Potential use of bitter melon (Momordica charantia) derived compounds as antidiabetics: In silico and in vivo studies

Investigation of the Influence of a Bitter Melon Product on Indicators of Cardiometabolic Health in Adults with Prediabetes

OBJECTIVE

The purpose of this study was to assess the impact of bitter melon extract supplementation on glycemia in individuals with prediabetes.

METHODS

This was a 12-week randomized, parallel, placebo-controlled study where 75 adults with prediabetes were randomly allocated into the low-dose bitter melon (300 mg/day) (n = 26), high-dose bitter melon (600 mg/day) (n = 24), or control (n = 25) groups.

RESULTS

At baseline and weeks 6 and 12, anthropometrics were measured, and fasting blood samples were obtained. The high-dose (1.05% ± 10.2%) and low-dose bitter melon (3.35% ± 13.2%) groups showed smaller increases in blood glucose levels at 12 wk, compared to the control group (11.0% ± 16.3%) (p < 0.05). A subgroup analysis of participants with age ≥ the median demonstrated a greater reduction in glycated hemoglobin at 12 wk in the high-dose bitter melon group (median change: -0.20%; IQRL: -0.20%, -0.05%) vs. the control group (median change: 0.00%; IQRL: -0.10%, 0.20%) (p = 0.017). Compliance with the interventions was >95%, and the study products were tolerated well.

CONCLUSION

The bitter melon extract may help maintain a healthy level of glucose in adults with prediabetes.

Bambusa vulgaris leaf extract inhibits the inflammatory and oxidative pathways in streptozotocin-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional and medicinal plant treatments for diabetes mellitus (DM) include Bambusa vulgaris (Shrad.), but little is known about the mechanism.

AIM OF THE STUDY

This study investigated the antioxidant and hepatoprotective effects of B. vulgaris.

MATERIALS AND METHODS

DM was induced by intraperitoneal injection of streptozotocin (60 mg/kg). Thirty (30) male Wistar rats were then divided into six groups: control; diabetic control; metformin (100 mg/kg); 50, 100, and 200 mg/kg of B. vulgaris (BV) treated. Fasting blood glucose and weights of rats were monitored at three-day intervals and sacrifice was done after twenty-one days. The activities of SOD, CAT, and liver marker enzymes were investigated. The expressions of insulin-sensitive (TGR5, GLP-1), pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, ICAM), and antioxidant genes (SOD, CAT) were investigated using RT-PCR. Schrödinger suites and Auto-Dock Vina were used for docking B. vulgaris phytocompounds identified from works of literature with TGR-5. The liver's histology was also assessed.

RESULTS

BV increased antioxidant activities and reduced liver marker activities in the serum. BV downregulated the expressions of genes associated with inflammation and upregulated antioxidant and insulin-sensitive genes relative to diabetic control. BV regenerated the liver architectural tissue degenerated by inflammation due to STZ. B. vulgaris phytocompounds like farobin A (-11.493 kcal/mol), orientin (-12.296 kcal/mol), and rutin (-12.581 kcal/mol) have better binding energy with TGR5 than metformin (-1.961 kcal/mol).

CONCLUSION

The hepatoprotective and ameliorative effect of B. vulgaris in DM could be due to its ability to boost antioxidant status and insulin secretion and reduce inflammation.

Momordica charantia Extract Ameliorates Melanoma Cell Proliferation and Invasion into Mouse Lungs by Suppressing PAX3 Expression

Melanomas, which develop on malignant transformations of melanocytes, are highly malignant and prone to metastasis; therefore, effective drugs are required. The Momordica charantia (MC) extract has been shown to suppress cancer cell proliferation and invasion; however, the effect of the MC extract on melanoma in living organisms remains unclear. In this study, we investigated the mechanism underlying the amelioration of melanoma cell extravasation into mouse lungs by the MC extract. Male C57BL/6j mice (aged 8 weeks) were injected with B16 melanoma cells (1 × 105 cells/mouse). Subsequently, they were orally administered the MC extract daily for 2 weeks; mouse lung samples were obtained on the final day and analyzed. The MC extract ameliorated melanoma proliferation and infiltration into the lungs caused by melanoma cell treatment. It also increased phosphatase and tensin homolog deletion from chromosome 10 and suppressed paired box gene 3 (PAX3) and the phosphatidylinositol trisphosphate/RAC-alpha serine/threonine-protein kinase/mammalian target of rapamycin complex 1 signaling. Furthermore, it decreased microphthalmia-associated transcription factors and induced the suppression of cyclin-dependent kinase 2, hepatocyte growth factor receptor, B-cell/CLL lymphoma 2, and Ras-related proteins. Our findings suggest that the MC extract suppresses tumor survival genes by regulating PAX3, thereby ameliorating melanoma proliferation and invasion.

Feasible mechanisms and therapeutic potential of food probiotics to mitigate diabetes‐associated cancers: A comprehensive review and in silico validation

People with diabetes mellitus (DM) and hyperglycemia are linked with cancer risk. Diabetes and cancer have been corroborated by high morbidity and mortality rates. Studies revealed that elevated levels of insulin secretions trigger insulin‐like growth factor 1 (IGF‐1) production. Moreover, IGF‐1 is a key regulator involved in promoting cancer cell progression and is linked with DM. Cancer drug resistance and ototoxic effects can adversely affect the health and lifespan of an individual. However, naturally derived bioactive compounds are gaining attention for their nontoxic properties and specific behavior. Likewise, probiotics have also been regarded as safe and successful alternatives to treat DM‐linked cancers. The present review aims to highlight the therapeutic potential and feasible functions of probiotics to mitigate or inhibit DM‐associated cancers. Meanwhile, the intracellular signaling cascades involved in promoting DM‐linked cancer are enumerated for future prospective research. However, metabolomics interactions and protein–protein interactions are to be discussed for deeper insights into affirmative principles in diabetic‐linked cancers. Drug discovery and innovative preclinical evaluation need further adjuvant and immune‐enhancement therapies. Furthermore, the results of the in silico assessment could provide scientific excellence of IGF‐1 in diabetes and cancer. Overall, this review summarizes the mechanistic insights and therapeutic targets for diabetes‐associated cancer.

The metabolic effect of Momordica charantia cannot be determined based on the available clinical evidence: a systematic review and meta-analysis of randomized clinical trials

Several studies have shown that Momordica charantia L. (Cucurbitaceae, bitter melon) has beneficial effects on metabolic syndrome (MetS) parameters and exerts antidiabetic, anti-hyperlipidemic, and anti-obesity activities. Since the findings of these studies are contradictory, the goal of this systematic review and meta-analysis was to assess the efficacy of bitter melon in the treatment of metabolic syndrome, with special emphasis on the anti-diabetic effect. Embase, Cochrane, PubMed, and Web of Science databases were searched for randomized controlled human trials (RCTs). The meta-analysis was reported according to the PRISMA statement. The primary outcomes of the review are body weight, BMI, fasting blood glucose, glycated hemoglobin A1c, systolic blood pressure, diastolic blood pressure, serum triglyceride, HDL, LDL, and total cholesterol levels. Nine studies were included in the meta-analysis with 414 patients in total and 4-16 weeks of follow-up. In case of the meta-analysis of change scores, no significant effect could be observed for bitter melon treatment over placebo on fasting blood glucose level (MD = -0.03; 95% CI: -0.38 to 0.31; I2 = 34%), HbA1c level (MD = -0.12; 95% CI: -0.35 to 0.11; I2 = 56%), HDL (MD = -0.04; 95% CI: -0.17 to 0.09; I2 = 66%), LDL (MD = -0.10; 95% CI: -0.28 to 0.08; I2 = 37%), total cholesterol (MD = -0.04; 95% CI: -0.17 to 0.09; I2 = 66%,), body weight (MD = -1.00; 95% CI: -2.59-0.59; I2 = 97%), BMI (MD = -0.42; 95% CI: -0.99-0.14; I2 = 95%), systolic blood pressure (MD = 1.01; 95% CI: -1.07-3.09; I2 = 0%) and diastolic blood pressure levels (MD = 0.24; 95% CI: -1.04-1.53; I2 = 0%). Momordica treatment was not associated with a notable change in ALT, AST, and creatinine levels compared to the placebo, which supports the safety of this plant. However, the power was overall low and the meta-analyzed studies were also too short to reliably detect long-term metabolic effects. This highlights the need for additional research into this plant in carefully planned clinical trials of longer duration.

New insights into anti-diabetes effects and molecular mechanisms of dietary saponins

Diabetes mellitus (DM) is a long-term metabolic disorder that manifests as chronic hyperglycemia and impaired insulin, bringing a heavy load on the global health care system. Considering the inevitable side effects of conventional anti-diabetic drugs, saponins-rich natural products exert promising therapeutic properties to serve as safer and more cost-effective alternatives for DM management. Herein, this review systematically summarized the research progress on the anti-diabetic properties of dietary saponins and their underlying molecular mechanisms in the past 20 years. Dietary saponins possessed the multidirectional anti-diabetic capabilities by concurrent regulation of various signaling pathways, such as IRS-1/PI3K/Akt, AMPK, Nrf2/ARE, NF-κB-NLRP3, SREBP-1c, and PPARγ, in liver, pancreas, gut, and skeletal muscle. However, the industrialization and commercialization of dietary saponin-based drugs are confronted with a significant challenge due to the low bioavailability and lack of the standardization. Hence, in-depth evaluations in pharmacological profile, function-structure interaction, drug-signal pathway interrelation are essential for developing dietary saponins-based anti-diabetic treatments in the future.

Cytotoxicity and maternal toxicity attributed to exposure to Momordica charantia L. (Cucurbitaceae) dry leaf extract

Momordica charantia L. (Cucurbitaceae), popularly known as "bitter melon" or "bitter gourd," is a climbing plant well-adapted to tropical countries. This plant is used traditionally to treat several conditions including diabetes mellitus, inflammation, liver dysfunctions, and cancer. Given the widespread ethnopharmacological use, this study aimed to examine the cytogenetic, maternal, and developmental toxicity attributed to exposure to dry extract of M. charantia leaves using Allium cepa and Wistar rats as test models. First, phytochemical characterization of the dry extract by high performance liquid chromatography (HPLC) analyses was performed. Then, Allium cepa roots were exposed to three different concentrations of the dry extract (0.25, 0.5, or 1 mg/ml) to determine the mitotic index, frequency of chromosomal aberrations, and nuclear abnormalities. In addition, pregnant Wistar rats were administered either 500; 1,000 or 2,000 mg/kg dry extract during the gestational period (GD) days 6-15, and subsequently possible toxic effect on the dams and fetuses were recorded. HPLC analyses confirmed rutin as the main secondary metabolite present in the dry extract. In the Allium cepa test, the dry extract was cytotoxic. In Wistar rats, dry extract administration reduced water and feed intake and mean body mass gain, indicating maternal toxicity during the organogenesis period. However, the dry extract did not markedly affect reproductive outcome parameters evaluated. Regarding developmental toxicity assessment, the dry extract treatment did not significantly alter number of skeletal malformations in the offspring. Data demonstrated that the dry extract of M. charantia leaves presents cytotoxicity and low maternal toxicity, indicating indiscriminate use needs to be avoided.

Therapeutic Investigation of Standardized Aqueous Methanolic Extract of Bitter Melon (Momordica charantia L.) for Its Potential against Polycystic Ovarian Syndrome in Experimental Animals’ Model: In Vitro and In Vivo Studies

Polycystic ovarian syndrome (PCOS) is an heterogenous, endocrine, metabolic, and multidisciplinary disorder of reproductive-aged females that aggravates insulin resistance, hyperandrogenism, obesity, menstrual irregularities, and infertility. Bitter melon is consumed as vegetable in various parts of the world. The purpose of this study was to provide the rationale for the folkloric uses of bitter melon (Momordica charantia L.) in reproductive abnormalities. HPLC analysis of standardized aqueous methanolic extract of bitter melon revealed the presence of various phytochemicals such as quercetin, gallic acid, benzoic acid, chlorogenic acid, syringic acid, p-coumaric acid, ferulic acid, and cinnamic acid. Twenty-five Swiss albino adult female rats (120–130 g) were acquired and divided into two groups (5 + 20). Letrozole (1 mg/kg p.o.) was used for four weeks to induce PCOS in twenty rats. Disease induction was confirmed by vaginal smear cytology analysis under the microscope. Animals were further divided into four groups, with one group as PCOS group, and the remaining three are treated with standardized extract of bitter melon (500 mg/kg p.o.), bitter melon plus metformin (500 mg/kg p.o.), and metformin alone for the period of next four weeks. After four weeks, the rats were euthanized at diestrus stage. Ovaries of the experimental animals were removed and fixed in 10% buffered formalin, and blood samples were obtained from direct cardiac puncture and stored. Ovaries histopathological analysis showed cystic follicles (9–10) in PCOS group, while, in all the treatment groups, we found developing and mature follicles. Similarly, hormone analysis showed significant (p < 0.001) reduction of LH surge, insulin, and testosterone levels and improvement in FSH levels. Lipid profile and antioxidant enzymes status were also significantly (p < 0.001) improved. In conclusion, the study validates the bitter melon potential as an insulin sensitizer and ovulation enhancer and authenticates its potential in PCOS management.

The Activity of Plant-Derived Ren’s Oligopeptides-1 against the Pseudorabies Virus

Newly synthesized Ren’s oligopeptides-1 was found to have an antiviral effect in clinical trials, and the purpose of this study was to further demonstrate the antiviral activity of Ren’s oligopeptides-1 against the PRV 152-GFP strain. We used the real-time cell analysis system (RTCA) to detect the cytotoxicity of different concentrations of Ren’s oligopeptides-1. We then applied high content screening (HCS) to detect the antiviral activity of Ren’s oligopeptides-1 against PRV. Meanwhile, the fluorescence signal of the virus was collected in real time and the expression levels of the related genes in the PK15 cells infected with PRV were detected using real-time PCR. At the mRNA level, we discovered that, at a concentration of 6 mg/mL, Ren’s oligopeptides-1 reduced the expression of pseudorabies virus (PRV) genes such as IE180, UL18, UL54, and UL21 at a concentration of 6 mg/mL. We then determined that Ren’s oligopeptides-1 has an EC50 value of 6 mg/mL, and at this level, no cytotoxicity was observed.

Momordica charantia nanoparticles potentiate insulin release and modulate antioxidant gene expression in pancreas of diabetic rats

Background

Green synthesis of nanoparticles with medicinal plants has inherent potential in the management of diabetes mellitus. This study synthesized Momordica charantia nanoparticles using silver nitrate to investigate the antidiabetic properties of this extract and the synthesized nanoparticles in vivo.

Results

The M. charantia nanoparticles used were synthesized biologically under ambient conditions from methanolic leaf extract of M. charantia using 1 mM concentration of aqueous silver nitrate and characterized using spectroscopic methods, FTIR and scanning electron microscopy. In vivo, the antidiabetic activity of M. charantia nanoparticle was assessed in streptozotocin-induced (65 mg/kg) rats. Rats were treated with M. charantia nanoparticle (50 mg/kg), aqueous leaf extract (100 mg/kg) metformin (100 mg/kg) and silver nitrate nanoparticle (10 mg/kg) for 21 days. Following treatment, rats were killed for biochemical analysis. Also, reverse transcript-polymerase chain reaction analyses of Takeda-G-protein-receptor-5, glucagon-like peptide-1, Insulin, superoxide dismutase, catalase and Nuclear factor-erythroid factor 2-related factor 2 (NRF2) - were carried out in the pancreas. A significant reduction in blood sugar levels was noted in rats treated with M. charantia nanoparticles. A reduction (p < 0.05) of pancreas alanine transaminase, aspartate aminotransferase and alkaline phosphatase was observed when compared with diabetic untreated rats. M. charantia nanoparticles significantly increase the antioxidant enzymes in diabetic rats when compared with diabetic untreated rats. The decrease in the level of triglyceride, cholesterol and low-density lipoprotein was observed when compared with diabetic control rats and also a significant increase in the expression of Takeda-G-protein-receptor-5, glucagon-like peptide-1, insulin, superoxide dismutase, catalase and NFE2-related factor 2 genes was observed when compared with diabetic untreated rats.

Conclusions

Momordica charantia nanoparticles exhibited potential antidiabetic activity in the rat model of diabetes and thus may serve as a therapeutic agent that could be developed for medical applications in the future.

Heterocyclic compounds as a magic bullet for diabetes mellitus: a review

Diabetes mellitus (DM) is a major metabolic disorder due to hyperglycemia, which is increasing all over the world. From the last two decades, the use of synthetic agents has risen due to their major involvement in curing of chronic diseases including DM. The core skeleton of drugs has been studied such as thiazolidinone, azole, chalcone, pyrrole and pyrimidine along with their derivatives. Diabetics assays have been performed in consideration of different enzymes such as α-glycosidase, α-amylase, and α-galactosidase against acarbose standard drug. The studied moieties were depicted in both models: in vivo as well as in vitro. Molecular docking of the studied compounds as antidiabetic molecules was performed with the help of Auto Dock and molecular operating environment (MOE) software. Amino acid residues Asp349, Arg312, Arg439, Asn241, Val303, Glu304, Phe158, His103, Lys422 and Thr207 that are present on the active sites of diabetic related enzymes showed interactions with ligand molecules. In this review data were organized for the synthesis of heterocyclic compounds through various routes along with their antidiabetic potential, and further studies such as pharmacokinetic and toxicology studies should be executed before going for clinical trials.

Diabetes mellitus (DM) is a major metabolic disorder due to hyperglycemia, which is increasing all over the world.

Effect of Chrysophyllum albidum fruit pulp powder on antioxidant and proinflammatory genes in non-diabetic and type 2 diabetic rats

Background

Diabetes mellitus (DM) is a metabolic disorder characterized by chronic hyperglycemia resulting from insulin deficiency or dysfunction. The imbalance between free radicals and antioxidants known as oxidative stress has been implicated in the pathogenesis and complications associated with DM. Chrysophyllum albidum is a seasonal fruit found to be rich in natural antioxidants.

Methods

DM was induced by high-fat diet dietary supplementation for 14 days followed by intraperitoneal injection of streptozotocin (35 mg/kg). Thirty-five experimental rats were then divided into seven groups viz.: non-diabetic control; diabetic control; metformin; diabetic and non-diabetic fed with 5 and 10% C. albidum fruit pulp powder (CAFPP). Fasting blood glucose was done with an automatic auto-analyzer and weights were monitored at three-day intervals. The expressions of Nrf2, SOD, CAT, GST, TNF-α, DPP4, and insulin were investigated using RT-PCR. Schrödinger suites was used for docking of C. albidum phytocompounds with insulin.

Results

Diabetic rats fed with CAFPP for thirteen days have their blood glucose lowered significantly (p < 0.05) and gained weight compared to diabetic control. CAFPP significantly (p < 0.05) up-regulated Nrf2, CAT, GST, SOD, and insulin genes expression in the diabetic group relative to diabetic control with concomitant down-regulation of TNF-α and DPP4 genes expression. Molecular docking of compounds previously characterized from C. albidum revealed that they are potent ligands of insulin receptors.

Conclusion

The study revealed that CAFPP could be effective in the management of DM-related oxidative stress by up-regulating antioxidant and down-regulating pro-inflammatory genes expression. It also positively modulates genes associated with glucose metabolism.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00921-0.

Molecular Docking and Simulation Studies of Antidiabetic Agents Devised from Hypoglycemic Polypeptide-P of Momordica charantia

Diabetes mellitus termed as metabolic disorder is a collection of interlinked diseases and mainly body's inability to manage glucose level which leads to cardiovascular diseases, renal failure, neurological disorders, and many others. The drugs contemporarily used for diabetes have many inevitable side effects, and many of them have become less responsive to this multifactorial disorder. Momordica charantia commonly known as bitter gourd has many bioactive compounds with antidiabetic properties. The current study was designed to use computational methods to discover the best antidiabetic peptides devised from hypoglycemic polypeptide-P of M. charantia. The binding affinity and interaction patterns of peptides were evaluated against four receptor proteins (i.e., as agonists of insulin receptor and inhibitors of sodium-glucose cotransporter 1, dipeptidyl peptidase-IV, and glucose transporter 2) using molecular docking approach. A total of thirty-seven peptides were docked against these receptors. Out of which, top five peptides against each receptor were shortlisted based on their S-scores and binding affinities. Finally, the eight best ligands (i.e., LIVA, TSEP, EKAI, LKHA, EALF, VAEK, DFGAS, and EPGGGG) were selected as these ligands strictly followed Lipinski's rule of five and exhibited good ADMET profiling. One peptide EPGGGG showed activity towards insulin and SGLT1 receptor proteins. The top complex for both these targets was subjected to 50 ns of molecular dynamics simulations and MM-GBSA binding energy test that concluded both complexes as highly stable, and the intermolecular interactions were dominated by van der Waals and electrostatic energies. Overall, the selected ligands strongly fulfilled the drug-like evaluation criterion and proved to have good antidiabetic properties.

Natural Antidiabetic Agents: Molecular Docking Study using the Extra Precision Method

Background:

Diabetes mellitus (DM) is the most severe, chronic metabolic disorder with abnormally elevated concentration of plasma glucose levels, leading to significant complications, such as diabetic neuropathy, retinopathy, and cardiovascular illnesses.

Objective:

Synthetic drugs have some disadvantages and limitations. Therefore, there is a continuous global and insisting need for new and better treatment options for Diabetes Mellitus.

Methods:

In this study, 42 natural anti-diabetic constituents like alkaloids, glycosides, and flavonoids were selected on the basis of mechanism of action on various molecular targets such as Glucokinase activator, Dipeptidyl peptidase 4 (DPP-4), peroxisome proliferator-activated receptors (PPARγ), and α-glucosidase inhibitor. To investigate the potential molecular targets for natural antidiabetcs agents, molecular docking study was carried out using the Glide module of Schrodinger Suit.

Results:

Interactions of specific amino acid of the targets with the atoms of the chemical constituents and their Gscore indicate the proper binding of chemical constituents with target. The results revealed that Myricetin, Quercetin ae interacts with active sites of the target chosen and can be used for the designing of novel compounds as anti-dibetics.

Conclusion:

Calculated GScore could be used as a preliminary tool for screening of anti-diabetic drugs before performing experimental activity.

Effects of Bitter Melon and a Chromium Propionate Complex on Symptoms of Insulin Resistance and Type 2 Diabetes in Rat Models

Trivalent chromium (Cr) and bitter melon (Momordica charantia L., BM) have been shown to independently interact with the insulin signaling pathway leading to improvements in the symptoms of insulin resistance and diabetes in some animal models and human subjects. The aim of this study was to examine whether the combination of the two nutritional supplements could potentially have additive effects on treating these conditions in high-fat-fed streptozotocin (STZ)-induced diabetic rats. The experiment was conducted with 110 male Wistar rats divided into eleven groups and fed either a control or high-fat diet for 7 weeks. Half of the rats on the high-fat diet were injected with STZ (30 mg/kg body mass) to induce diabetes. The high-fat (HF) diets were then supplemented with a combination of Cr (as chromium(III) propionate complex, Cr3: either 10 or 50 mg Cr/kg diet) and bitter melon (lyophilized whole fruit: either 10 or 50 g/kg diet) for 6 weeks. After termination of the experiment, blood and internal organs were harvested for blood biochemical, hematological, and mineral (Cr) analyses using appropriate analytical methods. It was found that neither Cr(III) nor BM was able to significantly affect blood indices in HF and diabetic rats, but BM tended to improve body mass gain, blood glucose, and LDL cholesterol values, but decreased Cr content in the liver and kidneys of the Cr-co-supplemented type 2 diabetic model of rats. Supplementary Cr(III) had no appreciable effect on glucose and lipid metabolism in high-fat-fed STZ-induced diabetic rats. Supplementary BM fruit powder had some observable effects on body mass of high-fat-fed rats; these effects seem to be dampened when BM was co-administered with Cr. Cr(III) and BM appear to act as nutritional antagonists when both administered in food, probably due to binding of Cr by the polyphenol-type compounds present in the plant material. Graphical Abstract.

Exploring Phytotherapeutic Alternatives for Obesity, Insulin Resistance and Diabetes Mellitus

At present, the pathologic spectrum of obesity-insulin resistance (IR)-diabetes mellitus (DM) represents not only a pressing matter in public health but also a paramount object of study in biomedical research, as they constitute major risk factors for cardiovascular disease (CVD), and other chronic non-communicable diseases (NCD). Phytotherapy, the use of medicinal herbs (MH) with treatment purposes, offers a wide array of opportunities for innovation in the management of these disorders; mainly as pharmacological research on small molecules accumulates. Several MH has displayed varied mechanisms of action relevant to the pathogenesis of obesity, IR and DM, including immunological and endocrine modulation, reduction of inflammation and oxidative stress (OS), regulation of appetite, thermogenesis and energy homeostasis, sensitisation to insulin function and potentiation of insulin release, among many others. However, the clinical correlates of these molecular phenomena remain relatively uncertain, with only a handful of MH boasting convincing clinical evidence in this regard. This review comprises an exploration of currently available preclinical and clinical research on the role of MH in the management of obesity, IR, and DM.

Aqueous extract of Solanum macrocarpon Linn leaves abates hyperglycaemia and expression of glucose transporters gene in alloxan-induced diabetic rats

PURPOSE

In this study, antihyperglycaemic and level of gene expression of glucose transporters in alloxan-induced diabetic rats administered aqueous extract of S. macrocarpon leaves were assessed.

METHOD AND RESULTS

Diabetes was induced by a single intraperitoneal (I.P) injection of freshly prepared alloxan. The animals were divided into six groups, euthanized on the fourteenth day of the experiment and different hyperglycaemic parameters were evaluated. Administration of different doses of the plant extract significantly (p < 0.05) reduced the fasting blood glucose level, glycated haemoglobin, serum lipid profiles, lipid peroxidation, and glucose-6-phosphatase. There was a significant (p < 0.05) increase in liver glycogen content, antioxidant enzyme activities, hexokinase activity, and expression of glucose transporter genes (GLUT-2 and GLUT-4) in diabetic rats administered different doses of S. macrocarpon.

CONCLUSION

It can be concluded that the aqueous extract of S. macrocarpon leaves could be helpful in the management of diabetes mellitus and its metabolic complications.

Cymbopogon citratus (DC.) Stapf mitigates ER-stress induced by streptozotocin in rats via down-regulation of GRP78 and up-regulation of Nrf2 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Endoplasmic reticulum (ER) stress plays a role in the pathogenesis of diabetes mellitus, contributing to pancreatic dysfunction and insulin resistance. Ameliorating ER stress may be a viable therapeutic approach in the proper management of diabetes mellitus. Cymbopogon citratus (C.citratus) has been used in traditional medicine in the management of diabetes mellitus. Although well known for its anti-diabetic effect, the mechanism underlying this effect remains unclear.

AIM OF THE STUDY

This study was designed to investigate the effect of C. citratus methanolic leaves extract on ER stress induced by streptozotocin (STZ) in wistar rats.

MATERIALS AND METHODS

STZ (60 mg/kg) was used to induce ER stress in the pancreas of rats. The rats were administered C. citratus methanolic leaves extract via gastric gavage at doses 100, 200 and 400 mg/kg for two weeks while metformin (100 mg/kg) was used as positive control. Fasting blood glucose (FBG), expression of ER-stress related genes (GRP78, CHOP, ATF4, TRB3, PERK, IRE1), antioxidant (Nrf2 and AhR) and pro-inflammatory (TNF-α) genes were determined. Possible compounds responsible for this effect were also predicted through molecular docking.

RESULTS

Induction of ER stress using STZ significantly increased FBG while administration of C. citratus methanolic extract restored it to normal control level (p < 0.05). Significant down-regulation of ER stress genes was observed upon treatment of ER stress induced rats with C. citratus methanolic extract when compared to ER-stress untreated rats. Significant up-regulation (p < 0.05) of genes coding for Nrf2 and AhR was also noticed upon treatment of ER stress induced rats with C. citratus methanolic extract. Molecular docking suggests that apigenin targets GRP78 with binding affinity of -9.3 kcal/mol while kaempferol and quercetin target Keap1 with binding affinity of -9.5 kcal/mol and may be responsible for this ameliorative effect on ER stress.

CONCLUSION

These observations suggest that C. citratus mitigate ER stress induced by STZ via its down-regulative effect on GRP78 and up-regulative effect on NRF2 signaling.

Antistress and anti-aging activities of Caenorhabditis elegans were enhanced by Momordica saponin extract

BACKGROUND

Momordica saponin extract (MSE) was found to not only improve longevity and neuroprotection but also alleviate fat accumulation in Caenorhabditis elegans in our previous study. However, the lipid-lowering activity of MSE alone could not fully explain its ability to improve health, so the antistress effects of MSE were further studied.

METHODS

Using C. elegans as an in vivo animal, the lifespan of MSE-treated C. elegans under various stressors (H₂O₂, paraquat and heat) and normal conditions was studied. Furthermore, the antioxidant activities of MSE were discussed. To study the underlying mechanisms, the expression of stress resistance genes and the resistance of related mutants to H₂O₂ stress were tested.

RESULTS

MSE significantly improved the lifespan of C. elegans under stress and normal conditions. Meanwhile, the mobility of C. elegans was also improved. Moreover, the activities of SOD and CAT and the ratio of GSH/GSSG were elevated. Consistently, the levels of ROS and lipid oxidation (the NEFA and MDA content) were reduced. Furthermore, MSE treatment upregulated the expression of the sod-3, sod-5, clt-1, clt-2, hsp-16.1 and hsp-16.2 genes. All biomarkers indicated that the antistress and anti-aging activities of MSE were due to its strong antioxidant activities. Finally, MSE induced nuclear DAF-16::GFP localization. Studies with mutants revealed that skn-1 and hsf-1 were involved in the activity of MSE, which might upregulate the expression of downstream stress-responsive genes.

CONCLUSIONS

Therefore, in addition to its lipid-lowering property, the ability of MSE to improve healthspan was also attributed to the stress resistance effect. Together, MSE might serve as a lead nutraceutical in geriatric research.

Antihyperglycaemia and related gene expressions of aqueous extract of Gongronema latifolium leaf in alloxan-induced diabetic rats

Context: Gongronema latifolium Benth (Asclepiadaceae) has been highly utilized in controlling diabetes mellitus traditionally in the eastern part of Nigeria. Objectives: Antihyperglycaemic and related gene expressions of aqueous extract of Gongronema latifolium leaf in alloxan-induced diabetic rats. Materials and methods: Forty-eight female Wistar rats were induced intraperitoneally using alloxan (150 mg/kg body weight). The rats were separated into six groups (n = 8) as follows: non-diabetic control, diabetic control, diabetic rats administered 5 mg/kg body weight of metformin, and diabetic rats administered 6.36, 12.72 and 25.44 mg/kg body weight (ethnobotanical doses) of G. latifolium orally daily. On the 14th day, the animals were sacrificed and different antihyperglycaemic parameters were evaluated as well as its related gene expressions. Results: Diabetic rats administered three doses of aqueous extract of G. latifolium significantly (p < 0.05) lowered the fasting blood glucose, glycated haemoglobin, serum lipid profiles, lipid peroxidation (5.62-1.2 μ/mg protein) levels, as well as gene expression of glucose-6-phosphatase in alloxan-induced diabetic rats. There was a significant (p < 0.05) increase in the liver glycogen content (16.23-112.5 mg glucose/2 g), antioxidant enzymes activities, glucose transporter (GLUT-2 and GLUT-4) levels and relative gene expression of hexokinase in diabetic rats administered different doses of aqueous extract of G. latifolium. Discussion and conclusions: It can be deduced that the aqueous extract of G. latifolium leaf at these doses may be useful in managing diabetes mellitus and its associated complications. Therefore, this extract may be a potent antidiabetic agent in clinical therapy in the future.