Silymarin: a novel antioxidant with antiglycation and antiinflammatory properties in vitro and in vivo

Flavonoids for treating pulmonary fibrosis: Present status and future prospects

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with an unknown underlying cause. There is no complete cure for IPF; however, two anti-fibrotic agents (Nintedanib and pirfenidone) are approved by the USFDA to extend the patient's life span. Therefore, alternative therapies supporting the survival of fibrotic patients have been studied in recent literature. The abundance of phenolic compounds, particularly flavonoids, has gathered attention due to their potential health benefits. Various flavonoids, like naringin, quercetin, baicalin, baicalein, puerarin, silymarin, and kaempferol, exhibit anti-inflammatory and anti-oxidant properties, which help decrease lung fibrosis. Various databases, including PubMed, EBSCO, ProQuest, and Scopus, as well as particular websites, such as the World Health Organisation and the National Institutes of Health, were used to conduct a literature search. Several mechanisms of action of flavonoids are reported with the help of in vivo and cell line studies emphasizing their ability to modulate oxidative stress, inflammation, and fibrotic processes in the lungs. They are reported for the restoration of biomarkers like hydroxyproline, cytokines, superoxide dismutase, malondialdehyde and others associated with IPF and for modulating various pathways responsible for the progression of pulmonary fibrosis. Yet, flavonoids have some drawbacks, such as poor solubility, challenging drug loading, stability issues, and scarce bioavailability. Therefore, novel formulations of flavonoids are explored, including liposomes, solid lipid microparticles, polymeric nanoparticles, nanogels, and nanocrystals, to enhance the therapeutic efficacy of flavonoids in pulmonary fibrosis. This review focuses on the role of flavonoids in mitigating idiopathic pulmonary fibrosis, their mode of action and novel formulations.

Effects of a Curcumin/Silymarin/Yeast-Based Mycotoxin Detoxifier on Redox Status and Growth Performance of Weaned Piglets under Field Conditions

The aim of this in vivo study was to investigate the effects of a novel mycotoxin detoxifier whose formulation includes clay (bentonite and sepiolite), phytogenic feed additives (curcumin and silymarin) and postbiotics (yeast products) on the health, performance and redox status of weaned piglets under the dietary challenge of fumonisins (FUMs). The study was conducted in duplicate in the course of two independent trials on two different farms. One hundred and fifty (150) weaned piglets per trial farm were allocated into two separate groups: (a) T1 (control group): 75 weaned piglets received FUM-contaminated feed and (b) T2 (experimental group): 75 weaned piglets received FUM-contaminated feed with the mycotoxin-detoxifying agent from the day of weaning (28 days) until 70 days of age. Thiobarbituric acid reactive substances (TBARSs), protein carbonyls (CARBs) and the overall antioxidant capacity (TAC) were assessed in plasma as indicators of redox status at 45 and 70 days of age. Furthermore, mortality and performance parameters were recorded at 28, 45 and 70 days of age, while histopathological examination was performed at the end of the trial period (day 70). The results of the present study reveal the beneficial effects of supplementing a novel mycotoxin detoxifier in the diets of weaners, including improved redox status, potential hepatoprotective properties and enhanced growth performance.

Impacts of Supplementation with Silymarin on Cardiovascular Risk Factors: A Systematic Review and Dose-Response Meta-Analysis

It has been suggested that silymarin (SIL) supplementation has positive effects on cardiovascular health and reduces the risk of cardiometabolic syndrome (CMS). This systematic review and dose-response meta-analysis assessed the impacts of SIL administration on cardiovascular risk factors. A systematic search of multiple databases was performed to identify eligible controlled trials published up to January 2023. The analysis used a random-effects model and included 33 trials with 1943 participants. It was revealed that SIL supplementation led to a notable reduction in serum levels of fasting blood glucose (FBG) (weighted mean difference (WMD): -21.68 mg/dL, 95% CI: -31.37, -11.99; p < 0.001), diastolic blood pressure (DBP) (WMD: -1.25 mmHg; 95% CI: -2.25, -0.26; p = 0.013), total cholesterol (TC) (WMD: -13.97 mg/dL, 95% CI: -23.09, -4.85; p = 0.003), triglycerides (TG) (WMD: -26.22 mg/dL, 95% CI: -40.32, -12.12; p < 0.001), fasting insulin (WMD: -3.76 mU/mL, 95% CI: -4.80, -2.72; p < 0.001), low-density lipoprotein (LDL) (WMD: -17.13 mg/dL, 95% CI: -25.63, -8.63; p < 0.001), and hemoglobin A1C (HbA1c) (WMD: -0.85%, 95% CI: -1.27, -0.43; p < 0.001) in the SIL-treated groups compared to their untreated counterparts. In addition, there were no substantial differences in body mass index (BMI), systolic blood pressure (SBP), C-reactive protein (CRP), body weight, and high-density lipoprotein (HDL) between the two groups. These outcomes suggest that SIL consumption reduces certain CMS risk factors and has favorable impacts on lipid and glycemic profiles with potential hypotensive effects. These findings should be supported by additional trials with larger sample sizes and longer durations.

Effects of a Multi-Component Mycotoxin-Detoxifying Agent on Oxidative Stress, Health and Performance of Sows

This in vivo study aimed to investigate the effects of a multi-component mycotoxin-detoxifying agent, containing clays (bentonite, sepiolite), phytogenic feed additives (curcumin, silymarin) and postbiotics (yeast cell wall, hydrolyzed yeast) on the antioxidant capacity, health and reproductive performance of pregnant and lactating sows challenged by mycotoxins. Eighty (80) primiparous sows (mean age 366 ± 3 days) per each of the two trial farms were divided into two groups in each farm: a) T1 (control group): 40 sows received the contaminated feed and b) T2 group (experimental group): 40 sows received the contaminated feed plus the mycotoxin-detoxifying agent, one month before farrowing until the end of the lactation period. Thiobarbituric acid reactive substances (TBARS), protein carbonyls (CARBS) and total antioxidant capacity (TAC) were evaluated as biomarkers of oxidative stress. Clinical and reproductive parameters were recorded. Our results indicate that the administration of a multi-component mycotoxin-detoxifying agent's administration in sow feed has beneficial effects on oxidative stress biomarkers and can improve sows' health and performance.

Role of Alternative Medical Systems in Adult Chronic Kidney Disease Patients: A Systematic Review of Literature

There is a growing interest in the use of alternative medical systems (AMS), such as traditional Chinese medicine (TCM), ayurveda, homeopathy, and naturopathy, among chronic kidney disease patients. This review summarizes the efficacy and safety of AMS interventions in chronic kidney disease (CKD) patients. A systematic review was conducted in MEDLINE, Embase, Scopus, CINAHL, CENTRAL, and PsycINFO in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Synthesis without meta-analysis (SWiM) guidelines. Randomized controlled trials (RCTs) which evaluated the use of AMS among adult CKD patients were included. The efficacy of each AMS was assessed based on improvement in biochemical markers or reduction in symptom severity scores. All adverse reactions were recorded. Of the 14,583 articles retrieved, 33 RCTs were included. TCM (n=20) and ayurveda (n=6) were the most well-studied. Majority of studies (66.7%) had a sample size <100. Common indications evaluated included improvement in renal function (n=12), proteinuria (n=5), and uremic pruritus (n=5). Among TCM, acupuncture and syndromes-based TCM granules formulation were shown to improve estimated glomerular filtration rate (eGFR) by 5.1-15.5% and 7.07-8.12% respectively. Acupuncture reduced uremic pruritus symptoms by 54.7-60.2% while Huangkui, Shenqi granules, and Tripterygium wilfordii Hook F reduced proteinuria by 18.6-50.7%, 61.8%, and 32.1% respectively. For Ayurveda, camel milk and Nigella sativa oil improved eGFR by 16.9% and 86.8%, respectively, while capsaicin reduced pruritus scores by 84.3%. Homeopathic verum medication reduced pruritus scores by 29.2-41.5%. Nausea was the most common adverse effect reported with alpha-keto amino acids (0.07%), Nigella sativa oil (7.04%), and silymarin (10%). TCM and ayurveda were more well-studied AMS therapies that demonstrated efficacy in CKD patients. RCTs with larger sample sizes are needed to ascertain the efficacy and safety of promising AMS.

Silymarin Modulates Microbiota in the Gut to Improve the Health of Sow from Late Gestation to Lactation

Inflammatory responses reduce milk production in lactating sows. Silymarin may modulate inflammatory reactions. Here, we aimed to verify whether dietary silymarin supplementation could alleviate inflammatory responses in lactating sows through microbiota change in the gut. We also investigated how silymarin impacts inflammatory response in lactating sows. One hundred and ten sows were randomly assigned to a control diet (basal diet) or treatment diet (basal diet and 40 g/d silymarin) from the 108th day of gestation to weaning. Blood, milk, and feces from sows were collected for analysis. It was shown in the results that dietary silymarin supplementation decreased the level of pro-inflammatory cytokine IL-1β (p < 0.05) on the 18th day of lactation in the blood of the sows. Dietary silymarin supplementation tended to decrease (p = 0.06) somatic cell count in the colostrum of sows. Dietary silymarin supplementation reduced the gut bacterial community and the richness of the gut microbial community (p < 0.01) using 16S rRNA gene sequencing. The fecal microbes varied at different taxonomic levels in the lactating sows with silymarin supplementation. The most representative changes included an increase in the relative abundance of Fibrobacteres and Actinobacteria (p < 0.05) and tended to reduce the relative abundance of Spirochaetaes and Tenericutes (p = 0.09, 0.06) at the phylum level. It is suggested that dietary silymarin supplementation in late gestation until lactation has anti-inflammatory effects in lactation sow, which could be associated with the modulation of gut microbiota.

Effects of Maturity and Thermal Treatment on Phenolic Profiles and In Vitro Health-Related Properties of Sacha Inchi Leaves

Sacha inchi (Plukenetia volubilis L.) has been adopted as a novel economic crop with well-studied nutritional and bioactive benefits for human health. Sacha inchi seeds and oil have high commercial value but scant research has focused on its leaves. This study investigated and compared phenolic compositions, antioxidant potentials and in vitro health-related properties of both young and mature sacha inchi leaves after freeze-drying and oven-drying processes. Results showed that p-coumaric acid, 4-hydroxybenzoic acid, ferulic acid and gallic acid were predominantly detected in both young and mature leaves that also exhibited similar total phenolic contents (TPCs), while higher TPCs were detected in freeze-dried than in oven-dried leaves. Mature leaves exhibited higher antioxidant potential than young leaves after freeze-drying, while the opposite results were observed for oven-drying. Overall in vitro health-related activities were higher in mature leaves compared to young leaves regardless of the drying process. Knowledge gained from this study can be used to encourage prospective utilization of sacha inchi leaves as a source of health-promoting compounds. This, in turn, will increase the commercial value of the leaves and provide a wider market variety of sacha inchi products.

Silymarin from Milk Thistle Fruits Counteracts Selected Pathological Changes in the Lenses of Type 1 Diabetic Rats

Diabetes is a metabolic disease affecting many tissues and organs. The main etiological factor for diabetic complications is hyperglycemia and subsequent pathologies, such as oxidative stress. One of the organs susceptible to the development of diabetic complications is the eye with all of its elements, including the lens. The aim of this study was to evaluate the effect of silymarin, an extract obtained from milk thistle fruit husks, on the oxidative stress markers in the lenses of type 1 diabetic rats. The study was performed on male rats in which type 1 diabetes was induced with 60 mg/kg streptozotocin injection. Diabetic animals were treated via an intragastric tube with silymarin at 50 and 100 mg/kg doses for four weeks. Multiple oxidative stress and polyol pathway-related parameters were measured in the lenses, and auxiliary biochemical tests in the serum were conducted. Diabetes induced severe pathological changes both in the lenses and the serum, and silymarin counteracted several of them. Nevertheless, the qualitative analyses encompassing all tested parameters indicate that silymarin slightly improved the overall state of diabetic animals. Upon the obtained results, it can be concluded that silymarin reveals a faint positive effect on the lenses in type 1 diabetic rats.

The effects of Silymarin on the features of cardiometabolic syndrome in adults: A systematic review and meta-analysis

Some medicinal herbs and their effective components showed positive effects on the features of the cardiometabolic syndrome (CMS). The aim of the present systematic review and meta-analysis is to examine the effects of silymarin on the components of CMS in adults. Four electronic databases including PubMed/Medline, Scopus, Web of Science, and Embase were systematically searched up to December 31, 2020 to identify all eligible clinical trials. A random-effect model using DerSimonian and Laird method was used to estimate the pooled weighted mean differences (WMDs) and the 95% confidence intervals (95%CIs). Finally, 11 clinical trials met the eligibility criteria. Our results demonstrated that silymarin significantly reduced the levels of fasting blood glucose (WMD: -17.96 mg/dL, 95% CI: -32.91, -3.02;I² : 82.4%, p < 0.001), hemoglobin A1C (WMD: -1.25%, 95% CI: -2.34, 0.16; I² : 92.9%, p ˂ 0.001), total cholesterol (WMD: -17.46 mg/dL, 95% CI: -30.98, -3.95; I²  = 62.9%, p = 0.006), triglyceride (WMD: -25.70 mg/dL, 95% CI: -47.23, -4.17; I² :54.3%, p = 0.025), low-density lipoprotein-cholesterol (WMD: -10.53, 95% CI: -19.12, -1.94; I2: 37.5%, p = 0.119) and increased high-density lipoprotein- cholesterol (WMD: 3.36 mg/dL, 95% CI: 0.88, 5.84; I² : 37.4%, p = 0.120) compared to placebo. However, its effects on BMI were not statistically significant. Silymarin can be an effective complementary therapy to improve most features of CMS. However, due to high heterogeneity and limited clinical trials in some parameters, further high-quality clinical trials are needed to confirm its efficacy.

Effect of Silymarin Treatment on Circulating Bilirubin and Cardiovascular Disease Risk Factors in Healthy Men: A Single-Blind, Randomized Crossover Trial

This clinical trial (ACTRN12619001296123) investigated the impact of silymarin (Legalon®) on circulating bilirubin concentration, lipid status, systemic inflammation, and antioxidant status. The study design was a randomized, placebo-controlled, single-blind crossover trial of healthy men (18-65 years), conducted at Griffith University, Gold Coast, Australia. Participants were recruited from Griffith University and were randomized to silymarin (140 mg silymarin capsules thrice daily) or placebo (3 capsules containing mannitol taken daily) for 14 days followed by a ≥4-week washout and crossover to the other arm. The main outcomes were whether silymarin treatment would increase serum bilirubin concentration by >0.29 mg/dL, change serum lipid status (cholesterol and triglycerides), inflammation (c-reactive protein), and antioxidant capacity (ferric reducing ability of plasma) compared with baseline. Silymarin consumption (n = 17) did not affect serum concentrations of unconjugated bilirubin (0.73 versus 0.67 mg/dL, P = .79), cholesterol (185 versus 189 mg/dL, P = .19), triglycerides (94.2 versus 92.3 mg/dL, P = .79), c-reactive protein (0.17 versus 0.09 mg/dL, P = .23), or antioxidant status (6.61 versus 6.67 mg Fe²⁺ /dL, P = .40). These findings challenge previous reports and manufacturer claims of hyperbilirubinemia following silymarin treatment and are critical to guiding researchers toward an effective means to mildly elevate bilirubin, which evidence suggests could protect from cardiovascular disease.

A combination of herbal compound (SPTC) along with exercise or metformin more efficiently alleviated diabetic complications through down-regulation of stress oxidative pathway upon activating Nrf2-Keap1 axis in AGE rich diet-induced type 2 diabetic mice

BACKGROUND

SPTC is a mix of four herbal components (Salvia officinalis, Panax ginseng, Trigonella foenum-graeceum, and Cinnamomum zeylanicum) which might be prevented the development of AGE rich diet-induced diabetic complication and liver injury through activated the nuclear factor erythroid-2-related-factor-2 (Nrf2) pathway. Nrf2, as a master regulator of antioxidant response elements by activating cytoprotective genes expression, is decreased oxidative stress that associated with hyperglycemia and increases insulin sensitivity. the aim of this study was to assess whether the combination therapy of SPTC along with exercise or metformin moderate oxidative stress related liver injurie with more favorable effects in the treatment of AGE rich diet-induced type 2 diabetic mice.

METHODS

We induced diabetes in C57BL/6 mice by AGE using a diet supplementation and limitation of physical activity. After 16 weeks of intervention, AGE fed mice were compared to control mice. Diabetic mice were assigned into seven experimental groups (each group; n = 5): diabetic mice, diabetic mice treated with SPTC (130 mg/kg), diabetic mice treated with Salvia Officinalis (65 mg/kg), diabetic mice treated with metformin (300 mg/kg), diabetic mice with endurance exercise training, diabetic mice treated with SPTC + metformin (130/300 mg/kg), diabetic mice treated with SPTC + exercise training.

RESULTS

SPTC + exercise and SPTC + metformin reduced diabetic complications like gain weight, water and calorie intake, blood glucose, insulin, and GLUT4 content more efficiently than each treatment. These combinations improved oxidative stress hemostasis by activating the Nrf2 signaling pathway and attenuating keap1 protein more significantly.

CONCLUSION

Eventually, combined treatment of SPTC with exercise or metformin as a novel approach had more beneficial effects to prevent the development of diabetes and oxidative stress associated with hyperglycemia.

Protective Effects of Ginger Extract against Glycation and Oxidative Stress-Induced Health Complications: An In Vitro Study

Protein glycation and oxidative stress lead to severe health complications in various diseases including diabetes mellitus. The intake of flavonoid-rich foods has been confirmed previously to have a positive effect on human health. Ginger is an important source of flavonoids and is one of the most widely used traditional medicines in many Asian countries. The aim of this study was to verify the therapeutic potential of methanolic extract from ginger against glycation and other oxidative stress-induced complications using in vitro study. In this study, quantitative estimations of antioxidant components such as total phenolic and flavonoids were determined by UV–visible spectrophotometry. The anti-inflammatory action of the ginger extract was checked by determining its protective action against the denaturation of proteins, anti-proteinase activity and its membrane stabilization effect. The anti-inflammatory action of ginger extract was found to be comparable with reference standard drugs. The antiglycating effect of ginger extract was investigated by placing bovine serum albumin (BSA) with glucose in the presence and absence of ginger extract for two weeks at 37 °C. The incubated samples were analyzed for the number of glycation products, secondary structural changes, aggregation and advanced glycation end products (AGEs) formation by checking browning intensity, determination of aggregation index and Congo red assays. Our findings demonstrated that ginger extract (600 µg/mL) significantly reduced the browning, secondary structural changes, aggregation and AGEs formation. Thus, it can be concluded from these results that ginger extract is a wealthy source of antioxidants and can be used to prevent the glycation and oxidative stress-induced damage of biomolecules in various health complications including inflammation.

Silymarin: not just another antioxidant

Silymarin (Silybum marianum; SM), popularly known as milk thistle, is an extract that has been used for many centuries to treat liver diseases. In recent years, several studies have shown that SM is not only just another antioxidant but also a multifunctional compound that exhibits several beneficial properties for use in the treatment and prevention of different types of pathologies and disorders. This review aims at demonstrating the main protective activities of SM in diseases, such as cancer, diabetes, hepatitis, non-alcoholic fatty liver disease, alcoholic liver disease, hepatitis C virus, hepatitis B virus, metabolic syndrome, depression, cardiovascular diseases and thalassemia, in addition to its photoprotective activity in in vitro tests and preclinical studies. Its main functions include antioxidant and anti-inflammatory effects, and it acts as modulator of signaling pathways. It has been suggested that SM presents great multifunctional potential and is capable of achieving promising results in different types of research. However, caution is still needed regarding its indiscriminate use in humans as there are only a few clinical studies relating to the adequate dose and the actual efficacy of this extract in different types of diseases.

Potential effect of advanced glycation end products (AGEs) on spermatogenesis and sperm quality in rodents

The aim of the present study was to assess whether dietary advanced glycation end products (AGEs) induce testicular dysfunction. Using a BALB/c mouse model, AGE intake and serum levels were found to increase in AGE diet-treated mice relative to the controls. Histopathological damage was detected in the testes and epididymides of the AGE diet-induced mice. The total number of epididymal sperm decreased, and increased abnormal sperm rate was found in the mice. Moreover, the mice testes showed an increased level of the receptor for AGEs (RAGE) and malondialdehyde (MDA). Using a Sprague-Dawley rat model, AGE diet-induced rats showed 3- to 4-fold higher AGE intake than the controls. In these rats, higher serum and sperm MDA levels, decreased epididymal sperm numbers, and increased abnormal sperm rates were also observed. Silymarin, a natural AGE inhibitor, was found to restore these AGE-induced phenomena. Concluding from the above findings, dietary AGEs may promote testicular dysfunction.

The effects of silymarin supplementation on metabolic status and oxidative stress in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of clinical trials

OBJECTIVE

The effect of silymarin supplementation on metabolic status and oxidative stress of subjects with type 2 diabetes mellitus (T2DM) has not been conclusively studied. Therefore, the efficacy of silymarin supplementation in these patients was assessed through a meta-analysis.

METHODS

The following databases were searched up to May 15, 2018: PubMed, Scopus, Ovid (Cochrane library), Google scholar and ISI web of science. All randomized clinical trials using silymarin supplements to improve T2DM included in this meta-analysis. Mean Difference (MD) was pooled using a random-effects model.

RESULTS

Eight eligible publications from seven trials were identified for the present meta-analysis. Our results revealed that supplementation with silymarin can decrease fasting blood sugar, hemoglobin A1C, insulin, low-density lipoprotein cholesterol and malondialdehyde and increase high-density lipoprotein cholesterol levels. However, silymarin did not have any significant effects on total cholesterol or triglyceride concentrations.

CONCLUSION

Our data suggest that silymarin supplements have beneficial effects on metabolic status and oxidative stress among patients with T2DM. However, there is currently insufficient evidence to make firm conclusions about the full efficacy of supplementation.

Silymarin prevents diabetes-induced hyperpermeability in human retinal endothelial cells

INTRODUCTION

Vascular endothelial growth factor (VEGF) plays an essential role in development of diabetic macular edema (DME). While there is evidence suggesting that silymarin, a flavonoid extracted from Silybum marianum, could be useful for prevention and treatment of diabetic nephropathy, no studies have been conducted in diabetic retinopathy (DR). The aim of this study was to assess the effect of silymarin on disruption of inner blood retinal barrier (BRB), the primary cause of DME.

MATERIALS AND METHODS

Human retinal endothelial cells (HRECs) were cultured under standard (5.5mM D-glucose) and diabetogenic conditions (25mM D-glucose and 25mM D-glucose + recombinant vascular endothelial growth factor [rVEGF, 25mg/mL]). To assess cell viability, three concentrations of silymarin were tested (2, 4 and 10μg/mL). The effect of silymarin on HREC disruption was determined using a dextran (70kD) permeability asssay.

RESULTS

No differences were found in the viability of HRECs treated with 2 or 4μg/mL of silymarin as compared to untreated cells, but viability significantly decreased after using 10μg/mL. The concentration of 4 μg/mL was therefore selected. Silymarin (4μg/mL) caused a significant decrease in VEGF-induced permeability in both media with 5.5nM (422±58 vs. 600±72 ng/mL/cm2; p<0.03) and 25nM of D-glucose (354 ± 28 vs. 567 ± 102 ng/mL/cm2; p<0.04).

DISCUSSION

Our results show that silymarin is effective for preventing hyperpermeability induced by diabetic conditions in HRECs. Further studies are needed to assess whether silymarin could be useful to treat DME.

Methylglyoxal displays colorectal cancer-promoting properties in the murine models of azoxymethane and CT26 isografts

Methylglyoxal (MG), a highly reactive carbonyl species (RCS) with pro-oxidant and proinflammatory properties, may be a colon tumor-promoting factor in food and biological systems. In the present study, we found that consumption of MG significantly deteriorated azoxymethane (AOM)-induced colonic preneoplastic lesions in ICR mice, in which biomarkers of oxidative stress and inflammation within the body and feces induced by MG-fueled carbonyl stress may have played important roles. Interestingly, exposure to MG also led to increases in the serum low-density lipoprotein (LDL)/high-density lipoprotein (HDL) ratio and fecal bile acid levels in mice, which may be critical factors involved in MG-induced colonic lesions. Additionally, MG treatment (50mg/kg body weight (BW); intraperitoneally) promoted tumor growth of CT26 isografts in mice partly by carbonyl stress-evoked protumorigenic responses, including low-grade inflammation and oxidative stress. Furthermore, primary tumor cells isolated from mice with MG-induced CT26 isografts had greater proliferative and migratory activities as well as stem-like properties compared to those isolated from the vehicle controls. Excitingly, enhanced expression or activation of proteins that modulate cell survival, proliferation, or migration/invasion was also observed in those cells. In conclusion, it is conceivable that MG-induced carbonyl stress may be the pivotal promoter involved in colon cancer progression.

Evaluation of dietary and lifestyle changes as modifiers of S100β levels in Alzheimer's disease

There is a significant body of research undertaken in order to elucidate the mechanisms underlying the pathology of Alzheimer's disease (AD), as well as to discover early detection biomarkers and potential therapeutic strategies. One such proposed biomarker is the calcium binding protein S100β, which, depending on its local concentration, is known to exhibit both neurotrophic and neuroinflammatory properties in the central nervous system. At present, relatively little is known regarding the effect of chronic S100β disruption in AD. Dietary intake has been identified as a modifiable risk factor for AD. Preliminary in vitro and animal studies have demonstrated an association between S100β expression and dietary intake which links to AD pathophysiology. This review describes the association of S100β to fatty acids, ketone bodies, insulin, and botanicals as well as the potential impact of physical activity as a lifestyle factor. We also discuss the prospective implications of these findings, including support of the use of a Mediterranean dietary pattern and/or the ketogenic diet as an approach to modify AD risk.

Silymarin Ameliorates Metabolic Dysfunction Associated with Diet-Induced Obesity via Activation of Farnesyl X Receptor

Background and purpose: Silymarin, a standardized extract of the milk thistle seeds, has been widely used to treat chronic hepatitis, cirrhosis, and other types of toxic liver damage. Despite increasing studies on the action of silymarin and its major active constituent, silybin in their therapeutic properties against insulin resistance, diabetes and hyperlipidaemia in vitro and in vivo, the mechanism underlying silymarin action remains unclear. Experimental approach: C57BL/6 mice were fed high-fat diet (HFD) for 3 months to induce obesity, insulin resistance, hyperlipidaemia, and fatty liver. These mice were then continuously treated with HFD alone or mixed with silymarin at 40 mg/100 g for additional 6 weeks. Biochemical analysis was used to test the serum lipid and bile acid profiles. Farnesyl X receptor (FXR) and nuclear factor kappa B (NF-κB) transactivities were analyzed in liver using a gene reporter assay based on quantitative RT-PCR. Key results: Silymarin treatment ameliorated insulin resistance, dyslipidaemia and inflammation, and reconstituted the bile acid pool in liver of diet-induced obesity. Associated with this, silybin and silymarin enhanced FXR transactivity. Consistently, in HepG2 cells, silybin inhibited NF-κB signaling, which was enhanced by FXR activation. Conclusion and implications: Our results suggest that silybin is an effective component of silymarin for treating metabolic syndrome by stimulating FXR signaling.

Providing the plant extract silymarin to lactating sows: effects on litter performance and oxidative stress in sows

Silymarin is an extract from the plant milk thistle that was shown to have antioxidant and hyperprolactinemic properties. Taking into account the essential role of prolactin for lactating sows and the systemic oxidative stress occurring during lactation, it is of interest to investigate the potential beneficial effects of silymarin on lactating sows. A study was therefore carried out to determine the effects of providing either 1 or 8 g/day of the plant extract silymarin to lactating sows. Sows in first, second or third parity were fed conventional diets during gestation and, at farrowing, were assigned as controls (CTL, n=33), or were fed 1 g/day (SYL1, n=33) or 8 g/day (SYL8, n=33) of silymarin. The silymarin was provided in two equal amounts per day, and was fed throughout a 20-day lactation. The performance of sows and their litters was assessed and circulating concentrations of prolactin (days 7 and 18), urea (days 7 and 18) and oxidative status, via protein carbonyls and superoxide dismutase activity (day 18), were measured in sows. Milk samples were obtained on day 18 to measure standard composition. There was no effect of silymarin (P>0.10) on circulating prolactin or urea, or on oxidative damage to proteins or antioxidant potential in sows. Lactation feed intake, backfat and BW of sows were unaffected by treatment (P>0.10) as was the case for milk composition and piglet growth (P>0.10). Results demonstrate that providing up to 8 g/day of the plant extract silymarin to lactating sows had no beneficial effects in terms of circulating prolactin concentrations or oxidative status of sows, or in terms of performances of sows and their litters.

Coadjuvants in the Diabetic Complications: Nutraceuticals and Drugs with Pleiotropic Effects

Because diabetes mellitus (DM) is a multifactorial metabolic disease, its prevention and treatment has been a constant challenge for basic and clinical investigators focused on translating their discoveries into clinical treatment of this complex disorder. In this review, we highlight recent experimental and clinical evidences of potential coadjuvants in the management of DM, such as polyphenols (quercetin, resveratrol and silymarin), cultured probiotic microorganisms and drugs acting through direct/indirect or pleiotropic effects on glycemic control in DM. Among several options, we highlight new promising therapeutic coadjuvants, including chemical scavengers, the probiotic kefir and the phosphodiesterase 5 inhibitors, which besides the reduction of hyperglycemia and ameliorate insulin resistance, they reduce oxidative stress and improve endothelial dysfunction in the systemic vascular circulation. In the near future, experimental studies are expected to clear the intracellular pathways involving coadjuvants. The design of clinical trials may also contribute to new strategies with coadjuvants against the harmful effects of diabetic complications.

Resveratrol protects against methylglyoxal-induced hyperglycemia and pancreatic damage in vivo

Methylglyoxal (MG) has been found to cause inflammation and insulin resistance in vitro and in vivo in recent studies. Resveratrol has been proposed as an effective treatment that helps lower the risk of developing complications of diabetes. To study the significance of glycosylation-related stress on the pathology of diabetes, the effects of resveratrol were examined in a mouse model of diabetes induced by MG. Resveratrol was given via oral gavage in MG-treated mice, and diabetes-related tests and markers were assessed using biochemical and immunohistochemical analyses. Treatment with resveratrol markedly improved blood glucose level from the oral glucose tolerance test and promoted nuclear factor erythroid 2-related factor-2 (Nrf2) phosphorylation (p < 0.05) in the pancreas of MG-treated mice. However, these effects were abolished by retinoic acid, Nrf2 inhibitor, in resveratrol and retinoic acid-treated and MG-induced mice. These findings support that resveratrol may be useful in the treatment of type-2 diabetes by protecting against pancreatic cell dysfunction.

Anti-glycation activities of phenolic constituents from Silybum marianum (Milk Thistle) flower in vitro and on human explants

Glycation is an ageing reaction of naturally occurring sugars with dermal proteins, with clinical signs appearing in vivo around age 30, and increasing steadily/regularly with age. The suppleness of the dermis is affected by the formation of bridges between proteins and sugars (Maillard's reaction). The accumulation of advanced glycation end products (AGEs) in skin plays a very important role in skin ageing. Therefore, natural compounds or extracts that possess antiglycation activities may have great anti-ageing potential. In the present study, Silybum marianum flower extract (SMFE) was demonstrated to possess antiglycation activity. We found that SMFE inhibits glycation reaction between BSA and glucose. In addition, antiglycation activity of SMFE was confirmed in a human skin explants model. SMFE reduced Nε-(carboxymethyl) lysine (CML) expression, whereas SMFE stimulated fibrillin-1 expression compared to treatment with methyglyoxal. An active ingredient contributing to the observed activities was identified as silibinin. The antiglycation activity of silibinin was dose-dependent. The beneficial effects of silibinin may be applied to prevention or management of AGE-mediated pathologies, targeting in a pleiotropic and complementary way the biochemical and cellular bases of skin aging.

Silybum marianum: Beyond Hepatoprotection

Silybum marianum is a medicinal plant that has long been used as hepatoprotective remedy. It has been used for the treatment of numerous liver disorders characterized by functional impairment or degenerative necrosis. Its hepatoprotective activity is unique and acts in different ways, including antioxidant and anti-inflammatory activities, cell permeability regulator and membrane stabilizer, stimulation of liver regeneration and inhibition of deposition in collagen fibers, which may lead to cirrhosis. Most of documented data with Silybum marianum are about liver disorders; however, recently several beneficial properties on a wide variety of other disorders such as renal protection, hypolipidemic and anti-atherosclerosis activities, cardiovascular protection, prevention of insulin resistance, especially in cirrhotic patients, cancer, and Alzheimer prevention. It is also used as a food remedy. This review article aims to present different aspects of Silybum marianum, especially the data in recently published articles about its effects on different diseases, apart from presenting the aspects of its hepatoprotection.

Protective effects of cyanidin-3-rutinoside against monosaccharides-induced protein glycation and oxidation

Cyanidin-3-rutinoside (C3R), a naturally occurring anthocyanin, is present in various fruits and vegetables as a colorant. C3R has been well characterized and demonstrated a number of biological activities attributed to its antioxidant properties. The present study compared the effectiveness of C3R against monosaccharide-induced protein glycation and oxidation in vitro using bovine serum albumin (BSA).The results demonstrated that C3R (0.125-1.00 mM) inhibited the formation of fluorescent AGEs in ribose-glycated BSA (2-52%), fructose-glycated BSA (81-93%), glucose-glycated BSA (30-74%) and galactose-glycated BSA (6-79%).Correspondingly, C3R (1.00 mM) decreased the level of N(ɛ)-(carboxymethyl) lysine (56-86%) in monosaccharide-induced glycation in BSA. C3R also reduced the level of fructosamine, β-amyloid cross structure, protein carbonyl content as well as the depletion of thiol in BSA/monosaccharide system. In summary, C3R might offer a new promising antiglycation agent for the prevention of diabetic complications by inhibiting AGE formation and oxidation-dependent protein damage.

Scopoletin protects against methylglyoxal-induced hyperglycemia and insulin resistance mediated by suppression of advanced glycation endproducts (AGEs) generation and anti-glycation

Recently, several types of foods and drinks, including coffee, cream, and cake, have been found to result in high methylglyoxal (MG) levels in the plasma, thus causing both nutritional and health concerns. MG can be metabolized by phase-II enzymes in liver through the positive regulation of nuclear factor-erythroid 2-related factor 2 (Nrf2). In this study, we investigated the ability of scopoletin (SP) to protect against MG-induced hyperglycemia and insulin resistance. Recently, SP was shown to be a peroxisome proliferator-activated receptor-γ activator to elevate insulin sensitivity. We investigated the effects of oral administration of SP on the metabolic, biochemical, and molecular abnormalities characteristic of type 2 diabetes in MG-treated Wistar rats to understand the potential mechanism of scopoletin for diabetes protection. Our results suggested that SP activated Nrf2 by Ser40 phosphorylation, resulting in the metabolism of MG into d-lactic acid and the inhibition of AGEs generation, which reduced the accumulation of AGEs in the livers of MG-induced rats. In this manner, SP improved the results of the oral glucose tolerance test and dyslipidemia. Moreover, SP also increased the plasma translocation of glucose transporter-2 and promoted Akt phosphorylation caused by insulin treatment in MG-treated FL83B hepatocytes. In contrast, SP effectively suppressed protein tyrosine phosphatase 1B (PTP1B) expression, thereby alleviating insulin resistance. These findings suggest that SP acts as an anti-glycation and anti-diabetic agent, and thus has therapeutic potential for the prevention of diabetes.

Recent development of plant products with anti-glycation activity: a review

This review article summarizes the plant natural products that inhibit glycation at different stages leading to the AGEs formation.

Inhibitory effect of paeoniflorin on methylglyoxal-mediated oxidative stress in osteoblastic MC3T3-E1 cells

PURPOSE

Methylglyoxal (MG) has been suggested to be one major source of intracellular reactive carbonyl compounds. In the present study, the effect of paeoniflorin on MG-induced cytotoxicity was investigated using osteoblastic MC3T3-E1 cells.

METHODS

Osteoblastic MC3T3-E1 cells were pre-incubated with paeoniflorin before treatment with MG, and markers of oxidative damage and mitochondrial function were examined.

RESULTS

Pretreatment of MC3T3-E1 cells with paeoniflorin prevented the MG-induced cell death and formation of intracellular reactive oxygen species, cardiolipin peroxidation, and protein adduct in osteoblastic MC3T3-E1 cells. In addition, paeoniflorin increased glutathione level and restored the activity of glyoxalase I to almost the control level. These findings suggest that paeoniflorin provide a protective action against MG-induced cell damage by reducing oxidative stress and by increasing MG detoxification system. Pretreatment with paeoniflorin prior to MG exposure reduced MG-induced mitochondrial dysfunction by preventing mitochondrial membrane potential dissipation and adenosine triphosphate loss. Additionally, the nitric oxide and nuclear respiratory factor 1 levels were significantly increased by paeoniflorin, suggesting that paeoniflorin may induce mitochondrial biogenesis. Paeoniflorin treatment decreased the levels of proinflammatory cytokines such as TNF-α and IL-6.

CONCLUSIONS

These findings indicate that paeoniflorin might exert its therapeutic effects via upregulation of glyoxalase system and mitochondrial function. Taken together, paeoniflorin may prove to be an effective treatment for diabeteic osteopathy.

Prevention of diabetes-induced cardiovascular complications upon treatment with antioxidants

Oxidative stress is considered to play an important role in the pathogenesis of diabetes-induced cardiovascular disease (CVD), which is invariably associated with abnormal blood lipid profile, insulin resistance and metabolic syndrome. Stress, smoking, high saturated fat intake as well as low fruit and vegetable intakes have been shown to increase oxidative stress and hyperlipidemia, which increase the predisposition of diabetic subjects to atherosclerosis, stroke and coronary heart disease. The oxidation of low-density lipoprotein by oxidative stress is essential for the development of atherosclerosis, and the reduction in oxidative stress as well as blood glucose and cholesterol is considered critical for the prevention of diabetes-induced CVD. Although epidemiological studies have demonstrated that vitamin C and vitamin E decrease the incidence of coronary heart disease, different clinical trials have failed to support the beneficial effect of these antioxidants. Nonetheless, it has been suggested that natural forms of these vitamins may be more efficacious than synthetic vitamins, and this may explain the inconsistencies in results. Antioxidants, N-acetyl-L-cysteine and resveratrol, have also been shown to attenuate the diabetes-induced cardiovascular complications. It has been indicated that the antioxidant therapy may be effective in a prevention strategy rather than as a treatment for CVD. The evidence presented here supports the view that cardiovascular complications in diabetes may be induced by oxidative stress and appropriate antioxidant therapy may be promising for attenuating the progression of diabetes-induced CVD.

Silibinin inhibits ICAM-1 expression via regulation of N-linked and O-linked glycosylation in ARPE-19 cells

To evaluate the effects of silibinin on intercellular adhesion molecule-1 (ICAM-1) expression, we used ARPE-19 cells as a model in which tumor necrosis factor (TNF-α) and interferon (IFN-γ) enhanced ICAM-1 expression. This upregulation was inhibited by silibinin. In an adherence assay using ARPE-19 and THP-1 cells, silibinin inhibited the cell adhesion function of ICAM-1. The inhibitory effects of silibinin on ICAM-1 expression were mediated via the blockage of nuclear translocation of p65 proteins in TNF-α and phosphorylation of STAT1 in IFN-γ-stimulated cells. In addition, silibinin altered the degree of N-linked glycosylation posttranslationally in ARPE-19 cells by significantly enhancing MGAT3 gene expression. Silibinin can increase the O-GlcNAc levels of glycoproteins in ARPE-19 cells. In a reporter gene assay, PUGNAc, which can also increase O-GlcNAc levels, inhibited NF-κB reporter activity in TNF-α-induced ARPE-19 cells and this process was augmented by silibinin treatment. Overexpression of OGT gene was associated with reduced TNF-α-induced ICAM-1 levels, which is consistent with that induced by silibinin treatment. Taken together, silibinin inhibits ICAM-1 expression and its function through altered O-linked glycosylation in NF-κB and STAT1 signaling pathways and decreases the N-linked glycosylation of ICAM-1 transmembrane protein in proinflammatory cytokine-stimulated ARPE-19 cells.

Effects of the plant extract silymarin on prolactin concentrations, mammary gland development, and oxidative stress in gestating gilts

The impacts of supplementing the diet of gestating gilts twice daily with 4 g of the plant extract silymarin on circulating hormonal concentrations, oxidative status, mammary development, and mammary gene expression at the end of gestation were determined. Gilts were fed conventional diets during gestation and on d 90 they were assigned as controls (CTL; n = 16) or treated (TRT; n = 17) animals. Treatment consisted of providing 4 g of silymarin twice daily until d 110, at which time all gilts were slaughtered to collect mammary tissue for compositional analyses and measures of gene expression and oxidative status, and liver and corpora lutea for measures of oxidative stress variables. Blood samples for hormonal assays and evaluation of oxidative stress biomarkers were obtained on d 89, 94, and 109 of gestation. Silymarin increased (P = 0.05) circulating concentrations of prolactin over all samples in the repeated in time analysis. In separate analyses for each sampling time, prolactin concentrations in TRT gilts tended (P < 0.10) to be greater than in CTL gilts on d 94 of gestation. Repeated in time analysis also revealed that silymarin reduced (P ≤ 0.05) plasmatic accumulation of biomarkers of oxidative damage to protein (protein carbonyls) between d 89 and 109. There was no effect (P > 0.10) of treatment on progesterone, estradiol, leptin, or 8-hydroxy-2'-deoxyguanosine concentrations. Percent fat in mammary parenchyma was greater (P ≤ 0.05), percent protein was lesser (P ≤ 0.05), and concentrations of both RNA (P ≤ 0.01) and DNA (P < 0.05) were lesser in TRT than CTL gilts. Mammary parenchyma from TRT gilts had lower (P ≤ 0.05) mRNA abundance for STAT5A and leptin and tended to have lower (P ≤ 0.10) abundance for STAT5B than CTL gilts. Silymarin reduced (P ≤ 0.001) protein carbonyls concentrations in liver of TRT gilts. No effect of treatment was observed on antioxidant gene expression and enzymatic activities in liver samples while total superoxide dismutase activity tended to be higher (P ≤ 0.10) in the corpora lutea of TRT animals when compared with CTL. This is the first demonstration that, in female pigs, silymarin can increase prolactin concentrations and protect against oxidative stress, yet the increase in prolactin was not enough to have beneficial effects on mammary gland development in late gestation.

Beneficial effects of Camellia Oil (Camellia oleifera Abel.) on ketoprofen-induced gastrointestinal mucosal damage through upregulation of HO-1 and VEGF

Nonsteroidal anti-inflammatory drugs, such as ketoprofen, are generally used to treat pain and inflammation and as pyretic agents in clinical medicine. However, the usage of these drugs may lead to oxidative injury to the gastrointestinal mucosa. Camellia oil ( Camellia oleifera Abel.) is commonly used in Taiwan and China as cooking oil. Traditional remedies containing this oil exert beneficial health effects on the bowel, stomach, liver, and lungs. However, the effects of camellia oil on ketoprofen-induced oxidative gastrointestinal mucosal lesions remain unknown. The objective of this study was to evaluate the effect of camellia oil on ketoprofen-induced acute gastrointestinal ulcers. The results showed that treatment of Int-407 cells with camellia oil (50-75 μg/mL) not only increased the levels of heme oxygenase-1 (HO-1), glutathione peroxidase (GPx), and superoxide dismutase (SOD) mRNA expression but also increased vascular endothelial growth factor (VEGF) and prostaglandin E2 (PGE2) protein secretion, which served as a mucosal barrier against gastrointestinal oxidative injury. Moreover, Sprague-Dawley (SD) rats treated with camellia oil (2 mL/kg/day) prior to the administration of ketoprofen (50 mg/kg/day) successfully inhibited COX-2 protein expression, inhibited the production of interleukin-6 (IL-6) and nitrite oxide (NO), reversed the impairment of the antioxidant system, and decreased oxidative damage in the gastrointestinal mucosa. More importantly, pretreatment of SD rats with camellia oil strongly inhibited gastrointestinal mucosal injury induced by ketoprofen, which was proved by the histopathological staining of gastrointestinal tissues. Our data suggest that camellia oil exerts potent antiulcer effects against oxidative damage in the stomach and intestine induced by ketoprofen.

Suppression of dimerumic acid on hepatic fibrosis caused from carboxymethyl-lysine (CML) by attenuating oxidative stress depends on Nrf2 activation in hepatic stellate cells (HSCs)

Hyperglycemia facilitates the formation of advanced glycation end-products (AGEs) in type-2 diabetes. Evidence indicates that carboxymethyl-lysine (CML) is highly prevalent in diabetes, resulting in hepatic fibrosis. The current study was designed to evaluate the effects of dimerumic acid (DMA) identified from Monascus-fermented products on receptor for AGEs (RAGE) signal and hepatic stellate cells (HSCs) activation by CML treatment. We found that DMA (50 μM) eliminated collagen generation, mRNA expressions of α-smooth muscle actin (α-SMA), platelet-derived growth factor-β receptor (PDGF-βR), and procollagen 1a1 (proCol-1a1) in CML (100 μg/ml)-treated HSCs, and these effects were similar to allyl isothiocyanate (AITC; 50 μM). In addition, the suppression of α-SMA, PDGF-βR, proCol-1a1 by DMA were abolished while nuclear factor-erythroid 2-related factor 2 (Nrf2) silence in CML-treated HSCs. These findings suggested that DMA and AITC increased Nrf2 and glutamate-cysteine ligase (GCL) activities thereby inhibiting oxidative stress caused by CML and showing anti-fibrogentic effect in HSCs.

Antioxidation and antiglycation of Fagopyrum tataricum ethanol extract

Fagopyrum tataricum is used for the treatment of type 2 diabetes mellitus in Taiwan. The aim of this study was to evaluate the inhibitory effects of 75 % ethanol extract of buckwheat (EEB) and rutin on carbohydrate-metabolized enzymes, including α-amylase and α-glucosidase, which are related to hyperglycemia. The rutin dosage (40 μg/mL) was equivalent to that of EEB (200 μg/mL). In addition, the antioxidant and antiglycation activities of EEB and rutin were investigated. Results showed that both EEB and rutin exerted free radical (DPPH and ABTS) scavenging activity. They also attenuated protein glycation to lower the generation of advanced glycation end-products (AGEs) through the suppression of fructosamine and α-dicarbonyl compounds. Moreover, EEB and rutin also inhibited α-amylase and α-glucosidase activity. Taken together, these findings suggest that EEB and rutin may reduce oxidative stress, AGEs formation, and carbohydrate-metabolized enzymes hence EEB may use as protection agent in diabetic patients.

Dimerumic acid attenuates receptor for advanced glycation endproducts signal to inhibit inflammation and diabetes mediated by Nrf2 activation and promotes methylglyoxal metabolism into d-lactic acid

This study was designed to evaluate the effects of dimerumic acid (DMA) on receptor for advanced glycation endproducts (RAGE) signal activation and THP-1 monocyte inflammation treated with S100b, a specific ligand of RAGE. We found that DMA inhibited inflammatory cytokine production via upregulation of nuclear factor-erythroid 2-related factor 2 (Nrf2) and alleviated oxidative stress through attenuation of p47phox translocation to the membrane of S100b-treated THP-1 monocytes. We found that DMA activated Nrf2 mediated by the p38 kinase pathway in THP-1 monocytes. However, anti-inflammatory activity of DMA was attenuated by Nrf2 siRNA treatment. In an animal model, methylglyoxal (MG; 200mg/kg bw) was chosen to induce diabetes in Balb/C mice (6 weeks) in this work. The in vivo verification of anti-inflammation in peripheral blood mononuclear cells by DMA treatment was confirmed by tumor necrosis factor-α and interleukin-1β measurements. Oral glucose tolerance test, insulin tolerance test, hyperinsulinemia, and hyperglycemia were improved in MG-treated mice by DMA treatment and these effects were greater than those of silymarin and N-acetylcysteine. Furthermore, DMA increased hepatic glyoxalase mRNA and glutathione mediated by Nrf2 activation to metabolize MG into d-lactic acid, thereby reducing serum and hepatic AGE levels and suppressing inflammatory factor generation in MG-treated mice. However, DMA did not exert the antiglycation activity in MG-bovine serum albumin incubation. Taken together, the results indicate that DMA is a novel antioxidant and Nrf2 activator that lowers AGE levels and may prove to be an effective treatment for diabetes.

The antioxidant silybin prevents high glucose-induced oxidative stress and podocyte injury in vitro and in vivo

Podocyte injury, a major contributor to the pathogenesis of diabetic nephropathy, is caused at least in part by the excessive generation of reactive oxygen species (ROS). Overproduction of superoxide by the NADPH oxidase isoform Nox4 plays an important role in podocyte injury. The plant extract silymarin is attributed antioxidant and antiproteinuric effects in humans and in animal models of diabetic nephropathy. We investigated the effect of silybin, the active constituent of silymarin, in cultures of mouse podocytes and in the OVE26 mouse, a model of type 1 diabetes mellitus and diabetic nephropathy. Exposure of podocytes to high glucose (HG) increased 60% the intracellular superoxide production, 90% the NADPH oxidase activity, 100% the Nox4 expression, and 150% the number of apoptotic cells, effects that were completely blocked by 10 μM silybin. These in vitro observations were confirmed by similar in vivo findings. The kidney cortex of vehicle-treated control OVE26 mice displayed greater Nox4 expression and twice as much superoxide production than cortex of silybin-treated mice. The glomeruli of control OVE26 mice displayed 35% podocyte drop out that was not present in the silybin-treated mice. Finally, the OVE26 mice experienced 54% more pronounced albuminuria than the silybin-treated animals. In conclusion, this study demonstrates a protective effect of silybin against HG-induced podocyte injury and extends this finding to an animal model of diabetic nephropathy.

Effects of monascin on anti-inflammation mediated by Nrf2 activation in advanced glycation end product-treated THP-1 monocytes and methylglyoxal-treated wistar rats

Hyperglycemia is associated with advanced glycation end products (AGEs). This study was designed to evaluate the inhibitory effects of monascin on receptor for advanced glycation end product (RAGE) signal and THP-1 monocyte inflammation after treatment with S100b, a specific ligand of RAGE. Monascin inhibited cytokine production by S100b-treated THP-1 monocytes via up-regulation of nuclear factor-erythroid 2-related factor-2 (Nrf2) and alleviated p47phox translocation to the membrane. Methylglyoxal (MG, 600 mg/kg bw) was used to induce diabetes in Wistar rats. Inhibitions of RAGE and p47phox by monascin were confirmed by peripheral blood mononuclear cells (PBMCs) of MG-induced rats. Silymarin (SM) was used as a positive control group. It was found that monascin promoted heme oxygenase-1 (HO-1) expression mediated by Nrf2. Suppressions of AGEs, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-β) in serum of MG-induced rats were attenuated in the monascin administration group treated with retinoic acid (RA). RA treatment resulted in Nrf2 inactivation by increasing RA receptor-α (RARα) activity, suggesting that RA acts as an inhibitor of Nrf2. The results showed that monascin exerted anti-inflammatory and antioxidative effects mediated by Nrf2 to prevent the development of diseases such as type 2 diabetes caused by inflammation.