Gracilaria chorda subcritical-water extracts as ameliorant of insulin resistance induced by high-glucose in zebrafish and dexamethasone in L6 myotubes.

Background and aim: Insulin resistance (IR) is a pathological condition in which cells fail to respond normally to insulin. Loss of insulin sensitivity disrupts glucose homeostasis and elevates the risk of developing the metabolic syndrome that includes Type 2 diabetes. This study assesses the effect on subcritical-water extract of Gracilaria chorda (GC) at 210 °C (GCSW210) in IR induction models of high glucose (HG)-induced zebrafish larvae and dexamethasone (DEX)-induced L6 myotubes. Experimental procedure: The dose of HG and DEX for IR induction in zebrafish larvae and L6 myotubes was 130 mM or 0.5 µM. The capacity of glucose uptake was quantified by fluorescence staining or intensity. In addition, the activation of protein and mRNA expressions for insulin signaling (insulin-dependent or independent pathways) was measured. Results and conclusion: Exposure of zebrafish larvae to HG significantly reduced the intracellular glucose uptake with dose-dependnet manner compared to control. However, the group treated with GCSW210 significantly averted HG levels like the insulin-treated group, and significantly up- or down-regulated the mRNA expressions related to insulin production (insα) and insulin signaling pathways. Moreover, the treatment with GCSW210 effectively regulated the protein expression of PI3K/AKT, AMPK, and GLUT4 involved in the action of insulin in IR models of L6 myotubes compared to DEX-treated control. Our data indicate that GCSW210 stimulates activation of PI3K/AKT and AMPK pathways to attenuate the development of IR induced by HG in zebrafish and DEX in L6 myotubes. In conclusion, GCSW210 is a potential agent for alleviating various diseases associated with the insulin resistance.

Caulerpa okamurae extract attenuates inflammatory interaction, regulates glucose metabolism and increases insulin sensitivity in 3T3-L1 adipocytes and RAW 264.7 macrophages.

OBJECTIVE: To examine whether Caulerpa okamurae ethanolic extract (COE) could inhibit obesity-mediated inflammation, improve glucose metabolism and increase insulin sensitivity, using in vitro cell models of RAW 264.7 macrophages and 3T3-L1 adipocytes. METHODS: We cocultured 3T3-L1 adipocytes in direct contact with lipopolysaccharide-stimulated RAW 264.7 macrophages and induced insulin resistance in 3T3-L1 adipocytes with tumor necrosis factor-α (TNF-α) in the presence or absence of 250 µg/mL of COE. We investigated various markers of inflammation, glucose regulation and insulin sensitivity in these models using Griess reagent to measure nitric oxide (NO) production, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxyglucose to measure glucose uptake, Western blot analysis to quantify protein expression and reverse transcriptase-polymerase chain reaction to evaluate mRNA expression. RESULTS: We found that COE (250 µg/mL) significantly inhibited the lipopolysaccharide-induced inflammatory response in RAW 264.7 macrophages by downregulating NO production, nitric oxide synthase 2 expression and nuclear translocation of nuclear factor-κB. COE also showed similar anti-inflammatory activity in coculture, along with decreased TNF-α, interleukin-6 and monocyte chemoattractant protein mRNA expression. In addition, COE also improved glucose uptake in coculture by upregulating glucose transporter-4 (GLUT-4) and adiponectin and reducing serine phosphorylation of insulin receptor substrate-1 (IRS1). In the TNF-α-induced insulin resistance model of 3T3-L1 adipocytes, COE significantly improved both basal and insulin-stimulated glucose uptake, accompanied by phosphorylation of IRS1 at tyrosine 632, phospho-5' adenosine monophosphate-activated protein kinase α and glycogen synthase kinase-3ß (Ser9) as well as upregulation of GLUT-4. CONCLUSION: Together, these findings suggest that COE has potential to treat or prevent obesity-induced metabolic disorders.

Tinospora cordifolia preserves pancreatic beta cells and enhances glucose uptake in adipocytes to regulate glucose metabolism in diabetic rats.

The purpose of this study was to evaluate the pancreatic beta cell protective and glucose uptake enhancing effect of the water extract of Tinospora cordifolia stem (TCSE) by using rat insulinoma (RIN)-m5F cells and 3 T3-L1 adipocytes. RIN-m5F cells were stimulated with interleukin-1ß and interferon-γ, and the effect of TCSE on insulin secretion and cytokine-induced toxicity was measured by ELISA and MTT assay, respectively. The glucose uptake and protein expression were measured by fluorometry and western blotting. Antidiabetic effect of TCSE was measured using streptozotocin-induced diabetic rats. TCSE dose dependently increased cell viability and insulin secretion in RIN-m5F cells. In addition, TCSE increased both the glucose uptake and glucose transporter 4 translocation in 3 T3-L1 adipocytes via PI3K pathway. Finally, TCSE significantly lowered blood glucose and diet intake and increased body weight in streptozotocin-induced diabetic rats. The level of serum insulin and hepatic glycogen was increased, whereas the level of serum triglyceride, total cholesterol, dipeptidyl peptidase-4, and thiobarbituric acid reactive substances was decreased in TCSE-administered rats. TCSE also increased glucose transporter 4 protein expression in the adipose tissue and liver of TCSE-fed diabetic rats. Our results suggested that TCSE preserved RIN-m5F cells from cytokine-induced toxicity and enhanced glucose uptake in 3 T3-L1 adipocytes, which may regulate glucose metabolism in diabetic rats.

Caulerpa okamurae extract inhibits adipogenesis in 3T3-L1 adipocytes and prevents high-fat diet-induced obesity in C57BL/6 mice.

Seaweeds are considered a potential source of antiobesity agents. Because Caulerpa, a seaweed, has been consumed for food in Japan, China, South Korea, and Australia, we hypothesized that Caulerpa okamurae may have antiobesity effects in an animal model of high-fat diet (HFD)-induced obesity in C57BL/6 mice. Herein, we found that the ethanolic extract of C okamurae (COE) significantly inhibited lipid accumulation and reduced the expression of the master regulator of adipogenesis, peroxisome proliferator-activated receptor-γ, sterol regulatory element binding protein-1c, and CCAAT/enhancer-binding protein-α in 3T3-L1 adipocytes. Moreover, COE significantly decreased body weight, fat weight, and liver weight in HFD-fed mice. This effect is comparable to that of positive control Garcinia cambogia extract, which has been approved by the Korean Food and Drug Administration as a weight loss food supplement in South Korea. Similarly, markers of weight gain such as free fatty acids, triglyceride, total cholesterol, glucose, and insulin in the plasma and free fatty acid, triglyceride, total cholesterol, and total lipid in the liver are significantly reduced in COE-treated HFD-fed mice. We found significantly reduced peroxisome proliferator-activated receptor-γ, CCAAT/enhancer-binding protein-α, fatty acid synthase, sterol regulatory element binding protein-1c, cluster of differentiation 36, and acetyl-CoA synthetase in the adipose tissue of COE-treated HFD-fed mice. In conclusion, our results demonstrated that COE is effective in preventing body weight gain and fat accumulation and reduces plasma and hepatic lipid profiles. Together, these findings suggest that C okamurae may be used as a possible treatment option for the management of obesity and associated metabolic disorders.

Korean Chungtaejeon tea extract attenuates body weight gain in C57BL/6J-Lep ob/ob mice and regulates adipogenesis and lipolysis in 3T3-L1 adipocytes.

OBJECTIVE: Traditional Korean Chungtaejeon (CTJ) tea is a type of fermented tea, which has received increasing attention in recent years because of its purported health benefits. The present study was designed to investigate the effect and mechanism of CTJ tea extract on body weight gain using C57BL/6J-Lep ob/ob mice and 3T3-L1 adipocytes, respectively. METHODS: The effects of CTJ on cell viability, lipid accumulation, and expression of protein and mRNA were measured in 3T3-L1 adipocytes by using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide, oil red O staining, Western blotting, and reverse transcriptase-polymerase chain reaction analyses. C57BL6J-Lep ob/ob mice were administered with CTJ (200 or 400 mg/kg body weight) for ten weeks. Then, body weight, food intake, total cholesterol, and triglyceride were measured in ob/ob mice. RESULTS: CTJ tea extract treated at 250 µg/mL (CTJ250) significantly suppressed lipid accumulation in the differentiated 3T3-L1 adipocytes. Likewise, CTJ250 significantly decreased the protein expression of peroxisome proliferator-activated receptorγ (PPARγ), CCAAT/enhancer-binding protein α, and adipocyte lipid-binding protein, and regulated the mRNA expression of PPARγ, sterol regulatory element-binding protein-1c gene, fatty acid synthase, adipocyte lipid-binding protein, hormone-sensitive lipase, carnitine palmitoyl transferase 1, cluster of differentiation 36, and acetyl-CoA carboxylase in the differentiated 3T3-L1 adipocytes. Mice administered with CTJ showed dose-dependent decrease in body weight gain, starting from week 4 of the experiment. CTJ tea extract administered at 400 mg/kg body weight significantly decreased fat mass, food efficacy ratio, and levels of plasma triglyceride and total cholesterol. CONCLUSION: CTJ attenuated weight gain in ob/ob mice and regulated the activity of the molecules involved in adipogenesis and lipolysis in 3T3-L1 adipocytes. CTJ is a potentially valuable herbal therapy for the prevention of obesity and/or obesity-related disorders.

Nelumbo Nucifera leaf extract attenuated pancreatic ß-cells toxicity induced by interleukin-1ß and interferon-γ, and increased insulin secrection of pancreatic ß-cells in streptozotocin-induced diabetic rats.

OBJECTIVE: To evaluate the effect of Nelumbo Nucifera leaf water extract (NNLE) on insulinoma (RIN) cells induced by interleukin-1ß (IL-1ß) and interferon-g (IFN-γ), and injured pancreatic ß-cells induced by Streptozotocin (STZ) in rats. METHODS: The anti-oxidative effects of NNLE were assessed using 1,1-diphenyl-2-picryl hydrazyl (DPPH) and nitric oxide (NO) scavenging assays. The inhibitory effect of NNLE on α-glucosidase and DPP (dipeptidyl peptidase)-IV was measured in vitro. Pancreatic ß-cell protective and insulin secretory effects were assessed, using IL-1ß and IFN-γ-induced rat RIN cells. STZ-induced diabetic rats were treated with 50, 100, and 400 mg/kg NNLE for 4 weeks. The effects of NNLE on blood glucose (BG), body weight (BW), and lipid profiles were measured. RESULTS: NNLE inhibited DPPH, NO, α-glucosidase, and DPP-IV which were directly linked to the function of ß-cells. Furthermore, NNLE protected RIN cells from toxicity induced by IL-1ß and IFN-γ, decreased NO production, and increased insulin secretion. NNLE caused a significant reduction in blood glucose, triglyceride (TG), total cholesterol (TC), blood urea nitrogen (BUN), and creatinine in STZ-induced diabetic rats. Furthermore, it significantly decreased BW loss in STZ-induced diabetic rats. CONCLUSION: Our results suggest that NNLE reduced the toxicity in insulinoma cells and increased insulin secretion in pancreatic ß-cells in STZ-induced diabetic rats.

Anti-Obesity Effects of the Mixture of Eriobotrya japonica and Nelumbo nucifera in Adipocytes and High-Fat Diet-Induced Obese Mice.

The present study is to evaluate the anti-obesity effects of Eriobotrya japonica (EJ), Nelumbo nucifera (NN), and their mixture (MIX, 1:1 ratio) in 3T3-L1 adipocytes and high-fat diet-induced obese mice. The treatment of EJ, NN, and MIX in 3T3-L1 adipocytes effectively inhibited lipid accumulation, significantly decreased expression of peroxisome proliferator-activated receptor gamma (PPARγ), sterol regulatory element binding protein (SREBP1c), and adipocyte lipid-binding protein (aP2), and significantly increased phosphorylation of AMP-activated protein kinase (AMPK). Moreover, oral treatment of MIX showed stronger effects than individual treatment. C57BL/6J mice (6 week old) were divided into two groups; low fat diet (LFD) containing 10% calories from fat and high fat diet (HFD) containing 60% calories from fat. The HFD groups were further divided into five subgroups; treated with distilled water (HFD), treated with 400 mg/kg EJ (EJ400), treated with 400 mg/kg NN (NN400), treated with 200 mg/kg MIX (MIX200), and treated with 400 mg/kg MIX (MIX400) during 13 weeks. In our results, the administration of EJ, NN, and MIX significantly decreased body weight (BW), fat weight, liver weight, hepatic triglyceride (TG) and total cholesterol (TC), lipid droplets in the liver, food efficacy ratio, and the plasma TG, TC, glucose, insulin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in a dose-dependent manner, and MIX treatment showed stronger effect than their individual treatments. Similarly, MIX treatment decreased the expression of PPARγ, SREBP-1c, FAS, and ACC more strongly in the adipose tissue than single treatments. In conclusion, the MIX of EJ and NN extract may strongly regulate BW gain than EJ or NN alone, and its anti-obesity effect is associated with the control of lipid metabolism, including adipogenesis and lipogenesis.

Selaginellin and biflavonoids as protein tyrosine phosphatase 1B inhibitors from Selaginella tamariscina and their glucose uptake stimulatory effects.

As part of an ongoing search for new antidiabetic agents from medicinal plants, the methanol extract of the aerial parts of Selaginella tamariscina was found to possess stimulatory effect on glucose uptake in 3T3-L1 adipocyte cells. Thus, bioassay-guided isolation of this active extract yielded two new compounds (1 and 2) along with five known biflavonoids (3-7). Their structures were elucidated by extensive analysis of spectroscopic and physicochemical data. The absolute configuration of compound 2 was determined by specific rotation and CD data analysis. All isolates exhibited potent inhibitory effects on PTP1B enzyme with IC50 values ranging from 4.5±0.1 to 13.2±0.8µM. Furthermore, the isolates (1-7) showed significant stimulatory effects on 2-NBDG uptake in 3T3-L1 adipocyte cells. Of these, compounds (1, 6, and 7) which exhibited mixed-competitive inhibition modes against PTP1B, showed potent stimulatory effects on 2-NBDG uptake. This result indicated the potential of these biflavonoids as lead molecules for development of antidiabetic agents and the beneficial use of S. tamariscina against hyperglycemia.

Lespedeza davurica (Lax.) Schindl. extract protects against cytokine-induced ß-cell damage and streptozotocin-induced diabetes.

Lespedeza has been used for the management of diabetes in folklore medicine. The purpose of this study is to investigate the protective effects of the methanol extract of Lespedeza davurica (LD) on cytokine-induced ß-cell damage and streptozotocin- (STZ-) induced diabetes. RINm5F cells were treated with interleukin- (IL-) 1ß and interferon- (IFN-) γ to induce pancreatic ß-cell damage. The exposure of LD extract significantly decreased cell death, nitric oxide (NO) production, nitric oxide synthase (iNOS) expression, and nucleus factor-kappa B (NF-κB) p65 activation. Antidiabetic effects of LD extract were observed by oral glucose tolerance test (OGTT) in normal rats and by checking the biochemical, physiological, and histopathological parameters in STZ-induced diabetic rats. In OGTT, glucose clearance levels improved by oral treatment of LD extract. The water intake, urine volume, blood glucose, and serum TG, TC, TBARS, and DPP-IV levels were significantly decreased, and liver glycogen content was significantly increased by treatment of LD extract (250 mg/kg BW) in STZ-induced diabetic rats. Also, insulin immunoreactivity of the pancreases was increased in LD extract administrated rats compared with diabetic control rats. These results indicate that LD extract may protect pancreatic ß-cell damage and regulate the blood glucose in STZ-induced diabetic rats.

Insulin-mimetic selaginellins from Selaginella tamariscina with protein tyrosine phosphatase 1B (PTP1B) inhibitory activity.

As part of an ongoing search for new antidiabetic agents from medicinal plants, three new (2, 4, and 5) and two known selaginellin derivatives (1 and 3) were isolated from a methanol extract of Selaginella tamariscina. The structures of the new compounds were determined by spectroscopic data analysis. All isolates showed strong glucose uptake stimulatory effects in 3T3-L1 adipocyte cells at a concentration of 5 µM. Furthermore, these compounds were found to possess inhibitory effects on PTP1B enzyme activity with IC50 values ranging from 4.6 ± 0.1 to 21.6 ± 1.5 µM. Compound 2 showed the greatest potency, with an IC50 value of 4.6 ± 0.1 µM, when compared with the positive control (ursolic acid, IC50 = 3.5 ± 0.1 µM). Therefore, these selaginellin derivatives may have value as new lead compounds for the development of agents against type 2 diabetes.

Active compounds isolated from traditional Chinese prescription Wen-Pi-Tang protecting against peroxynitrite-induced LLC-PK(1) cell damage.

Wen-Pi-Tang, a traditional Chinese prescription, has been widely used for the treatment of patients with moderate chronic renal failure in China. Although the protective effect of Wen-Pi-Tang on peroxynitrite (ONOO(-))-induced renal tubular epithelial LLC-PK(1) cell damage was elucidated in our previous research, the active components of Wen-Pi-Tang have not yet been fully clarified. Therefore in the present study, we investigated the active components by using a cellular ONOO(-)generation system. As a result, p-coumaric acid, 4-(4'-hydroxylphenyl)-2-butanone 4'-O-glucopyranoside, gallic acid 3-O-(6'-O-galloyl)-beta-d-glucopyranoside, procyanidin B-1, procyanidin B-3, and (+)-catechin were isolated as active compounds inhibiting cellular ONOO(-) formation and cytotoxicity. In particular, the content of (+)-catechin was significantly higher than those of the other compounds, and the (+)-catechin structure was located in procyanidins B-1 and B-3. Therefore, the major bioactivity of Wen-Pi-Tang against ONOO(-)-induced cytotoxicity in LLC-PK(1) cells was thought to be mediated by (+)-catechin. Although we cannot disregard the synergetic effect of various components in Wen-Pi-Tang, (+)-catechin is a major active compound protecting against ONOO(-)-induced LLC-PK(1) cell damage and may be used as an index to qualify the ONOO(-)-inhibitory activity of Wen-Pi-Tang extract.

Antioxidant effect of Wen-Pi-Tang and its component crude drugs on oxidative stress.

Oxidative stress plays a key role in the pathophysiologic process of acute and chronic renal diseases. Intracellular component such as lipids, proteins and nucleic acids are easily and rapidly oxidized by excessive reactive oxygen species (ROS), and such reactions lead to increased levels of lipid peroxide. The present study examined the antioxidant effects of Wen-Pi-Tang and its component crude drugs on 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)- or 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN)-induced ROS generation and lipid peroxidation of linoleic acid. As a result, Wen-Pi-Tang significantly decreased AAPH or AMVN-induced ROS in renal mitochondrial particles. For the components in Wen-Pi-Tang's prescription, Rhei Rhizoma and Glycyrrhizae Radix extracts strongly inhibited peroxide levels, but Ginseng Radix, Aconiti Tuber and Zingiberis Rhizoma extracts were comparably low. Rhei Rhizoma extract showed the strongest inhibitory activity on oxidative injury, and two of its tannin compounds, (-)-epicatechin 3-O-gallate and procyanidin B-2 3,3'-di-O-gallate, inhibited AAPH or AMVN-induced ROS significantly. Thus, the present data suggest that Wen-Pi-Tang and its component crude drugs effectively prevent biological toxicity on oxidative stress through potent antioxidant and anti-lipid peroxidation activities.

Glycyrrhizae Radix attenuates peroxynitrite-induced renal oxidative damage through inhibition of protein nitration.

We investigated the protective effects of Glycyrrhizae Radix extract against peroxynitrite (ONOO-)-induced oxidative stress under in vivo as well as in vitro conditions. The extract showed strong ONOO- and nitric oxide (NO) scavenging effects under in vitro system, in particular higher activity against ONOO-. Furthermore, elevations of plasma 3-nitrotyrosine levels, indicative of in vivo ONOO- generation and NO production, were shown using a rat in vivo ONOO(-)-generation model of lipopolysaccharide injection plus ischemia-reperfusion. The administration of Glycyrrhizae Radix extract at doses of 30 and 60 mg/kg body weight/day for 30 days significantly reduced the concentrations of 3-nitrotyrosine and NO and decreased inducible NO synthase activity. In addition, the nitrated tyrosine protein level and myeloperoxidase activity in the kidney were significantly lower in rats given Glycyrrhizae Radix extract than in control rats. However, the administration of Glycyrrhizae Radix extract did not result in either significant elevation of glutathione levels or reduction of lipid peroxidation in renal mitochondria. Moreover, the in vivo ONOO- generation system resulted in renal functional impairment, reflected by increased plasma levels of urea nitrogen and creatinine, whereas the administration of Glycyrrhizae Radix extract reduced these levels significantly, implying that the renal dysfunction induced by ONOO- was ameliorated. The present study suggests that Glycyrrhizae Radix extract could protect the kidneys against ONOO- through scavenging ONOO- and/or its precursor NO, inhibiting protein nitration and improving renal dysfunction caused by ONOO-.

(-)-Epicatechin 3-O-gallate ameliorates the damages related to peroxynitrite production by mechanisms distinct from those of other free radical inhibitors.

This study was carried out to elucidate whether the protective activity of (-)-epicatechin 3-O-gallate (ECg) against excessive peroxynitrite (ONOO(-)) production, is distinct from the activity of several well-known free radical inhibitors, the ONOO(-) inhibitors ebselen and uric acid, the superoxide anion (O(2)(-)) scavenger copper zinc superoxide dismutase (CuZnSOD) and the selective inducible nitric oxide synthase inhibitor L-N(6)-(1-iminoethyl)lysine hydrochloride (L-NIL). To generate ONOO(-), male Wistar rats (n = 6/group) were subjected to ischaemia-reperfusion process together with lipopolysaccharide (LPS) injection. Although ECg did not scavenge the ONOO(-) precursors nitric oxide (NO) and O(2)(-), it reduced the 3-nitrotyrosine level, a property similar to that of uric acid, but distinct from L-NIL. In addition, the elevation in myeloperoxidase activity was reversed by the administration of ECg, uric acid and SOD, but not by that of L-NIL. Furthermore, ECg was the more potent scavenger of the ONOO(-) decomposition product, the hydroxyl radical (*OH), than any other free radical inhibitor tested. The LPS plus ischaemia-reperfusion process resulted in renal dysfunction, estimated by measuring the parameters of renal function--serum urea nitrogen and creatinine levels. However, administration of ECg ameliorated renal dysfunction more than that of the other free radical inhibitors. Moreover, ECg reduced the excessive uric acid level, while the others did not, suggesting a property of ECg distinct from the others. Furthermore, proteinuria, which was demonstrated by the low- and high-molecular weight (LMW and HMW) protein bands of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern, caused by LPS plus ischaemia-reperfusion, was attenuated by administration of ECg and L-NIL, after which the HMW band intensities decreased and LMW protein bands were absent. This study indicates that, in an in-vivo model of ONOO(-) generation, ECg, L-NIL and uric acid exert stronger protective activity against ONOO(-)-induced oxidative damage than SOD and ebselen, and that the mechanism whereby ECg protects against ONOO(-) is distinct from that of L-NIL or uric acid.

Protection by the Chinese prescription Wen-Pi-Tang against renal tubular LLC-PK1 cell damage induced by 3-morpholinosydnonimine.

We investigated the effects of Wen-Pi-Tang extract on the protective mechanisms of renal tubular LLC-PK1 cells, as renal tubular cells are the most vulnerable renal tissue to oxidative stress. Exposure to 800 microM 3-morpholinosydnonimine (SIN-1) resulted in a marked increase in cellular peroxynitrite (ONOO-), which converted nonfluorescent dihydrorhodamine 123 to fluorescent rhodamine 123, a detectable probe for the long-lived ONOO-. In addition, it resulted in apoptotic cell death, assessed by a DNA fragmentation assay. However, treatment with Wen-Pi-Tang extract, at concentrations of 50 and 100 microg mL(-1) together with SIN-1 protected renal tubular cells against ONOO- through scavenging ONOO- and inhibiting apoptotic cell death in a dose-dependent manner. Moreover, treatment with Wen-Pi-Tang extract both before and after exposure to SIN-1 was also protective: it reduced cellular ONOO- levels, increased cell viability and decreased the DNA fragmentation rate. These results suggest that Wen-Pi-Tang would have protective activity against ONOO- -induced renal tubular injury through the inhibition of ONOO- production and apoptotic cell death by both preventing and treating renal injury. Furthermore, morphological characteristics of apoptosis were observed in SIN-1 treated tubular cells, while the addition of Wen-Pi-Tang extract with SIN-1 attenuated these morphological changes. ONOO- generated by SIN-1 also disturbed the cell cycle by decreasing the cellular G2/M phase ratio, while Wen-Pi-Tang extract regulated the cell cycle by G2/M phase arrest.

Protective effects of Acanthopanax Radix extract against endotoxemia induced by lipopolysaccharide.

Endotoxemia causes an enhanced production of reactive oxygen radicals, which contribute to multiple organ dysfunction. When rats were given intravenous lipopolysaccharide and tested 6 h later we found that the activities of catalase and glutathione peroxidase (GSH-Px) in kidney, were acutely suppressed while in serum the levels of nitric oxide (NO), lipid peroxidation, urea nitrogen and creatinine were significantly increased, indicating the excessive production of reactive oxygen radicals and the presence of renal injury. Pretreatment of rats with Acanthopanax Radix extract administered orally for 30 days reduced the NO and lipid peroxidation levels, increased the activities of catalase and GSH-Px, and attenuated the renal dysfunction. These results suggested that scavenging of reactive oxygen radicals is part of the mechanism by which Acanthopanax Radix extract works as an effective agent in preventing multiple organ dysfunction.

The inhibitory effects of 12 medicinal plants and their component compounds on lipid peroxidation.

The antioxidative activities of 12 medicinal plants and the compounds isolated from them were investigated using the thiocyanate method to evaluate inhibitory effects on lipid peroxidation in the linoleic acid system. The peroxide levels gradually increased during incubation in the presence of linoleic acid over 3 days, and most of the plants inhibited lipid peroxidation. In particular, of the plants tested, Cudrania tricuspidata, Zanthoxylum piperitum, Houttuynia cordata and Ulmus parvifolia reduced lipid peroxidation more effectively as lipid peroxidation progressed, resulting in inhibition of about 80% relative to the control value by the 3rd day of incubation. In addition, the polyphenols isolated from the plants also showed marked and dose-dependent inhibitory effects on lipid peroxidation. The compounds with the strongest activities were 3,4-dihydroxylbenzoic acid, quercetin, the quercetin glycosides quercetin-3-O-beta-D-galactoside, quercetin-3-O-alpha-L-rhamnoside, quercetin-3-O-beta-D-glucoside and quercetin-3-O-rutinose, catechin, gallic acid, methyl gallate and rosamultin isolated from Zanthoxylum piperitum, Houttuynia cordata, Rosa rugosa and Cedrela sinensis. Moreover, quercetin glycosides showed stronger activity than quercetin, suggesting that glycosylation increases the antioxidative activity of quercetin. Our results indicate that the medicinal plants and their polyphenols show promise as therapeutic agents for various disorders involving free radical reactions.

Prevention of peroxynitrite-induced renal injury through modulation of peroxynitrite production by the Chinese prescription Wen-Pi-Tang.

The effect of Wen-Pi-Tang extract on renal injury induced by peroxynitrite (ONOO-) production was investigated using rats subjected to intravenous lipopolysaccharide (LPS) injection and then renal ischemia followed by reperfusion. The plasma level of 3-nitrotyrosine, a marker of cytotoxic ONOO formation in vivo, was enhanced markedly in control rats subjected to LPS plus ischemia-reperfusion, but was significantly reduced by the oral administration of Wen-Pi-Tang extract, at doses of 62.5 and 125 mg/kg body weight/day, for 30 days prior to LPS plus ischemia-reperfusion. The activities of inducible nitric oxide synthase (iNOS) and xanthine oxidase (XOD) in renal tissue of control and Wen-Pi-Tang extract-treated rats did not change significantly, while those of the antioxidant enzymes, superoxide dismutase, catalase and glutathione peroxidase, were significantly increased by the administration of Wen-Pi-Tang extract, indicating that Wen-Pi-Tang improved the defense system by scavenging free radicals, not by directly inhibiting nitric oxide and superoxide production by iNOS and XOD. In addition, the levels of the hydroxylated products, m- and p-tyrosine, declined, whereas that of phenylalanine increased, after oral administration of Wen-Pi-Tang extract. Furthermore, the elevated plasma urea nitrogen and creatinine levels resulting from LPS plus ischemia-reperfusion process were significantly reduced by Wen-Pi-Tang extract, implying amelioration of renal impairment. The present study indicates that Wen-Pi-Tang extract contributes to the regulation of ONOO- formation and plays a beneficial role against ONOO(-) -induced oxidative injury and renal dysfunction in vivo.