Green tea and one of its constituents, Epigallocatechine-3-gallate, are potent inhibitors of human 11β-hydroxysteroid dehydrogenase type 1

(-)-Epigallocatechin 3-gallate protects pancreatic β-cell against excessive autophagy-induced injury through promoting FTO degradation

Excessive macroautophagy/autophagy leads to pancreatic β-cell failure that contributes to the development of diabetes. Our previous study proved that the occurrence of deleterious hyperactive autophagy attributes to glucolipotoxicity-induced NR3C1 activation. Here, we explored the potential protective effects of (-)-epigallocatechin 3-gallate (EGCG) on β-cell-specific NR3C1 overexpression mice in vivo and NR3C1-enhanced β cells in vitro. We showed that EGCG protects pancreatic β cells against NR3C1 enhancement-induced failure through inhibiting excessive autophagy. RNA demethylase FTO (FTO alpha-ketoglutarate dependent dioxygenase) caused diminished m6A modifications on mRNAs of three pro-oxidant genes (Tlr4, Rela, Src) and, hence, oxidative stress occurs; by contrast, EGCG promotes FTO degradation by the ubiquitin-proteasome system in NR3C1-enhanced β cells, which alleviates oxidative stress, and thereby prevents excessive autophagy. Moreover, FTO overexpression abolishes the beneficial effects of EGCG on β cells against NR3C1 enhancement-induced damage. Collectively, our results demonstrate that EGCG protects pancreatic β cells against NR3C1 enhancement-induced excessive autophagy through suppressing FTO-stimulated oxidative stress, which provides novel insights into the mechanisms for the anti-diabetic effect of EGCG.Abbreviation 3-MA: 3-methyladenine; AAV: adeno-associated virus; Ad: adenovirus; ALD: aldosterone; AUC: area under curve; βNR3C1 mice: pancreatic β-cell-specific NR3C1 overexpression mice; Ctrl: control; CHX: cycloheximide; DEX: dexamethasone; DHE: dihydroethidium; EGCG: (-)-epigallocatechin 3-gallate; FTO: FTO alpha-ketoglutarate dependent dioxygenase; GSIS: glucose-stimulated insulin secretion; HFD: high-fat diet; HG: high glucose; i.p.: intraperitoneal; IOD: immunofluorescence optical density; KSIS: potassium-stimulated insulin secretion; m6A: N6-methyladenosine; MeRIP-seq: methylated RNA immunoprecipitation sequencing; NO: nitric oxide; NR3C1/GR: nuclear receptor subfamily 3, group C, member 1; NR3C1-Enhc.: NR3C1-enhancement; NAC: N-acetylcysteine; NC: negative control; PBS: phosphate-buffered saline; PI: propidium iodide; OCR: oxygen consumption rate; Palm.: palmitate; RELA: v-rel reticuloendotheliosis viral oncogene homolog A (avian); RNA-seq: RNA sequencing; O2.-: superoxide anion; SRC: Rous sarcoma oncogene; ROS: reactive oxygen species; T2D: type 2 diabetes; TEM: transmission electron microscopy; TLR4: toll-like receptor 4; TUNEL: terminal dUTP nick-end labeling; UTR: untranslated region; WT: wild-type.

The Mechanism of Kelulut Honey in Reversing Metabolic Changes in Rats Fed with High-Carbohydrate High-Fat Diet

Metabolic syndrome (MetS) is composed of central obesity, hyperglycemia, dyslipidemia and hypertension that increase an individual's tendency to develop type 2 diabetes mellitus and cardiovascular diseases. Kelulut honey (KH) produced by stingless bee species has a rich phenolic profile. Recent studies have demonstrated that KH could suppress components of MetS, but its mechanisms of action are unknown. A total of 18 male Wistar rats were randomly divided into control rats (C group) (n = 6), MetS rats fed with a high carbohydrate high fat (HCHF) diet (HCHF group) (n = 6), and MetS rats fed with HCHF diet and treated with KH (HCHF + KH group) (n = 6). The HCHF + KH group received 1.0 g/kg/day KH via oral gavage from week 9 to 16 after HCHF diet initiation. Compared to the C group, the MetS group experienced a significant increase in body weight, body mass index, systolic (SBP) and diastolic blood pressure (DBP), serum triglyceride (TG) and leptin, as well as the area and perimeter of adipocyte cells at the end of the study. The MetS group also experienced a significant decrease in serum HDL levels versus the C group. KH supplementation reversed the changes in serum TG, HDL, leptin, adiponectin and corticosterone levels, SBP, DBP, as well as adipose tissue 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) level, area and perimeter at the end of the study. In addition, histological observations also showed that KH administration reduced fat deposition within hepatocytes, and prevented deterioration of pancreatic islet and renal glomerulus. In conclusion, KH is effective in preventing MetS by suppressing leptin, corticosterone and 11βHSD1 levels while elevating adiponectin levels.

DNA Methylation Is a Potential Biomarker for Cardiometabolic Health in Mexican Children and Adolescents

DNA methylation (DNAm) is a plausible mechanism underlying cardiometabolic abnormalities, but evidence is limited among youth. This analysis included 410 offspring of the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) birth cohort followed up to two time points in late childhood/adolescence. At Time 1, DNAm was quantified in blood leukocytes at long interspersed nuclear elements (LINE-1), H19, and 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD-2), and at Time 2 in peroxisome proliferator-activated receptor alpha (PPAR-α). At each time point, cardiometabolic risk factors were assessed including lipid profiles, glucose, blood pressure, and anthropometry. Linear mixed effects models were used for LINE-1, H19, and 11β-HSD-2 to account for the repeated-measure outcomes. Linear regression models were conducted for the cross-sectional association between PPAR-α with the outcomes. DNAm at LINE-1 was associated with log glucose at site 1 [β = -0.029, p = 0.0006] and with log high-density lipoprotein cholesterol at site 3 [β = 0.063, p = 0.0072]. 11β-HSD-2 DNAm at site 4 was associated with log glucose (β = -0.018, p = 0.0018). DNAm at LINE-1 and 11β-HSD-2 was associated with few cardiometabolic risk factors among youth in a locus-specific manner. These findings underscore the potential for epigenetic biomarkers to increase our understanding of cardiometabolic risk earlier in life.

A Case Report of Cushing's Disease Presenting With Psychosis and Muscle Weakness Postpartum

Cushing's syndrome is a condition leading to overproducing of cortisol by the adrenal glands. If the pituitary gland overproduces cortisol, it is called Cushing's disease. Cushing's syndrome and even Cushing's disease during and after pregnancy are rare events. There is not enough literature and guidance for managing and treating these patients. The diagnosis of Cushing's syndrome in pregnancy is often delayed because the symptoms overlap. We presented a thin 31-year-old woman, admitted 2 months after a normal-term delivery, with an atypical presentation of Cushing's disease, unusual clinical features, and a challenging clinical course. She had no clinical discriminatory features of Cushing's syndrome. Given that the patient only presented with psychosis and proximal myopathy and had an uncomplicated pregnancy, our case was considered unusual. The patients also had hyperpigmentation and severe muscle weakness which are among the less common presentations of Cushing's syndrome. Our findings suggest that an early diagnosis of Cushing's disease is important in pregnancy period for its prevalent fetal and maternal complications, and it should be treated early to optimize fetal and maternal outcomes as there is an increasing trend toward live births in treated participants.

Antioxidant Properties and Beneficial Cardiovascular Effects of a Natural Extract of Pomegranate in Healthy Volunteers: A Randomized Preliminary Single-Blind Controlled Study

Pomegranates are known to possess anti-hypertensive, anti-atherogenic and cardioprotective effects mainly due to their pleiotropic effects on various cellular pathways, especially those triggered by oxidative stress. The aim of this study was to investigate the effect of natural standardized pomegranate (PE) extract on cardiovascular risk factors in 24 healthy volunteers who participated in a randomized, single-blind placebo-controlled study. There were 12 subjects in the PE group and 12 in the placebo group. Variables were measured at baseline and after 14 and 28 days of supplementation are anthropometry, BP, pulse wave velocity, fat and lean body mass, salivary and urinary cortisol, and cortisone, total phenolics, antioxidant capacity and lipid peroxidation. Urinary total phenolics excretion and antioxidant capacity were significantly increased after 14 and 28 days of PE intake. At day 28, there were also statistically significant decreases in systolic and diastolic blood pressure (BP), pulse wave velocity, body fat and fat mass, as well as an increase in lean body mass. Significant changes in the placebo group were not found. Glucocorticoid levels showed a significant decrease in saliva cortisol at day 28 (morning) in the PE group, and cortisol/cortisone ratio was significantly decreased following 28 days of PE intake at morning, noon, and evening. Urine free cortisol was significantly reduced at day 14. These findings suggest that pomegranate extract intake may improve antioxidant and oxidative stress status and play a beneficial role in the attenuation of some cardiovascular risk factors. Future studies should concentrate on overweight and older people.

Cross-Talk between Obesity and Diabetes: Introducing Polyphenols as an Effective Phytomedicine to Combat the Dual Sword Diabesity

: Obesity-associated diabetes mellitus, a chronic metabolic affliction accounting for 90% of all diabetic patients, has been affecting humanity extremely badly and escalating the risk of developing other serious disorders. It is observed that 0.4 billion people globally have diabetes, whose major cause is obesity. Currently, innumerable synthetic drugs like alogliptin and rosiglitazone are being used to get through diabetes, but they have certain complications, restrictions with severe side effects, and toxicity issues. Recently, the frequency of plant-derived phytochemicals as advantageous substitutes against diabesity is increasing progressively due to their unparalleled benefit of producing less side effects and toxicity. Of these phytochemicals, dietary polyphenols have been accepted as potent agents against the dual sword "diabesity". These polyphenols target certain genes and molecular pathways through dual mechanisms such as adiponectin upregulation, cannabinoid receptor antagonism, free fatty acid oxidation, ghrelin antagonism, glucocorticoid inhibition, sodium-glucose cotransporter inhibition, oxidative stress and inflammation inhibition etc. which sequentially help to combat both diabetes and obesity. In this review, we have summarized the most beneficial natural polyphenols along with their complex molecular pathways during diabesity.

The Impact of Epigallocatechin Gallate and Coconut Oil Treatment on Cortisol Activity and Depression in Multiple Sclerosis Patients

(1) Background: Multiple sclerosis (MS) is pathogenically characterized by high oxidative stress and symptomatically by progressive muscle loss and increased body fat associated with the presence of depression. Epigallocatechin gallate (EGCG) (particularly present in green tea) and ketone bodies (in particular beta-hydroxybutyrate (BHB)), whose main source is coconut oil, have shown emotional benefits and body fat loss. The aim of this study was to assess the impact of EGCG and coconut oil on cortisol activity related to fat loss and depression in MS patients. (2) Methods: The study involved 51 MS patients who were randomly divided into an intervention group or a control group. The intervention group received 800 mg of EGCG and 60 mL of coconut oil, which were included in their daily diet for four months. The control group received placebo and all patients followed an isocaloric diet. A blood sample was collected before and after the four-month period, and levels of cortisol, albumin and BHB were measured in serum. In addition, immediately before and after the intervention, anthropometric variables were measured: waist-to-hip ratio (WHR), body fat mass percentage, fat weight, total weight, and muscle mass percentage. Depression was assessed with the Beck Depression Inventory II (BDI-II). (3) Results: No significant changes were obtained in cortisol levels in any of the groups, and there was a significant increase in albumin in the blood of the intervention group only that could lead to a decrease in serum free cortisol. In addition, it was observed a significant decrease in levels of depression and abdominal fat. (4) Conclusions: EGCG combined with coconut oil increase the concentration of albumin in blood and produce less depression in MS patients.

Research progress on the potential delaying skin aging effect and mechanism of tea for oral and external use

Skin aging is characterized by the gradual loss of elasticity, the formation of wrinkles and various color spots, the degradation of extracellular matrix proteins, and the structural changes of the dermis. With the increasingly prominent problems of environmental pollution, social pressure, ozone layer thinning and food safety, skin problems have become more and more complex. The skin can reflect the overall health of the body. Skincare products for external use alone cannot fundamentally solve skin problems; it needs to improve the overall health of the body. Based on the literature review in recent 20 years, this paper systematically reviewed the potential delaying effect of tea and its active ingredients on skin aging by oral and external use. Tea is the second-largest health drink after water. It is rich in tea polyphenols, l-theanine, tea pigments, caffeine, tea saponins, tea polysaccharides and other secondary metabolites. Tea and its active substances have whitening, nourishing, anti-wrinkle, removing spots and other skincare effects. Its mechanism of action is ultraviolet absorption, antioxidant, anti-inflammatory, inhibition of extracellular matrix aging, inhibiting the accumulation of melanin and toxic oxidation products, balancing intestinal and skin microorganisms, and improving mood and sleep, among other effects. At present, tea elements skincare products are deeply loved by consumers. This paper provides a scientific theoretical basis for tea-assisted beauty and the high-end application of tea in skincare products.

Modulation of the hypothalamic-pituitary-adrenal (HPA) axis by plants and phytonutrients: a systematic review of human trials

INTRODUCTION

The hypothalamic-pituitary-adrenal (HPA) axis plays a central role in the stress response. Plants, herbs, spices, and plant-based nutrients may influence HPA-axis activity.

OBJECTIVE

To evaluate randomised controlled, human trials assessing the effects of single plants or phytonutrients on HPA-axis related hormones.

METHODS

A systematic review of PubMed, Cochrane library, and the Cumulative Index to Nursing and Allied Health Literature was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria comprised of human, randomised controlled studies with a control intervention examining the effects of a single herb, spice, plant, or extract on pre- and post-changes in blood, saliva, urine, or hair concentrations of cortisol, cortisone, corticotrophin-releasing hormone, or adrenocorticotropic hormone. Databases were searched from inception until October 2020.

RESULTS

Fifty-two studies were identified examining the effects of ashwagandha, Korean ginseng, St John's Wort, cannabidiol, Rhodiola rosea, curcumin, cherry juice, asparagus, Jiaogulan, Black cohosh, Siberian ginseng, Bacopa monnieri, blueberries, green tea, Caralluma fimbriata, cashew apple juice, melon, American ginseng, Ginkgo biloba, grape juice, grapefruit juice, rosella, hops, mangosteen, holy basil, and pomegranate juice. Due to significant variability in study designs, the effect of phytonutrients on HPA-axis activity in humans was unclear. The most consistent finding was a morning, cortisol-lowering effect from ashwagandha supplementation.

CONCLUSION

For most phytonutrients, the effects of supplementation on HPA-axis activity in humans is unclear. Before more definitive conclusions about the effects of phytonutrients on the HPA-axis can be made, further research is required.

The counteracting effects of (-)-Epigallocatechin-3-Gallate on the immobilization stress-induced adverse reactions in rat pancreas

Many studies suggest that Epigallocatechin-3-Gallate (EGCG) has many protective effects. But little is known about its protective effects against chronic restraint stress-induced damage in rats. The aim was to demonstrate the potential protective effects of EGCG against harmful pancreatic damage to the immobilization stress in the rat model. Forty rats, 2 months old, were divided into four groups (n = 10): control group; EGCG group, rats received EGCG by gavage (100 mg/kg /day) for 30 days; stressed group, rats exposed to immobilization stress; and stressed with EGCG group, rats exposed to immobilization stress and received EGCG for 30 days. Glycemic status parameters, corticosterone, and inflammatory markers were investigated on the first day, 15th day, and the 30th day of the experiment. Pancreatic oxidative stress markers and cytokines were evaluated. Histological, immunohistological, and statistical studies were performed. On the 15th day, fasting blood glucose (FBG), fasting plasma insulin (FPI), homeostatic model assessment for insulin resistance (HOMA-IR), and fasting plasma corticosterone were significantly higher in the stressed group when compared with first and 30th day in the same group as well as when compared with control and stressed with EGCG groups. The stressed group revealed significantly higher pancreatic IL-1β, IL-6, TNF-α, MDA, and NO, serum amylase and serum lipase, and significantly lower GSH, SOD, and CAT when compared to control and stressed with EGCG groups. EGCG treatment attenuated the pancreatic stress-induced cellular degeneration, leucocytic infiltration, and cytoplasmic vacuolations; significantly decreased area percentage of collagen fibers; and significantly increased mean area percentage of insulin immunopositive cell as compared with stressed group. EGCG is a protective agent against immobilization stress because of its anti-diabetic, anti-inflammatory, and and anti-oxidative stress properties, as confirmed by biochemical and histological alterations.

Phytochemicals as Potential Epidrugs in Type 2 Diabetes Mellitus

Type 2 diabetes Mellitus (T2DM) prevalence has significantly increased worldwide in recent years due to population age, obesity, and modern sedentary lifestyles. The projections estimate that 439 million people will be diabetic in 2030. T2DM is characterized by an impaired β-pancreatic cell function and insulin secretion, hyperglycemia and insulin resistance, and recently the epigenetic regulation of β-pancreatic cells differentiation has been underlined as being involved. It is currently known that several bioactive molecules, widely abundant in plants used as food or infusions, have a key role in histone modification and DNA methylation, and constituted potential epidrugs candidates against T2DM. In this sense, in this review the epigenetic mechanisms involved in T2DM and protein targets are reviewed, with special focus in studies addressing the potential use of phytochemicals as epidrugs that prevent and/or control T2DM in vivo and in vitro. As main findings, and although some controversial results have been found, bioactive molecules with epigenetic regulatory function, appear to be a potential replacement/complementary therapy of pharmacological hypoglycemic drugs, with minimal side effects. Indeed, natural epidrugs have shown to prevent or delay the T2DM development and the morbidity associated to dysfunction of blood vessels, eyes and kidneys due to sustained hyperglycemia in T2DM patients.

Effects of epigallocatechin-3-gallate of Camellia sinensis leaves on blood pressure, lipid profile, atherogenic index of plasma and some inflammatory and antioxidant markers in type 2 diabetes mellitus patients: a clinical trial

BACKGROUND

In patients with type 2 diabetes mellitus (T2DM) the inflammatory and metabolic responses to epigallocatechin-3-gallate (EGCG) are unknown.

OBJECTIVES

Evaluate the impacts of EGCG on metabolic factors and some biomarkers of stress oxidative in patients with T2DM.

METHODS

In this randomized, double-blind, placebo-controlled trial, 50 patients with T2DM consumed either 2 tablets (300 mg) EGCG (n=25) or wheat flour as placebo (n=25) for 2 months. The total antioxidant capacity (TAC), interleukin-6 (IL-6), lipid profile, mean arterial pressure (MAP), atherogenic index of plasma (AIP) were evaluated before and after the intervention.

RESULTS

The finding of present study exhibited a significant increase in the serum levels of TAC after the EGCG supplementation (p=0.001). Also, in compare with control group, the mean changes of TAC were significantly higher in supplement group (p=0.01). In intervention group, a significant decrease was observed in the mean levels of triglyceride, total cholesterol, diastolic blood pressure (DBP), AIP, and MAP (p<0.05). Taking EGCG resulted in the mean changes of total cholesterol, MAP and DBP were significantly lower in compare with control group (p<0.05).

CONCLUSIONS

This study recommended that EGCG supplementation may be improved blood pressure, lipid profile, AIP, and oxidative status in patients with T2DM.

DIA-DB: A Database and Web Server for the Prediction of Diabetes Drugs

The DIA-DB is a web server for the prediction of diabetes drugs that uses two different and complementary approaches: (a) comparison by shape similarity against a curated database of approved antidiabetic drugs and experimental small molecules and (b) inverse virtual screening of the input molecules chosen by the users against a set of therapeutic protein targets identified as key elements in diabetes. As a proof of concept DIA-DB was successfully applied in an integral workflow for the identification of the antidiabetic chemical profile in a complex crude plant extract. To this end, we conducted the extraction and LC-MS based chemical profile analysis of Sclerocarya birrea and subsequently utilized this data as input for our server. The server is open to all users, registration is not necessary, and a detailed report with the results of the prediction is sent to the user by email once calculations are completed. This is a novel public domain database and web server specific for diabetes drugs and can be accessed online through http://bio-hpc.eu/software/dia-db/.

In silico analysis of antidiabetic potential of phenolic compounds from blue corn (Zea mays L.) and black bean (Phaseolus vulgaris L.)

The growing interest in bioactive compounds, especially in polyphenols, is due to their abundance in the human diet and potentially positive effects on health. The consumption of polyphenols has been shown to possess anti-diabetic properties by preventing insulin resistance or insulin secretion through different signaling pathways, this effect is associated with their capacity to exert genomic modulations. Several studies have suggested that polyphenols could also bind to cellular proteins and modulate their activity, however, the mechanisms of action underlying their beneficial effects are complex and are not fully understood. The aim of this work was to characterize phenolic compounds present in blue corn and black bean extracts as well as identify their potential interactions with target proteins involved in diabetes pathogenesis using in silico approach. Total polyphenols content of both blue corn and black beans was identified using UPLC-ESI/qTOF/MS and quantified by colorimetric assays. In this work we identified twenty-eight phenolic compounds in the extracts, mainly anthocyanins, flavonols, hydroxycinamic acids, dihydroxybenzoic acids, flavones, isoflavones, and flavanols. Interactome of these compounds with thirteen target proteins involved in type 2 diabetes mellitus was performed in-silico. In total, 312 bioactive compounds/protein interaction analyses were acquired. Molecular docking results highlighted that nine of the top ten interactions correspond to anthocyanins, cyanidin 3-glucoside with 11β-HS, GFAT, PPARG; delphinidin 3-glucoside with 11β-HS, GFAT, PTP and RTKs; and petunidin 3-glucoside with 11β-HS and PTP. These proteins are involved in mechanisms regulating functions such as inflammation, insulin resistance, oxidative stress, glucose and lipid metabolism. In conclusion, this work provides a prediction of the potential molecular mechanism of black bean and blue corn polyphenols, specifically anthocyanins and could constitute new pathways by which compounds exert their antidiabetic benefits.

Progress in 11β-HSD1 inhibitors for the treatment of metabolic diseases: A comprehensive guide to their chemical structure diversity in drug development

11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is a key metabolic enzyme that catalyzing the intracellular conversion of inactive glucocorticoids to physiologically active ones. Work over the past decade has demonstrated the aberrant overexpression of 11β-HSD1 contributed to the pathophysiological process of metabolic diseases like obesity, type 2 diabetes mellitus, and metabolic syndromes. The inhibition of 11β-HSD1 represented an attractive therapeutic strategy for the treatment of metabolic diseases. Therefore, great efforts have been devoted to developing 11β-HSD1 inhibitors based on the diverse molecular scaffolds. This review focused on the structural features of the most important 11β-HSD1 inhibitors and categorized them into natural products derivatives and synthetic compounds. We also briefly discussed the optimization process, binding modes, structure-activity relationships (SAR) and biological evaluations of each inhibitor. Moreover, the challenges and directions for 11β-HSD1 inhibitors were discussed, which might provide some useful clues to guide the future discovery of novel 11β-HSD1 inhibitors.

Network pharmacology-based analysis on bioactive anti-diabetic compounds in Potentilla discolor bunge

ETHNOPHARMACOLOGICAL RELEVANCE

Potentilla discolor Bunge (PDB) is a commonly used herbal for alleviating diabetes mellitus and its complications. Although accumulating evidences show the anti-diabetic efficacy of PDB, the vital anti-diabetic compounds and their functional targets remain elusive.

AIM OF THE STUDY

To investigate the anti-diabetic ingredients and their functional mechanisms in PDB, gas chromatograph-mass spectrometry analysis was performed on PDB extract and 21 were testified as anti-diabetic compounds.

MATERIALS AND METHODS

Subsequently their potential protein targets were also identified. The bioinformatics analysis was implemented by network pharmacology-based approaches. STRING analysis was performed to reveal enrichment of these target proteins, protein-protein interactions, pathways and related diseases. Cytoscape was used to determine the potential protein targets for these components in PDB, indicating that 21 anti-diabetic compounds in PDB regulate 33 diabetes-related proteins in 28 signal pathways and involve 21 kinds of diabetes-related diseases. Among the 21 potential anti-diabetic components predicted by network analysis, tricetin was firstly experimentally validated at the molecular and cellular level.

RESULTS

Results indicated that this active small-molecule compound may have beneficial effects on improving glucose uptake.

CONCLUSIONS

We envisage that network analysis will be useful in screening bioactive compounds of medicinal plants.

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.

Regular consumption of green tea improves pulse pressure and induces regression of left ventricular hypertrophy in hypertensive patients

This study characterized the effects of regular green tea (GT) and hot water (HW) ingestion on systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), and left ventricular hypertrophy (LVH) in two equal, sex- and age-matched groups; Grp1 and Grp2 (n = 100 each; age 53 ± 4 years) of hypertensive patients. Grp1 had regular GT treatment, followed by HW ingestion, whereas Grp2 had HW ingestion followed by GT treatment for periods of 4 months each. Electrocardiographic (ECG) and echocardiographic assessments of LVH were made before and at the end of both periods. SBP was lowered significantly by 6.6%; DBP by 5.1%, and PP by 9.1% by the end of month 4 of GT treatment in Grp1. Upon GT cessation and HW ingestion, SBP, DBP, and PP returned to pretreatment levels over 4 months. In Grp2, SBP, DBP, and PP were reduced insignificantly by 1.5%, 1.0%, and 2.3% by the end of the 4th month of HW ingestion. Conversely, over 4 months of GT treatment, SBP, DBP, and PP were significantly lowered by 5.4%, 4.1%, and 7.7% from the baseline values, respectively. ECG and echocardiographic evidence of LVH was shown in 20% of Grp1 and 24% of Grp2 patients before intervention. This was significantly lowered to 8% and 10% in Grp1 and Grp2 by GT treatment. However, this increased to 16% following HW ingestion in Grp1. HW ingestion did mot induce regression of LVH in Grp2. Thus, regular GT ingestion has cardiovascular protective effects.

Expression and activity of the cortisol-activating enzyme 11β-hydroxysteroid dehydrogenase type 1 is tissue and species-specific

The microsomal enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) interconverts glucocorticoid receptor-inert cortisone (11-dehydrocorticosterone in rodents) to its receptor-active form cortisol (corticosterone in rodents). Thus, 11β-HSD1 amplifies glucocorticoid action at the tissue level. According to the current literature, dysregulation of glucocorticoid signaling may contribute to the pathogenesis of the metabolic syndrome in which regeneration of cortisol by 11β-HSD1 may be an important factor. This is why the enzyme has been very intensely investigated as a potential therapeutic target to treat metabolic complications such as obesity and diabetes type 2. However, due to controversial results from the various animal and human studies as well as from different findings with regard to tissue-specific expression and activity, the varied results unfortunately do not yield a consistent picture. Therefore, the precise role of 11β-HSD1 in the development of complications associated with the metabolic syndrome has still not been deciphered yet. Overall, the prominent role of this enzyme in the pathogenesis of the metabolic syndrome becomes more and more dubious and therefore further studies are necessary to clarify its role finally. This short review gives an overview on the main contradicting findings on the role of 11β-HSD1 in the development of visceral obesity and diabetes type 2.

In Vitro and In Silico Studies of the Molecular Interactions of Epigallocatechin-3-O-gallate (EGCG) with Proteins That Explain the Health Benefits of Green Tea

Green tea has been shown to have beneficial effects on many diseases such as cancer, obesity, inflammatory diseases, and neurodegenerative disorders. The major green tea component, epigallocatechin-3-O-gallate (EGCG), has been demonstrated to contribute to these effects through its anti-oxidative and pro-oxidative properties. Furthermore, several lines of evidence have indicated that the binding affinity of EGCG to specific proteins may explain its mechanism of action. This review article aims to reveal how EGCG-protein interactions can explain the mechanism by which green tea/EGCG can exhibit health beneficial effects. We conducted a literature search, using mainly the PubMed database. The results showed that several methods such as dot assays, affinity gel chromatography, surface plasmon resonance, computational docking analyses, and X-ray crystallography have been used for this purpose. These studies have provided evidence to show how EGCG can fit or occupy the position in or near functional sites and induce a conformational change, including a quaternary conformational change in some cases. Active site blocking, steric hindrance by binding of EGCG near an active site or induced conformational change appeared to cause inhibition of enzymatic activity and other biological activities of proteins, which are related to EGCG’s biological oligomer and formation of their toxic aggregates, leading to the prevention of neurodegenerative diseases and amyloidosis. In conclusion, these studies have provided useful information on the action of green tea/catechins and would lead to future studies that will provide further evidence for rational EGCG therapy and use EGCG as a lead compound for drug design.

Epigallocatechin-3-Gallate Ameliorates Glucocorticoid-Induced Osteoporosis of Rats in Vivo and in Vitro

Background: Prolonged administration of overdoses of glucocorticoids results in increased bone remodeling, leading to glucocorticoid-induced osteoporosis (GIO), which is primarily due to the dysfunction and apoptosis of osteoblasts. The present study investigated the therapeutic effect and molecular mechanism of action of epigallocatechin-3-gallate (EGCG), a bioactive catechin in green tea, in high-dose dexamethasone-induced osteoblast differentiation in vivo and in vitro. Methods: The anti-dexamethasone (DEX) effects of EGCG on primary osteoblasts were determined on the basis of cell viability and alkaline phosphatase (ALP) and total cellular superoxide dismutase (SOD) activities. Flow cytometry and Western blot analysis were also used to evaluate the expression of related biomarkers in vitro, and bone microarchitecture was also extensively examined in a rat model in vivo. Results: The results showed that EGCG pretreatment significantly increased osteoblast viability and ALP and SOD activities when cells were exposed to DEX. Alizarin red staining indicated that there was more mineralization with EGCG pretreatment, countering DEX effects. EGCG reduced DEX-induced reactive oxygen species at both the mitochondrial and cellular levels in osteoblasts by activating the nuclear factor erythroid-derived 2-like-2 (Nrf2) pathway. In addition, EGCG protected osteoblasts from apoptosis. EGCG also regulated the formation of active glucocorticoid by 11β-hydroxysteroid dehydrogenase activity. Furthermore, femoral micro-computed tomography scans revealed that EGCG improved bone microstructure and mitigated DEX-induced deterioration of bone quality. Conclusion: These findings suggested that EGCG reversed GIO in rats by protecting osteoblasts by activating the Nrf2 signaling pathway.

Beneficial metabolic effects of dietary epigallocatechin gallate alone and in combination with exendin-4 in high fat diabetic mice

OBJECTIVE

Significant attempts are being made to generate multifunctional, hybrid or peptide combinations as novel therapeutic strategies for type 2 diabetes, however this presents key challenges including design and pharmaceutical development. In this study, we evaluated metabolic properties of oral nutritional supplement epigallocatechin gallate (EGCG) in combination with GLP-1 agonist exendin-4 in a mouse model of dietary-induced diabetes and obesity.

METHODS

EGCG, exendin-4 or combination of both were administered twice-daily over 28 days to high fat (HF) mice on background of low-dose streptozotocin. Energy intake, body weight, fat mass, glucose tolerance, insulin sensitivity, lipid profile, biochemical and hormone markers, and islet histology were examined.

RESULTS

All treatment groups exhibited significantly reduced body weight, fat mass, circulating glucose and insulin concentrations, and HbA1c levels which were independent of changes in energy intake. Similarly, there was marked improvement in glycaemic control, glucose-stimulated insulin release, insulin sensitivity, total cholesterol and triglycerides, with most prominent effects observed following combination therapy. Circulating corticosterone concentrations and 11beta-hydroxysteroid dehydrogenase type1 (11β-HSD1) staining (in pancreas) were beneficially decreased without changes in circulating interleukin 6 (IL-6), alanine transaminase (ALT) and glutathione reductase. Combination therapy resulted in increased islet area and number, beta cell area, and pancreatic insulin content. Generally, metabolic effects were much more pronounced in mice which received combination therapy.

CONCLUSIONS

EGCG alone and particularly in combination with exendin-4 exerts positive metabolic properties in HF mice. EGCG may be useful dietary adjunct alongside GLP-1 mimetics in treatment of diabetes and related disorders.

Functional Foods and Lifestyle Approaches for Diabetes Prevention and Management

Functional foods contain biologically active ingredients associated with physiological health benefits for preventing and managing chronic diseases, such as type 2 diabetes mellitus (T2DM). A regular consumption of functional foods may be associated with enhanced anti-oxidant, anti-inflammatory, insulin sensitivity, and anti-cholesterol functions, which are considered integral to prevent and manage T2DM. Components of the Mediterranean diet (MD)-such as fruits, vegetables, oily fish, olive oil, and tree nuts-serve as a model for functional foods based on their natural contents of nutraceuticals, including polyphenols, terpenoids, flavonoids, alkaloids, sterols, pigments, and unsaturated fatty acids. Polyphenols within MD and polyphenol-rich herbs-such as coffee, green tea, black tea, and yerba maté-have shown clinically-meaningful benefits on metabolic and microvascular activities, cholesterol and fasting glucose lowering, and anti-inflammation and anti-oxidation in high-risk and T2DM patients. However, combining exercise with functional food consumption can trigger and augment several metabolic and cardiovascular protective benefits, but it is under-investigated in people with T2DM and bariatric surgery patients. Detecting functional food benefits can now rely on an "omics" biological profiling of individuals' molecular, genetics, transcriptomics, proteomics, and metabolomics, but is under-investigated in multi-component interventions. A personalized approach for preventing and managing T2DM should consider biological and behavioral models, and embed nutrition education as part of lifestyle diabetes prevention studies. Functional foods may provide additional benefits in such an approach.

Unfolding Novel Mechanisms of Polyphenol Flavonoids for Better Glycaemic Control: Targeting Pancreatic Islet Amyloid Polypeptide (IAPP)

Type 2 diabetes (T2D) is characterised by hyperglycaemia resulting from defective insulin secretion, insulin resistance, or both. The impact of over-nutrition and reduced physical activity, evidenced by the exponential rise in obesity and the prevalence of T2D, strongly supports the implementation of lifestyle modification programs. Accordingly, an increased consumption of fruits and plant-derived foods has been advocated, as their intake is inversely correlated with T2D prevalence; this has been attributed, in part, to their contained polyphenolic compounds. Over the last decade, a body of work has focussed on establishing the mechanisms by which polyphenolic compounds exert beneficial effects to limit carbohydrate digestion, enhance insulin-mediated glucose uptake, down-regulate hepatic gluconeogenesis and decrease oxidative stress; the latter anti-oxidative property being the most documented. Novel effects on the inhibition of glucocorticoid action and the suppression of amylin misfolding and aggregation have been identified more recently. Amyloid fibrils form from spontaneously misfolded amylin, depositing in islet cells to elicit apoptosis, beta cell degeneration and decrease insulin secretion, with amyloidosis affecting up to 80% of pancreatic islet cells in T2D. Therefore, intervening with polyphenolic compounds offers a novel approach to suppressing risk or progression to T2D. This review gives an update on the emerging mechanisms related to dietary polyphenol intake for the maintenance of glycaemic control and the prevention of T2D.

Neuroendocrinological and Epigenetic Mechanisms Subserving Autonomic Imbalance and HPA Dysfunction in the Metabolic Syndrome

Impact of environmental stress upon pathophysiology of the metabolic syndrome (MetS) has been substantiated by epidemiological, psychophysiological, and endocrinological studies. This review discusses recent advances in the understanding of causative roles of nutritional factors, sympathomedullo-adrenal (SMA) and hypothalamic-pituitary adrenocortical (HPA) axes, and adipose tissue chronic low-grade inflammation processes in MetS. Disturbances in the neuroendocrine systems for leptin, melanocortin, and neuropeptide Y (NPY)/agouti-related protein systems have been found resulting directly in MetS-like conditions. The review identifies candidate risk genes from factors shown critical for the functioning of each of these neuroendocrine signaling cascades. In its meta-analytic part, recent studies in epigenetic modification (histone methylation, acetylation, phosphorylation, ubiquitination) and posttranscriptional gene regulation by microRNAs are evaluated. Several studies suggest modification mechanisms of early life stress (ELS) and diet-induced obesity (DIO) programming in the hypothalamic regions with populations of POMC-expressing neurons. Epigenetic modifications were found in cortisol (here HSD11B1 expression), melanocortin, leptin, NPY, and adiponectin genes. With respect to adiposity genes, epigenetic modifications were documented for fat mass gene cluster APOA1/C3/A4/A5, and the lipolysis gene LIPE. With regard to inflammatory, immune and subcellular metabolism, PPARG, NKBF1, TNFA, TCF7C2, and those genes expressing cytochrome P450 family enzymes involved in steroidogenesis and in hepatic lipoproteins were documented for epigenetic modifications.

Endocrine disruptors and other inhibitors of 11β-hydroxysteroid dehydrogenase 1 and 2: Tissue-specific consequences of enzyme inhibition

Numerous chemicals in the environment have the ability to interact with the endocrine system. These compounds are called endocrine disruptors (EDs). Exposure to EDs represents one of the hypotheses for decreasing fertility, the increased risk of numerous cancers and obesity, metabolic syndrome and type 2 diabetes. There are various mechanisms of ED action, one of which is their interference in the action of 11β-hydroxysteroid dehydrogenase (11βHSD) that maintains a balance between active and inactive glucocorticoids on the intracellular level. This enzyme has two isoforms and is expressed in various tissues. Inhibition of 11βHSD in various tissues can have different consequences. In the case of EDs, the results of exposure are mainly adverse; on the other hand pharmaceutically developed inhibitors of 11βHSD type 1 are evaluated as an option for treating metabolic syndrome, as well as related diseases and depressive disorders. This review focuses on the effects of 11βHSD inhibitors in the testis, colon, adipose tissue, kidney, brain and placenta.

Vascular and metabolic actions of the green tea polyphenol epigallocatechin gallate

Epidemiological studies demonstrate robust correlations between green tea consumption and reduced risk of type 2 diabetes and its cardiovascular complications. However, underlying molecular, cellular, and physiological mechanisms remain incompletely understood. Health promoting actions of green tea are often attributed to epigallocatechin gallate (EGCG), the most abundant polyphenol in green tea. Insulin resistance and endothelial dysfunction play key roles in the pathogenesis of type 2 diabetes and its cardiovascular complications. Metabolic insulin resistance results from impaired insulin-mediated glucose disposal in skeletal muscle and adipose tissue, and blunted insulin-mediated suppression of hepatic glucose output that is often associated with endothelial/vascular dysfunction. This endothelial dysfunction is itself caused, in part, by impaired insulin signaling in vascular endothelium resulting in reduced insulin-stimulated production of NO in arteries, and arterioles that regulate nutritive capillaries. In this review, we discuss the considerable body of literature supporting insulin-mimetic actions of EGCG that oppose endothelial dysfunction and ameliorate metabolic insulin resistance in skeletal muscle and liver. We conclude that EGCG is a promising therapeutic to combat cardiovascular complications associated with the metabolic diseases characterized by reciprocal relationships between insulin resistance and endothelial dysfunction that include obesity, metabolic syndrome and type 2 diabetes. There is a strong rationale for well-powered randomized placebo controlled intervention trials to be carried out in insulin resistant and diabetic populations.

The role of phytochemicals as micronutrients in health and disease

PURPOSE OF REVIEW

Intake of dietary phytochemicals has frequently been associated with health benefits. Noninfectious diseases including cardiovascular disease (CVD), cancer and diabetes are major causes of death, whereas dementia cases are also increasing to 'epidemic' proportion. This review will focus on recent progress on mechanisms underlying the potential role of dietary phytochemicals in CVD, diabetes, cancer and dementia, with consideration of the latest clinical data.

RECENT FINDINGS

The association of tea (Camellia sinensis), particularly catechins, with reported mechanistic effects for CVD, diabetes, cancer and cognition contributes to our understanding of the suggested benefits of tea consumption on health from limited and inconclusive clinical trial and epidemiological data. Resveratrol, which occurs in grapes (Vitis vinifera) and wine, and curcumin, a component of turmeric (Curcuma longa), are also emerging as potentially relevant to health, particularly for CVD and dementia, with some promising data also concluded for curcumin in cancer. Other phytochemicals mechanistically relevant for health include anthocyanins, isoflavones and glucosinolates, which are also discussed.

SUMMARY

Evidence for the role of phytochemicals in health and disease is growing, but associations between phytochemicals and disease need to be more firmly understood and established from more robust clinical data using preparations that have been phytochemically characterized.

Aging in blood vessels. Medicinal agents FOR systemic arterial hypertension in the elderly

Aging impairs blood vessel function and leads to cardiovascular disease. The mechanisms underlying the age-related endothelial, smooth muscle and extracellular matrix vascular dysfunction are discussed. Vascular dysfunction is caused by: (1) Oxidative stress enhancement. (2) Reduction of nitric oxide (NO) bioavailability, by diminished NO synthesis and/or augmented NO scavenging. (3) Production of vasoconstrictor/vasodilator factor imbalances. (4) Low-grade pro-inflammatory environment. (5) Impaired angiogenesis. (6) Endothelial cell senescence. The aging process in vascular smooth muscle is characterized by: (1) Altered replicating potential. (2) Change in cellular phenotype. (3) Changes in responsiveness to contracting and relaxing mediators. (4) Changes in intracellular signaling functions. Systemic arterial hypertension is an age-dependent disorder, and almost half of the elderly human population is hypertensive. The influence of hypertension on the aging cardiovascular system has been studied in models of hypertensive rats. Treatment for hypertension is recommended in the elderly. Lifestyle modifications, natural compounds and hormone therapies are useful for initial stages and as supporting treatment with medication but evidence from clinical trials in this population is needed. Since all antihypertensive agents can lower blood pressure in the elderly, therapy should be based on its potential side effects and drug interactions.