Using Bitter Melon to Treat Diabetes

Saponins from Momordica charantia exert hypoglycemic effect in diabetic mice by multiple pathways

The antidiabetic activity of saponins extracted from Momordica charantia (MCS) on streptozotocin-induced diabetic mice was investigated in order to elucidate the mechanism of MCS for exerting hypoglycemic effects. Saponins were first extracted from M. charantia L. and their composition was analyzed. The diabetic Kunming mice were fed low-dose saponins from M. charantia L. and high-dose MCS, using normal mice and diabetic mice as controls. Body weight, blood glucose level, oral glucose tolerance, serum C-peptide level, hepatic antioxidant capacity, hepatic glycogen and hexokinase in liver tissues, serum blood lipid level, and alpha-glucosidase activity in small intestines were measured, and microstructure of pancreatic islet was analyzed. The results showed that the total content of seven triterpenoid compounds in MCS was 18.24 μg/mg, with Momordicoside K having the highest content at 11.66 μg/mg. Diabetic mice treated with MCS at 100 and 200 mg/kg body weight daily for 30 days showed a maximum glucose reduction (p < .05) of 12.63% and 26.47%, respectively. MCS significantly decreased levels of postprandial hyperglycemia, serum lipid, α-glucosidase activity, and liver malondialdehyde. Additionally, levels of serum C-peptide and liver glycogen, as well as hexokinase and antioxidant enzyme activity, were significantly increased compared to the diabetic control groups. Histopathological results showed that MCS markedly reduced degenerative changes in islet β-cells. It is concluded that MCS exerts antidiabetic effects by improved hypoglycemic, hypolipidemic, and antioxidant effects, increased hexokinase activity and glycogen synthesis, and enhanced reparative effects on the histological architecture and insulin secretion function of the pancreas.

Jayaprakasha G, S. Patil B. Anti-Inflammatory, Antidiabetic Properties and In Silico Modeling of Cucurbitane-Type Triterpene Glycosides from Fruits of an Indian Cultivar of Momordica charantia L

Diabetes mellitus is a chronic disease and one of the fastest-growing health challenges of the last decades. Studies have shown that chronic low-grade inflammation and activation of the innate immune system are intimately involved in type 2 diabetes pathogenesis. Momordica charantia L. fruits are used in traditional medicine to manage diabetes. Herein, we report the purification of a new 23-O-β-d-allopyranosyl-5β,19-epoxycucurbitane-6,24-diene triterpene (charantoside XV, 6) along with 25ξ-isopropenylchole-5(6)-ene-3-O-β-d-glucopyranoside (1), karaviloside VI (2), karaviloside VIII (3), momordicoside L (4), momordicoside A (5) and kuguaglycoside C (7) from an Indian cultivar of Momordica charantia. At 50 µM compounds, 2–6 differentially affected the expression of pro-inflammatory markers IL-6, TNF-α, and iNOS, and mitochondrial marker COX-2. Compounds tested for the inhibition of α-amylase and α-glucosidase enzymes at 0.87 mM and 1.33 mM, respectively. Compounds showed similar α-amylase inhibitory activity than acarbose (0.13 mM) of control (68.0–76.6%). Karaviloside VIII (56.5%) was the most active compound in the α-glucosidase assay, followed by karaviloside VI (40.3%), while momordicoside L (23.7%), A (33.5%), and charantoside XV (23.9%) were the least active compounds. To better understand the mode of binding of cucurbitane-triterpenes to these enzymes, in silico docking of the isolated compounds was evaluated with α-amylase and α-glucosidase.

Effects of 22 traditional anti-diabetic medicinal plants on DPP-IV enzyme activity and glucose homeostasis in high-fat fed obese diabetic rats

The present study investigated the effects of hot water extracts of 22 medicinal plants used traditionally to treat diabetes on Dipeptidyl peptidase-IV (DPP-IV) activity both in vitro and in vivo in high-fat fed (HFF) obese-diabetic rats. Fluorometric assay was employed to determine the DPP-IV activity. For in vivo studies, HFF obese-diabetic rats were fasted for 6 h and blood was sampled at different times before and after the oral administration of the glucose alone (18 mmol/kg body weight) or with either of the four most active plant extracts (250 mg/5 ml/kg, body weight) or established DPP-IV inhibitors (10 μmol/5 ml/kg). DPP-IV inhibitors: sitagliptin, vildagliptin and diprotin A, decreased enzyme activity by a maximum of 95-99% (P<0.001). Among the 22 natural anti-diabetic plants tested, AnogeissusLatifolia exhibited the most significant (P<0.001) inhibitory activity (96 ± 1%) with IC50 and IC25 values of 754 and 590 μg/ml. Maximum inhibitory effects of other extracts: Aegle marmelos, Mangifera indica, Chloropsis cochinchinensis, Trigonella foenum-graecum and Azadirachta indica were (44 ±7%; 38 ± 4%; 31±1%; 28±2%; 27±2%, respectively). A maximum of 45% inhibition was observed with >25 μM concentrations of selected phytochemicals (rutin). A.latifolia, A. marmelos, T. foenum-graecum and M. indica extracts improved glucose tolerance, insulin release, reduced DPP-IV activity and increased circulating active GLP-1 in HFF obese-diabetic rats (P<0.05-0.001). These results suggest that ingestion of selected natural anti-diabetic plants, in particular A. latifolia, A. marmelos, T. foenum-graecum and M. indica can substantially inhibit DPP-IV and improve glucose homeostasis, thereby providing a useful therapeutic approach for the treatment of T2DM.

Health Beliefs and Practices of African Immigrants in Canada

A purposive sample of 14 immigrants living in Ontario, Canada, participated in two focus groups. The researchers used semi-structured interviews to collect data and five themes emerged from the data: beliefs about diabetes were centered on diverse factors, preserving culture through food preferences and preparation, cultural practices to stay healthy, cultural practices determined number of servings of fruit and vegetables per day, and engaging in physical activity to stay healthy. Findings indicated how health beliefs and cultural practices influenced behavior in preventing type 2 diabetes (T2D). Future research should focus on other high-risk minority groups (South Asian, Caribbean, and Latin American) to examine their health beliefs and cultural practices and use these finding to develop best practice guidelines, which should be incorporated into culturally tailored interventions.

Bitter melon extracts in diabetic and normal rats favorably influence blood glucose and blood pressure regulation

Bitter melon (BM) was tested in normal and streptozotocin (STZ)-induced diabetic rats. First, normal and diabetic Wistar rats were given four test extracts (EX-1-EX-4) of a wild-genotype BM or metformin by intubation. Second, normal Sprague-Dawley rats were divided into control and three test groups given for 52 days one of three BM preparations in food: Chinese or Indian commercial preparations or EX-4 from experiment I. In experiment I, extracts of BM administered at 50 mg/kg of body weight in normal rats reduced blood sugar for 4 hours without, unlike metformin, inducing hypoglycemia. In STZ-induced diabetic rats, two extracts administered at 250 mg/kg decreased glucose levels to values comparable to metformin at 150 mg/kg. At 4 hours, EX-1 and EX-4 significantly reduced blood glucose 67% and 63%, respectively, compared with metformin's 54%. In experiment II, all test groups had lowered systolic, but not diastolic, blood pressure. The China and EX-4 arms had significantly lowered serum glucose levels compared with the control. In the glucose tolerance test, only EX-4 had significantly lowered glucose levels. Only EX-4 had significantly lowered angiotensin converting enzyme (ACE) activity. All active arms showed significance in the losartan challenge (the renin-angiotensin system [RAS]), with the greatest effect in the EX-4 group. In the N(ω)-nitro-l-arginine-methyl ester challenge, only EX-4 exhibited a significant impact on the nitric oxide system, suggesting higher activity in this group. In the STZ-induced diabetic rat model, wild-type BM powerfully lowered glucose levels, and, in healthy adult rats, wild-type BM exhibited beneficial effects in the regulation of blood glucose, in RAS and ACE inhibition, and in nitric oxide generation.