thus, the need for better treatment options. This study sought to investigate the protective action of Double Stem Cell® (DSC), a blend of stem cells extracts from Swiss apples (Malus Domestica) and Burgundy grapes (Vitis vinifera) on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism in mice and genetic model of PD in Drosophila melanogaster. Male albino mice were pretreated with MPTP (4 × 20 mg/kg, i.p., two hourly in 8 h), twelve hours before administration of DSC (8, 40, or 200 mg/kg, p.o.). Thereafter, behavioural, biochemical and immunohistochemical assays were carried out. The impact of vehicle or DSC supplementation on α-synuclein aggregation was evaluated in Drosophila melanogaster using the UAS-Gal4 system, female DDC-Gal4 flies were crossed with male UAS-α-synuclein, the progenies were examined for fecundity, locomotion, memory, and lifespan. MPTP-induced motor deficits in open field test (OFT), working memory impairment (Y-maze test (YMT)) and muscle incoordination (rotarod test) were ameliorated by DSC (8, 40 or 200 mg/kg) through dose-dependent and significant improvements in motor, cognitive and motor coordination. Moreso, MPTP exposure caused significant increase in lipid peroxidation and decrease in antioxidant enzymes activities (glutathione, catalase and superoxide dismutase) in the midbrain which were attenuated by DSC. MPTP-induced expression of microglia (iba-1), astrocytes (glia fibrillary acidic protein; GFAP) as well as degeneration of dopamine neurons (tyrosine hydroxylase positive neurons) in the substantia nigra (SN) were reversed by DSC. Supplementation of flies feed with graded concentration of DSC (0.8, 4 or 20 mg/ml) did not affect fecundity but improved climbing activity and lifespan. Findings from this study showed that Double Stem Cell improved motor and cognitive functions in both mice and Drosophila through attenuation of neurotoxin-induced oxidative stress and neuroinflammation.

Long-term exposure to environmental diclofenac concentrations impairs growth and induces molecular changes in Lymnaea stagnalis freshwater snails

As pharmaceutical substances are highly used in human and veterinary medicine and subsequently released in the environment, they represent emerging contaminants in the aquatic compartment. Diclofenac (DCF) is one of the most commonly detected pharmaceuticals in water and little research has been focused on its long-term effects on freshwater invertebrates. In this study, we assessed the chronic impacts of DCF on the freshwater gastropod Lymnaea stagnalis using life history, behavioral and molecular approaches. These organisms were exposed from the embryo to the adult stage to three environmentally relevant DCF concentrations (0.1, 2 and 10 μg/L). The results indicated that DCF impaired shell growth and feeding behavior at the juvenile stage, yet no impacts on hatching, locomotion and response to light stress were noted. The molecular findings (metabolomics and transcriptomic) suggested that DCF may disturb the immune system, energy metabolism, osmoregulation and redox balance. In addition, prostaglandin synthesis could potentially be inhibited by DCF exposure. The molecular findings revealed signs of reproduction impairment but this trend was not confirmed by the physiological tests. Combined omics tools provided complementary information and enabled us to gain further insight into DCF effects in freshwater organisms.

The role of glial-neuronal metabolic cooperation in modulating progression of multiple sclerosis and neuropathic pain

While the etiology of multiple sclerosis (MS) remains unclear, research from the clinic and preclinical models identified the essential role of inflammation and demyelination in the pathogenesis of MS. Current treatments focused on anti-inflammatory processes are effective against acute episodes and relapsing-remitting MS, but patients still move on to develop secondary progressive MS. MS progression is associated with activation of microglia and astrocytes, and importantly, metabolic dysfunction leading to neuronal death. Neuronal death also contributes to chronic neuropathic pain. Metabolic support of neurons by glia may play central roles in preventing progression of MS and chronic neuropathic pain. Here, we review mechanisms of metabolic cooperation between glia and neurons and outline future perspectives exploring metabolic support of neurons by glia.

Lipoic Acid Prevents High-Fat Diet-Induced Hepatic Steatosis in Goto Kakizaki Rats by Reducing Oxidative Stress Through Nrf2 Activation

Prevention of hepatic fat accumulation may be an important approach for liver diseases due to the increased relevance of hepatic steatosis in this field. This study was conducted to investigate the effects of the antioxidant α-lipoic acid (α-LA) on hepatic steatosis, hepatocellular function, and oxidative stress in a model of type 2 diabetes fed with a high fat diet (HFD). Goto-Kakizaki rats were randomly divided into four groups. The first group received only a standard rat diet (control GK) including groups 2 (HFD), 3 (vehicle group), and 4 (α-LA group), which were given HFD, ad libitum during three months. Wistar rats are the non-diabetic control group. Carbohydrate and lipid metabolism, liver function, plasma and liver tissue malondialdehyde (MDA), liver GSH, tumor necrosis factor-α (TNF-α) and nuclear factor E2 (erythroid-derived 2)-related factor-2 (Nrf2) levels were assessed in the different groups. Liver function was assessed using quantitative hepatobiliary scintigraphy, serum aspartate, and alanine aminotransferases (AST, ALT), alkaline phosphatase, gamma-glutamyltranspeptidase, and bilirubin levels. Histopathologically steatosis and fibrosis were evaluated. Type 2 diabetic animals fed with HFD showed a marked hepatic steatosis and a diminished hepatic extraction fraction and both were fully prevented with α-LA. Plasma and liver tissue MDA and hepatic TNF-α levels were significantly higher in the HFD group when compared with the control group and significantly lower in the α-LA group. Systemic and hepatic cholesterol, triglycerides, and serum uric acid levels were higher in hyperlipidemic GK rats and fully prevented with α-LA. In addition, nuclear Nrf2 activity was significantly diminished in GK rats and significantly augmented after α-LA treatment. In conclusion, α-LA strikingly ameliorates steatosis in this animal model of diabetes fed with HFD by decrementing the inflammatory marker TNF-α and reducing oxidative stress. α-LA might be considered a useful therapeutic tool to prevent hepatic steatosis by incrementing antioxidant defense systems through Nrf2 and consequently decreasing oxidative stress and inflammation in type 2 diabetes.

Protective Effect of Aqueous Extract from the Leaves of Justicia tranquebariesis against Thioacetamide-Induced Oxidative Stress and Hepatic Fibrosis in Rats

The present study aims to examine the protective effect of Justicia tranquebariesis on thioacetamide (TAA)-induced oxidative stress and hepatic fibrosis. Male Wister albino rats (150–200 g) were divided into five groups. Group 1 was normal control. Group 2 was J. tranquebariensis (400 mg/kg bw/p.o.)-treated control. Group 3 was TAA (100 mg/kg bw/s.c.)-treated control. Groups 4 and 5 were orally administered with the leaf extract of J. tranquebariensis (400 mg/kg bw) and silymarin (50 mg/kg bw) daily for 10 days with a subsequent administration of a single dose of TAA (100 mg/kg/s.c.). Blood and livers were collected and assayed for various antioxidant enzymes (SOD, CAT, GPx, GST, GSH, and GR). Treatment with J. tranquebariensis significantly reduced liver TBARS and enhanced the activities of antioxidant enzymes in TAA-induced fibrosis rats. Concurrently, pretreatment with J. tranquebariensis significantly reduced the elevated liver markers (AST, ALT, ALP, GGT, and TB) in the blood. In addition, J. tranquebariensis- and silymarin- administered rats demonstrated the restoration of normal liver histology and reduction in fibronectin and collagen deposition. Based on these findings, J. tranquebariensis has potent liver protective functions and can alleviate thioacetamide-induced oxidative stress, hepatic fibrosis and possible engross mechanisms connected to antioxidant potential.

Curcumin and its synthetic analogue dimethoxycurcumin differentially modulates antioxidant status of normal human peripheral blood mononuclear cells

Curcumin is a polyphenol derived from the herb Curcuma longa, which has been extensively studied in terms of its antitumour, antioxidant, and chemopreventive activity as well as various other effects. In the present work we compared curcumin with its synthetic analogue dimethoxycurcumin (dimc) in terms of its antioxidant enzyme-modulating effects in human peripheral blood mononuclear cells (PBMC). We found that these compounds modulate antioxidant enzymes differentially. Both curcumin and dimethoxycurcumin effected a decrease in lipid peroxidation status in PBMC, however, curcumin had better activity in this regard. An increase in the activity of catalase was seen in the case of curcumin-treated PBMC, whereas dimc increased catalase activity significantly to almost twofold level. Real time-polymerase chain reaction (RT-PCR) analysis revealed significant up-regulation of catalase at mRNA level post treatment with curcumin as well as dimc, however, dimc had better activity in this regard. Glutathione reductase (GR) activity and reduced glutathione levels increased in the case of peripheral blood mononuclear cells (PBMC) treated with curcumin, however, the trend was reversed with dimethoxycurcumin where, both glutathione reductase activity and reduced glutathione levels were significantly reduced. RT-PCR analysis of glutathione reductase mRNA levels showed decrease in mRNA levels post treatment with dimethoxycurcumin (dimc) further corroborating GR enzyme assay results, however, we could not obtain significant result post curcumin treatment. NFkB reporter assay and western blot analysis of nuclear as well as cytosolic fractions of NFkB revealed that curcumin inhibits NFkB activation whereas inhibition was much less with dimc. It has been reported that curcumin and dimc exerts differential cytotoxicity in normal and tumour cells and the reason for this had been attributed to the differential uptake of these compounds by normal cells and tumour cells. Based on our results we propose that differential modulation of antioxidant enzymes via NFkB pathway could be the reason behind differential cytotoxicity of dimc as well as curcumin in normal cells and tumour cells in addition to differential uptake of these compounds as reported previously.

Monascus-fermented red mold dioscorea protects mice against alcohol-induced liver injury, whereas its metabolites ankaflavin and monascin regulate ethanol-induced peroxisome proliferator-activated receptor-γ and sterol regulatory element-binding transcription factor-1 expression in HepG2 cells

BACKGROUND

Alcoholic hepatitis is a necroinflammatory process that is associated with fibrosis and leads to cirrhosis in 40% of cases. The hepatoprotective effects of red mold dioscorea (RMD) from Monascus purpureus NTU 568 were evaluated in vivo using a mouse model of chronic alcohol-induced liver disease (ALD).

RESULTS

ALD mice were orally administered vehicle (ALD group) or vehicle plus 307.5, 615.0 or 1537.5 mg kg^-1 (1 ×, 2 × and 5 ×) RMD for 5 weeks. RMD lowered serum leptin, hepatic total cholesterol, free fatty acid and hepatic triglyceride levels and increased serum adiponectin, hepatic alcohol dehydrogenase and antioxidant enzyme levels. Furthermore, ankaflavin (AK) and monascin (MS), metabolites of RMD fermented with M. purpureus 568, induced peroxisome proliferator-activated receptor-γ expression and the concomitant suppression of ethanol-induced elevation of sterol regulatory element-binding transcription factor-1 and TG in HepG2 cells.

CONCLUSION

These results indicate the hepatoprotective effect of Monascus-fermented RMD. Moreover, AK and MS were identified as the active constituents of RMD for the first time and were shown to protect against ethanol-induced liver damage. © 2017 Society of Chemical Industry.

Chemical methods for mapping cysteine oxidation

Methods to characterise oxidative modifications of cysteine help clarify their role in protein function in both healthy and diseased cells.

Deep Sea Water Improves Abnormalities in Lipid Metabolism through Lipolysis and Fatty Acid Oxidation in High-Fat Diet-Induced Obese Rats

Deep sea water (DSW) is a natural marine resource that has been utilized for food, agriculture, cosmetics, and medicine. The aim of this study was to investigate whether DSW has beneficial lipid metabolic effects in an animal model. Our previous in vitro study indicated that DSW significantly decreased the intracellular triglyceride and glycerol-3-phosphate dehydrogenase activity in 3T3-L1 adipocytes. DSW also inhibited the gene levels of adipocyte differentiation, lipogenesis, and adipocytokines, and up-regulated gene levels of lipolysis and fatty acid oxidation. In the present study, the results showed that body weight, liver, adipose tissue, hepatic triglycerides and cholesterol, and serum parameters in the high-fat diet (HFD) + DSW groups were significantly lower compared to the HFD group. Moreover, the fecal output of total lipids, triglycerides, and cholesterol in the HFD + DSW groups was significantly higher than that of the HFD group. Regarding gene expression, DSW significantly increased the gene levels of lipolysis and fatty acid oxidation, and decreased the gene levels of adipocytokine in the adipose tissue of rats with HFD-induced obesity. These results indicate a potential molecular mechanism by which DSW can suppress obesity in rats with HFD-induced obesity through lipolysis and fatty acid oxidation.

Rhizophora mucronata attenuates beta-amyloid induced cognitive dysfunction, oxidative stress and cholinergic deficit in Alzheimer's disease animal model

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, characterized by accumulation and deposition of Aβ peptide in human brain. The present study aimed to determine the protective effect of catechin rich extract of MERM (methanolic extract of Rhizophora mucronata) on Aβ (25-35) induced cognitive impairment and neuronal toxicity in mice. In the present study AD characteristics were induced by intracerberoventricular administration of aggregated Aβ (25-35) in the Swiss albino mice. Learning and memory deficits were assessed using behavioral assays such as Morris water maze, Y-maze and step down avoidance tasks. Oxidative stress mediated impairment were assessed by measuring the activities of enzymatic and non-enzymatic antioxidants, level of apoptotic protein and oxidative markers in the hippocampus and frontal cortex region. Histolopathological analysis of brain was also carried out. Results illustrated that oral treatment of MERM (200 and 400 mg/kg bw) significantly attenuated Aβ (25-35) induced memory impairment as evaluated by behavioral tests. In addition treatment with MERM attenuated the elevation of β-secretase activity accompanying the reduced level of Aβ (25-35) in the cortex and hippocampus of brain. MERM also enhanced the cognitive function by significantly inhibiting AChE, BuChE and MAO-B. Furthermore, MERM attenuated lipid peroxidation, protein oxidation, restored the antioxidant status and inhibited neuronal apoptosis by down-regulating the level of caspase 3 and Bax protein. These data suggest that MERM rich in catechin can act as promising drug for AD treatment because of its antioxidant, anti-apoptotic and reducing Aβ oligomer activities.

Metabolic Activation of Rhein: Insights into the Potential Toxicity Induced by Rhein-Containing Herbs

Rhein is a major component of the many medicinal herbs such as rhubarb. Despite wide use, intoxication cases associated with rhein-containing herbs are often reported. The present work aimed to investigate if rhein was subject to metabolic activation leading to toxicity. Upon incubations with different species of liver microsomes, three monoglucuronides were identified, corresponding to two hydroxyl glucuronides and one acyl glucuronide via the carboxyl group, respectively. Further study revealed that rhein acyl glucuronide was chemically reactive, and showed cytotoxicity toward hepatocarcinoma cells. In addition, significant species differences in glucuronidation of rhein were observed between laboratory animals and humans. Reaction phenotyping experiments demonstrated that rhein acyl glucuronide was catalyzed predominantly by uridine 5'-diphospho-glucuronosyltransferase 1A1, 1A9, and 2B7. Taken together, the present study confirmed that rhein could be metabolically activated via the formation of acyl glucuronide, especially in human.

Shinzami Korean purple-fleshed sweet potato extract prevents ischaemia-reperfusion-induced liver damage in rats

BACKGROUND

This study was designed to investigate the hepatoprotective effect of an extract from Shinzami, a variety of purple sweet potato, in rats injured by hepatic ischaemia-reperfusion (I/R).

RESULTS

Pretreatment with Shinzami extract decreased the aspirate aminotransferase and alanine aminotransferase serum levels in our hepatic I/R rat model. The glutathione level and superoxide dismutase activity level were significantly higher in the rats pretreated with the Shinzami extract compared with the hepatic I/R rats, and the glutathione peroxidase activity level was higher in pretreated rats. The total anthocyanins extracted from Shinzami, however, only increased the superoxide dismutase activity level in the hepatic I/R rats. Rats pretreated with the Shinzami extract or anthocyanins demonstrated attenuated hepatic pathological changes, such as hepatic distortion, haemorrhage, necrosis and inflammatory cell infiltration compared with the hepatic I/R control rats.

CONCLUSION

Shinzami extract and anthocyanins have a hepatoprotective effect on the liver damage induced by hepatic I/R by improving antioxidant status. Furthermore, the Shinzami extract may have a more potent effect on the antioxidant status compared with the Shinzami anthocyanins alone.

Impact of oxidative stress on exercising skeletal muscle

It is well established that muscle contractions during exercise lead to elevated levels of reactive oxygen species (ROS) in skeletal muscle. These highly reactive molecules have many deleterious effects, such as a reduction of force generation and increased muscle atrophy. Since the discovery of exercise-induced oxidative stress several decades ago, evidence has accumulated that ROS produced during exercise also have positive effects by influencing cellular processes that lead to increased expression of antioxidants. These molecules are particularly elevated in regularly exercising muscle to prevent the negative effects of ROS by neutralizing the free radicals. In addition, ROS also seem to be involved in the exercise-induced adaptation of the muscle phenotype. This review provides an overview of the evidences to date on the effects of ROS in exercising muscle. These aspects include the sources of ROS, their positive and negative cellular effects, the role of antioxidants, and the present evidence on ROS-dependent adaptations of muscle cells in response to physical exercise.

Activation of SIRT3 by the NAD⁺ precursor nicotinamide riboside protects from noise-induced hearing loss

Intense noise exposure causes hearing loss by inducing degeneration of spiral ganglia neurites that innervate cochlear hair cells. Nicotinamide adenine dinucleotide (NAD(+)) exhibits axon-protective effects in cultured neurons; however, its ability to block degeneration in vivo has been difficult to establish due to its poor cell permeability and serum instability. Here, we describe a strategy to increase cochlear NAD(+) levels in mice by administering nicotinamide riboside (NR), a recently described NAD(+) precursor. We find that administration of NR, even after noise exposure, prevents noise-induced hearing loss (NIHL) and spiral ganglia neurite degeneration. These effects are mediated by the NAD(+)-dependent mitochondrial sirtuin, SIRT3, since SIRT3-overexpressing mice are resistant to NIHL and SIRT3 deletion abrogates the protective effects of NR and expression of NAD(+) biosynthetic enzymes. These findings reveal that administration of NR activates a NAD(+)-SIRT3 pathway that reduces neurite degeneration caused by noise exposure.

Schisandra Chinensis Baillon regulates the gene expression of phase II antioxidant/detoxifying enzymes in hepatic damage induced rats

BACKGROUND/OBJECTIVES

This study investigated the antioxidant activities and hepatoprotective effects of Schisandra chinensis Baillon extract (SCE) against tert-butyl hydroperoxide (t-BHP)-induced oxidative hepatic damage in rats.

MATERIALS/METHODS

Sprague-Dawley (SD) rats were pretreated with SCE (300, 600, and 1,200 mg/kg BW) or saline once daily for 14 consecutive days. On day 14, each animal, except those belonging to the normal control group, were injected with t-BHP (0.8 mmol/kg BW/i.p.), and all of the rats were sacrificed 16 h after t-BHP injection.

RESULTS

Although no significant differences in AST and ALT levels were observed among the TC and SCE groups, the high-dose SCE group showed a decreasing tendency compared to the TC group. However, erythrocyte SOD activity showed a significant increase in the low-dose SCE group compared with the TC group. On the other hand, no significant differences in hepatic total glutathione (GSH) level, glutathione reductase (GR), and glutathione peroxidase (GSH-Px) activities were observed among the TC and SCE groups. Hepatic histopathological evaluation revealed that pretreatment with SCE resulted in reduced t-BHP-induced incidence of lesions, such as neutrophil infiltration, swelling of liver cells, and necrosis. In particular, treatment with a high dose of SCE resulted in induction of phase II antioxidant/detoxifying enzyme expression, such as glutathione S-transferase (GST) and glutamate-cysteine ligase catalytic subunit (GCLC).

CONCLUSIONS

Based on these results, we conclude that SCE exerts protective effects against t-BHP induced oxidative hepatic damage through the reduction of neutrophil infiltration, swelling of liver cells, and necrosis. In addition, SCE regulates the gene expression of phase II antioxidant/detoxifying enzymes independent of hepatic antioxidant enzyme activity.

N-acetylcysteine amide preserves mitochondrial bioenergetics and improves functional recovery following spinal trauma

Mitochondrial dysfunction is becoming a pivotal target for neuroprotective strategies following contusion spinal cord injury (SCI) and the pharmacological compounds that maintain mitochondrial function confer neuroprotection and improve long-term hindlimb function after injury. In the current study we evaluated the efficacy of cell-permeating thiol, N-acetylcysteine amide (NACA), a precursor of endogenous antioxidant glutathione (GSH), on mitochondrial function acutely, and long-term tissue sparing and hindlimb locomotor recovery following upper lumbar contusion SCI. Some designated injured adult female Sprague-Dawley rats (n=120) received either vehicle or NACA (75, 150, 300 or 600mg/kg) at 15min and 6h post-injury. After 24h the total, synaptic, and non-synaptic mitochondrial populations were isolated from a single 1.5cm spinal cord segment (centered at injury site) and assessed for mitochondrial bioenergetics. Results showed compromised total mitochondrial bioenergetics following acute SCI that was significantly improved with NACA treatment in a dose-dependent manner, with maximum effects at 300mg/kg (n=4/group). For synaptic and non-synaptic mitochondria, only 300mg/kg NACA dosage showed efficacy. Similar dosage (300mg/kg) also maintained mitochondrial GSH near normal levels. Other designated injured rats (n=21) received continuous NACA (150 or 300mg/kg/day) treatment starting at 15min post-injury for one week to assess long-term functional recovery over 6weeks post-injury. Locomotor testing and novel gait analyses showed significantly improved hindlimb function with NACA that were associated with increased tissue sparing at the injury site. Overall, NACA treatment significantly maintained acute mitochondrial bioenergetics and normalized GSH levels following SCI, and prolonged delivery resulted in significant tissue sparing and improved recovery of hindlimb function.

N-acetylcysteine amide preserves mitochondrial bioenergetics and improves functional recovery following spinal trauma

Mitochondrial dysfunction is becoming a pivotal target for neuroprotective strategies following contusion spinal cord injury (SCI) and the pharmacological compounds that maintain mitochondrial function confer neuroprotection and improve long-term hindlimb function after injury. In the current study we evaluated the efficacy of cell-permeating thiol, N-acetylcysteine amide (NACA), a precursor of endogenous antioxidant glutathione (GSH), on mitochondrial function acutely, and long-term tissue sparing and hindlimb locomotor recovery following upper lumbar contusion SCI. Some designated injured adult female Sprague-Dawley rats (n=120) received either vehicle or NACA (75, 150, 300 or 600mg/kg) at 15min and 6h post-injury. After 24h the total, synaptic, and non-synaptic mitochondrial populations were isolated from a single 1.5cm spinal cord segment (centered at injury site) and assessed for mitochondrial bioenergetics. Results showed compromised total mitochondrial bioenergetics following acute SCI that was significantly improved with NACA treatment in a dose-dependent manner, with maximum effects at 300mg/kg (n=4/group). For synaptic and non-synaptic mitochondria, only 300mg/kg NACA dosage showed efficacy. Similar dosage (300mg/kg) also maintained mitochondrial GSH near normal levels. Other designated injured rats (n=21) received continuous NACA (150 or 300mg/kg/day) treatment starting at 15min post-injury for one week to assess long-term functional recovery over 6weeks post-injury. Locomotor testing and novel gait analyses showed significantly improved hindlimb function with NACA that were associated with increased tissue sparing at the injury site. Overall, NACA treatment significantly maintained acute mitochondrial bioenergetics and normalized GSH levels following SCI, and prolonged delivery resulted in significant tissue sparing and improved recovery of hindlimb function.

Omega-3 fatty acid obtained from Nannochloropsis oceanica cultures grown under low urea protect against Abeta-induced neural damage

Amyloid-beta (Abeta) protein is a key factor in the pathogenesis of Alzheimer's disease (AD). Moreover, it has been reported that oxidative stress is involved in the biochemical pathway by which Abeta can lead to neuronal dysfunction. Recently, docosahexaenoic acid (DHA; C22:6) and eicosapentaenoic acid (EPA; C20:5n-3) have been reported to protect against AD. However, these omega-3 fatty acids are frequently obtained from fish oil and may contain heavy metals. In this study, we utilized Nannochloropsis oceanica to produce omega-3 fatty acid. We observed that when urea levels (nitrogen source) were lowered from 2 to 0.2 g/L in Nannochloropsis oceanica cultures, EPA production increased. Moreover, EPA in Nannochloropsis oceanica effectively promoted antioxidant activity to counter the Abeta-induced oxidative stress in Neuro-2A cells. These results indicate that Nannochloropsis oceanica may be potentially used as a therapeutic agent or as a functional food that promotes protection against AD.

Induction of Nrf2-dependent Antioxidation and Protection Against Carbon Tetrachloride-induced Liver Damage by Andrographis Herba (chuān xīn lián) Ethanolic Extract

Andrographis paniculata is a traditional Chinese herb and displays diverse biological activities including antioxidation, anti-tumorigenesis, anti-virus, and anti-atherogenesis. In this study, we investigated the up-regulation of ethanolic extract of A. paniculata (APE) on the antioxidant defense in rat livers and whether this enhancement protected against carbon tetrachloride (CCl₄)-induced liver damage. Male Sprague-Dawley rats were orally administered (i.g.) 0, 0.75, or 2 g/kg/d APE for 5 d. At d 6, rats were sacrificed and liver tissues were removed. Some animals (n=8) were intraperitoneally injected CCl₄ (1 mL/kg, 50% in olive oil) and blood was drawn 24 h after CCl₄ treatment. The results showed that APE increased hepatic glutathione (GSH) content and superoxide dismutase, GSH peroxidase, and GSH S-transferase activities in a dose-dependent manner (p < 0.05). Results of immunoblotting and RT-PCR revealed that rats treated with APE had higher glutamate cysteine ligase catalytic and modifier subunits, heme oxygenase 1, superoxide dismutase 1, and GSH S-transferase Ya and Yb protein and mRNA expression than those of control rats. Moreover, APE increased Nrf2 nuclear translocation and Nrf2 binding to DNA in rat liver. In the presence of CCl₄, APE decreased hepatic thiobarbituric acid-reactive substances production and plasma aspartate aminotransferase and alanine aminotransferase activities. These results suggest that APE protection against CCl₄ insult is attributed, at least in part, to its up-regulation of antioxidant defense in rat liver.

Antihepatoma and liver protective potentials of ganoderma lucidum ( ling zhi) fermented in a medium containing black soybean ( hēi dòu) and astragalus membranaceus ( shēng huáng qí)

The antihepatoma activity and liver protective function of the fermentation products (5 L fermenator) of Ganoderma lucidum (GL; 靈芝 Ling Zhi) cultivated in a medium containing black soybean (BS; 黑豆 Hēi Dòu) and Astragalus membranaceus (AM; 生黃耆 Shēng Huáng Qí) at different fermentation temperatures were investigated in this study. Hep 3B cells pretreated with lovastatin were used to study the antihepatoma activity, and possible active components were analyzed by reverse-phase high-performance liquid chromatography. Carbon tetrachloride (CCl₄)-induced primary rat hepatocyte injury was further used to evaluate the liver protective activity of the fermentation products. While all the GL broth filtrates do not inhibit the growth of Hep 3B cells, the ethanolic extract from GL-2 mycelia (GL-2-mE), cultivated in the medium containing BS (50 g/L) and AM (20 g/L) at 24°C for 11 days showed the best antihepatoma activity (IC₅₀ 26.6 μg/mL) than the other ethanolic extracts from GL mycelia, GL fruiting body, BS, and AM did. The antihepatoma activities were correlated with some unknown active components in these samples. Furthermore, GL-2-mE (100 μg/mL) without harmful effect on the growth of normal primary rat hepatocytes significantly maintained cell viability, reduced lactate dehydrogenase leakage, lowered lipid peroxidation, and increased glutathione peroxidase and glutathione S-transferase activities in the CCl₄-induced damaged primary rat hepatocytes.

The Antidiabetic Effect of Garlic Oil is Associated with Ameliorated Oxidative Stress but Not Ameliorated Level of Pro-inflammatory Cytokines in Skeletal Muscle of Streptozotocin-induced Diabetic Rats

Oxidative stress and inflammatory condition has been broadly accepted being associated with the progression of diabetes. On the other hand, garlic (大蒜 dà suàn, bulb of Allium sativum) has been shown to possess both antioxidant and anti-inflammatory action in several clinical conditions. Our previous study demonstrated that treatment with garlic oil improves oral glucose tolerance and insulin tolerance and improves the insulin-stimulated utilization of glucose to synthesize glycogen in skeletal muscle in streptozotocin (STZ)-induced diabetes, in vivo and ex vivo, respectively. The aim of the present study is to investigate the antioxidant and anti-inflammatory effects of garlic oil (GO) in the skeletal muscle of diabetic rats. Rats with STZ-induced diabetes received GO (10, 50, or 100 mg/kg body weight) or corn oil by gavage every other day for 3 weeks. Control rats received corn oil only. GO dose-dependently improved insulin sensitivity, as assessed by the insulin tolerance test, and oral glucose tolerance. GO significantly elevated total glutathione and glutathione peroxidase activity and lowered the nitrate/nitrite content in skeletal muscle at 50 and 100 mg/kg and significantly elevated glutathione reductase activity and lowered lipid peroxidation at 100 mg/kg. By contrast, GO did not reverse diabetes-induced elevation of IL-1β and TNF-α in skeletal muscle at any tested dose. On the other hand, GO elevated the expression of GLUT4 in skeletal muscle along with glycogen content as observed with PAS staining. In conclusion, the antidiabetic effect of garlic oil is associated with ameliorated oxidative stress in skeletal muscle.

Red Mold Rice against Hepatic Inflammatory Damage in Zn-deficient Rats

The protective effect of red mold rice (RMR) against liver injury in rats fed with a Zn-deficient diet for 12 weeks was investigated in this study. Rats were orally administered RMR (151 mg/kg body weight or 755 mg/kg body weight; 1 × dose or 5 × dose, respectively) with or without Zn once a day for 4 consecutive weeks. The severity of liver damage was evaluated by measuring the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in Zn-deficient rats. RMR significantly inhibited the elevation of serum ALT levels by Zn-deficient induction. Hepatic antioxidase activity was also significantly increased in the RMR + Zn group (RZ), thereby suppressing the productions of reactive oxygen species (ROS) and proinflammatory cytokines in the liver of Zn-deficient rats. These findings suggested that RMR exerted hepatoprotective effects against Zn deficiency-induced liver inflammation.

Trikatu, a herbal compound that suppresses monosodium urate crystal-induced inflammation in rats, an experimental model for acute gouty arthritis

Gout is an inflammatory joint disorder characterized by hyperuricaemia and precipitation of monosodium urate crystals in the joints. In the present study, we aimed to investigate the anti-inflammatory effect of trikatu, a herbal compound in monosodium urate crystal-induced inflammation in rats, an experimental model for acute gouty arthritis. Paw volume and levels/activities of lysosomal enzymes, lipid peroxidation, anti-oxidant status and histopathological examination of ankle joints were determined in control and monosodium urate crystal-induced rats. In addition, analgesic (acetic acid-induced writhing response), anti-pyretic (yeast-induced pyrexia) and gastric ulceration effects were tested. The levels of lysosomal enzymes, lipid peroxidation and paw volume were significantly increased, and anti-oxidant status was found to be reduced in monosodium urate crystal-induced rats, whereas the biochemical changes were reverted to near normal levels upon trikatu (1000 mg/kg b.wt) administration. The trikatu has also been found to exhibit significant analgesic and anti-pyretic effects with the absence of gastric damage. In conclusion, the present results clearly indicated that trikatu exert a potent anti-inflammatory effect against monosodium urate crystal-induced inflammation in rats in association with analgesic and anti-pyretic effects in the absence of gastrointestinal damage.

p-Coumaric acid, a common dietary polyphenol, protects cadmium chloride-induced nephrotoxicity in rats

The present study was conducted to elucidate the protective role of p-coumaric acid, a common dietary polyphenol against cadmium induced nephrotoxicity in rats. For the purpose of comparison, a standard reference drug silymarin (50 mg/kg b. wt) was used. In this experiment, the animals were divided into four groups, with each consisting of six animals. The animals in Group I animals received saline and served as a control group and those in Group II received cadmium chloride (3 mg/kg b. wt) subcutaneously once daily for 3 weeks, but Group III and IV animals received cadmium chloride followed by p-coumaric acid (100 mg/kg b. wt, oral) and silymarin (50 mg/kg b. wt, oral), respectively, daily for 3 weeks. At the end of the treatment, the animals were sacrificed, and the blood and kidney samples were collected. The results obtained in this study revealed the fact that the levels of lipid peroxidation, lysosomal enzymes, glycoprotein, cadmium and metallothionein were increased in the cadmium chloride alone treated rats and antioxidant status was found to be decreased, when compared to the control group. The levels of kidney functional markers (urea, uric acid and creatinine) were also found to be abnormal in serum and urine of cadmium chloride alone treated rats. On the other hand, the administration of p-coumaric acid along with cadmium chloride significantly protected the biochemical alterations as observed in the cadmium chloride alone treated rats as evidenced by histopathology. Thus, the oral administration of p-coumaric acid significantly protected the cadmium-induced nephrotoxicity in rats.

Sodium arsenite-induced cardiotoxicity in rats: protective role of p-coumaric acid, a common dietary polyphenol

This study was performed to investigate the ameliorative role of p-coumaric acid against sodium arsenite-induced cardiotoxicity in rats. Sodium arsenite (5 mg/kg/b.wt) was orally administered once a day for 30 days to the animals to induce cardiotoxicity. After the experimental period, cardiotoxicity was assessed by estimating the levels of lipid peroxidation, anti-oxidant status (superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, glutathione reductase, total reduced glutathione, protein sulfyhydryl and non-protein sulfhydryl groups) and DNA fragmentation in the cardiac tissue of control and experimental rats. In addition, cardiac tissue specific serum markers (triacylglycerides, total cholesterol, low-density lipoprotein cholesterol and high density lipoprotein cholesterol) in serum and histopathological changes in the cardiac tissue were also evaluated. From the results obtained in our study, sodium arsenite administration to the rats increased lipid peroxidation, DNA fragmentation, triacylglycerides, total cholesterol and low-density lipoprotein cholesterol, whereas antioxidant status and high-density lipoprotein cholesterol were found to be reduced. However, p-coumaric acid (75 and100 mg/kg/b.wt) treatment orally once per day for 30 days, immediately before a daily administration of sodium arsenite protected the abnormal biochemical abnormalities observed in the cardiac tissue of sodium arsenite treated rats as evidenced by the cardiac histopathology. For comparison purpose, a standard antioxidant vitamin C (100 mg/kg/b.wt) was used. In conclusion, this study concluded that p-coumaric acid could be a promising candidate for protecting the sodium arsenite-induced cardiotoxicity in rats through its antioxidant character.

Potential antioxidant properties and hepatoprotective effects of an aqueous extract formula derived from three Chinese medicinal herbs against CCl(4)-induced liver injury in rats

The hepatoprotective effects of an aqueous extract formula (AEF) derived from Artemisia capillaris, Lonicera japonica and Silybum marianum (ratio 1:1:1) were evaluated by its antioxidant properties and its attenuation of carbon tetrachloride (CCl(4))-induced liver damage in rats. The antioxidant analyses revealed that the AEF showed higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and superoxide anion radical scavenging activities as well as ferric reducing antioxidant potential (FRAP) and Trolox equivalent antioxidant capacity (TEAC) compared with the individual herbs, suggesting a synergism in antioxidation between the three herbs. The animal experiments showed that the CCl(4) treatment increased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, but decreased triglyceride (TG) and glutathione (GSH) levels as well as glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) activities. However, AEF administration can successfully lower serum ALT and AST activities, restore the GSH level, ameliorate or restore GPx and CAT activities as well as improve SOD action depending on AEF dosage. Histological examination of liver showed that CCl(4) increased the extent of bile duct proliferation, necrosis, fibrosis and fatty vacuolation throughout the liver, but AEF can improve bile duct proliferation, vacuolation and fibrosis, and restore necrosis. The present study demonstrated the hepatoprotective potential of AEF as an alternative to the traditional silymarin.

Allicin modulates the antioxidation and detoxification capabilities of primary rat hepatocytes

The effect of allicin, an active ingredient of garlic, on lactate dehydrogenase (LDH) leakage, lipid peroxidation, glutathione (GSH) content, and GSH-related enzyme activity was investigated in primary hepatocytes. In this study, allicin was synthesized in our laboratory as an experimental material, and primary hepatocytes isolated from Sprague-Dawley rats were used as an experimental model. According to the results, hepatocytes treated with 10 μM allicin did not differ from the control on LDH leakage during various incubation times. When the hepatocytes were treated with 10 μM allicin, their levels of thiobarbituric acid reactive-substances (TBARS) did not differ significantly from that of the control within the 8-h incubation. However, the TBARS values of hepatocytes treated with 30 and 50 μM allicin were higher compared to the control after incubation for 4 h and 8 h, respectively. The hepatocyte intracellular GSH content was significantly higher than that of the control after 30 μM allicin treatment, but treatment with 50 μM allicin caused a significant GSH depletion after incubation for 4 h or longer. In addition, when hepatocytes were treated for 24 h with 10 or 30 μM allicin, glutathione peroxidase (GPx) activity was significantly increased compared to that of the control, whereas 50 μM allicin treatment for 24 h or longer significantly decreased the GPx activity. Glutathione reductase (GRd) activity was significantly increased when the hepatocytes were treated with 10 μM allicin for 24 h, but GRd activity significantly decreased when the hepatocytes were treated with 50 μM allicin. However, hepatocytes treated for 24 h with 10 or 30 μM allicin showed significantly increased glutathione S-transferase (GST) activity compared to the control. These results suggest that 10 μM allicin potentially enhances the antioxidation and detoxification capabilities of primary rat hepatocytes.

Hepatoprotective activity of Tribulus terrestris extract against acetaminophen-induced toxicity in a freshwater fish (Oreochromis mossambicus)

The potential protective role of Tribulus terrestris in acetaminophen-induced hepatotoxicity in Oreochromis mossambicus was investigated. The effect of oral exposure of acetaminophen (500 mg/kg) in O. mossambicus at 24-h duration was evaluated. The plant extract (250 mg/kg) showed a remarkable hepatoprotective activity against acetaminophen-induced hepatotoxicity. It was judged from the tissue-damaging level and antioxidant levels in liver, gill, muscle and kidney tissues. Further acetaminophen impact induced a significant rise in the tissue-damaging level, and the antioxidant level was discernible from the enzyme activity modulations such as glutamate oxaloacetic transaminase, glutamate pyruvic transaminase, alkaline phosphatase, acid phosphatase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, lipid peroxidase and reduced glutathione. The levels of all these enzymes have significantly (p < 0.05) increased in acetaminophen-treated fish tissues. The elevated levels of these enzymes were significantly controlled by the treatment of T. terrestris extract (250 kg/mg). Histopathological changes of liver, gill and muscle samples were compared with respective controls. The results of the present study specify the hepatoprotective and antioxidant properties of T. terrestris against acetaminophen-induced toxicity in freshwater fish, O. mossambicus.

Interleukin-6 counteracts therapy-induced cellular oxidative stress in multiple myeloma by up-regulating manganese superoxide dismutase

IL (interleukin)-6, an established growth factor for multiple myeloma cells, induces myeloma therapy resistance, but the resistance mechanisms remain unclear. The present study determines the role of IL-6 in re-establishing intracellular redox homoeostasis in the context of myeloma therapy. IL-6 treatment increased myeloma cell resistance to agents that induce oxidative stress, including IR (ionizing radiation) and Dex (dexamethasone). Relative to IR alone, myeloma cells treated with IL-6 plus IR demonstrated reduced annexin/propidium iodide staining, caspase 3 activation, PARP [poly(ADP-ribose) polymerase] cleavage and mitochondrial membrane depolarization with increased clonogenic survival. IL-6 combined with IR or Dex increased early intracellular pro-oxidant levels that were causally related to activation of NF-κB (nuclear factor κB) as determined by the ability of N-acetylcysteine to suppress both pro-oxidant levels and NF-κB activation. In myeloma cells, upon combination with hydrogen peroxide treatment, relative to TNF (tumour necrosis factor)-α, IL-6 induced an early perturbation in reduced glutathione level and increased NF-κB-dependent MnSOD (manganese superoxide dismutase) expression. Furthermore, knockdown of MnSOD suppressed the IL-6-induced myeloma cell resistance to radiation. MitoSOX Red staining showed that IL-6 treatment attenuated late mitochondrial oxidant production in irradiated myeloma cells. The present study provides evidence that increases in MnSOD expression mediate IL-6-induced resistance to Dex and radiation in myeloma cells. The results of the present study indicate that inhibition of antioxidant pathways could enhance myeloma cell responses to radiotherapy and/or chemotherapy.

Fagopyrum tataricum (buckwheat) improved high-glucose-induced insulin resistance in mouse hepatocytes and diabetes in fructose-rich diet-induced mice

Fagopyrum tataricum (buckwheat) is used for the treatment of type 2 diabetes mellitus in Taiwan. This study was to evaluate the antihyperglycemic and anti-insulin resistance effects of 75% ethanol extracts of buckwheat (EEB) in FL83B hepatocytes by high-glucose (33 mM) induction and in C57BL/6 mice by fructose-rich diet (FRD; 60%) induction. The active compounds of EEB (100 μg/mL; 50 mg/kg bw), quercetin (6 μg/mL; 3 mg/kg bw), and rutin (23 μg/mL; 11.5 mg/kg bw) were also employed to treat FL83B hepatocytes and animal. Results indicated that EEB, rutin, and quercetin + rutin significantly improved 2-NBDG uptake via promoting Akt phosphorylation and preventing PPARγ degradation caused by high-glucose induction for 48 h in FL83B hepatocytes. We also found that EEB could elevate hepatic antioxidant enzymes activities to attenuate insulin resistance as well as its antioxidation caused by rutin and quercetin. Finally, EEB also inhibited increases in blood glucose and insulin levels of C57BL/6 mice induced by FRD.

Hepatoprotection of emodin and Polygonum multiflorum against CCl(4)-induced liver injury

CONTEXT

Polygonum multiflorum is known as a medicinal plant. It has been used as a folk medicine which showed antioxidative property.

OBJECTIVE

Protective effects of the water extracts (w/v:1/10) from fresh P. multiflorum (WEP) on carbon tetrachloride (CCl(4))-induced liver damage in rats were investigated.

MATERIALS AND METHODS

CCl(4) was used for inducing liver damage of SD rats, and WEP and emodin were fed for eight consecutive weeks.

RESULTS

We found that emodin levels in fresh WEP was higher than that in ripening WEP. Rats were administered WEP and emodin, the main active compound, for 56 consecutive days. WEP significantly lowered the serum levels of hepatic enzyme markers, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and reduced the generation of malonaldehyde. Treatment with WEP recovered glutathione S-transferase and catalase activity in rats as compared to treatment with CCl(4) alone. In addition, serum tumor necrosis factor-α, an inflammatory marker, was found to decrease in rats treated with WEP. In histopathological evaluation, fatty degeneration and necrosis were found to be significantly decreased in the CCl(4) plus WEP treatment group.

DISCUSSION AND CONCLUSION

WEP may be effective in attenuating liver damage by reducing lipid peroxidation as well as by positively modulating inflammation.

Effect of diallyl sulfide on in vitro and in vivo Nrf2-mediated pulmonic antioxidant enzyme expression via activation ERK/p38 signaling pathway

Increasing oxidative stress is intimately involved in the pathogenesis of lung failure. Nuclear factor-erythroid 2 related factor 2 (Nrf2) is a key element in redox homeostasis. Nrf2 regulates antioxidant-associated genes that are often the target of phytochemicals in chemoprevention. This study evaluated the effect of diallyl sulfide (DAS), which is present in garlic, on the expression of antioxidant enzymes in the rat lung and the Nrf2 modulation in MRC-5 lung cells. DAS increased the activities of glutathione S-transferase, glutathione reductase, and catalase as well as the GSH/GSSG ratio compared with the lung of untreated control rats (p < 0.05). The pulmonic superoxide dismutase, glutathione peroxidase, NAD(P)H:quinone oxidoreductase 1, and catalase mRNA levels were also significantly increased (p < 0.05) after DAS treatment. Following DAS treatment, DAS level was measured in the plasma after 7 days of oral administration, and the C(max) value was 15 ± 4.2 μM. The total amount of pulmonic Nrf2 and the nuclear translocation of Nrf2 were elevated in DAS-treated rats, clarifying the effect of DAS on the modulation of antioxidant enzymes. Furthermore, DAS could induce nuclear translocation of Nrf2 via ERK/p38 signaling pathway in lung MRC-5 cells. This study demonstrates that DAS administration can significantly induce the activity of antioxidant enzymes in rat lungs and suggests a possible use for DAS as a dietary preventive agent against oxidative stress-induced lung injury.

Monascin from red mold dioscorea as a novel antidiabetic and antioxidative stress agent in rats and Caenorhabditis elegans

Monascin is a major yellow compound from red mold dioscorea. We investigated monascin to test whether this compound acts as an antidiabetic and antioxidative stress agent in diabetic rats and Caenorhabditis elegans. The mechanisms by which monascin exerts its action in vivo were also examined. Streptozotocin (STZ)-induced diabetic rats were given monascin at 30 mg/kg/day and sacrificed after 8 weeks. Blood glucose and serum insulin, triglyceride, total cholesterol, and high-density lipoprotein and antioxidative enzymes in the pancreas of rats were measured. In addition, monascin was evaluated for stress resistance and potential associated mechanisms in C. elegans. Throughout the 8-week experimental period, significantly lowered blood glucose, serum triglyceride, and total cholesterol and higher high-density lipoprotein levels were observed in monascin-treated rats. Monascin-treated rats showed higher serum insulin level, lower reactive oxygen species production, and higher activities of glutathione peroxidase, superoxide dismutase, and catalase in the pancreas compared to diabetic control rats. In addition, monascin significantly induced the hepatic mRNA levels of FOXO3a, FOXO1, MnSOD, and catalase in STZ-induced diabetic rats. Monascin-treated C. elegans showed an increased survival rate during oxidative stress and heat stress treatments compared to untreated controls. Moreover, monascin extended the life span under high-glucose conditions and enhanced expression of small heat shock protein (sHSP-16.2), superoxide dismutase (SOD-3), and glutathione S-transferase (GST-4) in C. elegans. Finally, we showed that monascin affected the subcellular distribution of the FOXO transcription factor DAF-16, whereas it was unable to enhance oxidative stress resistance in the daf-16 deletion mutant in C. elegans. Mechanistic studies in rats and C. elegans suggest that the protective effects of monascin are mediated via regulation of the FOXO/DAF-16-dependent insulin signaling pathway by inducing the expression of stress response/antioxidant genes, thereby enhancing oxidative stress resistance.

6-gingerol, an active ingredient of ginger, protects acetaminophen-induced hepatotoxicity in mice

OBJECTIVE

To investigate the hepatoprotective efficacy of 6-gingerol against acetaminophen-induced hepatotoxicity in mice.

METHODS

Mice were injected with a single dose of acetaminophen (900 mg/kg) to induce hepatotoxicity, while 6-gingerol (30 mg/kg) or the standard drug silymarin (25 mg/kg) was given 30 min after the acetaminophen administration. The mice were sacrificed 4 h after acetaminophen injection to determine the activities of liver marker enzymes such as aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP), total bilirubin in serum, and lipid peroxidation and antioxidant status (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione transferase and glutathione) in liver homogenate.

RESULTS

The treatment of 6-gingerol and silymarin to acetaminophen-induced hepatotoxicity showed significant hepatoprotective effect by lowering the hepatic marker enzymes (AST, ALT, and ALP) and total bilirubin in serum (P<0.05). In addition, 6-gingerol and silymarin treatment prevented the elevation of hepatic malondialdehyde formation and the depletion of antioxidant status in the liver of acetaminophen-intoxicated mice (P<0.05).

CONCLUSION

The results evidently demonstrate that 6-gingerol has promising hepatoprotective effect which is comparable to the standard drug silymarin.

Protective effect of Monascus-fermented red mold rice against alcoholic liver disease by attenuating oxidative stress and inflammatory response

Monascus purpureus NTU 568 fermented rice is reported to exhibit a wide variety of biological effects, including antitumor, antihypertriglyceridemia, antioxidant, and anti-inflammatory activities. However, its role in the pathogenesis of alcoholic liver disease remains obscure. In this study, the hepatoprotective effects of Monascus-fermented red mold rice (RMR) was evaluated in vivo using chronic alcohol-induced mice as an experimental model. The alcohol-induced mice were orally treated with RMR at 307.5 mg/kg (1-fold), 615 mg/kg (2-fold), and 1537.5 mg/kg (5-fold) for 5 weeks, whereas controls received vehicle only. Treatment with RMR significantly attenuated the increased level of serum transaminases (aspartate aminotransferase and alanine aminotransferase) and hepatic triglyceride and total cholesterol accumulation. Furthermore, RMR elevates hepatic antioxidant ability that reduced hepatic cell damage (steatosis) and decreased tissue inflammatory cytokine levels. These findings suggest that Monascus-fermented RMR may represent a novel, protective strategy against alcoholic liver disease by attenuating oxidative stress, inflammatory response, and steatosis.

Antioxidant properties of Lactobacillus-fermented and non-fermented Graptopetalum paraguayense E. Walther at different stages of maturity

Accumulation of bioactive compounds, during developmental stages of Graptopetalum paraguayense E. Walther, was investigated between 30 and 90days as a function of physiological maturity. Three distinct phases were defined: immature phase (30days), intermediate developmental phase (30-60days), and maturation phase (60-90days). Gallic acid and quercetin, antioxidative bioactive compounds, were identified as biomarkers for determining the optimum physiological maturity stage in G. paraguayense E. Walther. With regard to the antioxidant activity of G. paraguayense E. Walther at different developmental stages, the results indicated that the leaves of immature G. paraguayense E. Walther had the highest 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonate) (ABTS-), superoxide radical-, and 1,1-diphenyl-2-picrylhydrazyl (DPPH·)-scavenging activities. Fermentation of G. paraguayense E. Walther with Lactobacillus plantarum BCRC 10357 significantly increased the level of flavonoids and total phenolics, including quercetin and gallic acid. Total phenols were the major naturally occurring antioxidant components in lactic acid bacteria-fermented G. paraguayense E. Walther.

Oral administration of Trapa taiwanensis Nakai fruit skin extracts conferring hepatoprotection from CCl4-caused injury

As a folk medicine, the hot-water infusion of water caltrop fruits has been used to protect the liver. In this study, the outer skins of mature water caltrop fruits ( Trapa taiwanensis Nakai) were removed, forced-air-dried, pulverized, and subjected to extraction with hot water, and the infusion was lyophilized and pulverized to prepare a hot water extract of T. taiwanensis (HWETT). HWETT was subjected to assays of α,α-diphenyl-β-picrylhydrazyl scavenging activity, reducing power, Trolox equivalent antioxidant capacity, and antioxidative potency, and all determinations showed HWETT to be a potent antioxidant. As further analyzed with LC-MS, two major HPLC-detected components were elucidated as gallic acid and ellagic acid. Hepatoprotective activity of HWETT was assessed with Sprague-Dawley male rats by oral administration. Six groups of rats (n = 8 for each) were respectively treated, namely, control, CCl(4) (20% CCl(4)/olive oil by 2.0 mL/kg bw), CCl(4) and Silymarin (200 mg/kg bw), CCl(4) and low HWETT dose (12.5 mg/kg bw), CCl(4) and medium HWETT dose (25 mg/kg bw), and CCl(4) and high HWETT dose (125 mg/kg bw). After 8 weeks, all animals were fasted for an additional day and sacrificed to collect blood, liver, and kidney for analyses. Histopathological examinations showed that oral administrations with Silymarin and HWETT were effective in protecting the liver from CCl(4)-caused fatty change. Oral administration of HWETT at 125 mg/kg bw was more effective than was Silymarin at 200 mg/kg bw. On biochemical analyses, oral administrations with HWETT at medium and high doses were effective (p < 0.05) in lowering CCl(4)-caused increases of alanine aminotransferase and aspartate aminotransferase activities. It is of merit to demonstrate HWETT as a potent source of antioxidants and hepatoprotective agents.

Hepatoprotection of Graptopetalum paraguayense E. Walther on CCl₄-induced liver damage and inflammation

AIM OF THIS STUDY

Graptopetalum paraguayense E. Walther, a vegetable consumed in Taiwan, has been used in folk medicine for protection against liver injury, although its actual efficacy remains uncertain. Therefore, we investigated the protective effects of Graptopetalum paraguayense E. Walther against carbon tetrachloride (CCl(4))-induced liver damage in rats.

MATERIALS AND METHODS

Water extracts of Graptopetalum paraguayense E. Walther (WGP) were administered for 8 consecutive weeks to male Sprague-Dawley rats. And a dose-dependent manner in preventing liver damage was confirmed. Moreover, the major ingredient of WGP, gallic acid, was also orally administrated in the CCl(4)-induced rats. The hepatoprotective activity was assessed using various biochemical parameters such as antioxidant enzymes and histopathological studies.

RESULTS

WGP ranging from 50 to 300 mg/kg bw administrations significantly lowered serum aspartate transaminase (AST) and alanine transaminase (ALT) levels, and inhibited malondialdehyde (MDA) generation in CCl(4)-treated rats. WGP increased cellular GSH level and antioxidant enzymes, including superoxide dismutase, glutathione reductase, and catalase. Serum tumor necrosis factor-alpha (TNF-α) was decreased in the group treated with CCl(4) plus WGP (150 and 300 mg/kg bw). Histopathological examination of livers showed that WGP reduced fatty degeneration, cytoplasmic vacuolization and necrosis in CCl(4)-treated rats. In contrary, 10mg/kg bw of gallic acid was administrated, this dose was related with WGP (300 mg/kg bw), and had significantly decreased the AST and ALT compared to the CCl(4)-treated group. Aforesaid results suggested that gallic acid from WGP offered antioxidative activity against CCl(4)-induced oxidative liver damage.

CONCLUSIONS

Taken together, this study is the first time to suggest that Graptopetalum paraguayense E. Walther exerts hepatoprotection via promoting antioxidative and anti-inflammatory properties against CCl(4)-induced oxidative liver damage.