Therapeutic Effects of Quercetin on Inflammation, Obesity, and Type 2 Diabetes

Pharmacological properties of Rheum turkestanicum Janisch

Medicinal herbs have been increasingly used worldwide for diseases prevention and treatment. Rheum turkestanicum Janisch. is a perennial shrub of the Polygonaceae family. Genus Rheum includes more than 60 species growing around the world which are used in foods and traditional medicines. R. turkestanicum is believed to be able to improve different kinds of disorders including diabetes, hypertension, jaundice and cancer. In recent years, this medicinal plant has been a subject of many experimental studies to document its health-beneficial properties. These studies have revealed antidiabetic, anticancer, nephroprotective, cardioprotective, and hepatoprotective properties of R. turkestanicum. The presence of flavonoids (e.g. epicatechin and quercetin) and anthraquinones (e.g. chrysophanol, physcion, and emodin) in R. turkestanicum justifies its health-beneficial effects. Nevertheless, possible therapeutic applications and safety of this plant still need to be elucidated in further clinical studies.

Quercetin inhibited mesangial cell proliferation of early diabetic nephropathy through the Hippo pathway

Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes and the leading cause of end-stage renal disease. The proliferation of glomerular mesangial cells (MCs) is a common and prominent pathological change of DN, which takes place at the early stage. Quercetin, a bioflavonoid compound, possesses therapeutic efficacy in cardiovascular and kidney diseases via anti-tumour, anti-oxidation, anti-virus, and anti-proliferation effects. However, the mechanism of quercetin in the proliferation of glomerular MCs in early DN has not been reported. In the present study, we investigated the effect of quercetin on the proliferation of glomerular MCs in high glucose-induced mouse glomerular MCs and in db/db mice. On this basis, we tried to clarify the specific mechanisms underlying these effects. The in vitro results showed that the proliferation of glomerular MCs was induced by high glucose, and the Hippo pathway was highly inactivated in high glucose-cultured MCs. Decreased phosphorylation of MST1 and Lats1 promoted expression and nuclear translocation of Yes-associated protein (YAP) and subsequently increased the combination of YAP and TEA/ATS domain (TEAD), which promoted the expression of the downstream target gene such as cyclinE. Quercetin effectively inhibited the high glucose-induced MC proliferation and reactivated the Hippo pathway. In vivo, the proliferation of glomerular MCs was increased, renal function was decreased, and blood fasting glucose was elevated in db/db mice. Furthermore, the Hippo pathway was inactivated in the renal cortex of db/db mice. Eight-week treatment of quercetin retarded MC proliferation, alleviated the renal function, and reactivated Hippo pathway in the renal cortex of db/db mice at 16 weeks. Our previous study clarified that the Hippo pathway was involved in MC proliferation of DN. The results revealed that quercetin inhibited MC proliferation in high glucose-treated mouse glomerular MCs and in DN via reactivation of the Hippo pathway.

Beyond tribulus (Tribulus terrestris L.): The effects of phytotherapics on testosterone, sperm and prostate parameters

ETHNO-PHARMACOLOGICAL RELEVANCE

Phytotherapeutic approaches have been widely proposed to improve male health. Despite the well-touted effects of tribulus (Tribulus terrestris L) on men's health, an optimal phytotherapy remains an elusive challenge.

AIM OF THE REVIEW

We sought to critically analyze the evidence in the phytotherapic literature beyond the effects of tribulus on testosterone (T) concentration and sperm analysis to also include indications for prostate health.

MATERIALS AND METHODS

A focused literature search was conducted to include studies published in Cochrane, Pubmed, and Web of Science databases between the years 2002 and 2018.

RESULTS

The use of tribulus and maca (Lepidium meyenii Walp, Brassicaceae) were not scientifically supported to improve serum T levels in men. Moderate evidence supports the use of long Jack (Eurycoma longifolia Jack, Simaroubaceae), mucuna (Mucuna pruriens (L.) DC., Fabaceae), ashwagandha (Withania somnifera (L.) Dunal, Solanaceae), fenugreek (Trigonella foenum-graceum L., Fabaceae), and black seeds (Nigella sativa L., Ranunculaceae) to increase total T and improve seminal parameters. Data suggests an increase in total T with the use of 5000 mg/d of powdered mucuna seed and ashwagandha root (151 and 143 ng/dL, respectively) over a 12-week period in patients with oligozoospermia. The use of mucuna was supported for patients with oligozoospermia to improve sperm parameters, with an increase of 83.3 million/mL observed after use of 5000 mg/d of powdered mucuna seed over a 12-week period. Evidence supporting the use of saw palmetto (Serenoa repens, (W.Bartram) Small, Arecaceae) to improve prostate health remains equivocal; whereas, evidence supporting the use of Pygeum africanum Hook.f., Rosaceae, Urtica dioica L., Urticaceae, beta-sitosterols, pollen extract, onion, garlic, and tomato, appears favorable and promising.

CONCLUSION

Scientific evidence supports the use of mucuna and ashwagandha as phytotherapics for improving serum T concentrations and semen parameters. Despite inconclusive evidence for use of tribulus as a T booster, it may provide advantageous effects on sperm parameters in men with idiopathic infertility. Nutraceutical strategies and some phytotherapics may also be effective to promote prostate health. Popular foodstuffs (onion, garlic, and tomato), nutraceutical agents (pollen extract and beta-sitosterols), and herbal medicines (Pygeum africanum and Urtica dioica) are rational approaches.

Metabolic and Epigenetic Action Mechanisms of Antidiabetic Medicinal Plants

Diabetes is a predominant metabolic disease nowadays due to the off-beam lifestyle of diet and reduced physical activity. Complications of the illness include the gene-environment interactions and the downstream genetic and epigenetic consequences, e.g., cardiovascular diseases, tumor progression, retinopathy, nephropathy, neuropathy, polydipsia, polyphagia, polyuria, and weight loss. This review sheds the light on the mechanistic insights of antidiabetic medicinal plants in targeting key organs and tissues involved in regulating blood glucose homeostasis including the pancreas, liver, muscles, adipose tissues, and glucose absorption in the intestine. Diabetes is also involved in modulating major epigenetic pathways such as DNA methylation and histone modification. In this respect, we will discuss the phytochemicals as current and future epigenetic drugs in the treatment of diabetes. In addition, several proteins are common targets for the treatment of diabetes. Some phytochemicals are expected to directly interact with these targets. We lastly uncover modeling studies that predict such plausible interactions. In conclusion, this review article presents the mechanistic insight of phytochemicals in the treatment of diabetes by combining both the cellular systems biology and molecular modeling.

A Selective Role of Dietary Anthocyanins and Flavan-3-ols in Reducing the Risk of Type 2 Diabetes Mellitus: A Review of Recent Evidence

Type 2 diabetes mellitus (T2DM) is the most common form of DM and its prevalence is increasing worldwide. Because it is a progressive disease, prevention, early detection and disease course modification are possible. Diet plays a critical role in reducing T2DM risk. Therapeutic dietary approaches routinely recommend diets high in plant foods (i.e., vegetables, fruits, whole-grains). In addition to essential micronutrients and fiber, plant-based diets contain a wide-variety of polyphenols, specifically flavonoid compounds. Evidence suggests that flavonoids may confer specific benefits for T2DM risk reduction through pathways influencing glucose absorption and insulin sensitivity and/or secretion. The present review assesses the relationship between dietary flavonoids and diabetes risk reduction reviewing current epidemiology and clinical research. Collectively, the research indicates that certain flavonoids, explicitly anthocyanins and flavan-3-ols and foods rich in these compounds, may have an important role in dietary algorithms aimed to address diabetes risk factors and the development of T2DM.

Quercetin and its derivative Q2 modulate chromatin dynamics in adipogenesis and Q2 prevents obesity and metabolic disorders in rats

Recently the attention of the scientific community has focused on the ability of polyphenols to counteract adverse epigenetic regulation involved in the development of complex conditions such as obesity. The aim of this study was to investigate the epigenetic mechanisms underlying the anti-adiposity effect of Quercetin (3,3',4',5,7-pentahydroxyflavone) and of one of its derivatives, Q2 in which the OH groups have been replaced by acetyl groups. In 3 T3-L1 preadipocytes, Quercetin and Q2 treatment induce chromatin remodeling and histone modifications at the 5' regulatory region of the two main adipogenic genes, c/EBPα and PPARγ. Chromatin immunoprecipitation assays revealed a concomitant increase of histone H3 di-methylation at Lys9, a typical mark of repressed gene promoters, and a decrease of histone H3 di-methylation at Lys 4, a mark of active transcription. At the same time, both compounds inhibited histone demethylase LSD1 recruitment to the 5' region of c/EBPα and PPARγ genes, a necessary step for adipogenesis. The final effect is a significant reduction in c/EBPα and PPARγ gene expression and attenuated adipogenesis. Q2 supplementation in rats reduced the gain in body weight and in white adipose tissue, as well as the increase in adipocyte size determined by high fat diet. Moreover, Q2 improved dyslipidemia, glucose tolerance and decreased the hepatic lipid accumulation by activating the expression of beta-oxidation related genes. Our data suggest that Q2, as well as Quercetin, has the potential to revert the unfavorable epigenomic profiles associated with obesity onset. This opens the possibility to use these compounds in targeted prevention strategies against obesity.

Effects of quercetin supplementation on glycemic control among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized controlled trials

This systematic review and meta-analysis of randomized controlled trials was performed to determine the effect of quercetin supplementation on glycemic control among patients with metabolic syndrome and related disorders. Databases including PubMed, MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials were searched until August 30, 2018. Nine studies with 10 effect sizes out of 357 selected reports were identified eligible to be included in current meta-analysis. The pooled findings indicated that quercetin supplementation did not affect fasting plasma glucose (FPG), homeostasis model of assessment-estimated insulin resistance, and hemoglobin A1c levels. In subgroup analysis, quercetin supplementation significantly reduced FPG in studies with a duration of ≥8 weeks (weighted mean difference [WMD]: -0.94; 95% confidence interval [CI; -1.81, -0.07]) and used quercetin in dosages of ≥500 mg/day (WMD: -1.08; 95% CI [-2.08, -0.07]). In addition, subgroup analysis revealed a significant reduction in insulin concentrations following supplementation with quercetin in studies that enrolled individuals aged <45 years (WMD: -1.36; 95% CI [-1.76, -0.97]) and that used quercetin in dosages of ≥500 mg/day (WMD: -1.57; 95% CI [-1.98, -1.16]). In summary, subgroup analysis based on duration of ≥8 weeks and used quercetin in dosages of ≥500 mg/day significantly reduced FPG levels.

Caloric Restriction Mimetics against Age-Associated Disease: Targets, Mechanisms, and Therapeutic Potential

The increase in life expectancy has boosted the incidence of age-related pathologies beyond social and economic sustainability. Consequently, there is an urgent need for interventions that revert or at least prevent the pathogenic age-associated deterioration. The permanent or periodic reduction of calorie intake without malnutrition (caloric restriction and fasting) is the only strategy that reliably extends healthspan in mammals including non-human primates. However, the strict and life-long compliance with these regimens is difficult, which has promoted the emergence of caloric restriction mimetics (CRMs). We define CRMs as compounds that ignite the protective pathways of caloric restriction by promoting autophagy, a cytoplasmic recycling mechanism, via a reduction in protein acetylation. Here, we describe the current knowledge on molecular, cellular, and organismal effects of known and putative CRMs in mice and humans. We anticipate that CRMs will become part of the pharmacological armamentarium against aging and age-related cardiovascular, neurodegenerative, and malignant diseases.

Halophytic Grasses, a New Source of Nutraceuticals? A Review on Their Secondary Metabolites and Biological Activities

The Poaceae family, known as grasses, is distributed worldwide and is considered the most important group of monocotyledonous crops. Salt stress is multifactorial, therefore to survive, halophytes evolved a variety of adaptations, which include the biosynthesis of different primary and secondary metabolites. This trait enhances the accumulation of important families of compounds crucial to the prevention of a variety of chronic diseases. Besides, if proven edible, these species could cope with the increased soil salinity responsible for the decline of arable land due to their high nutritional/nutraceutical value. Herein, the phytochemical investigations performed in halophytes from the Poaceae family as well as their biological properties were explored. Among the 65 genera and 148 species of known halophytic grasses, only 14% of the taxa were studied phytochemically and 10% were subjected to biological evaluation. Notably, in the studied species, a variety of compound families, as well as bioactivities, were demonstrated, highlighting the potential of halophytic grasses.

Effects of Quercetin Metabolites on Triglyceride Metabolism of 3T3-L1 Preadipocytes and Mature Adipocytes

Quercetin (Q) has rapid metabolism, which may make it worthwhile to focus on the potential activity of its metabolites. Our aim was to evaluate the triglyceride-lowering effects of Q metabolites in mature and pre-adipocytes, and to compare them to those induced by Q. 3T3-L1 mature and pre-adipocytes were treated with 0.1, 1 and 10 µM of Q, tamarixetin (TAM), isorhamnetin (ISO), quercetin-3-O-glucuronide (3G), quercetin-3-O-sulfate (3S), as well as with 3S and quercetin-4-O-sulfate (4S) mixture (3S+4S). Triglyceride (TG) content in both cell types, as well as free fatty acid (FFA) and glycerol in the incubation medium of mature adipocytes were measured spectrophotometrically. Gene expression was assessed by RT-PCR. In mature adipocytes, Q decreased TG at 1 and 10 µM, 3S metabolite at 1 and 10 µM, and 3S+4S mixture at 10 µM. 3S treatment modified the glucose uptake, and TG assembling, but not lipolysis or apoptosis. During differentiation, only 10 µM of ISO reduced TG content, as did Q at physiological doses. In conclusion, 3S metabolite but not ISO, 3G, 4S and TAM metabolites can contribute to the in vivo delipidating effect of Q.

Clinical effectiveness of quercetin supplementation in the management of weight loss: a pooled analysis of randomized controlled trials

Purpose: The previous investigations which considered the possible effect of the quercetin supplementation for overweight and obesity have led to inconsistent results. Here, we aimed to evaluate the effects of quercetin on weight loss using a meta-analysis of randomized controlled clinical trials (RCTs). Methods: Relevant studies were systematically searched from the MEDLINE, EMBASE, Google Scholar, and Scopus databases. RCTs that investigated the effects of quercetin on weight loss in humans were included for quality assessment, meta-analyses, sensitivity analysis, subgroup analyses, and publication bias assessment. Effect size was expressed as weighted mean difference (WMD) and 95% CI by using a random-effects model. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to rate the level of evidence. Results: Nine RCTs (11 treatment arms) with 525 participants were finally included for data pooling. Our meta-analysis revealed that daily quercetin supplementation did not significantly affect the body weight (WMD: -0.35 kg, 95% CI: -2.03, 1.33; P=0.68), body mass index (WMD: -0.04 kg/m², 95% CI: -0.54, 0.45; P=0.87), waist circumference (WMD: -0.37 cm, 95% CI: -1.81, 1.06; P=0.61), and waist to hip ratio (WMD: -0.01, 95% CI: -0.03, 0.01; P=0.48). Subgroup analysis could not identify factors significantly influencing these parameters. These results were robust in sensitivity analysis, and no significant publication bias was found. Conclusion: The current evidence suggests that quercetin intake did not show a notably favorable effect on weight loss. Future well-designed and long-term clinical trials are required to confirm these results.

Neuroprotective Effect of Quercetin Against the Detrimental Effects of LPS in the Adult Mouse Brain

Chronic neuroinflammation is responsible for multiple neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. Lipopolysaccharide (LPS) is an essential component of the gram-negative bacterial cell wall and acts as a potent stimulator of neuroinflammation that mediates neurodegeneration. Quercetin is a natural flavonoid that is abundantly found in fruits and vegetables and has been shown to possess multiple forms of desirable biological activity including anti-inflammatory and antioxidant properties. This study aimed to evaluate the neuroprotective effect of quercetin against the detrimental effects of LPS, such as neuroinflammation-mediated neurodegeneration and synaptic/memory dysfunction, in adult mice. LPS [0.25 mg/kg/day, intraperitoneally (I.P.) injections for 1 week]-induced glial activation causes the secretion of cytokines/chemokines and other inflammatory mediators, which further activate the mitochondrial apoptotic pathway and neuronal degeneration. Compared to LPS alone, quercetin (30 mg/kg/day, I.P.) for 2 weeks (1 week prior to the LPS and 1 week cotreated with LPS) significantly reduced activated gliosis and various inflammatory markers and prevented neuroinflammation in the cortex and hippocampus of adult mice. Furthermore, quercetin rescued the mitochondrial apoptotic pathway and neuronal degeneration by regulating Bax/Bcl2, and decreasing activated cytochrome c, caspase-3 activity and cleaving PARP-1 in the cortical and hippocampal regions of the mouse brain. The quercetin treatment significantly reversed the LPS-induced synaptic loss in the cortex and hippocampus of the adult mouse brain and improved the memory performance of the LPS-treated mice. In summary, our results demonstrate that natural flavonoids such as quercetin can be beneficial against LPS-induced neurotoxicity in adult mice.

Effect of Quercetin Monoglycosides on Oxidative Stress and Gut Microbiota Diversity in Mice with Dextran Sodium Sulphate-Induced Colitis

The pathogenesis of inflammatory bowel disease (IBD) is linked to an intricate association of environmental, microbial, and host-related factors. This study examined the potential effects of dietary addition of two preparations from onion, one comprising quercetin aglycone alone (Q: 0.15% polyphenols, quercetin aglycone:quercetin monoglycosides, 98:2) and another comprising quercetin aglycone with monoglycosides (Q+MQ: 0.15% total polyphenols, quercetin aglycone:quercetin monoglycosides, 69:31), on dextran sodium sulphate- (DSS-) induced colitis in mice. The results revealed a significant decrease in the body weight gain of the mice with DSS-induced colitis, which was counteracted by the dietary Q or Q+MQ supplementation. Meanwhile, the oxidative stress indicated by myeloperoxidase (MPO), reduced glutathione (GSH), malondialdehyde (MDA), and serum nitrate (NO) concentrations was higher in mice with DSS-induced colitis than in the control group mice, but dietary Q or Q+MQ supplementation counteracted this trend. The colitis mice demonstrated reduced Chao1, angiotensin-converting enzyme (ACE), and Shannon indices and an increased Simpson index, but the colitis mice receiving dietary Q or Q+MQ exhibited higher Chao1, ACE, and Shannon indices and a reduced Simpson index. In conclusion, this research showed that even at a low dose, dietary Q or Q+MQ supplementation counteracts DSS-induced colitis in mice, indicating that Q or Q+MQ may be used as an adjuvant therapy for IBD patients.

Effects of Quercetin on Lipid and Protein Damage in the Liver of Streptozotocin-Induced Experimental Diabetic Rats

Quercetin (QR) is part of a subclass of flavonoids called flavonols. We aimed to investigate the effect of QR on malondialdehyde (MDA), advanced oxidation protein products (AOPPs), and glutathione peroxidase (GSH-Px) activity in the liver of diabetic rats. We compared four groups of male adult Wistar albino rats: a control group, an untreated diabetic group, diabetic groups treated with QR, and QR group. Diabetes was induced by a single injection of streptozotocin (STZ) (50 mg/kg). Animals were kept in standard condition. On the 31st day of the study, the liver tissue was removed for biochemical parameters and histopathological evaluations. In an untreated diabetic group, liver MDA and AOPP levels were significantly higher than all groups. QR treatment significantly decreased the increased MDA, AOPP levels, and increased the decreased GSH-Px enzyme activity in liver tissues. The QR-treated rats in the diabetic group showed an improved histological appearance. Lesser vesicular vacuolization and fibrotic areas were observed in the QR-treated diabetic group than in the diabetic group. The STZ-induced liver injury is associated with oxidative stress, and coadministration of QR may reduce this damage effectively in a rat model. Our results are also supported by morphological improvement in liver tissue. Therefore, we think QR may be effective in treating hyperglycemia and oxidative damage in diabetes.

Regulation of Immune Function by Polyphenols

Immune dysfunction is caused by various factors, including changes in relevant immune regulators and environmental stress. Immune system imbalance leads to a variety of diseases in humans. Nutrition may play an essential role in immunity by interfering with proinflammatory cytokine synthesis, immune cell regulation, and gene expression. Polyphenols, one of many categories of natural substances, exhibit a range of biological activities. Polyphenols promote immunity to foreign pathogens via various pathways. Different immune cells express multiple types of polyphenol receptors that recognise and allow cellular uptake of polyphenols, which subsequently activate signalling pathways to initiate immune responses. Furthermore, the polyphenols curcumin and epigallocatechin gallate can induce epigenetic changes in cells. In summary, polyphenols can be used to regulate intestinal mucosal immune responses, allergic diseases, and antitumour immunity.

Quercetin prevents small intestinal damage and enhances intestinal recovery during methotrexate-induced intestinal mucositis of rats

Background

Gastrointestinal mucositis occurs as a consequence of cytotoxic treatment. Quercetin (QCT) is a bioflavonoid that exerts significant antioxidant activity and anti-inflammatory as well as anti-malignancy properties.

Objective

To evaluate the effects of oral QCT consumption in preventing intestinal mucosal damage and stimulating intestinal recovery following methotrexate (MTX)-induced intestinal damage in a rat model.

Design

Male Sprague–Dawley rats were divided into four groups: Control Group A (CONTR) – rats were treated with 2 cc of saline given by gavage for 6 days. Group B (CONTR-QCT) – rats were treated with QCT (100 mg/kg in 2 ml saline) given by gavage 3 days before and 3 days after intraperitoneal (IP) injection of saline. Group C (MTX) – rats were injected a single dose (25 mg/kg) of MTX IP. Group D (MTX-QCT) rats were treated with QCT (similar to Group B) 3 days before and 3 days after IP MTX injection. Intestinal mucosal parameters (bowel and mucosal weight, mucosal DNA and protein content, and villus height and crypt depth), enterocytes proliferation, and enterocyte apoptosis degree were investigated at sacrifice on the 4th day after MTX or saline injection.

Results

Administration of QCT to MTX-treated rats resulted in: (1) significant decrease in intestinal injury score, (2) significant increase in intestinal and mucosal weight in jejunum and ileum, (3) increase on the protein content of the ileum, (4) increase in the villus height in the ileum, (5) increase of crypt depth of jejunum and ileum, and (6) increase in cell proliferation in the jejunum and ileum compared to MTX-nontreated group.

Conclusions

Administration of QCT prevents intestinal damage and improves intestinal recovery following MTX-induced intestinal damage in a rat. We surmise that the effect of QCT is based on induction of cell proliferation in the crypt rather than inhibition of apoptosis.

Anti-Diabetic Effect of Cotreatment with Quercetin and Resveratrol in Streptozotocin-Induced Diabetic Rats

Quercetin and resveratrol are known to have beneficial effects on the diabetes and diabetic complication, however, the effects of combined treatment of these compounds on diabetes are not fully revealed. Therefore, the present study was designed to investigate the combined antidiabetic action of quercetin (QE) and resveratrol (RS) in streptozotocin (STZ)-induced diabetic rats. To test the effects of co-treated with these compounds on diabetes, serum glucose, insulin, lipid profiles, oxidative stress biomarkers, and ions were determined. Additionally, the activities of hepatic glucose metabolic enzymes and histological analyses of pancreatic tissues were evaluated. 50 male Sprague-Dawley rats were divided into five groups; normal control, 50 mg/kg STZ-induced diabetic, and three (30 mg/kg QE, 10 mg/kg RS, and combined) compound-treated diabetic groups. The elevated serum blood glucose levels, insulin levels, and dyslipidemia in diabetic rats were significantly improved by QE, RS, and combined treatments. Oxidative stress and tissue injury biomarkers were dramatically inhibited by these compounds. They also shown to improve the hematological parameters which were shown to the hyperlactatemia and ketoacidosis as main causes of diabetic complications. The compounds treatment maintained the activities of hepatic glucose metabolic enzymes and structure of pancreatic β-cells from the diabetes, and it is noteworthy that cotreatment with QE and RS showed the most preventive effect on the diabetic rats. Therefore, our study suggests that cotreatment with QE and RS has beneficial effects against diabetes. We further suggest that cotreatment with QE and RS has the potential for use as an alternative therapeutic strategy for diabetes.

Natural products for the treatment of type 2 diabetes mellitus: Pharmacology and mechanisms

Epidemiological studies have implied that diabetes mellitus (DM) will become an epidemic accompany with metabolic and endocrine disorders worldwide. Most of DM patients are affected by type 2 diabetes mellitus (T2DM) with insulin resistance and insulin secretion defect. Generally, the strategies to treat T2DM are diet control, moderate exercise, hypoglycemic and lipid-lowing agents. Despite the therapeutic benefits for the treatment of T2DM, most of the drugs can produce some undesirable side effects. Considering the pathogenesis of T2DM, natural products (NPs) have become the important resources of bioactive agents for anti-T2DM drug discovery. Recently, more and more natural components have been elucidated to possess anti-T2DM properties, and many efforts have been carried out to elucidate the possible mechanisms. The aim of this paper was to overview the activities and underlying mechanisms of NPs against T2DM. Developments of anti-T2DM agents will be greatly promoted with the increasing comprehensions of NPs for their multiple regulating effects on various targets and signal pathways.

Inducers of Senescence, Toxic Compounds, and Senolytics: The Multiple Faces of Nrf2-Activating Phytochemicals in Cancer Adjuvant Therapy

The reactivation of senescence in cancer and the subsequent clearance of senescent cells are suggested as therapeutic intervention in the eradication of cancer. Several natural compounds that activate Nrf2 (nuclear factor erythroid-derived 2-related factor 2) pathway, which is involved in complex cytoprotective responses, have been paradoxically shown to induce cell death or senescence in cancer. Promoting the cytoprotective Nrf2 pathway may be desirable for chemoprevention, but it might be detrimental in later stages and advanced cancers. However, senolytic activity shown by some Nrf2-activating compounds could be used to target senescent cancer cells (particularly in aged immune-depressed organisms) that escape immunosurveillance. We herein describe in vitro and in vivo effects of fifteen Nrf2-interacting natural compounds (tocotrienols, curcumin, epigallocatechin gallate, quercetin, genistein, resveratrol, silybin, phenethyl isothiocyanate, sulforaphane, triptolide, allicin, berberine, piperlongumine, fisetin, and phloretin) on cellular senescence and discuss their use in adjuvant cancer therapy. In light of available literature, it can be concluded that the meaning and the potential of adjuvant therapy with natural compounds in humans remain unclear, also taking into account the existence of few clinical trials mostly characterized by uncertain results. Further studies are needed to investigate the therapeutic potential of those compounds that display senolytic activity.

Quercetin decrease somatic cells count in mastitis of dairy cows

Quercetin is a dietary flavonoid which has an effect on inflammation, angiogenesis and vascular inflammation. In several other flavonoids (e.g. kaempferol, astragalin, alpinetin, baicalein, indirubin), anti-inflammatory mechanism was proven by using mice mastitis model. The aim of the current study was pilot analysis of quercetin tolerability and its impact on somatic cells count (SCC) after multiple intramammary treatment on dairy cows with clinical mastitis. Based on SCC and clinical investigation, 9 dairy cows with clinical mastitis of one quarter were selected for the pilot study. Baseline analysis (hematology, TNFα, SCC) was performed every 24h among all cows three days before the first dose (B1-B3). After the baseline monitoring (B1-B3) eight days treatment (D1-D8) was performed with a high and low dose. Selected blood parameters were analyzed. Starting from D1 to D8, a decrease of SCC in relation to baseline was characterized by declining trend. The presented results allowed the confirmation of the significant influence of quercetin on the reduction of SCC in mastitis in dairy cows after 8days of therapy.

Therapeutic Role and Drug Delivery Potential of Neuroinflammation as a Target in Neurodegenerative Disorders

Neuroinflammation, the condition associated with the hyperactivity of immune cells within the CNS (central nervous system), has recently been linked to a host range of neurodegenerative disorders. Targeting neuroinflammation could be of prime importance as recent research highlights the beneficial aspects associated with modulating the inflammatory mediators associated with the CNS. One of the main obstructions in neuroinflammatory treatments is the hindrance posed by the blood-brain barrier for the delivery of drugs. Hence, research has focused on novel modes of transport for drugs to cross the barrier through drug delivery and nanotechnology approaches. In this Review, we highlight the therapeutic advancement made in the field of neurodegenerative disorders by focusing on the effect neuroinflammation treatment has on these conditions.

Quality Control of the Root and Rhizome of Helminthostachys zeylanica (Daodi-Ugon) by HPLC Using Quercetin and Ugonins as Markers

Daodi-Ugon is the dried root and rhizome of Helminthostachys zeylanica (L.) Hook. and has been used for centuries in the treatment of inflammation, fever, pneumonia, burns, and various disorders. However, the chromatographic methods to determine the phytochemical composition of H. zeylanica have never been reported. This study not only aims to develop a valid high-performance liquid chromatography (HPLC) method and to establish a chromatographic fingerprint for the quality control of H. zeylanica, it also establish the proposed content limits of Quercetin, Ugonin J, and Ugonin M. An HPLC method with a RP₁₈ column (250 × 4.6 mm, 5 μm) was developed for the quantitative analysis of Quercetin, Ugonin J, and Ugonin M in H. zeylanica. A simple gradient of (A) methanol/(B) phosphoric acid in water (5–45 min, 70–80% A; 50–55 min, 80–70% A) was used and 360 nm was selected as the detection wavelength. The average contents and proposed content limits for H. zeylanica were calculated with a t-test and a measurement uncertainty test based on 20 batches of authentic H. zeylanica samples. Limits of detection (LOD), quantification (LOQ), linearity, precision, repeatability, stability, and recovery of the developed method were validated. All of the validation results of quantitative determination and fingerprinting methods were satisfactory. The developed method was then applied to assay the contents of Quercetin, Ugonin J, and Ugonin M and to acquire the fingerprints of all of the collected H. zeylanica samples. At the 99% confidence level, the calculated content limits were 56.45, 112.15, and 277.98 mg/kg for Quercetin, Ugonin J, and Ugonin M, respectively. Those validated HPLC quantitative method, fingerprinting profile, and the proposed content limits of three chemical markers that could be used in the quality control of H. zeylanica in the market.

Structure-Antioxidative and Anti-Inflammatory Activity Relationships of Purpurin and Related Anthraquinones in Chemical and Cell Assays

Anthraquinone (9,10-anthraquinone) and several hydroxy derivatives, including purpurin (1,2,4-trihydroxyanthraquinone), anthrarufin (1,5-dihydroxyanthraquinone), and chrysazin (1,8-dihydroxyanthraquinone), were evaluated for antioxidative and anti-inflammatory activities in chemical assays and mammalian cells (murine macrophage RAW 264.7 cells). Several tests were used to assess their activities: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical; ABTS radical cation; hydrogen peroxide scavenging; reduction of potassium ferricyanide; chelation of ferrous ions; inhibition of lipid peroxidation; inhibition of nitric oxide generation; scavenging of the intracellular hydroxyl radical; expression of NLRP3 polypeptide for inflammasome assembly; and quantitation of proinflammatory cytokine interleukin 1β (IL-1β) for inflammasome activation. The results show that purpurin, from the root of the madder plant (Rubia tinctorum L.), exhibited the highest antioxidative activity in both chemical and cultured cell antioxidant assays. The antioxidative activities of the other three anthraquinones were lower than that of purpurin. In addition, purpurin could down-regulate NLRP3 inflammasome assembly and activation, suggesting that it might protect foods against oxidative damage and prevent in vivo oxidative stress and inflammation. Structure-activity relationships and the significance of the results for food quality and human health are discussed.