Chlorogenic acid improves late diabetes through adiponectin receptor signaling pathways in db/db mice

Edgeworthia gardneri (Wall.) Meisn. Water Extract Ameliorates Palmitate Induced Insulin Resistance by Regulating IRS1/GSK3β/FoxO1 Signaling Pathway in Human HepG2 Hepatocytes

The flower of Edgeworthia gardneri (Wall.) Meisn is commonly used in beverage products in Tibet and has potential health benefits for diabetes. However, the mechanisms underlying anti-insulin resistance (IR) action of the flower of E. gardneri are not fully understood. This study aims to investigate the effects of the water extract of the flower of E. gardneri (WEE) on IR in palmitate (PA)-exposed HepG2 hepatocytes. WEE was characterized by UPLC analysis. PA-treated HepG2 cells were selected as the IR cell model. The cell viability was determined using MTT assay. Moreover, the glucose consumption and production were measured by glucose oxidase method. The glucose uptake and glycogen content were determined by the 2-NBDG (2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl) amino]-D-glucose) glucose uptake assay and anthrone-sulfuric acid assay, respectively. The intracellular triglyceride content was detected by oxidative enzymic method. Protein levels were examined by Western blotting. Nuclear localization of FoxO1 was detected using immunofluorescence analyses and Western blotting. The expression of FoxO1 target genes was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The viability of PA-treated HepG2 cells was concentration-dependently increased by incubation with WEE for 24 h. WEE treatment remarkably increased the consumption and uptake of glucose in PA-exposed HepG2 cells. Moreover, treatment with WEE significantly decreased the PA-induced over-production of glucose in HepG2 cells. After exposure of HepG2 cells with PA and WEE, the glycogen content was significantly elevated. The phosphorylation and total levels of IRβ, IRS1, and Akt were upregulated by WEE treatment in PA-exposed HepG2 cells. The phosphorylation of GSK3β was elevated after WEE treatment in PA-treated cells. WEE treatment also concentration-dependently downregulated the phosphorylated CREB, ERK, c-Jun, p38 and JNK in PA-exposed HepG2 cells. Furthermore, the nuclear protein level and nuclear translocation of FoxO1 were also suppressed by WEE. Additionally, PA-induced changes of FoxO1 targeted genes were also attenuated by WEE treatment. The GLUT2 and GLUT4 translocation were also promoted by WEE treatment in PA-treated HepG2 cells. Taken together, WEE has potential anti-IR effect in PA-exposed HepG2 cells; the underlying mechanism of this action may be associated with the regulation of IRS1/GSK3β/FoxO1 signaling pathway. This study provides a pharmacological basis for the application of WEE in the treatment of metabolic diseases such as type 2 diabetes mellitus.

Hypoglycemic effects of phenolic compound-rich aqueous extract from water dropwort (Oenanthe javanica DC.) on streptozotocin-induced diabetic mice

Phenolic compounds in water dropwort aqueous extract were identified, and the IRS-2/PI3K-AKT pathway and GLUT4 translocation were regulated for hypoglycemic action.

Beneficial effects of combination therapy of phloretin and metformin in streptozotocin-induced diabetic rats and improved insulin sensitivity in vitro

Phloretin combined with metformin ameliorates glucose and lipid metabolism in STZ-induced T2D rats via AKT/GLUT4 signaling pathways.

Regulation of growth performance and lipid metabolism in juvenile grass carp (Ctenopharyngodon idella) with honeysuckle (Lonicera japonica) extract

This study investigated the effects of honeysuckle extract (Lonicera japonica, HE) on the growth performance and lipid metabolism of juvenile grass carp (Ctenopharyngodon idella). HE at doses of 10 g kg^-1 (LHE), 20 g kg^-1 (MHE), and 40 g kg^-1 (HHE) were individually mixed with the basal diet and fed to grass carp for 10 weeks, and ginseng extract (20 g kg^-1, GSE) was used as a positive control. The results showed that HE administration exerted no effect on growth performance, but the hepatosomatic index (HSI) and muscle and liver lipid contents were significantly decreased in the LHE and MHE groups. The serum levels of LDL-c, total triglyceride (TG) and total cholesterol (TC) also declined in the HE-treated groups. Moreover, the disordered vacuolization and nucleus migration in the liver were alleviated in the MHE and HHE groups, and mRNA expressions of lipogenesis-related genes, such as acc1, fas, srebp1, and pparγ decreased. Similarly, the expression of genes related to lipolysis, such as cpt1, atgl, lpl, and pparα, was found to be significantly increased in the MHE and HHE groups compared with the control. Taken together, HE can effectively improve the lipid metabolism and ameliorate the lipid deposition of grass carp and thus may be a promising feed additive in aquaculture.

Potential nutraceutical and food additive properties and risks of coffee: a comprehensive overview

Coffee is a composite mixture of more than a thousand diverse phytochemicals like alkaloids, phenolic compounds, vitamins, carbohydrates, lipids, minerals and nitrogenous compounds. Coffee has multifunctional properties as a food additive and nutraceutical. As a nutraceutical, coffee has anti-inflammatory, anti-oxidant, antidyslipidemic, anti-obesity, type-2 diabetes mellitus (DM), and cardiovascular diseases (CVD), which can serve for the treatment and prevention of metabolic syndrome and associated disorders. On the other hand, as a food additive, coffee has antimicrobial activity against a wide range of microorganisms, inhibits lipid peroxidation (LPO), and can function as a prebiotic. The outcomes of different studies also revealed that coffee intake may reduce the incidence of numerous chronic diseases, like liver disease, mental health, and it also overcomes the all-cause mortality, and suicidal risks. In some studies, high intake of coffee is linked to increase CVD risk factors, like cholesterol, plasma homocysteine and blood pressure (BP). There is also a little evidence that associated the coffee consumption with increased risk of lung tumors in smokers. Among adults who consume the moderate amount of coffee, there is slight indication of health hazards with strong indicators of health benefits. Moreover, existing literature suggests that it may be cautious for pregnant women to eliminate the chances of miscarriages and impaired fetal growth. The primary purpose of this narrative review is to provide an overview of the findings of the positive impacts and risks of coffee consumption on human health. In conclusion, to date, the best available evidence from research indicates that drinking coffee up to 3-4 cups/day provides health benefits for most people.

Collaborative effects of chlorogenic acid and caffeine on lipid metabolismviathe AMPKα-LXRα/SREBP-1c pathway in high-fat diet-induced obese mice

The combination of CGA and caffeine exhibits anti-obesity effects and regulates lipid metabolismviathe AMPKα-LXRα/SREBP-1c signaling pathway in mice with high-fat diet-induced obesity.

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.

Effects of green coffee extract supplementation on anthropometric indices, glycaemic control, blood pressure, lipid profile, insulin resistance and appetite in patients with the metabolic syndrome: a randomised clinical trial

This study was conducted to elucidate the effects of decaffeinated green coffee bean extract (GCE) on anthropometric indices, glycaemic control, blood pressure, lipid profile, insulin resistance and appetite in patients with the metabolic syndrome (Mets). Subjects were randomly allocated to consume 400 mg GCE or placebo capsules twice per d for 8 weeks. Both groups were advised to follow an energy balanced diet. After GCE supplementation, systolic blood pressure (SBP) significantly reduced compared with the placebo group (−13·76 (sd 8·48) v. −6·56 (sd 9·58) mmHg, P=0·01). Also, GCE treatment significantly reduced fasting blood glucose (FBS) (−5·15 (sd 60·22) v. 29·42 (sd 40·01) mg/dl (−0·28 (SD 3·34) v. 1·63 (SD 2·22) mmol/l); P=0·03) and homoeostatic model of assessment of insulin resistance in comparison to placebo (−1·41 (sd 3·33) v. 1·23 (sd 3·84), P=0·02). In addition, waist circumference (−2·40 (sd 2·54) v. −0·66 (sd 1·17) cm, P=0·009) and appetite score (−1·44 (sd 1·72) v. −0·2 (sd 1·32), P=0·01) of the individuals supplemented with GCE indicated a significant decline. Besides, weight and BMI reduction in the intervention group was almost twice as much as the placebo group; however, this discrepancy was marginally significant (weight: −2·08 (sd 2·11) v. −0·92 (sd 1·30) kg, P=0·05). No difference was observed in terms of glycated Hb (HbA1c) percentage and lipid profile parameters between the two groups. To sum up, GCE administration had an ameliorating effect on some of the Mets components such as high SBP, high FBS and Mets main aetiological factors including insulin resistance and abdominal obesity. Furthermore, GCE supplementation could reduce appetite level.

Chlorogenic Acid: The Conceivable Chemosensitizer Leading to Cancer Growth Suppression

New paradigm in cancer pathogenesis revealed that microenvironmental conditions significantly contribute to cancer. Hence, Warburg stated that cancer is a metabolic disease. Chlorogenic acid (CGA) is a polyphenol that is found abundantly in coffee. This compound has proven ability in ameliorating some metabolic diseases through various pathways. This article will elaborate the potency of CGA as a chemosensitizer in suppressing tumor growth through a metabolic pathway. AMPK pathway is the main cell metabolic pathway that is activated by CGA in some studies. Moreover, CGA inhibited EGFR/PI3K/mTOR, HIF, VEGF pathways and MAPK/ERK pathway that may suppress tumor cell growth. Furthermore, CGA induced intracellular DNA damage and topoisomerase I- and II-DNA complexes formation that plays a key role in apoptosis. Conclusively, based on the ability of CGA in activate and inhibit some important pathways in cancer metabolism, it may act as a chemosensitizing agent leading to cancer growth suppression.

Effect of Chlorogenic Acid Administration on Glycemic Control, Insulin Secretion, and Insulin Sensitivity in Patients with Impaired Glucose Tolerance

Chlorogenic acid has been described as a novel polyphenol with metabolic effects on glucose homeostasis. The aim of this study was to evaluate the effect of chlorogenic acid administration on glycemic control, insulin secretion, and insulin sensitivity in patients with impaired glucose tolerance (IGT). A randomized, double-blind, placebo-controlled clinical trial was performed in 30 patients with IGT; 15 patients randomly assigned to oral chlorogenic acid received 400 mg three times per day for 12 weeks, and the other 15 patients received placebo in the same way. Before and after the intervention, anthropometric and metabolic measurements, including fasting plasma glucose (FPG), glycated hemoglobin A1c, and a lipid profile, were performed. Area under the curve of glucose and insulin as well as the insulinogenic, Stumvoll, and Matsuda indices were calculated. Wilcoxon, Mann-Whitney U, and chi-square tests were performed, and P ≤ .05 was considered statistically significant. There were significant decreases in FPG (5.7 ± 0.4 vs. 5.5 ± 0.4 mmol/L, P = .002), insulinogenic index (0.71 ± 0.25 vs. 0.63 ± 0.25, P = .028), body weight, body mass index, waist circumference, triglycerides, total cholesterol, low-density lipoprotein cholesterol, and very low-density lipoprotein levels in the chlorogenic acid group, with an increment in the Matsuda index (1.98 ± 0.88 vs. 2.30 ± 1.23, P = .002). There were no significant differences in the placebo group. In conclusion, chlorogenic acid administration in patients with IGT decreased FPG and insulin secretion, while increasing insulin sensitivity and improving both anthropometric evaluations and the lipid profile.

Chlorogenic acid (CGA): A pharmacological review and call for further research

Phenolic acids have recently gained substantial attention due to their various practical, biological and pharmacological effects. Chlorogenic Acid (CGA, 3-CQA) is a most abundant isomer among caffeoylquinic acid isomers (3-, 4-, and 5-CQA), that currently known as 5-CQA as per guidelines of IUPAC. It is one of the most available acids among phenolic acid compounds which can be naturally found in green coffee extracts and tea. CGA is an important and biologically active dietary polyphenol, playing several important and therapeutic roles such as antioxidant activity, antibacterial, hepatoprotective, cardioprotective, anti-inflammatory, antipyretic, neuroprotective, anti-obesity, antiviral, anti-microbial, anti-hypertension, free radicals scavenger and a central nervous system (CNS) stimulator. In addition, it has been found that CGA could modulate lipid metabolism and glucose in both genetically and healthy metabolic related disorders. It is speculated that CGA can perform crucial roles in lipid and glucose metabolism regulation and thus help to treat many disorders such as hepatic steatosis, cardiovascular disease, diabetes, and obesity as well. Furthermore, this phenolic acid (CGA) causes hepatoprotective effects by protecting animals from chemical or lipopolysaccharide-induced injuries. The hypocholesterolemic influence of CGA can result from the altered metabolism of nutrients, including amino acids, glucose and fatty acids (FA). The purpose of this review was to broaden the scope of knowledge of researchers to conduct more studies on this subject to both unveil and optimize its biological and pharmacological effects. As a result, CGA may be practically used as a natural safeguard food additive to replace the synthetic antibiotics and thereby reduce the medicinal cost.

Restoration of plasma markers of liver and kidney functions/integrity in alloxan-induced diabetic rabbits by aqueous extract of Pleurotus tuberregium sclerotia

The effect of aqueous extract of the sclerotia of Pleurotus tuberregium on the plasma electrolytes, and markers of liver and kidney functions/integrity of normal and alloxan-induced rabbits was investigated. Diabetes mellitus was induced by injection of alloxan (120mg/kg body weight), via the marginal ear vein. The extract was administered orally at 100, 200 and 300mg/kg (both to normal and diabetic rabbits), and metformin at 50mg/kg. Gas chromatographic-flame ionization detector analysis of the extract revealed the presence of twelve known phenolic acids, consisting mainly of caffeic acid (80.24%), chlorogenic acid (11.08%), piperic acid (6.11%), sinapinic acid (2.14%) and ferulic acid (0.34%). Compared to test control, the treatment significantly (p<0.05) lowered plasma activities of alkaline phosphatase, gamma glutamyltransferase, and alanine and aspartate transaminases. Also lowered were plasma unconjugated/conjugated bilirubin ratio and concentrations of urea, blood urea nitrogen, creatinine, sodium, and total and unconjugated bilirubin. It however, significantly (p<0.05) raised plasma potassium and calcium levels. Therefore, the modulation of plasma sodium and potassium is an indication of the diuretic potential of the extract. In addition, the extract had no deleterious effect on the liver and kidney of the treated animals, at least at the doses administered in this study.

Analytical Method for the Validation of Three Polyphenols as a Marker Compound for the Standardization of Solidago virgaurea subsp. gigantea Extracts and Antiadipogenesis of Harvesting Time and Location

Protocatechuic acid (PC), chlorogenic acid (CA), and kaempferol-3-O-rutinoside (K-O-R), isolated from the Solidago virgaurea subsp. gigantea (SV) extract, were quickly and efficiently separated using HPLC. Our chromatographic method was found to effectively separate PC, CA, and K-O-R at retention times of 5.36, 8.22, and 17.04 min, respectively. Linearity of PC, CA, and K-O-R was found to be in the range of 4.85-485.00, 47.5-1900.00, and 8.50-850.00 μg/ml. Recoveries ranged between 101.32 and 103.30%, 95.82 and 100.25%, and 96.18 and 99.37%, for PC, CA, and K-O-R, respectively. The antiadipogenesis activity of SV extracts collected from five different months and from seven different regions was evaluated using an Oil Red O staining assay in 3T3-L1 cells. Extract from SV collected in April from the Ulleung Island produced over 106.89% inhibition of adipogenesis without cytotoxicity at 50 μg/ml. This extract had a high amount of PC and K-O-R. The developed HPLC method was found to be fast, accurate, precise, and reproducible and could be applied to qualitative and quantitative analysis of three bioactive compounds in SV extracts. The SV extract collected in April from Ulleung Island can be used as a functional food ingredient preventing obesity.

Gene-Diet Interactions in Type 2 Diabetes: The Chicken and Egg Debate

Consistent evidence from both experimental and human studies indicates that Type 2 diabetes mellitus (T2DM) is a complex disease resulting from the interaction of genetic, epigenetic, environmental, and lifestyle factors. Nutrients and dietary patterns are important environmental factors to consider in the prevention, development and treatment of this disease. Nutritional genomics focuses on the interaction between bioactive food components and the genome and includes studies of nutrigenetics, nutrigenomics and epigenetic modifications caused by nutrients. There is evidence supporting the existence of nutrient-gene and T2DM interactions coming from animal studies and family-based intervention studies. Moreover, many case-control, cohort, cross-sectional cohort studies and clinical trials have identified relationships between individual genetic load, diet and T2DM. Some of these studies were on a large scale. In addition, studies with animal models and human observational studies, in different countries over periods of time, support a causative relationship between adverse nutritional conditions during in utero development, persistent epigenetic changes and T2DM. This review provides comprehensive information on the current state of nutrient-gene interactions and their role in T2DM pathogenesis, the relationship between individual genetic load and diet, and the importance of epigenetic factors in influencing gene expression and defining the individual risk of T2DM.

Chlorogenic Acid: Recent Advances on Its Dual Role as a Food Additive and a Nutraceutical against Metabolic Syndrome

Chlorogenic acid (5-O-caffeoylquinic acid) is a phenolic compound from the hydroxycinnamic acid family. This polyphenol possesses many health-promoting properties, most of them related to the treatment of metabolic syndrome, including anti-oxidant, anti-inflammatory, antilipidemic, antidiabetic, and antihypertensive activities. The first part of this review will discuss the role of chlorogenic acid as a nutraceutical for the prevention and treatment of metabolic syndrome and associated disorders, including in vivo studies, clinical trials, and mechanisms of action. The second part of the review will be dealing with the role of chlorogenic acid as a food additive. Chlorogenic acid has shown antimicrobial activity against a wide range of organisms, including bacteria, yeasts, molds, viruses, and amoebas. These antimicrobial properties can be useful for the food industry in its constant search for new and natural molecules for the preservation of food products. In addition, chlorogenic acid has antioxidant activity, particularly against lipid oxidation; protective properties against degradation of other bioactive compounds present in food, and prebiotic activity. The combination of these properties makes chlorogenic acid an excellent candidate for the formulation of dietary supplements and functional foods.

Catechol Groups Enable Reactive Oxygen Species Scavenging-Mediated Suppression of PKD-NFkappaB-IL-8 Signaling Pathway by Chlorogenic and Caffeic Acids in Human Intestinal Cells

Chlorogenic acid (CHA) and caffeic acid (CA) are phenolic compounds found in coffee, which inhibit oxidative stress-induced interleukin (IL)-8 production in intestinal epithelial cells, thereby suppressing serious cellular injury and inflammatory intestinal diseases. Therefore, we investigated the anti-inflammatory mechanism of CHA and CA, both of which inhibited hydrogen peroxide (H₂O₂)-induced IL-8 transcriptional activity. They also significantly suppressed nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcriptional activity, nuclear translocation of the p65 subunit, and phosphorylation of IκB kinase (IKK). Additionally, upstream of IKK, protein kinase D (PKD) was also suppressed. Finally, we found that they scavenged H₂O₂-induced reactive oxygen species (ROS) and the functional moiety responsible for the anti-inflammatory effects of CHA and CA was the catechol group. Therefore, we conclude that the presence of catechol groups in CHA and CA allows scavenging of intracellular ROS, thereby inhibiting H₂O₂-induced IL-8 production via suppression of PKD-NF-κB signaling in human intestinal epithelial cells.

Phloretin exerts hypoglycemic effect in streptozotocin-induced diabetic rats and improves insulin resistance in vitro

The present study investigated the possible antiobesity and hypoglycemic effects of phloretin (Ph). In an attempt to discover the hypoglycemic effect and potential mechanism of Ph, we used the streptozotocin-induced diabetic rats and (L6) myotubes. Daily oral treatment with Ph for 4 weeks significantly (P<0.05) reduced postprandial blood glucose and improved islet injury and lipid metabolism. Glucose consumption and glucose tolerance were improved by Ph via GOD–POD method. Western blot results revealed that the expression of Akt, PI3K, IRS-1, and GLUT4 were upregulated in skeletal muscle of type 2 diabetes (T2D) rats and in L6 myotubes by Ph. The immunofluorescence studies confirmed that Ph improved the translocation of GLUT4 in L6 myotubes. Ph exerted hypoglycemic effects in vivo and in vitro, hence it may play an important role in the management of diabetes.

Dodeca-2(E),4(E)-dienoic acid isobutylamide enhances glucose uptake in 3T3-L1 cells via activation of Akt signaling

Dodeca-2(E),4(E)-dienoic acid isobutylamide (DDI), an alkamide derived from the plant Echinacea purpurea, promotes adipocyte differentiation and activates peroxisome proliferator-activated receptor γ, which is associated with enhanced insulin sensitivity. In the present study, we investigated whether DDI may increase glucose uptake through activation of the insulin signaling pathway in 3T3-L1 adipocytes. DDI increased insulin-stimulated glucose uptake, and expression and translocation of glucose transporter 4 in adipocytes treated with sub-optimal levels of insulin. Additionally, DDI enhanced Akt phosphorylation, whereas phosphoinositide 3-kinase/Akt inhibitors suppressed DDI-induced glucose uptake. These results suggest that DDI may improve insulin sensitivity through the activation of Akt signaling, which leads to enhanced glucose uptake.

Plasma concentrations of coffee polyphenols and plasma biomarkers of diabetes risk in healthy Japanese women

Coffee consumption has been reported to reduce the risk of type 2 diabetes in experimental and epidemiological studies. This anti-diabetic effect of coffee may be attributed to its high content in polyphenols especially caffeic acid and chlorogenic acid. However, the association between plasma coffee polyphenols and diabetic risks has never been investigated in the literature. In this study, fasting plasma samples were collected from 57 generally healthy females aged 38-73 (mean 52, s.d. 8) years recruited in Himeji, Japan. The concentrations of plasma coffee polyphenols were determined by liquid chromatography coupled with mass tandem spectrometer. Diabetes biomarkers in the plasma/serum samples were analysed by a commercial diagnostic laboratory. Statistical associations were assessed using Spearman's correlation coefficients. The results showed that plasma chlorogenic acid exhibited negative associations with fasting blood glucose, glycated hemoglobin and C-reactive protein, whereas plasma total coffee polyphenol and plasma caffeic acid were weakly associated with these biomarkers. Our preliminary data support previous findings that coffee polyphenols have anti-diabetic effects but further replications with large samples of both genders are recommended.