Extracts of Momordica charantia suppress postprandial hyperglycemia in rats

A randomized, double-blind clinical trial of a herbal formulation (GlycaCare-II) for the management of type 2 diabetes in comparison with metformin

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a major public health concern with growing prevalence with multiple debilitating complications. GlycaCare-II is a proprietary herbal formulation supplement for T2DM containing extracts of Cinnamomum cassia, Momordica charantia, Pterocarpus marsupium, Gymnema sylvestre, Salacia reticulata, Eugenia jambolana, and a bioavailability enhancer piperine from Piper nigrum.

OBJECTIVE

The antihyperglycemic potential of GlycaCare-II was compared against metformin in a double-blind study.

DESIGN

It was a randomized, two-arm design on prediabetic (N = 29; 12 in metformin and 17 in GlycaCare-II arm, respectively) and newly diagnosed diabetic (N = 40; 16 in metformin and 24 in GlycaCare-II) patients for 120 days.

OUTCOME MEASURES

Changes in diabetic panel glycosylated hemoglobin (HbA1c), fasting blood sugar (FBS), and postprandial blood sugar (PBS) were the primary endpoints. Lipid profile, liver profile, thyroid-stimulating hormone, bilirubin and creatinine were the secondary endpoints.

RESULT

Twice a day treatment for 120 days with GlycaCare-II led to a statistically significant change in HbA1c (p < 0.001), FBS (p < 0.001), PBS (p < 0.001) on both prediabetic and newly diagnosed diabetic patients. GlycaCare-II showed a similar potential as metformin in the treatment of T2DM. In the prediabetic group, both GlycaCare-II and metformin were comparable for all the hyperglycemic index parameters. In the case of newly diagnosed diabetic patients, GlycaCare-II showed a significantly better reduction for PBS (p = 0.026) as compared to metformin, while all other parameters in the diabetic panel were comparable. No adverse events were reported throughout the trial period.

CONCLUSION

These results suggest that GlycaCare-II is effective in managing T2DM in both newly diagnosed diabetic and prediabetic patients.

Isolation and Structural Elucidation of Novel Antidiabetic Compounds from Leaves of Momordica balsamina Linn and Leptadenia hastata (Pers) Decne

The antihyperglycemic effect of the polyherbal combination of the leaves of Momordica balsamina Linn (MB) and Leptadenia hastata (pers) Decne (LH) have been reported in our previous study in addition to its documented dietary usages. However, the bioactive principles are yet to be fully elucidated. In the present study, bioactive antidiabetic compounds from the leaf extracts of Momordica balsamina Linn and Leptadenia hastata (pers) Decne were isolated and characterized. The plant leaves were fractionated with solvents in ascending order of polarity (hexane-chloroform-ethylacetate-methanol) using microwave assisted extraction method. The ethylacetate (MBE) and methanolic (LHM) leaf extracts of MB and LH, having the highest antihyperglycemic effects were purified by column chromatography and preparative thin layer chromatography. The antihyperglycemic activity of the isolated compounds was evaluated in streptozotocin (STZ)-induced diabetic rats and the structures of the most bioactive compounds were elucidated by ¹H and ¹³C Nuclear Magnetic Resonance (NMR) spectroscopy in comparison with reported literature. A pentacyclic triterpenoid (H3) and an isoflavone (LH2b) isolated from MBE and LHM with significant (p < 0.05) antihyperglycemic effects were identified as betulinic acid and 5-methyl genistein respectively. Our study isolated for the first time a triterpenoid and an isoflavone with potential antidiabetic effects from these indigenous antidiabetic plants. This further validates the traditional multi-therapeutic usage of the combination for the management of Diabetes Mellitus (DM) and its complications.

Bioanalytical method development for momordicinin and its application to long-term pharmacokinetics in diabetic rats

OBJECTIVE

To develop and validate bioanalytical RP-HPLC method to evaluate pharmacokinetics and tissue distribution pattern of momordicinin (MRN).

SIGNIFICANCE

MRN is one of the major cucurbitane triterpenoid found in Momordica charantia Linn (MC). However, MRN has not been explored for its pharmacokinetic profile, tissue distribution, and stability in order to establish it as an antidiabetic agent.

METHODS

In 28 days pharmacokinetic study, 54 diabetic male wistar rats were divided into three different groups and administered with 25, 50, and 100 mg/kg MRN orally. The blood samples were collected at 1, 7, 14, 21, and 28th day of the treatment and plasma quantification of MRN was done by validated RP-HPLC method. The rats were sacrificed at end of the study for tissue distribution.

RESULTS

The developed method was successfully applied to investigate pharmacokinetic profile of MRN. In pharmacokinetic analysis, the C_max for 25, 50, and 100 mg/kg was found to be 8.412, 10.443, and 11.829 µg/mL respectively suggesting the dose dependent activity. The maximum plasma concentration was achieved at 2 h for all doses. MRN showed major distribution in liver followed by kidney, spleen, and pancreas.

CONCLUSION

The newly developed and validated method was used to assay MRN in plasma as well as in tissues to evaluate pharmacokinetics of the drug for the first time. Undoubtedly, these findings can be taken into consideration while concluding its therapeutic effects after oral administration.

Double emulsion-based mayonnaise encapsulated with bitter gourd extract exhibits improvement in vivo anti-diabetic action in STZ induced rats

Bitter gourd contains charantin (steroidal saponins), insulin-like peptides, and alkaloids, which contribute to its hypoglycemic ability. The study aims to evaluate effects of anti-diabetic potential of bitter gourd (Momordica charantia) encapsulated double emulsion-based functional mayonnaise on the normal and streptozotocin-induced type 2 diabetes in albino male Wister rats. The rats were allocated into seven groups: a control group fed with synthetic diet (NC), two non-diabetic groups (NCM and NFM) and four diabetic-induced groups (DC, DCM, DFM, and DCMB) for 8 weeks and then analyzed for the various biochemical parameters. The results of this study revealed significant (p < 0.05) anti-diabetic potential in streptozotocin-induced diabetic male albino Wistar rats with decrease in blood glucose and HbA1c, increase in body weight, hemoglobin, and plasma insulin.

Exploring the inhibitory potentials of Momordica charantia bioactive compounds against Keap1-Kelch protein using computational approaches

The search for Keap1 inhibitors as potential Nrf2 activator is a way of increasing the antioxidant status of the human cellular environ. In this research, we used in silico methods to investigate Keap1-kelch inhibitory potential of Momordica charantia's bioactive compounds in order to predict their Nrf2 activating potential. ADMET profiling, physicochemical properties, molecular docking, molecular dynamics, and Molecular Mechanics-Poisson Boltzmann Surface Area (g_MMPBSA) free energy calculation studies were executed to drive home our aim. Out of all the bioactive compounds of Momordica charantia, catechin (CAT) and chlorogenic acid (CGA) were selected based on their ADMET profile, physicochemical properties, and molecular docking analysis. Molecular docking studies of CAT and CGA to Keap1 kelch domain showed that they have - 9.2 kJ/mol and - 9.1 kJ/mol binding energies respectively with CAT having four hydrogen bond interactions with Keap1 while CGA had three. Analysis after the 30 ns molecular dynamics simulation revealed that CAT and CGA were both stable, although with minimal conformational alterations at the kelch pocket of Keap1. Finally, MMPBSA calculation of the Gibbs free energy of each amino acid interaction with CAT and CGA revealed that CAT had a higher total binding energy than CGA. Therefore, the Keap1 inhibitory capacities and the molecular dynamic characters of CAT and CGA at the Kelch domain of Keap1 suggest a putative Nrf2 signaling activating prowess.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-021-00100-2.

Bitter Melon (Momordica charantia L.) Fruit Bioactives Charantin and Vicine Potential for Diabetes Prophylaxis and Treatment

Natural products are gaining clinical significance in modern day health care systems to prevent diseases. Bitter melon, a health promoting vegetable, is traditionally used for medical nutrition therapy to cure diabetes but to reap maximum health claims, vigilant control of its substances in diet is crucial as part of curative action for effective diabetes management. In the present research, first phase focused on detection of key bioactive components, i.e., charantin and vicine in different parts of its fruit. In the second phase, normal and hyperglycemic Sprague Dawley rats were fed on skin, flesh and whole fruit of bitter melon at 150 and 300 mg/kg body weight and assessed for diabetes prophylaxis and treatment. The highest amount of charantin (0.16 ± 0.02 mg/g) was recorded in flesh while vicine was present in abundance in whole fruit (0.21 ± 0.01 μg/100 g). In normal rats, bitter melon supplementation was helpful in managing the onset of diabetes. Hyperglycemic rats showed diabetic complications including polydipsia, polyuria, glycosuria, renal hypertrophy and increased glomerular filtration rate. However, bitter melon consumption showed significant improvements in these parameters. The most potent dose was 300 mg/kg whole fruit that resulted in 31.64% lowering of blood glucose level and 27.35% increase in insulin level in hyperglycemic rats.

Medicinal plants utilized in Thai Traditional Medicine for diabetes treatment: Ethnobotanical surveys, scientific evidence and phytochemicals

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes mellitus remains the most lethal metabolic disease of contemporaneous times and despite the therapeutic arsenal currently available, research on new antidiabetic agents remains a priority. In recent years, the revitalization of Thai Traditional Medicine (TTM) became a clear priority for the Thai government, and many efforts have been undertaken to accelerate research on herbal medicines and their use in medical services in various hospitals. Additionally, and particularly in rural areas, treatment of diabetes and associated symptomatology frequently relies on herbal preparations recommended by practitioners of TTM. In the current work, medicinal plants used in Thailand for treating diabetes, as well as their hypoglycaemic pharmacological evidences and potential therapeutic use for diabetes-related complications were reviewed.

MATERIALS AND METHODS

Ethnopharmacological information on the plant materials used in TTM for diabetes treatment was collected through literature search in a range of scientific databases using the search terms: diabetes, folk medicine, Thailand medicinal plants, traditional medicine. Information regarding scientific evidence on the antidiabetic effects of surveyed species was obtained considering not only the most common taxonomic designation, but also taxonomic synonyms, and including the keywords 'diabetes' and 'hypoglycaemic effect'.

RESULTS

A total of 183 species known to be used for diabetes management in TTM were reviewed, with 30% of them still lacking experimental evidences to support claims regarding the mechanisms and phytochemicals underlying their antidiabetic properties. Moreover, a total of 46 bioactives displaying effective antidiabetic effects have been isolated from 24 species, their underlying mechanism(s) of action being fully or partially disclosed.

CONCLUSIONS

We deliver the most extensive survey dealing with the ethnomedicinal knowledge of Thai medicinal plants utilized on diabetes management. We are certain that the current review will spark further research on Thai plants for the development of new standardized phytomedicines through drug discovery programmes.

Type 2 Diabetes Mellitus: A Review of Multi-Target Drugs

Diabetes Mellitus (DM) is a multi-factorial chronic health condition that affects a large part of population and according to the World Health Organization (WHO) the number of adults living with diabetes is expected to increase. Since type 2 diabetes mellitus (T2DM) is suffered by the majority of diabetic patients (around 90-95%) and often the mono-target therapy fails in managing blood glucose levels and the other comorbidities, this review focuses on the potential drugs acting on multi-targets involved in the treatment of this type of diabetes. In particular, the review considers the main systems directly involved in T2DM or involved in diabetes comorbidities. Agonists acting on incretin, glucagon systems, as well as on peroxisome proliferation activated receptors are considered. Inhibitors which target either aldose reductase and tyrosine phosphatase 1B or sodium glucose transporters 1 and 2 are taken into account. Moreover, with a view at the multi-target approaches for T2DM some phytocomplexes are also discussed.

Impact of Active Antihyperglycemic Components as Herbal Therapy for Preventive Health Care Management of Diabetes

Diabetes is a metabolic hyperglycemic condition that progressively develops, effect small and large sensory fibers in the affected population. It has various complications as hypertension, coronary artery disease, stroke, blindness, kidney disease as well as peripheral neuropathy. Sulfonylureas, thiazolidinediones, metformin, biguanidine, acarbose and insulin are commonly used drugs for diabetic patients, but these all have certain side effects. Even metformin, that is known as the miracle drug for diabetes has been found to be associated with side effects, as during treatment it involves complications with eyes, kidneys, peripheral nerves, heart and vasculature. In the present article, we hypothesize recent discoveries with respect to active ingredients from Indian medicinal plants i.e., polypeptide-p (protein analogue act as artificial insulin), charantin (a steroidal saponin), momordicin (an alkaloid) and osmotin (ubiquitous plant protein and animal analogue of human adeponectin) possessing anti-hyperglycemic potential for diabetes type II. Therefore, plants as herbal therapy have preventive care of hyperglycemia accompanied with healthy lifestyle which can provide significant decline in the incidences of diabetes in future.

Alpha Glucosidase Inhibitory Activities of Plants with Focus on Common Vegetables

Type-2 diabetes mellitus is one of the most prevalent metabolic diseases in the world, and is characterized by hyperglycemia (i.e., high levels of glucose in the blood). Alpha-glucosidases are enzymes in the digestive tract that hydrolyze carbohydrates into glucose. One strategy that has been developed to treat type-2 diabetes is inhibition of the activity of alpha-glucosidases using synthetic drugs. However, these inhibitors are usually associated with gastrointestinal side effects. Therefore, the development of inhibitors from natural products offers an alternative option for the control of hyperglycemia. In recent years, various studies have been conducted to identify alpha-glucosidases inhibitors from natural sources such as plants, and many candidates have transpired to be secondary metabolites including alkaloids, flavonoids, phenols, and terpenoids. In this review, we focus on the alpha-glucosidases inhibitors found in common vegetable crops and the major classes of phytochemicals responsible for the inhibitory activity, and also as potential/natural drug candidates for the treatment of type-2 diabetes mellitus. In addition, possible breeding strategies for production of improved vegetable crops with higher content of the inhibitors are also described.

In vitro and in silico elucidation of antidiabetic and anti-inflammatory activities of bioactive compounds from Momordica charantia L

Bitter melon (Momordica charantia) has been used to manage diabetes and related conditions in various parts of the world. In the present study, ten compounds were isolated from acetone and methanol extracts of bitter melon. The chemical structures of compounds were unambiguously elucidated by 1D, 2D NMR, and high-resolution mass spectra. Identified compounds 1-7 exhibited significant inhibition of α-amylase and moderate inhibition of α-glucosidase activities. Momordicoside G and gentisic acid 5-O-β-d-xyloside showed the highest inhibition of α-amylase (70.5%), and α-glucosidase (56.4%), respectively. Furthermore, molecular docking studies of isolated compounds 1-7 were able to bind to the active sites of both enzymes. Additionally, the isolated compounds 1-7 significantly attenuated lipopolysaccharide (LPS)-induced inflammation, downregulating the expression of pro-inflammatory markers NF-κB, INOS, IL-6, IL-1β, TNF-α, and Cox-2 in murine macrophage RAW 264.7 cells. One phenolic derivative, gentisic acid 5-O-β-d-xyloside, was isolated and identified for the first time from bitter melon, and significantly suppressed the expression of Cox-2 and IL-6 compared to the LPS-treated group. α-Amylase and α-glucosidase are targets of anti-diabetes drugs, our findings suggest that compounds purified from bitter melon may have potential to use as functional food ingredients for the prevention of type 2 diabetes and related inflammatory conditions.

Progress in the discovery of naturally occurring anti-diabetic drugs and in the identification of their molecular targets

Diabetes mellitus (DM), a chronic metabolic disease, severely affects patients' life and intensively increases risks of developing other diseases. It is estimated that 0.4 billion individuals worldwide are subjected to diabetes, especially type 2 diabetes mellitus. At present, although various synthetic drugs for diabetes such as Alogliptin and Rosiglitazone, etc. have been used to manage diabetes, some of them showed severe side effects. Given that the pathogenesis of type 2 diabetes mellitus, natural occurring drugs are beneficial alternatives for diabetes therapy with low adverse effects or toxicity. Recently, more and more plant-derived extracts or compounds were evaluated to have anti-diabetic activities. Their anti-diabetic mechanisms involve certain key targets like α-glucosidase, α-amylase, DPP-4, PPAR γ, PTP1B, and GLUT4, etc. Here, we summarize the newly found anti-diabetic (type 2 diabetes mellitus) natural compounds and extracts from 2011-2017, and give the identification of their molecular targets. This review could provide references for the research of natural agents curing type 2 diabetes mellitus (T2DM).

GLP-I secretion in healthy and diabetic Wistar rats in response to aqueous extract of Momordica charantia

BACKGROUND

Diabetes mellitus is one of the major global health disorders increasing at an alarming rate in both developed and developing countries. The objective of this study was to assess the effect of aqueous extract of Momordica charantia (AEMC) on fasting blood glucose (FBG), tissue glycogen, glycosylated haemoglobin, plasma concentrations of insulin and GLP-1 hormone (glucagon-like peptide 1) in healthy and diabetic wistar rats.

METHODS

Male Wistar rats (both normal and diabetic) were treated with AEMC by gavaging (300 mg/kg body wt/day for 28 days).

RESULTS

AEMC was found to increase tissue glycogen, serum insulin and GLP-1 non-significantly (P > 0.05) in normal, significantly (P < 0.01) in diabetic Wistar rats, whereas decrease in FBG and Glycosylated haemoglobin non-significantly (P > 0.05) in normal, significantly (P < 0.01) in diabetic Wistar rats. The elevation of GLP-1 level in normal and diabetic treated groups may be due to the L-cell regeneration and proliferation by binding with L-cell receptors and makes a conformational change, resulting in the activation of a series of signal transducers. The polar molecules of M. charantia also depolarize the L-cell through elevation of intracellular Ca²⁺ concentration and which in turn releases GLP-1. GLP-1 in turn elevates beta-cell proliferation and insulin secretion.

CONCLUSION

The findings tend to provide a possible explanation for the hypoglycemic action of M. charantia fruit extracts as alternative nutritional therapy in the management and treatment of diabetes.

Hypoglycemic and hypolipidemic activity of aqueous leaf extract of Passiflora suberosa L

Leaves of Passiflora suberosa L. (Family: Passifloraceae; common name: wild passion fruit, devil's pumpkin) are used in Sri Lankan traditional medicine for treating diabetes. The present study investigated the in vivo ability of P. suberosa leaves to manage blood sugar status and associated cholesterol levels. Mechanisms of action and toxicity were also determined. Phytochemical screening of aqueous extracts of P. suberosa leaves and carbohydrate content of the leaves were determined according to previously published methods. In two group of male mice (n = 9), effects on fasting and random blood glucose levels (BGLs) of different acute doses (0, 25, 50, 100 and 200 mg/kg) of the aqueous leaf extract (ALE) were evaluated at 1, 3, and 5 h post-treatment. In another set of mice, the fasting BGL was evaluated following treatment of 0 or 50 mg/kg ALE (dose prescribed in traditional medicine) for 30 consecutive days. The lipid profile, some mechanism of ALE action (diaphragm glucose uptake, glycogen content in the liver and skeletal muscles) and its toxicity (behavioural observation, food and water intake, hepatoxicity) were also assessed following 30-day treatment. However, sucrose and glucose tolerance tests and intestinal glucose uptake were conducted to determine portion of mechanisms of action following single dose of 50 mg/kg ALE. Phytochemical screening revealed the presence of alkaloids, unsaturated sterols, triterpenes, saponins, flavonoids, tannins and proanthocyanidins. Carbohydrate content of the leaves was 12.97%. The maximum hypoglycemic effect was observed after 4 h of 50 and 100 mg/kg ALE administration. The extract decreased fasting BGL (18%) following an oral sucrose challenge and inhibited (79%) glucose absorption from the intestine. Correspondingly, the levels of glycogen in the liver (61%) and in the skeletal muscles (57%) were found be higher than that of the control group. The levels of total cholesterol (17%) and tri-glyceraldehyde levels (12%) found to be reduced in treated groups. Furthermore, no significant toxic effects were observed in treated groups. The present results suggest that the leaves of P. suberosa can be used to manage blood glucose and cholesterol levels. Isolation of active compounds are recommended for further analysis.

Evaluation of anti-diabetic activity of AHPL/AYTAB/0513 tablet in streptozotocin induced diabetes in rats

Background:

Diabetes is a chronic, progressive disease associated with several complications leading to significant mortality and morbidity. Limitations and drawbacks of the conventional treatment generate need for safer, effective complimentary therapies to prevent complications, and maintain normoglycemic status.

Aim and Objectives:

The aim of this study is to to evaluate antidiabetic activity of AHPL/AYTAB/0513 tablet alone, oral hypoglycemic agents (OHA[s]), and combination of AHPL/AYTAB/0513 tablet and OHA(s) in streptozotocin-induced diabetes in rats.

Materials and Methods:

Totally, ten groups of animals were studied comparatively to evaluate antidiabetic activity of AHPL/AYTAB/0513 tablet, OHA(s), and combination of AHPL/AYTAB/0513 tablet and OHA(s). Blood glucose level (BGL), lipid profile, serum creatinine, serum insulin level, and histopathological characteristics of pancreas were studied to evaluate the efficacy of various formulations. Histopathological examination of kidney and heart was carried out to assess the ability of various formulations in preventing complications of diabetes.

Results:

There was a significant decrease in mean BGL, serum triglycerides, serum total cholesterol, low-density lipoprotein (LDL), very LDL, and serum creatinine levels in all formulations groups. Significant increase in mean serum insulin level and high-density lipoprotein level was observed when compared to diabetic control (DC) group. Recovery of pancreatic beta cells and prevention of damage to heart and kidney cells was significant in all the formulation groups as compared to DC group. None of the formulations tested in nondiabetic rat showed hypoglycemia suggesting safety of all the formulations.

Conclusion:

AHPL/AYTAB/0513 tablet alone and in combination with OHA(s) can be effectively used in the management of diabetes mellitus. In addition, AHPL/AYTAB/0513 tablet alone and in combination with OHA(s) help in prevention of diabetic complications. As an adjuvant to OHA(s), AHPL/AYTAB/0513 tablet can be more effective.

Acute effects of a beverage containing bitter melon extract (CARELA) on postprandial glycemia among prediabetic adults

Background:

Acute ingestion of bitter melon (BM) has been shown to suppress the postprandial glycemic response in diabetics, but its impact on glucose regulation among individuals with impaired glucose tolerance is unclear. Moreover, one's glucose tolerance level may influence the effectiveness of BM. This study aimed to examine the acute effects of a beverage containing BM extract on blood glucose regulation during an oral glucose tolerance test (OGTT) among prediabetics.

Methods:

Ten prediabetic adults completed two OGTTs—glucose only (D2) and glucose+BM (D3). Responders were identified as subjects whose area under the glucose curve (AUC_glu) during D3 was lower than D2. To compare the acute effects of the beverage among individuals with varying glucose tolerance levels, subjects were grouped by their glucose response pattern—Fast_peak (peak glucose (Glu_peak) at 30 min postglucose (30P)) and Slow_peak (Glu_peak after 30P).

Results:

During D3, responders (n=5) experienced a 13.2% reduction in AUC_glu (95% confidence interval (CI): −18.1% to −8.3%), 12.2% reduction in mean glucose (95% CI: −17.3% to −7.0%) and 10.6% reduction in Glu_peak (95% CI: −17.5% to −3.7%); plasma glucose was reduced by 9.1% at 30P (95% CI: −15.6% to −2.6%), −24.0% at 60P (95% CI: −36.8% to −11.2%) and −20.0% at 90P (95% CI: −35.8% to −4.2%) during D3. No between-trial differences were noted for Fast_peak or Slow_peak.

Conclusions:

Acute ingestion of BM prior to the second OGTT (D3) led to a reduced postprandial glucose response in 50% of the subjects but did not affect the insulin response. Furthermore, the effectiveness of the beverage was seemingly uninfluenced by the subjects' glucose tolerance level. Although BM has shown to aid blood glucose management in diabetics, it remains uncertain why only a portion of subjects responded positively to the BM extract in the current study.

In vitro and in vivo α-amylase and α-glucosidase inhibiting activities of the protein extracts from two varieties of bitter gourd (Momordica charantia L.)

Background

α-amylase and α-glucosidase digest the carbohydrates and increase the postprandial glucose level in diabetic patients. Inhibiting the activity of these two enzymes can control postprandial hyperglycemia, and reduce the risk of developing diabetes. Bitter gourd or balsam pear is one of the important medicinal plants used for controlling postprandial hyperglycemia in diabetes patients. However, there is limited information available on the presence of α-amylase and α-glucosidase inhibiting compounds. In the current study, the protein extracts from the fruits of M. charantia var. charantia (MCC) and M. charantia var. muricata (MCM) were tested for α-amylase and α-glucosidase inhibiting activities in vitro, and glucose lowering activity after oral administration in vivo.

Results

The protein extract from both MCC and MCM inhibited the activity of α-amylase and α-glucosidase through competitive inhibition, which was on par with Acarbose as indicated by in vitro percentage of inhibition (66 to 69 %) and IC50 (0.26 to 0.29 mg/ml). Both the protein extracts significantly reduced peak blood glucose and area under the curve in Streptozotocin-induced diabetic rats, which were orally challenged with starch and sucrose.

Conclusions

Protein extracts from the fruits of the two varieties of bitter gourd inhibited α-amylase and α-glucosidase in vitro and lowered the blood glucose level in vivo on par with Acarbose when orally administrated to Streptozotocin-induced diabetic rats. Further studies on mechanism of action and methods of safe and biologically active delivery will help to develop an anti-diabetic oral protein drug from these plants.

Hypoglycemic and hypolipidemic activities of aqueous extract of flowers from Nycantus arbor-tristis L. in male mice

BACKGROUND

Boiled aqueous extract of flowers (AEF) from Nyctanthes arbor-tristis L. are used in Sri Lankan traditional Ayruvedic Medicine to manage diabetes mellitus. AEF has widely been used as a folk medicine for the treatment of various ailments due to its therapeutic activity. However, little is known concerning therapeutic activity of the extract as well as its underline mechanisms and safety. Diabetes is known to increase low-density cholesterol and decrease high-density cholesterol thus triggering coronary diseases. Hence, the primary objective of the present study is to investigate the hypoglycemic and hypolipidemic activities of the AEF.

METHODS

AEF was prepared and male mice (n = 9 group) were gavaged either with 250, 500 and 750 mg/kg of AEF or distilled water (DW). Subsequently, fasting and random blood glucose concentrations were determined. To investigate mechanisms of actions of AEF, animals were orally administered with 500 mg/kg or the vehicle (DW) and glucose tolerance was performed before and after glucose challenge. For further studies, in vitro alpha-amylase assay and glucose absorption from the gastrointestinal tract were performed using 500 mg/kg of the extract. Additionally, glycogen content in the liver and skeletal muscles, a complete lipid profile assay, and toxicological and biochemical parameters were conducted after a chronic study.

RESULTS

Five hundred mg/kg and 750 mg/kg of AEF significantly (p < 0.01) reduced fasting blood glucose levels respectively by 49 and 39% at 4 h post-treatment, while 500 mg/kg of AEF also decreased the random blood glucose level significantly (p < 0.01) by 32% at 4 h post-treatment. AEF significantly inhibited glucose absorption by 85% from the intestine and increased diaphragm uptake of glucose by 64%. The extract also exhibited inhibition (16.66%) of alpha-amylase enzyme activity. It also decreased the level of total cholesterol (by 44.8%), triglyceride (by 53%) and increased (by 57%) the high-density lipoprotein cholesterol. Treatment with AEF did not induce any overt signs of toxicity or hepatotoxicity.

CONCLUSION

Results the present study indicated that AEF possess hypoglycemic and hypolipdemic properties. Therefore, AEF could be used as an alternative medicine in management of diabetes mellitus.

In vitro antidiabetic effects of selected fruits and vegetables against glycosidase and aldose reductase

In vitro antidiabetic effect of fruits and vegetables with reports as folk remedies were investigated. The antidiabetic effects were evaluated by comparing the inhibitory properties of α‐glycosidase, aldose reductase, and antioxidant activity. The results indicated that lychee extract exhibited the best dose‐dependent inhibitory activity against α‐glycosidase with IC₅₀ of 10.4 mg/mL, and lemon peel extract exhibited aldose reductase inhibitory potential with IC₅₀ value at 3.63 mg/mL. Besides, the result also showed that the inhibitory effects of blueberry and plum against α‐glycosidase were strong among the fruits samples. Bitter gourd and eggplant demonstrated significant inhibitory potential against aldose reductase, with IC₅₀ values at 8.55 mg/mL and 8.06 mg/mL, respectively. The result from correlation analysis part showed that the antioxidant activities of selected fruits and vegetables were found related to their health beneficial effects, as there was positive correlations between total flavonoids content (TFC) and aldose reductase inhibitory activity (r² = 0.556).

Lower hypoglycemic but higher antiatherogenic effects of bitter melon than glibenclamide in type 2 diabetic patients

Objective

Since antiquity bitter melon has been in use for treating diabetes but clinical trials show conflicting results about its usefulness. The present study aims to asses and compare the hypoglycemic and antiatherogenic effects as well as the safety of two different doses of bitter melon with glibenclamide.

Methods

A total of 95 participants were randomized into 3 groups; group I and group II received bitter melon (2 g/day and 4 g/day respectively) and group III received glibenclamide (5 mg/day) for 10 weeks. Glycemic control and antiatherogenic effects were determined by assessing glycohemoglobin (HbA1-c), fasting plasma glucose (FPG), 2 hour oral glucose tolerance test (OGTT), plasma sialic acid (PSA), systolic blood pressure (SBP), blood lipids and atherogenic index at different time periods.

Results

Compared to baseline, mean reduction in HbA1-c at the endpoint was significant among patients of group I, group II and group III (p ≤ 0.05, p ≤ 0.02 and p < 0.005 respectively) and same was the case for FPG (p ≤ 0.05, p < 0.04, p < 0.003 respectively), but the improvement in 2 hour OGTT was significant only in group III (p < 0.03). The decrease in PSA was observed only among group I and group II with the later showing significant reduction from baseline (p < 0.01). In group III, the level slightly increased. Parameters including blood lipids, atherogenic index, body weight and SBP improved among patients of group I and group II but deteriorated among group III patients.

Conclusions

Our study concludes that bitter melon has a weaker hypoglycemic effect but ameliorates the diabetes associated cardiovascular (CV) risk factors more effectively than glibenclamide.

Trial registration

The trial was registered with Naseer Teaching Hospital Clinical Trials Registry number GU2014492233.

Effect of wild bitter gourd treatment on inflammatory responses in BALB/c mice with sepsis

Background/Introduction: Wild bitter gourd (Momordica charantia L. var. abbreviate Seringe) common vegetable in Asia, is used in traditional medicine to treat various diseases, including inflammation. Extant literature indicates that wild bitter gourds have components that activate PPARα and PPARγ. This research probed influence of adding wild bitter gourd to diets on inflammation responses in mice with sepsis.

Purpose: This study evaluated influence of eating wild bitter gourd on inflammation responses in mice with sepsis.

Methods: We injected intraperitoneal LPS to induce sepsis. Male BALB/c mice were divided normal, sepsis, positive control, and three experimental groups. The latter ate diets with low (1%), moderate (2%), and high (10%) ratios of wild bitter gourd lyophilized powder. Before mice were sacrificed, with the exception of the normal group, intraperitoneal injection of LPS induced sepsis in each group; positive control group was injected with LPS after PDTC.

Results: This experiment revealed weights in groups with added wild bitter gourd starkly lower than those of the remaining groups. Blood lipids (TG, cholesterol, and NEFA) were also lower in comparison to the sepsis group, and blood glucose concentrations recovered and approached normal levels. Blood biochemistry values related to inflammation reactions indicated GOT, GPT, C-RP, and NO concentrations of groups with wild bitter gourd added all lower than that of the sepsis group. Secretion levels of the spleen pro-inflammatory cytokines IL-1, IL-6, and TNF-α tallied significantly lower in comparison to the sepsis group, whereas secretion levels of IL-10 anti-inflammatory cytokine increased. Expression level of proteins NF-κB, iNOS, and COX-2 were inhibited significantly.

Conclusion: Wild bitter gourd in diets promoted lipid metabolism, improved low blood glucose in sepsis, and attenuated inflammatory stress. These findings suggested that this plant food might provide medical benefits for certain persons.

Anti-inflammatory effect of Momordica charantia in sepsis mice

Wild bitter gourd (Momordica charantia L. var. abbreviate Seringe), a common vegetable in Asia, is used in traditional medicine to treat various diseases, including inflammation. Extant literature indicates that wild bitter gourds have components that activate PPARα and PPARγ. This research probed the influence of adding wild bitter gourd to diets on inflammation responses in mice with sepsis induced by intraperitoneal injection of LPS. Male BALB/c mice were divided normal, sepsis, positive control, and three experimental groups. The latter ate diets with low (1%), moderate (2%), and high (10%) ratios of wild bitter gourd lyophilized powder. Before mice were sacrificed, with the exception of the normal group, intraperitoneal injection of LPS induced sepsis in each group; positive control group was injected with LPS after PDTC. This experiment revealed starkly lower weights in groups with added wild bitter gourd than those of the remaining groups. Blood lipids (TG, cholesterol, and NEFA) were also lower in comparison to the sepsis group, and blood glucose concentrations recovered and approached normal levels. Blood biochemistry values related to inflammation reactions indicated GOT, GPT, C-RP, and NOconcentrations of groups with added wild bitter gourd were all lower than those of the sepsis group. Secretion levels of the spleen pro-inflammatory cytokines IL-1, IL-6, and TNF-α tallied significantly lower in comparison to the sepsis group, whereas secretion levels of IL-10 anti-inflammatory cytokine increased. Expression level of proteins NF-κB, iNOS, and COX-2 were significantly inhibited. Results indicate wild bitter gourd in diets promoted lipid metabolism, reducing fat accumulation, and improving low blood glucose in sepsis. Addition of wild bitter gourd can reduce inflammation biochemical markers or indicators and pro-inflammatory cytokines in the body, hence improving the inflammation responses in mice with sepsis.

Glucosidase inhibitory activity and antioxidant activity of flavonoid compound and triterpenoid compound from Agrimonia Pilosa Ledeb

BACKGROUND

In Chinese traditional medicine, Agrimonia pilosa Ledeb (APL) exhibits great effect on treatment of type 2 diabetes mellitus (T2DM), however its mechanism is still unknown. Considering that T2DM are correlated with postprandial hyperglycemia and oxidative stress, we investigated the α-glucosidase inhibitory activity and the antioxidant activity of flavonoid compound (FC) and triterpenoid compound (TC) from APL.

METHODS

Entire plants of APL were extracted using 95% ethanol and 50% ethanol successively. The resulting extracts were partitioned and isolated by applying liquid chromatography using silica gel column and Sephadex LH 20 column to give FC and TC. The content of total flavonoids in FC and the content of total triterpenoids in TC were determined by using UV spectrophotometry. HPLC analysis was used to identify and quantify the monomeric compound in FC and TC. The α-glucosidase inhibitory activities were determined using the chromogenic method with p-nitrophenyl-α-D-glucopyranoside as substrate. Antioxidant activities were assessed through three kinds of radical scavenging assays (DPPH radical, ABTS radical and hydroxyl radical) & β-carotene-linoleic acid assay.

RESULTS

The results indicate FC is abundant of quercitrin, and hyperoside, and TC is abundant of 1β, 2β, 3β, 19α-tetrahydroxy-12-en-28-oic acid (265.2 mg/g) and corosolic acid (100.9 mg/g). The FC & the TC have strong α-glucosidase inhibitory activities with IC50 of 8.72 μg/mL and 3.67 μg/mL, respectively. We find that FC show competitive inhibition against α-glucosidase, while the TC exhibits noncompetitive inhibition. Furthermore, The FC exhibits significant radical scavenging activity with the EC50 values of 7.73 μg/mL, 3.64 μg/mL and 5.90 μg/mL on DPPH radical, hydroxyl radical and ABTS radical, respectively. The FC also shows moderate anti-lipid peroxidation activity with the IC50 values of 41.77 μg/mL on inhibiting β-carotene bleaching.

CONCLUSION

These results imply that the FC and the TC could be responsible for the good clinical effects of APL on T2MD through targeting oxidative stress and postprandial hyperglycaemia. So APL may be good sources of natural antioxidants and α-glucosidase inhibitors exhibiting remarkable potential value for the therapy of T2DM.

Role of GLP-1 in the Hypoglycemic Effects of Wild Bitter Gourd

This study aimed to examine the role of GLP-1 in the hypoglycemic activity of wild bitter gourd (Momordica charantia L., BG). In vitro, the GLP-1 secretion in STC-1, a murine enteroendocrine cell line, was dose dependently stimulated by water extract (WE), its fractions (WEL, >3 kD and WES, <3 kD), and a bitter compounds-rich fraction of BG. These stimulations were partially inhibited by probenecid, a bitter taste receptor inhibitor, and by U-73122, a phospholipase Cβ2 inhibitor. These results suggested that the stimulation might involve, at least in part, certain bitter taste receptors and/or PLCβ2-signaling pathway. Two cucurbitane triterpenoids isolated from BG, 19-nor-cucurbita-5(10),6,8,22-(E),24-pentaen-3β-ol, and 5β,19-epoxycucurbita-6,24-diene-3β,23ξ-diol (karavilagenine E,) showed relative high efficacy in the stimulation. In vivo, mice fed BG diet showed higher insulinogenic index in an oral glucose tolerance test. A single oral dose of WE or WES pretreatment significantly improved intraperitoneal glucose tolerance. A single oral dose of WES significantly decreased glucose and increased insulin and GLP-1 in serum after 30 min. This acute hypoglycemic effect of WES was abolished by pretreatment with exendin-9, a GLP-1 receptor antagonist. Our data provide evidence that BG stimulates GLP-1 secretion which contributes, at least in part, to the antidiabetic activity of BG through an incretin effect.

Mexican antidiabetic herbs: valuable sources of inhibitors of α-glucosidases

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.

Nutritional supplements and their effect on glucose control

As diabetes mellitus (DM) continues to be a growing health concern, many people have been turning to natural health products (NHPs) in order to manage this condition, adjunctive to, or even in place of conventional therapies. In order to keep up with this trend, research focussing on the efficacy and mechanisms behind the most common NHPs has been growing amongst the scientific community. The purpose of this chapter is to search and compile scientific literature focussing on the most commonly used NHPs in diabetes treatment, so to educate health professionals on the efficacy, safety and dosage of these products. From our findings, it is apparent that there are promising results from many studies on the potential benefit of NHPs in the treatment of diabetes. Nonetheless, many of the herbs and single nutraceuticals still require further studies in order to confirm safety, dosage and potential interactions with standard conventional therapies. Soluble fibre, alpha lipoic acid, milk thistle, prickly pear cactus and pycnogenol appear to be the most beneficial in the treatment of diabetes.

Herbal medicines for the management of diabetes

Herbal medicines have been used in the management of diabetes in traditional medicine. This chapter reviews recent findings of the most popular herbs reported to treat diabetes through their relevant mechanistic pathways. These include increased insulin secretion, improvement in insulin sensitivity, enhanced glucose uptake by adipose and muscle tissues, inhibition of glucose absorption from intestine, inhibition of glucose production from hepatocytes and anti-inflammatory activities. The pharmacological activities have highlighted the potential efficacy of these herbal medicines in the management of diabetes.

Comprehensive Evaluation of Anti-hyperglycemic Activity of Fractionated Momordica charantia Seed Extract in Alloxan-Induced Diabetic Rats

The present study evaluates anti-hyperglycemic activity of fractionated Momordica charantia (bitter gourd) seed extracts. Fasting blood glucose levels were evaluated before and after administration of different fractions of the seed extract. Among the three fractions tested, fraction Mc-3 (15 mg/kg b.wt.) showed the maximum anti-hyperglycemic activity and reduced blood glucose levels in experimental diabetic rats significantly. The activities of the key regulatory enzymes of glucose metabolism (hexokinase, pyruvate kinase, lactate dehydrogenase, and glucose-6-phosphate dehydrogenase) were determined in Mc-3-treated diabetic animals. Once-daily administration of the fraction Mc-3 for prolonged period of 18 days to the experimental diabetic animals did not result in any nephrotoxicity or hepatotoxicity as evident from insignificant changes in biochemical parameters indicative of liver and kidney functions. Further fractionation of the fraction Mc-3 by size exclusion chromatography resulted in a fraction, designated Mc-3.2, possessing anti-hyperglycemic activity. The fraction Mc-3.2 showed the presence of a predominant protein band of ~11 kDa on SDS-PAGE. Loss in anti-hyperglycemic activity of the Mc-3.2 upon protease treatment indicates the proteinaceous nature of the anti-hyperglycemic principles. Overall, the results suggest that Momordica charantia seeds contain an effective anti-hyperglycemic protein(s) which may find application in treatment of diabetes without evident toxic effects.

Antidiabetic potentials of Momordica charantia: multiple mechanisms behind the effects

Momordica charantia fruits are used as a vegetable in many countries. From time immemorial, it has also been used for management of diabetes in the Ayurvedic and Chinese systems of medicine. Information regarding the standardization of this vegetable for its usage as an antidiabetic drug is scanty. There are many reports on its effects on glucose and lipid levels in diabetic animals and some in clinical trials. Reports regarding its mechanism of action are limited. So in the present review all the information is considered to produce some concrete findings on the mechanism behind its hypoglycemic and hypolipidemic effects. Studies have shown that M. charantia repairs damaged β-cells, increases insulin levels, and also enhance the sensitivity of insulin. It inhibits the absorption of glucose by inhibiting glucosidase and also suppresses the activity of disaccharidases in the intestine. It stimulates the synthesis and release of thyroid hormones and adiponectin and enhances the activity of AMP-activated protein kinase (AMPK). Effects of M. charantia like transport of glucose in the cells, transport of fatty acids in the mitochondria, modulation of insulin secretion, and elevation of levels of uncoupling proteins in adipose and skeletal muscles are similar to those of AMPK and thyroxine. Therefore it is proposed that effects of M. charantia on carbohydrate and fat metabolism are through thyroxine and AMPK.

Functional food and diabetes: a natural way in diabetes prevention?

Diabetes shows a wide range of variation in prevalence around the world and it is expected to affect 300 million by the year 2025. In a prevention framework where banning policies and educational strategies lead the interventions, functional foods (FFs) with their specific health effects could, in the future, indicate a new mode of thinking about the relationships between food and health in everyday life. Functional ingredients, such as stevioside, cinnamon, bitter melon, garlic and onion, ginseng, Gymnema sylvestre and fenugreek, have been addressed for their specific actions towards different reactions involved in diabetes development. New strategies involving the use of FF should be validated through large-scale population trials, considering validated surrogate end points to evaluate the effect of FF in prevention of chronic diseases such as type 2 diabetes mellitus.

Effects of xylitol on metabolic parameters and visceral fat accumulation

Xylitol is widely used as a sweetener in foods and medications. Xylitol ingestion causes a small blood glucose rise, and it is commonly used as an alternative to high-energy supplements in diabetics. In previous studies, a xylitol metabolite, xylulose-5-phosphate, was shown to activate carbohydrate response element binding protein, and to promote lipogenic enzyme gene transcription in vitro; however, the effects of xylitol in vivo are not understood. Here we investigated the effects of dietary xylitol on lipid metabolism and visceral fat accumulation in rats fed a high-fat diet. Sprague-Dawley rats were fed a high-fat diet containing 0 g (control), 1.0 g/100 kcal (X1) or 2.0 g/100 kcal (X2) of xylitol. After the 8-week feeding period, visceral fat mass and plasma insulin and lipid concentrations were significantly lower in xylitol-fed rats than those in high-fat diet rats. Gene expression levels of ChREBP and lipogenic enzymes were higher, whereas the expression of sterol regulatory-element binding protein 1c was lower and fatty acid oxidation-related genes were significantly higher in the liver of xylitol-fed rats as compared with high-fat diet rats. In conclusion, intake of xylitol may be beneficial in preventing the development of obesity and metabolic abnormalities in rats with diet-induced obesity.

Wild bitter gourd extract up-regulates mRNA expression of PPARα, PPARγ and their target genes in C57BL/6J mice

ETHNOPHARMACOLOGICAL RELEVANCE

Wild bitter gourd (Momordica charantia Linn. var. abbreviata ser.) was commonly used as a medicinal herb in Asia, Africa, and South America because of its anti-diabetic, antibacterial, anti-viral, and chemopreventive functions.

MATERIALS AND METHODS

C57BL/6J mice were orally administered with 250, 500 or 1000mg/kg BW of WBGE in 0.2mL/mouse of olive oil daily for 2 weeks.

RESULTS

Compared to control (vehicle treated) mice, mice receiving WBGE showed significantly higher PPARα, ACO (acyl-CoA oxidase) and L-FABP (liver-fatty acid binding protein) mRNA expression, ACO activity and protein in the liver (P<0.05), as clofibrate-treated mice. WBGE treatment also resulted in significantly higher PPARγ and LPL (lipoprotein lipase) mRNA (P<0.05) in the epididymal adipose tissue. Liver triglyceride and non-esterified fatty acid concentration in WBGE treated mice were significantly lower than those of control mice (P<0.05). Plasma adiponectin level was significantly higher in mice receiving WBGE than in control mice (P<0.05), as the rosiglitazone treated mice.

CONCLUSION

Results of this study demonstrated that WBGE also activates PPARα and PPARγ signaling pathway in vivo.

Anti-diabetic and hypoglycaemic effects of Momordica charantia (bitter melon): a mini review

It has been estimated that up to one-third of patients with diabetes mellitus use some form of complementary and alternative medicine. Momordica charantia (bitter melon) is a popular fruit used for the treatment of diabetes and related conditions amongst the indigenous populations of Asia, South America, India and East Africa. Abundant pre-clinical studies have documented the anti-diabetic and hypoglycaemic effects of M. charantia through various postulated mechanisms. However, clinical trial data with human subjects are limited and flawed by poor study design and low statistical power. The present article reviews the clinical data regarding the anti-diabetic potentials of M. charantia and calls for better-designed clinical trials to further elucidate its possible therapeutic effects.