3-methylquercetin and Diabetes-Mellitus--Type-2

Diabetes mellitus, especially type 2 (T2DM), is a major public health problem globally. DM is characterized by high levels of glycemia and insulinemia due to impaired insulin secretion and insulin sensitivity of the cells, known as insulin resistance. T2DM causes multiple and severe complications such as nephropathy, neuropathy, and retinopathy causing cell oxidative damages in different internal tissues, particularly the pancreas, heart, adipose tissue, liver, and kidneys. Plant extracts and their bioactive phytochemicals are gaining interest as new therapeutic and preventive alternatives for T2DM and its associated complications. In this regard, isorhamnetin, a plant flavonoid, has long been studied for its potential anti-diabetic effects. This review describes its impact on reducing diabetes-related disorders by decreasing glucose levels, ameliorating the oxidative status, alleviating inflammation, and modulating lipid metabolism and adipocyte differentiation by regulating involved signaling pathways reported in the in vitro and in vivo studies. Additionally, we include a post hoc whole-genome transcriptome analysis of biological activities of isorhamnetin using a stem cell-based tool.

Topics: Animals; Diabetes Mellitus, Type 2; Gene Expression Profiling; Humans; Inflammation; Lipid Metabolism; Oxidative Stress; Quercetin

Type II-diabetes mellitus (TII-DM) has been regarded as one of the most important public health problems in all nations in the 21st century. Although allopathic therapies remain the most important for the initial management of TII-DM, herbal remedies have gained wide acceptance for treating this condition. These alternative therapies are particularly valued in countries such as Mexico, rich in medicinal plants strongly attached to the cultural values of the population. Medicinal plants are prized sources of α-glucosidase inhibitors, which delay the liberation of glucose from complex carbohydrates, retarding glucose absorption, and thus controlling the characteristic hyperglycemia of TII-DM. Among the plant species used for treating diabetes in Mexico only 38 have been analyzed for their inhibitory activity of α-glucosidases. Most of these studies, reviewed in the present work, have focused on the evaluation of different types of extracts on the activity of α-glucosidases from diverse sources. Four species have been thoroughly analyzed in order to discover novel α-glucosidase inhibitors, namely, Hintonia latiflora and Hintonia standleyana (Rubiaceae), Ligusticum porteri (Apiaceae), and Brickellia cavanillesii (Asteraceae). Their ethnomedical uses, pharmacological and toxicological studies, chemical composition, and antihyperglycemic principles with α-glucosidase inhibitory activity are summarized.

Topics: Diabetes Mellitus, Type 2; Glycoside Hydrolase Inhibitors; Hypoglycemic Agents; Mexico; Molecular Structure; Plants, Medicinal

Background: Isorhamnetin is a flavonoid that is found in medical plants. Several studies showed that isorhamnetin has anti-inflammatory and anti-obesity effects. This study aims to investigate the anti-diabetic effects of isorhamnetin in a high-fat diet and Streptozotocin-(HFD/STZ)-induced mice model of type 2 diabetes. Materials and Methods: Mice were fed with HFD followed by two consecutive low doses of STZ (40 mg/kg). HFD/STZ diabetic mice were treated orally with isorhamnetin (10 mg/kg) or (200 mg/kg) metformin for 10 days before sacrificing the mice and collecting plasma and soleus muscle for further analysis. Results: Isorhamnetin reduced the elevated levels of serum glucose compared to the vehicle control group (p < 0.001). Isorhamnetin abrogated the increase in serum insulin in the treated diabetic group compared to the vehicle control mice (p < 0.001). The homeostasis model assessment of insulin resistance (HOMA-IR) was decreased in diabetic mice treated with isorhamnetin compared to the vehicle controls. Fasting glucose level was significantly lower in diabetic mice treated with isorhamnetin during the intraperitoneal glucose tolerance test (IPGTT) (p < 0.001). The skeletal muscle protein contents of GLUT4 and p-AMPK-α were upregulated following treatment with isorhamnetin (p > 0.01). LDL, triglyceride, and cholesterol were reduced in diabetic mice treated with isorhamnetin compared to vehicle control (p < 0.001). Isorhamnetin reduced MDA, and IL-6 levels (p < 0.001), increased GSH levels (p < 0.001), and reduced GSSG levels (p < 0.05) in diabetic mice compared to vehicle control. Conclusions: Isorhamnetin ameliorates insulin resistance, oxidative stress, and inflammation. Isorhamnetin could represent a promising therapeutic agent to treat T2D.

Topics: Animals; Blood Glucose; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diet, High-Fat; Disease Models, Animal; Glucose; Hypoglycemic Agents; Inflammation; Insulin Resistance; Mice; Oxidative Stress; Streptozocin

We intended to examine the molecular mechanism of action of isorhamnetin (IHN) to regulate the pathway of insulin signaling. Molecular analysis, immunofluorescence, and histopathological examination were used to assess the anti-hyperglycemic and insulin resistance lowering effects of IHN in streptozotocin /high fat diet-induced type 2 diabetes using Wistar rats. At the microscopic level, treatment with IHN resulted in the restoration of myofibrils uniform arrangement and adipose tissue normal architecture. At the molecular level, treatment with IHN at three different doses showed a significant decrease in m-TOR, IGF1-R & LncRNA-RP11-773H22.4. expression and it up-regulated the expression of AKT2 mRNA, miR-1, and miR-3163 in both skeletal muscle and adipose tissue. At the protein level, IHN treated group showed a discrete spread with a moderate faint expression of m-TOR in skeletal muscles as well as adipose tissues. We concluded that IHN could be used in the in ameliorating insulin resistance associated with type 2 diabetes mellitus.

Topics: Adipose Tissue; Animals; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; MicroRNAs; Myofibrils; Proto-Oncogene Proteins c-akt; Quercetin; Rats, Wistar; Receptor, IGF Type 1; RNA, Long Noncoding; Signal Transduction; TOR Serine-Threonine Kinases

Polyphenols are phytochemicals that possess antioxidant and anti-inflammatory properties and improve glucose metabolism in animal experiments, although data from prospective epidemiologic studies examining polyphenol intakes in relation to type 2 diabetes (T2D) risk are inconsistent.. We examined urinary excretion of select flavonoid and phenolic acid metabolites, as biomarkers of intake, in relation to T2D risk.. Eight polyphenol metabolites (naringenin, hesperetin, quercetin, isorhamnetin, catechin, epicatechin, caffeic acid, and ferulic acid) were quantified in spot urine samples by liquid chromatography/mass spectrometry among 1111 T2D case-control pairs selected from the Nurses' Health Study (NHS) and NHSII.. Higher urinary excretion of hesperetin was associated with a lower T2D risk after multivariate adjustment: the OR comparing top vs. bottom quartiles was 0.68 (95% CI: 0.49, 0.96), although a linear trend was lacking (P = 0.30). The other measured polyphenols were not significantly associated with T2D risk after multivariate adjustment. However, during the early follow-up period [≤ 4.6 y (median) since urine sample collection], markers of flavanone intakes (naringenin and hesperetin) and flavonol intakes (quercetin and isorhamnetin) were significantly associated with a lower T2D risk. The ORs (95% CIs) comparing extreme quartiles were 0.61 (0.39, 0.98; P-trend: 0.03) for total flavanones and 0.55 (0.33, 0.92; P-trend: 0.04) for total flavonols (P-interaction with follow-up length: ≤ 0.04). An inverse association was also observed for caffeic acid during early follow-up only: the OR was 0.52 (95% CI: 0.32, 0.84; P-trend: 0.03). None of these markers was associated with T2D risk during later follow-up. Metabolites of flavan-3-ols and ferulic acid were not associated with T2D risk in either period.. These results suggest that specific flavonoid subclasses, including flavanones and flavonols, as well as caffeic acid, are associated with a lower T2D risk in relatively short-term follow-up but not during longer follow-up. Substantial within-person variability of the metabolites in single spot urine samples may limit the ability to capture associations with long-term disease risk.

Topics: Adult; Aged; Aged, 80 and over; Caffeic Acids; Case-Control Studies; Catechin; Coumaric Acids; Diabetes Mellitus, Type 2; Female; Flavanones; Follow-Up Studies; Hesperidin; Humans; Hydroxybenzoates; Middle Aged; Nutrition Assessment; Polyphenols; Prospective Studies; Quercetin; Risk Factors; Surveys and Questionnaires