Anti-diabetic Effect of Punica granatum Flower Polyphenols Extract in Type 2 Diabetic Rats: Activation of Akt/GSK-3β and Inhibition of IRE1α-XBP1 Pathways

Cardioprotective Effects of 'Vasant Kusumakar Rasa,' a Herbo-metallic Formulation, in Type 2 Diabetic Cardiomyopathy in Rats

Diabetic cardiomyopathy (DCM) is one of the serious complications of type 2 diabetes mellitus. Vasant Kusumakar Rasa (VKR) is a Herbo-metallic formulation reported in Ayurveda, an Indian system of medicine. The present work was designed to study the effect of VKR in cardiomyopathy in type 2 diabetic rats. Diabetes was induced by feeding a high-fat diet (HFD) for 2 weeks followed by streptozotocin (STZ) administration (35 mg/kg i.p.). VKR was administered orally at dose of 28 and 56 mg/kg once a day for 16 weeks. The results of the study indicated that VKR treatment significantly improved the glycemic and lipid profile, serum insulin, CK-MB, LDH, and cardiac troponin-I when compared to diabetic control animals. VKR treatment in rats significantly improved the hemodynamic parameters and cardiac tissue levels of TNF-α, IL-1β, and IL- 6 were also reduced. Antioxidant enzymes such as GSH, SOD, and catalase were improved in all treatment groups. Heart sections stained with H & E and Masson's trichome showed decreased damage to histoarchitecture of the myocardium. Expression of PI3K, Akt, and GLUT4 in the myocardium was upregulated after 16 weeks of VKR treatment. The study data suggested the cardioprotective capability of VKR in the management of diabetic cardiomyopathy in rats.

Endoplasmic reticulum stress mechanisms and exercise intervention in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a metabolic disease primarily characterized by insulin resistance (IR) and insufficient insulin secretion. The unfolded protein response (UPR) overactivation induced by endoplasmic reticulum stress (ERS) appears to play a key role in this process, although the exact pathogenesis of T2DM is not fully understood. Studies have demonstrated that appropriate exercise can regulate ERS in the heart, liver, pancreas, skeletal muscle, and other body tissues leading to an improvement in diabetes and its complications. However, the exact mechanism remains unclear. By analyzing the relationship between ERS, T2DM pathology, and exercise intervention, this review concludes that exercise can increase insulin sensitivity, inhibit IR, promote insulin secretion and alleviate T2DM by regulating ERS. This paper specifically reviews the signaling pathways by which ERS induces diabetes, the mechanisms of exercise regulation of ERS in diabetes, and the varying effects of different types of exercise on diabetes improvement through ERS mechanisms. Physical exercise is an effective non-pharmacological intervention for T2DM. Thus, further exploration of how exercise regulates ERS in diabetes could refine "precision exercise medicine" for diabetes and identify new drug targets.

Revealing metabolic and biochemical variations via 1H NMR metabolomics in streptozotocin-nicotinamide-induced diabetic rats treated with metformin

The increasing prevalence of lean diabetes has prompted the generation of animal models that mimic metabolic disease in humans. This study aimed to determine the optimum streptozotocin-nicotinamide (STZ-NA) dosage ratio to elicit lean diabetic features in a rat model. It also used a proton nuclear magnetic resonance (1H NMR) urinary metabolomics approach to identify the metabolic effect of metformin treatment on this novel rat model. Three different STZ-NA dosage regimens (by body weight: Group A: 110 mg/kg NA and 45 mg/kg STZ; Group B: 180 mg/kg NA and 65 mg/kg STZ and Group C: 120 mg/kg NA and 60 mg/kg STZ) were administered to Sprague-Dawley rats along with oral metformin. Group A diabetic rats (A-DC) showed favorable serum biochemical analyses and a more positive response toward oral metformin administration relative to the other STZ-NA dosage ratio groups. Orthogonal partial least squares-discriminant analysis (OPLS-DA) revealed that glucose, citrate, pyruvate, hippurate, and methylnicotinamide differentiating the OPLS-DA of A-MTF rats (Group A diabetic rats treated with metformin) and A-DC model rats. Subsequent metabolic pathway analyses revealed that metformin treatment was associated with improvement in dysfunctions caused by STZ-NA induction, including carbohydrate metabolism, cofactor metabolism, and vitamin and amino acid metabolism. In conclusion, our results identify the best STZ-NA dosage ratio for a rat model to exhibit lean type 2 diabetic features with optimum sensitivity to metformin treatment. The data presented here could be informative to improve our understanding of non-obese diabetes in humans through the identification of possible activated metabolic pathways in the STZ-NA-induced diabetic rats model.

Centella asiatica mitigates the detrimental effects of Bisphenol-A (BPA) on pancreatic islets

Bisphenol-A (BPA) is widely used in food packaging and household products, leading to daily human exposure and potential health risks including metabolic diseases like type 2 diabetes mellitus (T2DM). Understanding BPA's mechanisms and developing intervention strategies is urgent. Centella asiatica, a traditional herbal medicine containing pentacyclic triterpenoids, shows promise due to its antioxidant and anti-inflammatory properties, utilized for centuries in Ayurvedic therapy. We investigated the effect of Centella asiatica (CA) ethanol extract on BPA-induced pancreatic islet toxicity in male Swiss albino mice. BPA administration (10 and 100 μg/kg body weight, twice daily) for 21 days caused glucose homeostasis disturbances, insulin resistance, and islet dysfunction, which were partially mitigated by CA supplementation (200 and 400 mg/kg body weight). Additionally, heightened oxidative stress, elevated levels of proinflammatory cytokines, loss of mitochondrial membrane potential (MMP), abnormal cell cycle, and increased apoptosis were implicated in the detrimental impact of BPA on the endocrine pancreas which were effectively counteracted by CA supplementation. In summary, CA demonstrated a significant ability to mitigate BPA-induced apoptosis, modulate redox homeostasis, alleviate inflammation, preserve MMP, and regulate the cell cycle. As a result, CA emerged as a potent agent in neutralizing the diabetogenic effects of BPA to a considerable extent.

Antidiabetic effect of Ardisia elliptica extract and its mechanisms of action in STZ-NA-induced diabetic rat model via 1H-NMR-based metabolomics

ETHNOPHARMACOLOGICAL RELEVANCE

Ardisia elliptica Thunb. (AE) (Primulaceae) is a medicinal plant found in the Malay Peninsula and has been traditionally used to treat diabetes. However, limited studies to date in providing scientific evidence to support the antidiabetic efficacy of this plant by in-vitro and in-vivo models.

AIM OF THE STUDY

To investigate the anti-hyperglycemic potential of AE through in-vitro enzymatic activities and streptozotocin-nicotinamide (STZ-NA) induced diabetic rat models using proton-nuclear magnetic resonance (1H-NMR)-based metabolomics approach.

MATERIALS AND METHODS

Anti-α-amylase and anti-α-glucosidase activities of the hydroethanolic extracts of AE were evaluated. The absolute quantification of bioactive constituents, using ultra-high performance liquid chromatography (UHPLC) was performed for the most active extract. Three different dosage levels of the AE extract were orally administered for 4 weeks consecutively in STZ-NA induced diabetic rats. Physical assessments, biochemical analysis, and an untargeted 1H-NMR-based metabolomics analysis of the urine and serum were carried out on the animal model.

RESULTS

Type 2 diabetes mellitus (T2DM) rat model was successfully developed based on the clear separation observed between the STZ-NA induced diabetic and normal non-diabetic groups. Discriminating biomarkers included glucose, citrate, succinate, allantoin, hippurate, 2-oxoglutarate, and 3-hydroxybutyrate, as determined through an orthogonal partial least squares-discriminant analysis (OPLS-DA) model. A treatment dosage of 250 mg/kg body weight (BW) of standardized 70% ethanolic AE extract mitigated increase in serum glucose, creatinine, and urea levels, providing treatment levels comparable to that obtained using metformin, with flavonoids primarily contribute to the anti-hyperglycemic activities. Urinary metabolomics disclosed that the following disturbed metabolism pathways: the citrate cycle (TCA cycle), butanoate metabolism, glycolysis and gluconeogenesis, pyruvate metabolism, and synthesis and degradation of ketone bodies, were ameliorated after treatment with the standardized AE extract.

CONCLUSIONS

This study demonstrated the first attempt at revealing the therapeutic effect of oral treatment with 250 mg/kg BW of standardized AE extract on chemically induced T2DM rats. The present study provides scientific evidence supporting the ethnomedicinal use of Ardisia elliptica and further advances the understanding of the fundamental molecular mechanisms affected by this herbal antidote.

Neuroprotective Effects of Isolated Mangiferin from Swertia chirayita Leaves Regulating Oxidative Pathway on Streptozotocin-Induced Diabetic Neuropathy in Experimental Rats

BACKGROUND

Oxidative stress has an important role in the pathogenesis and development of diabetic peripheral neuropathy (DPN), the most common and debilitating complication of diabetes mellitus. Swertia chirayita is a rich source of phenolic constituents and has hypoglycemic, anti-inflammatory, and antioxidant properties.

AIMS

This study was performed to evaluate the neuroprotective effect in diabetes by enhancing antioxidant defense against oxidative stress, which exhibits a neuroprotective effect in streptozotocin- induced diabetic rats.

OBJECTIVES

The objective of this study was to elucidate the therapeutic potential of bioactive compounds of Swertia chirayita for diabetic complications.

METHODS

The present work focused on isolating the bioactive from the leaves of Swertia absinthe for acute toxicity studies, assessing its protective effects against diabetes and diabetic neuropathy as well as its mode of action in STZ-induced Wistar rats. The local area of Moradabad is the place from where the leaves of Swertia chirayita were gathered. Mangiferin was isolated and identified using spectroscopic techniques, such as UV, HPLC, 1H NMR, C13 NMR, MAS, and FTIR. Mangiferin was administered in doses of 15 and 30 mg/kg to test its effect on experimentally induced diabetes. The sciatic nerves of all groups were examined histopathologically. The protective effect of the drug against diabetes and diabetic neuropathy was demonstrated by measures, such as blood glucose level, body weight, food intake, thermal hyperalgesia, grip strength, spontaneous locomotor test, and lipid profile analysis. Sciatic nerve cells of the treated groups showed less inflammation, degeneration, and necrosis.

RESULTS

The results of this study confirmed that mangiferin alleviated diabetic neuropathic pain, possibly by reducing inflammatory cytokines (TNF-α, TGF-β1, IL-1β, and IL-6), strong antioxidant activity, and NGF in sciatic nerves. It may be a therapeutic agent.

CONCLUSION

Our results suggested that active phytochemicals of Swertia chirayita showed preventive and curative effects against STZ-induced diabetic neuropathy in rats, which might be due to its antioxidant, anti-inflammatory, and anti-apoptotic properties.

Overview of Natural Supplements for the Management of Diabetes and Obesity

Bioactive compounds found in various natural sources, such as fruits, vegetables, and herbs, have been studied for their potential benefits in managing obesity and diabetes. These compounds include polyphenols, flavonoids, other antioxidants, fiber, and certain fatty acids. Studies have found that these compounds may improve insulin sensitivity, regulate blood sugar levels, and promote weight loss. However, the effects of these compounds can vary depending on the type and amount consumed, as well as individual factors, such as genetics and lifestyle. Nutraceutical substances have multifaceted therapeutic advantages, and they have been reported to have disease-prevention and health-promoting properties. Several clinically used nutraceuticals have been shown to target the pathogenesis of diabetes mellitus, obesity, and metabolic syndrome and their complications and modulate various clinical outcomes favorably. This review aims to highlight and comment on some of the most prominent natural components used as antidiabetics and in managing obesity.

An insight into the neuroprotective effects and molecular targets of pomegranate (Punica granatum) against Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease that still has no permanent cure. The drugs prescribed in the present days are only for symptomatic relief for the patients. Many studies correlating the reduction in the incidence of AD with the diet consumed have been published. These studies showed that a diet rich in polyphenols is associated with a decrease in the incidence of AD. The present review is focused on the ability of pomegranate and its bioactive components to ameliorate the progression of AD and their ability to exert a neuroprotective effect. Various studies showing the ability of pomegranate in inhibiting enzymes, reducing reactive oxygen species, inhibition of microglial activation, inhibition of tau protein hyperphosphorylation, maintenance of synaptic plasticity, anti-inflammatory activity and its ability to inhibit Beta secretase-1 (BACE-1) has been reviewed in this article. In spite of the lack of studies on humans, there are compelling evidence indicating that pomegranate can reduce various risk factors involved in the causation of AD and thus can be used as a persistent nutraceutical to slow ageing and for providing neuroprotection for the treatment of AD.Highlights An overview of traditional and pharmacological uses of pomegranate (POM).Potential of POM in the treatment of neurodegenerative diseases especially in AD.Insight into the molecular mechanisms of neuroprotective effects of POM in AD.Clinical evaluation studies involving POM and its bioactive components.

An Overview of the Health Benefits, Extraction Methods and Improving the Properties of Pomegranate

Pomegranate (Punica granatum L.) is a polyphenol-rich edible food and medicinal plant of ancient origin, containing flavonols, anthocyanins, and tannins, with ellagitannins as the most abundant polyphenols. In the last decades, its consumption and scientific interest increased, due to its multiple beneficial effects. Pomegranate is a balausta fruit, a large berry surrounded by a thick colored peel composed of exocarp and mesocarp with edible arils inside, from which the pomegranate juice can be produced by pressing. Seeds are used to obtain the seed oil, rich in fatty acids. The non-edible part of the fruit, the peel, although generally disposed as a waste or transformed into compost or biogas, is also used to extract bioactive products. This review summarizes some recent preclinical and clinical studies on pomegranate, which highlight promising beneficial effects in several fields. Although further insight is needed on key aspects, including the limited oral bioavailability and the role of possible active metabolites, the ongoing development of suitable encapsulation and green extraction techniques enabling the valorization of waste pomegranate products point to the great potential of pomegranate and its bioactive constituents as dietary supplements or adjuvants in therapies of cardiovascular and non-cardiovascular diseases.

Metabolic Alterations in Streptozotocin-nicotinamide-induced Diabetic Rats Treated with Muntingia calabura Extract via 1H-NMR-based Metabolomics

Diabetes mellitus (DM) is a metabolic endocrine disorder caused by decreased insulin concentration or poor insulin response. Muntingia calabura (MC) has been used traditionally to reduce blood glucose levels. This study aims to support the traditional claim of MC as a functional food and blood-glucose-lowering regimen. The antidiabetic potential of MC is tested on a streptozotocin-nicotinamide (STZ-NA)-induced diabetic rat model by using the ¹H-NMR-based metabolomic approach. Serum biochemical analyses reveal that treatment with 250 mg/kg body weight (bw) standardized freeze-dried (FD) 50% ethanolic MC extract (MCE 250) shows favorable serum creatinine (37.77 ± 3.53 µM), urea (5.98 ± 0.84 mM) and glucose (7.36 ± 0.57 mM) lowering capacity, which was comparable to the standard drug, metformin. The clear separation between diabetic control (DC) and normal group in principal component analysis indicates the successful induction of diabetes in the STZ-NA-induced type 2 diabetic rat model. A total of nine biomarkers, including allantoin, glucose, methylnicotinamide, lactate, hippurate, creatine, dimethylamine, citrate and pyruvate are identified in rats' urinary profile, discriminating DC and normal groups through orthogonal partial least squares-discriminant analysis. Induction of diabetes by STZ-NA is due to alteration in the tricarboxylic acid (TCA) cycle, gluconeogenesis pathway, pyruvate metabolism and nicotinate and nicotinamide metabolism. Oral treatment with MCE 250 in STZ-NA-induced diabetic rats shows improvement in the altered carbohydrate metabolism, cofactor and vitamin metabolic pathway, as well as purine and homocysteine metabolism.

Tea polyphenol EGCG ameliorates obesity-related complications by regulating lipidomic pathway in leptin receptor knockout rats

Tea polyphenol EGCG has been widely recognized for antiobesity effects. However, the molecular mechanism of lipidomic pathway related to lipid-lowering effect of EGCG is still not well understood. The aim of this study was to investigate the effects and mechanism of EGCG activated hepatic lipidomic pathways on ameliorating obesity-related complications by using newly developed leptin receptor knockout (Lepr KO) rats. Results showed that EGCG supplementation (100 mg/kg body weight) significantly decreased total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels both in the serum and liver, and significantly improved glucose intolerance. In addition, EGCG alleviated fatty liver development and restored the normal liver function in Lepr KO rats. Liver lipidomic analysis revealed that EGCG dramatically changes overall composition of lipid classes. Notably, EGCG significantly decreased an array of triglycerides (TGs) and diglycerides (DGs) levels. While EGCG increased 31 glycerophospholipid species and 1 sphingolipid species levels, such as phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), phosphatidylserines (PSs) and phosphatidylinositols (PIs) levels in the liver of Lepr KO rats. Moreover, 14 diversely regulated lipid species were identified as potential lipid biomarkers. Mechanistic analysis revealed that EGCG significantly activated the SIRT6/AMPK/SREBP1/FAS pathway to decrease DGs and TGs levels and upregulated glycerophospholipids synthesis pathways to increase glycerophospholipid level in the liver of Lepr KO rats. These findings suggested that the regulation of glycerolipids and glycerophospholipid homeostasis might be the key pathways for EGCG in ameliorating obesity-related complications in Lepr KO rats.

Antihyperglycemic Potential of Spondias mangifera Fruits via Inhibition of 11β-HSD Type 1 Enzyme: In Silico and In Vivo Approach

The 11 β- hydroxysteroid dehydrogenase 1 (11 β-HSD1) is hypothesized to play a role in the pathogenesis of type 2 diabetes and its related complications. Because high glucocorticoid levels are a risk factor for metabolic disorders, 11β-HSD1 might be a viable therapeutic target. In this investigation, docking experiments were performed on the main constituents of Spondias mangifera (SM) oleanolic acid, β-amyrin, and β-sitosterol to ascertain their affinity and binding interaction in the human 11β-hydroxysteroid dehydrogenase-1 enzyme’s active region. The results of in vitro 11β HSD1 inhibitory assay demonstrated that the extract of S. mangifera had a significant (p < 0.05) decrease in the 11-HSD1% inhibition (63.97%) in comparison to STZ (31.79%). Additionally, a non-insulin-dependent diabetic mice model was used to examine the sub-acute anti-hyperlipidemic and anti-diabetic effects of SM fruits. Results revealed that, in comparison to the diabetic control group, SM fruit extract (SMFE) extract at doses of 200 and 400 mg/kg body weight considerably (p < 0.05 and p < 0.01) lowered blood glucose levels at 21 and 28 days, as well as significantly decreased total cholesterol (TC) and triglycerides (TG) and enhanced the levels of high-density lipoprotein (HDL). After 120 and 180 s of receiving 200 and 400 mg/kg SMFE, respectively, disease control mice showed significantly poorer blood glucose tolerance (p < 0.05 and p < 0.01). SMFE extract 200 (p < 0.05), SMFE extract 400 (p < 0.01), and Glibenclamide at a dosage of 5 mg/kg body weight all resulted in statistically significant weight increase (p < 0.01) when compared to the diabetic control group after 28 days of treatment. According to in silico, in vitro, and in vivo validation, SMFE is a prospective medication with anti-diabetic and hypoglycemic effects.

Anthocyanin-rich extract from black beans exerts anti-diabetic effects in rats through a multi-genomic mode of action in adipose tissue

Black beans (BB) are an important source of a range of plant bioactive compounds including polyphenols, particularly anthocyanins. Several studies support that consumption of BB is associated with health benefits, including prevention of type 2 diabetes mellitus (T2DM). However, molecular mechanisms underlying the potential health properties of BB on adipose tissue (AT) are still largely unknown. The purpose of this study was to investigate multi-genomic effects of BB intake and identify regulatory networks potentially mediating T2DM on AT. Male Wistar diabetic rats consumed an anthocyanin-rich black bean extract for 5 weeks. Global gene expression from AT, protein coding and non-coding RNA profiles were determined using RNAseq. Biological function analyses were performed using a variety of bioinformatic tools. The evaluation of global gene expression profiles exhibited significant change following BB consumption with 406 significantly differentially expressed genes, 33 miRNA and 39 lncRNA and 3 snRNA. Functional analyses indicated that these genes play an important role in regulation of PI3K signaling, NIN/NF-kB signaling, insulin secretion, and endoplasmic reticulum (ER) organization. Interestingly, transcription factors such as GATA2, or POU2AF1 demonstrated to modulate their activity by BB extract by direct interaction with polyphenol metabolites, or by interactions with cell signaling proteins, like PKB, AKT or PI3K, that could control transcription factor activity and as a result impact on adipogenesis regulation. Therefore, the constant consumption of an anthocyanin-rich black bean extract may have anti-diabetic protective effects by modulating gene expression, resulting in a promising alternative for T2DM patients.

Anthocyanin-rich extract from black beans exerts anti-diabetic effects in rats through a multi-genomic mode of action in adipose tissue

Black beans (BB) are an important source of a range of plant bioactive compounds including polyphenols, particularly anthocyanins. Several studies support that consumption of BB is associated with health benefits, including prevention of type 2 diabetes mellitus (T2DM). However, molecular mechanisms underlying the potential health properties of BB on adipose tissue (AT) are still largely unknown. The purpose of this study was to investigate multi-genomic effects of BB intake and identify regulatory networks potentially mediating T2DM on AT. Male Wistar diabetic rats consumed an anthocyanin-rich black bean extract for 5 weeks. Global gene expression from AT, protein coding and non-coding RNA profiles were determined using RNAseq. Biological function analyses were performed using a variety of bioinformatic tools. The evaluation of global gene expression profiles exhibited significant change following BB consumption with 406 significantly differentially expressed genes, 33 miRNA and 39 lncRNA and 3 snRNA. Functional analyses indicated that these genes play an important role in regulation of PI3K signaling, NIN/NF-kB signaling, insulin secretion, and endoplasmic reticulum (ER) organization. Interestingly, transcription factors such as GATA2, or POU2AF1 demonstrated to modulate their activity by BB extract by direct interaction with polyphenol metabolites, or by interactions with cell signaling proteins, like PKB, AKT or PI3K, that could control transcription factor activity and as a result impact on adipogenesis regulation. Therefore, the constant consumption of an anthocyanin-rich black bean extract may have anti-diabetic protective effects by modulating gene expression, resulting in a promising alternative for T2DM patients.

Amelioration of hyperglycemia and hyperlipidemia in a high-fat diet-fed mice by supplementation of a developed optimized polyherbal formulation

This study evaluated in vivo anti-diabetic and anti-obesity activity of a polyherbal formulation's methanolic extract containing an optimized ratio of edible seeds (Salvia hispanica, Chenopodium quinoa, Nelumbo nucifera). Diet-induced obese mice model (C57BL/6) was developed by feeding the mice a high-fat diet for 10 weeks resulting in hyperglycemia and obesity. Different doses (125, 250 and 500 mg/kg of body weight) of formulation were administered orally daily for 6 weeks. Fasting blood glucose and body weight were monitored throughout the study. At the end of the study, serum parameters were analyzed and histological examinations were performed. There was a significant reduction in fasting blood glucose levels and body weight in animal groups receiving polyherbal formulation. Lipid profile was improved as revealed by a reduction in serum triglycerides and total cholesterol. Histological study showed an improvement in liver, kidney and pancreatic sections of treated mice. High-performance thin layer chromatography was performed to identify the phytochemicals responsible for the above-mentioned bioactivities. The results revealed the presence of flavonoid (rutin) in seeds of N.nucifera and in the polyherbal formulation. For the first time, this study demonstrated the anti-diabetic and anti-obesity potential of the optimized formulation. The formulation can be used as a potential therapy for management of diabesity.

Pharmacologically Active Phytomolecules Isolated from Traditional Antidiabetic Plants and Their Therapeutic Role for the Management of Diabetes Mellitus

Diabetes mellitus is a chronic complication that affects people of all ages. The increased prevalence of diabetes worldwide has led to the development of several synthetic drugs to tackle this health problem. Such drugs, although effective as antihyperglycemic agents, are accompanied by various side effects, costly, and inaccessible to the majority of people living in underdeveloped countries. Medicinal plants have been used traditionally throughout the ages to treat various ailments due to their availability and safe nature. Medicinal plants are a rich source of phytochemicals that possess several health benefits. As diabetes continues to become prevalent, health care practitioners are considering plant-based medicines as a potential source of antidiabetic drugs due to their high potency and fewer side effects. To better understand the mechanism of action of medicinal plants, their active phytoconstituents are being isolated and investigated thoroughly. In this review article, we have focused on pharmacologically active phytomolecules isolated from medicinal plants presenting antidiabetic activity and the role they play in the treatment and management of diabetes. These natural compounds may represent as good candidates for a novel therapeutic approach and/or effective and alternative therapies for diabetes.

Protective Mechanism of Fagopyrum esculentum Moench. Bee Pollen EtOH Extract Against Type II Diabetes in a High-Fat Diet/Streptozocin-Induced C57BL/6J Mice

Bee pollen is known as a natural nutrient storehouse and plays a key role in many biological processes. Based on the preliminary separation, identification, and characterization of the main active components of Fagopyrum esculentum Moench. bee pollen (FBP), the protective effects of F. esculentum bee pollen extract (FBPE) on high-fat-diet (HFD) and streptozocin (STZ) induced type II diabetes mellitus (T2DM) was evaluated in this study. The results revealed that FBPE contains 10 active compounds mainly including luteolin (9.46 g/kg), resveratrol (5.25 g/kg), kaemferol (3.67 g/kg), etc. The animal experiment results showed that FBPE could improve HFD-STZ induced T2DM mice. Moreover, the underlying mechanism of the above results could be: (i) FBPE could reduce the inflammation related to phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway, and (ii) the gut microbiota remodeling. The results of correlation analysis showed Candidatus Arthromitus and SMB53 indicated positive correlations to tumor necrosis factor-α (TNF-α); Coprococcus, Ruminocossus, and Odoribacteraceae reported negative correlations to transforming growth factor-β (TGF-β). That FBPE has an outstanding ability to improve T2DM and could be used as a kind of potential functional food for the prevention of T2DM.

Punicalagin protects against the development of pancreatic injury and insulitis in rats with induced T1DM by reducing inflammation and oxidative stress

Pancreatic inflammation and oxidative damage remain major concerns in type 1 diabetes mellitus (T1DM). Punicalagin, a major polyphenol in pomegranates, exhibited antioxidant and protective effects on several organs in case of T1DM; however, no study has yet explored the protective effects of punicalagin on the pancreas and islets of Langerhans. T1DM was induced by injecting 40 mg/kg streptozotocin (STZ) intraperitoneally. Punicalagin (1 mg/kg ip) was injected daily for 15 days after T1DM induction. In diabetic rats, punicalagin treatment lowered the levels of inflammatory biomarkers (monocyte chemoattractant protein-1 and C-reactive protein) and adhesion molecules (E-selectin, intercellular adhesion molecule, and vascular cell adhesion molecule) while activating myeloperoxidase activity. Treatment of diabetic rats with punicalagin improved glutathione content and superoxide dismutase, catalase, and glutathione peroxidase activities; upregulated serum paraoxonase-1 activity; and prevented the elevation lipid peroxidation and protein oxidation products in the pancreas. Furthermore, punicalagin protected the pancreas against STZ-induced histopathological alterations and increased immune-reactive β-cells while reducing leucocyte infiltration into the islets of Langerhans, leading to normalized blood glucose and insulin levels. These findings indicated that punicalagin might protect against the development of insulitis in T1DM. In conclusion, punicalagin exerts a strong protective effect on the pancreas against oxidative injury and inflammation in STZ-induced experimental T1DM. The present results recommend punicalagin as a potential adjuvant for reducing diabetes-associated insulitis.

Flavonoid constituents of Amomum tsao-ko Crevost et Lemarie and their antioxidant and antidiabetic effects in diabetic rats - in vitro and in vivo studies

Amomum tsao-ko Crevost et Lemarie (A. tsao-ko) is a well-known dietary spice and traditional Chinese medicine. This study aimed to identify the flavonoids in A. tsao-ko and evaluate their antioxidant and antidiabetic activities in in vitro and in vivo studies. A. tsao-ko methanol extracts possessed a high flavonoid content (1.21 mg QE per g DW) and a total of 29 flavonoids were identified by employing UPLC-MS/MS. In vitro, A. tsao-ko demonstrated antioxidant activity (ORAC value of 34276.57 μM TE/100 g DW, IC₅₀ of ABTS of 3.49 mg mL^-1 and FRAP value of 207.42 μM Fe²⁺ per g DW) and α-amylase and α-glucosidase inhibitory ability with IC₅₀ values of 14.23 and 1.76 mg mL^-1, respectively. In vivo, type 2 diabetes mellitus (T2DM) models were induced by a combined high-fat diet (HFD) and streptozotocin (STZ) injection in rats. Treatment with the A. tsao-ko extract (100 mg freeze-dried powder per kg bw) for 6 weeks could significantly improve impaired glucose tolerance, decrease the levels of fasting blood glucose (FBG), insulin, and malondialdehyde (MDA), and increase the superoxide dismutase (SOD) level. Histopathology revealed that the A. tsao-ko extract preserved the architecture and function of the pancreas. In conclusion, the flavonoid composition of A. tsao-ko exhibits excellent antioxidant and antidiabetic activity in vitro and in vivo. A. tsao-ko could be a novel natural material and developed as a related functional food and medicine in T2DM management.

Blackthorn Flower Extract Impact on Glycaemic Homeostasis in Normoglycaemic and Alloxan-Induced Hyperglycaemic C57BL/6 Mice

Research background

The use of plants and their extracts in treatments of chronic diseases is widely known in traditional medicine. The aim of this study is to determine the effects of 10-day consumption of blackthorn (Prunus spinosa L.) flower extract on blood glucose, glycaemic load, serum α-amlyase activity and insulin concentration in normoglycaemic and hyperglycaemic (alloxan-induced) mice model.

Experimental approach

Normoglycaemic and hyperglycaemic (treated with alloxan, 150 mg per kg body mass) C57BL/6 mice were administered daily, during 10 days, blackthorn flower extract by gavage. The sugar mass concentration within the extract was determined by HPLC analysis. In mice, blood and serum blood glucose concentrations, and oral glucose tolerance test were determined by blood glucometer. Serum insulin concentration was determined by ELISA assay and α-amylase activity by colourimetric assay.

Results and conclusions

The blackthorn flower extract increased glucose concentrations in normoglycaemic mice by 30% after the 1st and 5th day and by 17% after the 10th day of consumption. It is a consequence of released sugars because sugar analysis revealed 59.8 mg/L monosaccharides, mainly fructose (55.7 mg/L) and glucose (24.3 mg/L) in the extract. On the contrary, the extract consumption reduced serum blood glucose in hyperglycaemic mice by 29% after 10 days of treatment. Oral glucose tolerance test also confirmed that in the hyperglycaemic group treated with blackthorn flower extract glucose homeostasis was improved and showed decrease in blood glucose. Serum insulin concentration increased by 49% and serum α-amylase activity by 46% after 10 days of treatment with blackthorn flower extract in hyperglycaemic group. Thus, it can be concluded that blackthorn flower extract improved glucose tolerance, enhanced insulin secretion and lowered serum α-amylase activity.

Novelty and scientific contribution

The obtained results show for the first time the potential of blackthorn (Prunus spinosa L.) flower extract in hyperglycaemia management.

Antidiabetic Medicinal Plants Used in Democratic Republic of Congo: A Critical Review of Ethnopharmacology and Bioactivity Data

Several studies have been conducted and published on medicinal plants used to manage Diabetes Mellitus worldwide. It is of great interest to review available studies from a country or a region to resort to similarities/discrepancies and data quality. Here, we examined data related to ethnopharmacology and bioactivity of antidiabetic plants used in the Democratic Republic of Congo. Data were extracted from Google Scholar, Medline/PubMed, Scopus, ScienceDirect, the Wiley Online Library, Web of Science, and other documents focusing on ethnopharmacology, pharmacology, and phytochemistry antidiabetic plants used in the Democratic Republic of Congo from 2005 to September 2021. The Kew Botanic Royal Garden and Plants of the World Online web databases were consulted to verify the taxonomic information. CAMARADES checklist was used to assess the quality of animal studies and Jadad scores for clinical trials. In total, 213 plant species belonging to 72 botanical families were reported. Only one plant, Droogmansia munamensis, is typically native to the DRC flora; 117 species are growing in the DRC and neighboring countries; 31 species are either introduced from other regions, and 64 are not specified. Alongside the treatment of Diabetes, about 78.13% of plants have multiple therapeutic uses, depending on the study sites. Experimental studies explored the antidiabetic activity of 133 plants, mainly in mice, rats, guinea pigs, and rabbits. Several chemical classes of antidiabetic compounds isolated from 67 plant species have been documented. Rare phase II clinical trials have been conducted. Critical issues included poor quality methodological protocols, author name incorrectly written (16.16%) or absent (14.25%) or confused with a synonym (4.69%), family name revised (17.26%) or missing (1.10%), voucher number not available 336(92.05%), ecological information not reported (49.59%). Most plant species have been identified and authenticated (89.32%). Hundreds of plants are used to treat Diabetes by traditional healers in DRC. However, most plants are not exclusively native to the local flora and have multiple therapeutic uses. The analysis showed the scarcity or absence of high-quality, in-depth pharmacological studies. There is a need to conduct further studies of locally specific species to fill the gap before their introduction into the national pharmacopeia.

Antioxidant and anticancer potentials of edible flowers: where do we stand?

Edible flowers are attracting special therapeutic attention and their administration is on the rise. Edible flowers play pivotal modulatory roles on oxidative stress and related interconnected apoptotic/inflammatory pathways toward the treatment of cancer. In this review, we highlighted the phytochemical content and therapeutic applications of edible flowers, as well as their modulatory potential on the oxidative stress pathways and apoptotic/inflammatory mediators, resulting in anticancer effects. Edible flowers are promising sources of phytochemicals (e.g., phenolic compounds, carotenoids, terpenoids) with several therapeutic effects. They possess anti-inflammatory, anti-diabetic, anti-microbial, anti-depressant, anxiolytic, anti-obesity, cardioprotective, and neuroprotective effects. Edible flowers potentially modulate oxidative stress by targeting erythroid nuclear transcription factor-2/extracellular signal-regulated kinase/mitogen-activated protein kinase (Nrf2/ERK/MAPK), reactive oxygen species (ROS), nitric oxide (NO), malondialdehyde (MDA) and antioxidant response elements (AREs). As the interconnected pathways to oxidative stress, inflammatory mediators, including tumor necrosis factor (TNF)-α, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), interleukins (ILs) as well as apoptotic pathways such as Bcl-2-associated X protein (Bax), Bcl-2, caspase and cytochrome C are critical targets of edible flowers in combating cancer. In this regard, edible flowers could play promising anticancer effects by targeting oxidative stress and downstream dysregulated pathways.

Silencing circANKRD36 inhibits streptozotocin-induced insulin resistance and inflammation in diabetic rats by targeting miR-145 via XBP1

BACKGROUND

Diabetes mellitus (DM) is defined as a group of metabolic diseases characterized by hyperglycemia, which results from a deficiency in insulin secretion and/or insulin action. In diabetic patients, type 2 diabetes mellitus (T2DM) is in the majority. We explored the effects of circANKRD36 on streptozotocin (STZ)-induced insulin resistance and inflammation in diabetic rats with the aim of uncovering the underlying mechanism.

METHODS

STZ was used to induce the in vivo T2DM rat model. After circANKRD36 interference, blood glucose, insulin and adiponectin were respectively detected. Hematoxylin and eosin (H&E), enzyme-linked immunosorbent assay (ELISA) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) were conducted to examine inflammation and apoptosis in T2DM rats, and western blot was used for detecting apoptosis-related proteins. The binding relationships among circANKRD36, miR-145 and XBP1 were examined by luciferase reporter assay.

RESULTS

Results showed that circANKRD36 was expressed at a high level in T2DM rats, while silencing circANKRD36 led to decreased blood glucose and insulin, accompanied by increased adiponectin level, and ameliorating insulin resistance. Silencing circANKRD36 alleviated the inflammation and suppressed cell apoptosis in the pancreatic tissues of T2DM rats, which was abated by miR-145 inhibitor. The binding of miR-145 to XBP1 was then confirmed. Additionally, miR-145 inhibitor increased the level of XBP1 in T2DM rats, which was decreased in the presence of circANKRD36 silencing.

CONCLUSION

This study is the first to prove that silencing circANKRD36 inhibits STZ-induced insulin resistance and inflammation in diabetic rats by targeting miR- 145 via XBP1. The results warrant the importance of circRNAs as drug target and thereby pave way for the development of newer therapeutic measures for T2DM.

Glycolipid metabolism and liver transcriptomic analysis of the therapeutic effects of pressed degreased walnut meal extracts on type 2 diabetes mellitus rats

Walnut meal (WM) is rich in polyphenols which exhibit multiple therapeutic effects. The purpose of this study was to investigate the therapeutic effects of walnut meal extracts (WMP) on glycolipid metabolism and liver transcriptomics in T2DM rats. A T2DM rat model was established by using a high-fat diet combined with streptozotocin. A 5-week WMP therapy showed the effects of decreasing water intake, excretion, fasting blood glucose, fasting insulin, and insulin resistance, increasing β-cell function and insulin sensitivity index; meanwhile regulating dysfunctional lipid metabolism and reducing inflammation; improving body weight, oral glucose tolerance test and insulin sensitivity; and increasing the activities of SOD and CAT while decreasing the MDA levels in the liver and serum of T2DM rats. Moreover, 10 key differentially expressed genes were identified by RNA-seq, including Gck, RT1-Ba, Fasn, Slc13a3, Cd74, Jun, Cyp4a1, Myh7b, Plin3, and Got1, and they were highly potentially related to glycolipid metabolism. Our results suggested that WMP exhibited the anti-diabetic effect and could regulate glycolipid metabolism in T2DM rats. This finding might assist in identifying potential therapeutic targets for T2DM prevention and intervention.

Wound healing activity of neferine in experimental diabetic rats through the inhibition of inflammatory cytokines and nrf-2 pathway

The diabetic foot ulcer (DFU) may be associated with late healing and septic manifestation, subsequently lead to amputation which is an overpriced incident. Neferine is an alkaloid found lotus. Neferine possesses many physiological functions such as anti-inflammatory, antioxidant, antimicrobial activity and anticancer effect. The aim of the present study was to evaluate the effect of topical application based on neferine, in streptozotocin-induced diabetic incision wound models rats. The data demonstrated wound healing activities via macroscopic, biochemical, histological, immuno-histochemical, immunofluorescent and molecular methods. There was significant acceleration in wound closure rate, decrease in the period of re-epitalization, higher amount of collagen and protein content in neferine treated group when compared with diabetic wound control. Histological data evidence collagen formation in skin and marked granulation with more connective tissue markers. The augmentation of serum insulin and HDL was dissimilar with blood glucose reduction and decreased lipid level (TC, TG and LDL). The healing effect was additionally validated by decreased lipid peroxidation and enhanced antioxidants. Concurrently, the mRNA level of Nrf-2, collagen-1, TGF-β and α-SMA were decreased with Kaep-1 increased significantly. This enhancement was achieved through downregulation of inflammatory mediators such as nuclear factor kappa-light-chain-enhancer of activated B cells, tumour necrosis factor-α, interleukin-1β, interleukin-8, inducible nitric oxide synthase, and cyclooxygenase-2, and upregulation of growth factor such as in groups treated with neferine. The western blot results reveal the macrophage (CD 68 and CD 163) involved in wound healing markedly elevated. Hence, the results indicate that neferine significantly promotes a fast and efficient wound healing in diabetic rats.

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.

Pomegranate: Nutraceutical with Promising Benefits on Human Health

Pomegranate is an old plant made up by flowers, roots, fruits and leaves, native to Central Asia and principally cultivated in the Mediterranean and California (although now widespread almost all over the globe). The current use of this precious plant regards not only the exteriority of the fruit (employed also for ornamental purpose) but especially the nutritional and, still potential, health benefits that come out from the various parts composing this one (carpellary membranes, arils, seeds and bark). Indeed, the phytochemical composition of the fruit abounds in compounds (flavonoids, ellagitannins, proanthocyanidins, mineral salts, vitamins, lipids, organic acids) presenting a significant biological and nutraceutical value. For these reasons, pomegranate interest is increased over the years as the object of study for many research groups, particularly in the pharmaceutical sector. Specifically, in-depth studies of its biological and functional properties and the research of new formulations could be applied to a wide spectrum of diseases including neoplastic, cardiovascular, viral, inflammatory, metabolic, microbial, intestinal, reproductive and skin diseases. In this review, considering the increasing scientific and commercial interest of nutraceuticals, we reported an update of the investigations concerning the health-promoting properties of pomegranate and its bioactive compounds against principal human pathologies.

Fluoxetine regulates glucose and lipid metabolism via the PI3K‑AKT signaling pathway in diabetic rats

Diabetes mellitus poses a major threat towards global heath due to a lack of effective treatment. Fluoxetine hydrochloride, a selective 5-hydroxytryptamine reuptake inhibitor, is the most commonly used antidepressant in clinical therapy; however, the potential molecular mechanisms of fluoxetine in diabetes remain unknown. In the present study, reduced glucose, total cholesterol and triglyceride levels and lipid metabolism, as well as upregulated proliferator-activated receptor γ, fatty acid synthase and lipoprotein lipase, and downregulated sterol regulatory element-binding protein 1-c were detected in rats with streptozotocin (STZ)-induced diabetes following treatment with fluoxetine. Furthermore, fluoxetine significantly inhibited the expression levels of glucose metabolism-associated proteins in liver tissues, including glycogen synthase kinase 3β (GSK-3β), glucose-6 phosphatase catalytic subunit (G6PC), phosphoenolpyruvate carboxykinase (PEPCK) and forkhead box protein O1 (FOXO1). In addition, fluoxetine treatment notably attenuated morphological liver damage in rats with STZ-induced diabetes. Additionally, fluoxetine could inhibit the phosphatidylinositol 3-kinase-protein kinase B (PI3K-AKT) signaling pathway, whereas LY294002, a specific inhibitor of PI3K, suppressed the function of PI3K-AKT signaling and suppressed the expression levels of glucose metabolism-associated proteins, including GSK-3β, G6PC, PEPCK and FOXO1 in BRL-3A cells. The results of the present study revealed that fluoxetine may regulate glucose and lipid metabolism via the PI3K-AKT signaling pathway in diabetic rats.

An update on the health benefits promoted by edible flowers and involved mechanisms

The aim of this review is to provide new findings on health effects of edible flowers since 2015. The antioxidant, anti-inflammatory, anti-cancer, hepatoprotective, neuroprotective, anti-diabetic, anti-osteoporosis, anti-obesity, and anti-hypertensive have been reviewed, and the effective concentrations of flower extracts have been summarized. Among all the health benefits mentioned, anti-osteoporosis, anti-obesity, and anti-hypertensive have rarely been mentioned before 2015. Some health benefits mechanisms of edible flowers were discussed frequently after 2015. Some newly found phytochemicals such as polysaccharides were shown to be beneficial to human health. Species of Rosa, Chrysanthemum, and Osmanthus have been reported to exert different health effects on human. For the toxicity studies, the safe level of flower extracts in cell and animal models were at hundreds of parts per million (ppm) level. In consideration of health promoting effects and toxicities of edible flowers, they could serve as potential natural health products for different health benefits.

Efficacy of Qurs-e-Gulnar in Ziabetus (type 2 Diabetes Mellitus): a single blind randomized controlled trial

BACKGROUND AND OBJECTIVES

Diabetes is a serious threat to global health that respects neither socioeconomic status nor national boundaries. Globally, diabetes is among the top 10 causes of death. Unani system argued the effectiveness of several anti-hyperglycemic drugs, and all such drugs looked-for to be validated on scientifically. Hence a clinical trial was contemplated to evaluate the clinical efficacy of Qurs-e-Gulnar in the management of Diabetes Mellitus.

METHODS

This study was conducted as single blind randomized control, on 40 patients of type 2 diabetes with the test (n=20) and control (n=20) groups for 45 days. Test group received Qurs-e-Gulnar at the dose of three Qurs twice a day, and control group received two capsules Diabeat^® twice a day before meal. Subjective (at 0, 15th, 30th, and 45th) and objective parameters were assessed as pre-post treatment respectively.

RESULTS

After treatment with test compound significant reduction was observed in all the subjective parameters viz. polyuria, polydipsia, polyphagia and tiredness in comparison of control group. The objective parameters FBS and PPBS was found to be significantly reduced (p<0.001) in both the groups where as HbA1c was found unchanged in test group but control drug showed highly significant reduction in HbA1c (p<0.001).The results were assessed statistically using two tailed Student's t-test, and Fischer exact test.

CONCLUSION

On the basis of above observation it is concluded that the test compound Qurs-e-Gulnar has significant anti-diabetic effect which is evidentially observed both in subjective and objective parameters in test group in comparison of control group (CTRI/2017/07/009060).

Evaluation of the in vitro ⍺-amylase inhibitory, antiglycation, and antioxidant properties of Punica granatum L. (pomegranate) fruit peel acetone extract and its effect on glucose uptake and oxidative stress in hepatocytes

Punica granatum L. (pomegranate) is a widely eaten fruit. The antidiabetic, antioxidative, and antilipidemic properties of the hydroalcoholic extracts of the different plant's parts have been extensively studied, with scarce information on the acetone extract (ACE). This study investigated antidiabetic, antioxidative, and antiobesogenic properties of ACE of the fruit peel. Preliminary data showed that ACE showed stronger antioxidant (radical-scavenging IC₅₀  = 1.56 μg/ml) and ⍺-amylase inhibitory (IC₅₀  = 10.6 μg/ml) properties than the hydroalcoholic extracts and Acarbose. The ACE inhibited protein glycation and lipase activity. In hepatocytes, ACE impaired oxidative stress-induced lipid peroxidation and reduced glutathione depletion but increased glucose uptake without decreasing the cell viability. HPLC analysis showed predominant presence of bioactive phenolic acids (ferulic, caffeic, and gallic acids) in this extract. This study suggests that ACE of P. granatum fruit peel may be an understudied extract that contains potent antidiabetic and antioxidative bioactive principles with minimal toxicity. PRACTICAL APPLICATIONS: Plant derived medicines have been an affordable and effective alternative therapy for many metabolic diseases, including diabetes. The fruit juice and fruits of pomegranate is widely consumed for the palatable taste and cardiovascular benefits. This study provides preliminary experimental evidences confirming that of the acetone extracts of pomegranate fruit peel, which has been sparsely studied, may possess more potent antidiabetic and antioxidative property than to the routinely studied hydroalcoholic counterparts. Additionally, the acetone extract is rich in bioactive phenolic acids, suggesting that the acetone extract of pomegranate fruit peel may be a promising candidate for further antidiabetic study and a source of bioactive principles for the management of diabetes and oxidative complications.

Flavonoids and type 2 diabetes: Evidence of efficacy in clinical and animal studies and delivery strategies to enhance their therapeutic efficacy

Diabetes mellitus type 2 (T2DM) is a metabolic disorder develops due to the overproduction of free radicals where oxidative stress could contribute it. Possible factors are defective insulin signals, glucose oxidation, and degradation of glycated proteins as well as alteration in glutathione metabolism which induced hyperglycemia. Previous studies revealed a link between T2DM with oxidative stress, inflammation and insulin resistance which are assumed to be regulated by numerous cellular networks such as NF-κB, PI3K/Akt, MAPK, GSK3 and PPARγ. Flavonoids are ubiquitously present in the nature and classified according to their chemical structures for example, flavonols, flavones, flavan-3-ols, anthocyanidins, flavanones, and isoflavones. Flavonoids indicate poor bioavailability which could be improved by employing various nano-delivery systems against the occurrences of T2DM. These bioactive compounds exert versatile anti-diabetic activities via modulating targeted cellular signaling networks, thereby, improving glucose metabolism, α -glycosidase, and glucose transport or aldose reductase by carbohydrate metabolic pathway in pancreatic β-cells, hepatocytes, adipocytes and skeletal myofibres. Moreover, anti-diabetic properties of flavonoids also encounter diabetic related complications. This review article has designed to shed light on the anti-diabetic potential of flavonoids, contribution of oxidative stress, evidence of efficacy in clinical, cellular and animal studies and nano-delivery approaches to enhance their therapeutic efficacy. This article might give some new insights for therapeutic intervention against T2DM in near future.

Protective Effect of Pomegranate (Punica granatum) Extract against Diabetic Changes in Adult Male Rat Liver: Histological Study

BACKGROUND

Diabetes mellitus could be result from disorders in insulin secretion or receptors, characterized by hyperglycemia. Natural antioxidants including pomegranate have hypoglycemic effect.

AIM OF THE WORK

The present research was designed to evaluate the possible protective role of pomegranate peel extract (PPE) against diabetic-induced hepatic complication.

MATERIALS AND METHODS

Forty-eight male Wistar rats, weighed 200-250 g and aged 3 months, were sorted into four groups: Group 1: Used as control, Group 2: Normal rats received PPE (200 mg/kg bw/day) given orally for 11 consecutive weeks. Group 3: Streptozotocin (STZ)-diabetic rats, injected with 55 mg/kg bw of STZ, and Group 4: Normal rats received PPE for 11 weeks and then rats were injected with STZ (55 mg/kg/bw). Effectiveness of the PPE was assessed by measuring serum glucose and histopathology of liver tissue. Liver enzymes were also assayed. PPE was found to control diabetic hyperglycemia and decrease in body weight. Histological examination showed that pretreatment with PPE provided preservation against diabetes-induced hepatic histological changes (necrotic and apoptosis).

RESULT

Alanine aminotransferase, alanine phosphatase, and aspartate aminotransferase levels were significantly elevated in Group 3 diabetics and decreased in Group 4 which confirmed histological finding.

CONCLUSION

This study confirmed the hypothesized possible protective effect of PPE against diabetic-induced histological and functional alteration of rat liver and advised its use by diabetic patients.

Syzygium cumini Leaf Extract Reverts Hypertriglyceridemia via Downregulation of the Hepatic XBP-1s/PDI/MTP Axis in Monosodium L-Glutamate-Induced Obese Rats

Syzygium cumini is used worldwide for the treatment of metabolic syndrome-associated outcomes. Previously, we described the antihypertriglyceridemic effect of the hydroethanolic extract of S. cumini leaf (HESc) in monosodium L-glutamate- (MSG-) induced obese rats. This study sought to investigate the molecular mechanisms underlying the antihypertriglyceridemic effect of HESc in MSG-obese rats. Newborn male Wistar rats were injected subcutaneously with MSG (4.0 g/kg/day, obese group) or saline 1.25% (1.0 mL/kg/day, lean group), from 2nd through 10th postnatal day. At 8 weeks old, obese rats started to be orally treated with HESc (0.5 or 1.0 g/kg/day, n = 7) or saline 0.9% (1 mL/kg/day, n = 7). Lean rats received saline solution (1 mL/kg/day, n = 7). Upon 8-week treatment, animals were euthanized for blood and tissue collection. Another set of adult nonobese Wistar rats was used for the assessment of HESc acute effects on Triton WR1339-induced hypertriglyceridemia. HESc reduced weight gain, as well as adipose tissue fat pads, without altering food intake of obese rats. HESc restored fasting serum glucose, triglycerides, total cholesterol, and free fatty acids, as well as insulin sensitivity, to levels similar to lean rats. Additionally, HESc halved the triglyceride content into very low-density lipoprotein particles, as well as healed liver steatosis, in obese rats. Hepatic protein expression of the endoplasmic reticulum chaperone GRP94 was decreased by HESc, which also downregulated the hepatic triglyceride secretion pathway by reducing the splicing of X-box binding protein 1 (XBP-1s), as well as protein disulfide isomerase (PDI) and microsomal triglyceride transfer protein (MTP) translational levels. This action was further corroborated by the acute inhibitory effect of HESc on triglyceride accumulation on Triton WR1339-treated rats. Our data support the downregulation of the XBP-1s/PDI/MTP axis in the liver of MSG-obese rats as a novel feasible mechanism for the antihypertriglyceridemic effect promoted by the polyphenolic phytocomplex present in S. cumini leaf.