Antidiabetic effects of novel ellagic acid nanoformulation: Insulin-secreting and anti-apoptosis effects

Pomegranate (Punica granatum L.) phytochemicals target the components of metabolic syndrome

Pomegranate (Punica granatum L.) is a multipurpose dietary and medicinal plant known for its ability to promote various health benefits. Metabolic syndrome (MetS) is a complex metabolic disorder driving health and socioeconomic challenges worldwide. It may be characterized by insulin resistance, abdominal obesity, hypertension, and dyslipidemia. This study aims to conduct a review of pomegranate's effects on MetS parameters using a mechanistic approach relying on pre-clinical studies. The peel, juice, roots, bark, seeds, flowers, and leaves of the fruit present several bioactive compounds that are related mainly to anti-inflammatory and antioxidant activities as well as cardioprotective, antidiabetic, and antiobesity effects. The use of the juice extract can work as a potent inhibitor of angiotensin-converting enzyme activities, consequently regulating blood pressure. The major bioactive compounds found within the fruit are phenolic compounds (hydrolysable tannins and flavonoids) and fatty acids. Alkaloids, punicalagin, ellagitannins, ellagic acid, anthocyanins, tannins, flavonoids, luteolin, and punicic acid are also present. The antihyperglycemia, antihyperlipidemia, and weight loss promoting effects are likely related to the anti-inflammatory and antioxidant effects. When considering clinical application, pomegranate extracts are found to be frequently well-tolerated, further supporting its efficacy as a treatment modality. We suggest that pomegranate fruit, extract, or processed products can be used to counteract MetS-related risk factors. This review represents an important step towards exploring potential avenues for further research in this area.

Evaluation of phytochemical profile, and antioxidant, antidiabetic activities of indigenous Thai fruits

Background

This research aims to explore the phenolics identification, phenolics quantification, antioxidant and potential biofunctional properties of lesser-known Thai fruits and their potency to treat type 2 diabetes mellitus (T2DM). Including, Antidesma puncticulatum, Dillenia indica, Diospyros decandra, Elaeagnus latifolia, Flacourtia indica, Garcinia dulcis, Lepisanthes fruticose, Mimusops elengi, Muntingia calabura, Phyllanthus reticulatus, Streblus asper, Syzygium cumini, Syzygium malaccense, Willughbeia edulis and Schleichera oleosa were analyzed by their phenolic and flavonoid content. These fruits have received limited scientific attention, prompting an investigation into their health benefits, particularly their relevance to diabetes management.

Methods

The study utilized methanolic crude extracts to measure phenolic and flavonoid levels. Additionally, UHPLC-DAD was utilized to identify and quantify phenolics. The methanolic extracts were assessed for antioxidant and antidiabetic abilities, including α-glucosidase and α-amylase inhibition.

Results and Conclusion

The study highlighted S. cumini as a rich source of phenolic (980.42 ± 0.89 mg GAE/g and flavonoid (3.55 ± 0.02 mg QE/g) compounds with strong antioxidant activity (IC50 by DPPH; 3.00 ± 0.01 µg/ml, IC50 by ABTS; 40 ± 0.01 µg/ml, FRAP; 898.63 ± 0.02 mg TE/ml). Additionally, S. cumini exhibited promising antidiabetic effects (S. cumini IC50; 0.13 ± 0.01 mg/ml for α-glucosidase inhibition, 3.91 ± 0.05 mg/ml for α-amylase inhibition), compared to Acarbose (IC50; 0.86 ± 0.01 mg/ml for α-glucosidase inhibition, 0.39 ± 0.05 mg/ml for α-amylase inhibition). Remarkably, compounds like catechins, gallic acid, kaempferol, and ellagic acid were identified in various quantities.This study suggests that these fruits, packed with phenolics, hold the potential to be included in an anti-diabetic diet and even pharmaceutical applications due to their health-promoting properties.

Ellagic acid as potential therapeutic compound for diabetes and its complications: a systematic review from bench to bed

Diabetes mellitus (DM) is a worldwide-concerning disease with a rising prevalence. There are many ongoing studies aimed at finding new and effective treatments. Ellagic acid (EA) is a natural polyphenolic compound abundant in certain fruits and vegetables. It is the objective of this investigation to assess the effectiveness and preventive mechanisms of EA on DM and associated complications. This systematic review used PubMed, Scopus, and Google Scholar as search databases using a predetermined protocol from inception to June 2024. We assessed all related English studies, including in vitro, in vivo, and clinical trials. EA counteracted DM and its complications by diminishing inflammation, oxidative stress, hyperglycemia, apoptosis, insulin resistance, obesity, lipid profile, and histopathological alterations. Several mechanisms contributed to the anti-diabetic effect of EA, the most significant being the upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), peroxisome proliferator-activated receptor gamma (PPAR-γ), protein kinase B, and downregulation of nuclear factor-kappa-B (NF-κB) gene expression. EA also revealed protective effects against diabetes complications, such as diabetic-induced hepatic damage, testicular damage, endothelial dysfunction, muscle dysfunction, retinopathy, nephropathy, cardiomyopathy, neuropathy, and behavioral deficit. Administration of EA could have various protective effects in preventing, treating, and alleviating DM and its complications. Although it could be considered a cost-effective, safe, and accessible treatment, to fully establish the effectiveness of EA as a medication for DM, it is crucial to conduct further well-designed studies.

Effects of Ellagic Acid on Glucose and Lipid Metabolism: A Systematic Review and Meta-Analysis

Background

Abnormal glucose and lipid metabolism (GALM) serve as both a cause and an inducer for the development of the disease. Improvement and treatment of GALM are an important stage to prevent the occurrence and development of the disease. However, current clinical treatment for GALM is limited. Ellagic acid (EA), a common polyphenol present in foods, has been shown to improve abnormalities in GALM observed in patients suffering from metabolic diseases.

Objective

This study used a meta-analysis method to systematically assess the effects of EA on GALM.

Method

As of November 8, 2023, a comprehensive search was conducted across 5 databases, namely, PubMed, Embase, Web of Science, Cochrane Library, and Google Scholar to identify randomized controlled trials (RCTs) in which EA served as the primary intervention for diseases related to GALM. The risk of bias within the included studies was assessed according to the Cochrane Handbook. All statistical analyzes were performed using RevMan 5.4 software.

Results

In this study, a total of 482 articles were retrieved, resulting in the inclusion of 10 RCTs in the meta-analysis. The results showed that EA could reduce fasting blood glucose (FBG) (p = 0.008), increase insulin secretion (p = 0.01), improve insulin resistance index (HOMA-IR) (p = 0.003), decrease triglyceride (TG) (p = 0.004), and reduce cholesterol (Chol) (p = 0.04) and low-density lipoprotein (LDL-c) (p = 0.0004). EA had no significant effect on waist circumference (WC), body weight (BW), body mass index (BMI), 2 hours after prandial blood glucose (2 h-PG), total cholesterol (TC), and high-density lipoprotein (HDL-c).

Conclusions

The effect of improvement in glucose and lipids of EA was closely related to the dose and the intervention time. EA can improve GALM caused by diseases. To corroborate the findings of this study and improve the reliability of the results, EA is imperative to refine the research methodology and increase the sample size in future investigations.

Sono-assembly of ellagic acid into nanostructures significantly enhances aqueous solubility and bioavailability

INTRODUCTION

Ellagic acid (EA), commonly found in foods, offers significant health benefits in combating chronic diseases. However, its therapeutic potential is hindered by its extremely poor solubility and bioavailability.

METHOD

In this study, EA nanoparticles (EA NPs) were produced using a sono-assembly method, without additional agents.

RESULTS

EA NPs exhibited stick-like nanoparticle structures with an average size of 147.3 ± 0.73 nm. EA NPs likely adopt a tunnel-type solvate structure, with 4 water participating in disruption of intramolecular hydrogen bonds in EA and establishment of intermolecular hydrogen bonds between EAs. Importantly, EA NPs exhibited remarkable enhancements in water solubility, with 120.7-fold increase in water, and 97.8-fold increase in pH 6.8 buffer. Moreover, ex vivo intestinal permeability studies demonstrated significant improvements (P < 0.5). These findings were further supported by in vivo pharmacokinetic studies, where EA NPs significantly enhanced the relative bioavailability of EA by 4.69 times.

An Insight of Naturally Occurring Phytoconstituents and Novel Approaches Towards the Treatment of Diabetes

BACKGROUND

The rising in diabetes incidents has clearly become one main worldwide health problem. Individuals suffering from diabetes are still more susceptible to many long-term and short-term side effects, which most often cause fatalities. Even though chemically synthesized anti-diabetic entities are capable of helping manage and treat, there has been significant risks related with their prolong and repetitive use. Hence, there is a requirement for safer and novel approaches that might be formed and utilized.

OBJECTIVE

Aim of the present review is to explain the naturally occurring phytochemicals and novel approach as anti-diabetic agents in the treatment of diabetes and its related issues.

METHOD

A survey of Google scholar, Research Gate, Pubmed, Science Direct, NCBI database was carried out conducted to determine a most hopeful phytochemicals and novel drug delivery systems in the management of diabetes.

RESULT

The study stressed the significance of phytomolecules and some novel approaches researched or reported in the literature for the management and cure of diabetes. It is suggested that changes in lifestyle can help patients and like nutritional support, assessment and lifestyle guidance must be individualized based on physical and functional capacity. Further evaluations and improved preventative medicine were the result of improving patient outcomes.

CONCLUSION

Conventional or synthetic drugs provide relief for short time but nanoformulations of phytomolecules offer an improved therapeutic with fewer negative side effects. Herbal medicines are rich in phytoconstituents and possess variety of health benefits. This review is compilation of phytoconstituents and novel drug delivery system of phytomolecules i.e. nanoparticles, niosomes, microsphere, microparticle and others.

Flavonoids, Isoflavonoids and others Bioactives for Insulin Sensitizations

Diabetes is a chronic condition that has an impact on a huge part of the world. Both animals and humans have been demonstrated to benefit from natural goods, and organisms (animals, or microbes). In 2021, approximately 537 million adults (20-79 years) are living with diabetes, making it the one of the biggest cause of death worldwide. Various phytoconstituent preserved β- cells activity helps to prevent the formation of diabetes problems. As a result, β-cells mass and function are key pharmaceutical targets. The purpose of this review is to provide an overview of flavonoids' effects on pancreatic β-cells. Flavonoids have been demonstrated to improve insulin release in cell lines of isolated pancreatic islets and diabetic animal models. Flavonoids are thought to protect β-cells by inhibiting nuclear factor-κB (NF-κB) signaling, activating the phosphatidylinositol 3-kinase (PI3K) pathway, inhibiting nitric oxide production, and lowering reactive oxygen species levels. Flavonoids boost β-cells secretory capacity by improving mitochondrial bioenergetic function and increasing insulin secretion pathways. Some of the bioactive phytoconstituents such as S-methyl cysteine sulfoxides stimulate insulin synthesis in the body and increase pancreatic output. The berberine increased insulin secretion in the HIT-T15 and Insulinoma 6 (MIN6) mouse cell line. Epigallocatechin-3-Gallate protects against toxicity accrued by cytokines, reactive oxygen species (ROS), and hyperglycemia. Quercetin has been proven to boost insulin production by Insulinoma 1 (INS-1) cells and also protect cell apoptosis. Overall flavonoids have beneficial effects on β-cells by prevented their malfunctioning or degradation and improving synthesis or release of insulin from β-cells.

Potential roles of ellagic acid on metabolic variables in diabetes mellitus: A systematic review

Diabetes mellitus is a widespread endocrine disorder globally. Due to its antioxidant and anti-inflammatory properties, ellagic acid has the potential to improve the metabolic effects of chronic non-communicable diseases. This systematic review summarizes current evidence about the potential effects of ellagic acid on metabolic variables in diabetes mellitus. A comprehensive systematic literature search was conducted in databases such as PubMed, Scopus, EMBASE, ProQuest and Google Scholar from inception until March 2022. All animal studies and clinical trials were eligible for inclusion. Studies using in vitro models or published in a non-English language were excluded. Of 1320 articles, 23 were selected for assessment, including 21 animal studies and two randomized controlled trial studies. Following ellagic acid administration, findings reported improvement in FBS, HbA1c, insulin (20, 8 and 12 studies, respectively), TG, TC, HDL-C (13, 10 and 5 studies, respectively), MDA, GSH, CAT, SOD (11, 6, 3 and 4 studies, respectively), and TNF-α and IL-6 (6 and 3 studies, respectively). In conclusion, ellagic acid may improve glycaemic indicators, dyslipidaemia, oxidative stress and inflammation in diabetes mellitus. However, further clinical trials are needed to explore the mechanisms more precisely and to observe the applied consequences.

In Vivo Evaluation of Nanoemulsion Formulations for Metformin and Repaglinide Alone and Combination

Repaglinide and Metformin are used to treat Type 2 diabetes. Repaglinide with poor water solubility has relatively low oral bioavailability (56%) and undergoes hepatic first-pass metabolism. The oral bioavailability of metformin HCl is also low (about 50-60%). The purpose of this study was to prepare nanoemulsion formulations containing metformin HCl or repaglinide alone or in combination and characterize them in vitro and in vivo. Nanoemulsion formulations containing metformin HCl and/or repaglinide were successfully prepared and in vitro characterized. In addition, in vivo efficacy of nanoemulsion formulations was evaluated in a streptozotocin-nicotinamide-induced diabetic rat model. Biochemical, histopathological, and immunohistochemical evaluations were also performed. The mean droplet size and zeta potential values of nanoemulsion formulations were in the range of 110.15±2.64-120.23±2.16 nm and -21.95 - -24.33 mV, respectively. The percent entrapment efficiency values of nanoemulsion formulations were in the range of 93.600%-96.152%. All nanoemulsion formulations had a PDI of ≤0.223. A statistically significant decrease was observed in the blood glucose values of the diabetic rats treated with nanoemulsion formulations containing active substance/substances, compared to diabetic rats (control) (p<0.05). Nanoemulsion formulations (especially nanoemulsion containing metformin HCl and repaglinide combination) have a better antidiabetic activity and are more effective in reducing oxidative stress caused by diabetes.

Attenuation of Hyperlipidemia by Medicinal Formulations of Emblica officinalis Synergized with Nanotechnological Approaches

The ayurvedic herb Emblica officinalis (E. officinalis) is a gift to mankind to acquire a healthy lifestyle. It has great therapeutic and nutritional importance. Emblica officinalis, also known as Indian gooseberry or Amla, is a member of the Euphorbiaceae family. Amla is beneficial for treating illnesses in all its forms. The most crucial component is a fruit, which is also the most common. It is used frequently in Indian medicine as a restorative, diuretic, liver tonic, refrigerant, stomachic, laxative, antipyretic, hair tonic, ulcer preventive, and for the common cold and fever. Hyperlipidemia is also known as high cholesterol or an increase in one or more lipid-containing blood proteins. Various phytocompounds, including polyphenols, vitamins, amino acids, fixed oils, and flavonoids, are present in the various parts of E. officinalis. E. officinalis has been linked to a variety of pharmacological effects in earlier studies, including hepatoprotective, immunomodulatory, antimicrobial, radioprotective, and hyperlipidemic effects. The amla-derived active ingredients and food products nevertheless encounter challenges such as instability and interactions with other food matrices. Considering the issue from this perspective, food component nanoencapsulation is a young and cutting-edge field for controlled and targeted delivery with a range of preventative activities. The nanoformulation of E. officinalis facilitates the release of active components or food ingredients, increased bioaccessibility, enhanced therapeutic activities, and digestion in the human body. Accordingly, the current review provides a summary of the phytoconstituents of E. officinalis, pharmacological actions detailing the plant E. officinalis's traditional uses, and especially hyperlipidemic activity. Correspondingly, the article describes the uses of nanotechnology in amla therapeutics and functional ingredients.

Ellagic acid: insight into its protective effects in age-associated disorders

The disparity in the free radical generation and the production of antioxidants to counteract its effect is known as oxidative stress. Oxidative stress causes damage to the macromolecules such as lipids, carbohydrates, proteins, and DNA and RNA. The oxidative damage to the cellular components leads to a process of aging and various age-associated disorders. The literature survey for this review was done using PubMed, Google Scholar, and Science Direct. The papers showing the studies related to aging and age-associated disorders have been selected for reviewing this paper. Ellagic acid has been used as the keyword, and more emphasis has been put on papers from the last 10 years. However, some papers with significant studies prior to 10 years have also been considered. Almost 250 papers have been studied for reviewing this paper, and about 135 papers have been cited. Ellagic acid (EA) is present in high quantities in pomegranate and various types of berries. It is known to possess the antioxidant potential and protects from the harmful effects of free radicals. Various studies have shown its effect to protect cardiovascular, neurodegenerative, cancer, and diabetes. The present review focuses on the protective effect of ellagic acid in age-associated disorders. The effect of EA has been studied in various chronic disorders but the scope of this review is limited to cancer, diabetes, cardiovascular and neurodegenerative disorders. All the disease aspects have not been addressed in this particular review.

Piperine ameliorates ischemic stroke-induced brain injury in rats by regulating the PI3K/AKT/mTOR pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Piperine (PIP), a main active component isolated from Piper nigrum L., exerts neuroprotective effects in a rat model of ischemic stroke (IS). However, studies on the effects of PIP on neuroprotection and autophagy after IS are limited.

AIM OF THE STUDY

This study aimed to prove the protective effects of PIP against brain IS and elucidate its underlying mechanisms.

MATERIALS AND METHODS

Specific pathogen-free male Sprague-Dawley rats were selected to establish a permanent middle cerebral artery occlusion model. The experiment was randomly divided into six groups: sham group, model group, PIP intervention group (10, 20, and 30 mg/kg group), and nimodipine group (Nimo group, 12 mg/kg). Neurological function score, postural reflex score, body swing score, balance beam test, and grip strength test were used to detect behavioral changes of rats. The area of cerebral infarction was detected by TTC staining, and the number and morphological changes of neurons were observed by Nissl and HE staining. In addition, the ultrastructure of hippocampal dentate gyrus neurons was observed using a transmission electron microscope. Western blot was used to detect the expression of PI3K/AKT/mTOR signaling pathway proteins and autophagy-related proteins, namely, Beclin1 and LC3, in the hippocampus and cortex. Cell experiments established an in vitro model of oxygen-glucose deprivation (OGD) with the HT22 cell line to verify the mechanism. The experiment was divided into five groups: control group, OGD group, OGD + PIP 20 μg/mL group, OGD + PIP 30 μg/mL group, and OGD + PIP 40 μg/mL group. CCK-8 was used to measure cell activity, and Western blot was used to measure the expression of PI3K/AKT/mTOR signaling pathway proteins and autophagy-related proteins (Beclin1 and LC3).

RESULTS

Compared with the model group, the neurological function scores, body swing scores, and postural reflex scores of rats in the 10, 20, and 30 mg/kg PIP intervention groups and Nimo groups decreased, whereas the balance beam score and grip test scores increased (all p < 0.05). After 10, 20, and 30 mg/kg PIP and Nimo intervention, the cerebral infarction area of pMCAO rats was reduced (p < 0.01), and Nissl and HE staining results showed that the number of neurons survived in the 30 mg/kg PIP and Nimo intervention groups increased. Cell morphology and structure were significantly improved (p < 0.05). Most of the hippocampal dentate gyrus neurons and their organelles gradually returned to normal in the 30 mg/kg PIP and Nimo intervention groups, with less neuronal damage. The expression levels of p-mTOR, p-AKT, and p-PI3K in the hippocampus and cortex of the 30 mg/kg PIP and Nimo intervention groups decreased, whereas the expression level of PI3K increased (all p < 0.05). In addition, the expression level of autophagy-related proteins, namely, Beclin1 and LC3-II, in the 30 mg/kg PIP and Nimo intervention groups decreased (all p < 0.05). Results of CCK-8 showed that after 1 h of OGD, the 30 and 40 μg/mL PIP intervention groups had higher cell viability than the OGD group (p < 0.01). Western blot results showed that compared with the OGD group, the expression level of p-mTOR, p-AKT, and p-PI3K in the 30 and 40 μg/mL PIP intervention groups decreased, and the expression level of PI3K increased (all p < 0.05). Moreover, the expression level of autophagy-related proteins, namely, Beclin1 and LC3-II, in the 30 and 40 μg/mL PIP intervention groups decreased (all p < 0.05).

CONCLUSIONS

This study shows that PIP is a potential compound with neuroprotective effects. PIP can inhibit the PI3K/AKT/mTOR pathway and autophagy. Its inhibition of autophagy is possibly related to modulating the PI3K/AKT/mTOR pathway. These findings provide new insights into the use of PIP for the treatment of IS and its underlying mechanism.

Ellagic acid attenuates muscle atrophy in STZ-induced diabetic mice

Diabetes is closely connected with skeletal muscle dysfunction. Ellagic acid (EA) possesses a variety of bio-effects and is applied to the improvement of diabetes. The purpose of this study was to explore the potential improvement effect and mechanisms of EA in streptozotocin (STZ)-induced diabetic muscle atrophy. The model of diabetic mice was established by intra-peritoneal STZ to evaluate treatment effect of EA (100 mg/kg/d for 8 weeks) on muscle atrophy. Our data exhibited that EA enhanced fiber size and weight of gastrocnemius, and promoted grip strength to relieve STZ-induced muscle lesions. In serum, the levels of Creatine kinase (CK), lactate dehydrogenase (LDH), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL) were inhibited, while high-density lipoprotein cholesterol (HDL) level was enhanced by EA treatment in diabetic mice. In gastrocnemius, EA decreased Atrogin-1 and MuRF-1 expressions to relieve STZ-induced muscle atrophy. Moreover, EA increased NRF-1 and PGC-1alpha expressions to alleviate mitochondrial disorder. Meanwhile, EA suppressed CHOP and GRP-87 levels to relieve ER stress. Lastly, EA inhibited BAX expressions and enhanced Bcl-2 expressions to mitigate apoptosis. In conclusion, EA is preventing the event of STZ-induced gastrocnemia by amelioration of mitochondrial dysfunction, ER stress and apoptosis, and could be used in the protection and therapeutic of muscle atrophy in diabetes.

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.

Computation Screening of Multi-Target Antidiabetic Properties of Phytochemicals in Common Edible Mediterranean Plants

Diabetes mellitus is a metabolic disease and one of the leading causes of deaths worldwide. Numerous studies support that the Mediterranean diet has preventive and treatment effects on diabetes. These effects have been attributed to the special bioactive composition of Mediterranean foods. The objective of this work was to decipher the antidiabetic activity of Mediterranean edible plant materials using the DIA-DB inverse virtual screening web server. A literature review on the antidiabetic potential of Mediterranean plants was performed and twenty plants were selected for further examination. Subsequently, the most abundant flavonoids, phenolic acids, and terpenes in plant materials were studied to predict their antidiabetic activity. Results showed that flavonoids are the most active phytochemicals as they modulate the function of 17 protein-targets and present high structural similarity with antidiabetic drugs. Their antidiabetic effects are linked with three mechanisms of action, namely (i) regulation of insulin secretion/sensitivity, (ii) regulation of glucose metabolism, and (iii) regulation of lipid metabolism. Overall, the findings can be utilized to understand the antidiabetic activity of edible Mediterranean plants pinpointing the most active phytoconstituents.

Ellagic acid regulates hyperglycemic state through modulation of pancreatic IL-6 and TNF- α immunoexpression

Background

Objective

Methods

Results

Conclusion

Ellagic Acid: A Review on Its Natural Sources, Chemical Stability, and Therapeutic Potential

Ellagic acid (EA) is a bioactive polyphenolic compound naturally occurring as secondary metabolite in many plant taxa. EA content is considerable in pomegranate (Punica granatum L.) and in wood and bark of some tree species. Structurally, EA is a dilactone of hexahydroxydiphenic acid (HHDP), a dimeric gallic acid derivative, produced mainly by hydrolysis of ellagitannins, a widely distributed group of secondary metabolites. EA is attracting attention due to its antioxidant, anti-inflammatory, antimutagenic, and antiproliferative properties. EA displayed pharmacological effects in various in vitro and in vivo model systems. Furthermore, EA has also been well documented for its antiallergic, antiatherosclerotic, cardioprotective, hepatoprotective, nephroprotective, and neuroprotective properties. This review reports on the health-promoting effects of EA, along with possible mechanisms of its action in maintaining the health status, by summarizing the literature related to the therapeutic potential of this polyphenolic in the treatment of several human diseases.

Preventive Effect of Ellagic Acid on Cardiac Dysfunction in Diabetic Mice through Regulating DNA Hydroxymethylation

Ellagic acid (EA) improves mitochondrial dysfunction and protects diabetic hearts. The mitochondrial tricarboxylic acid (TCA) cycle regulates DNA 5-hydroxymethylcytosine (5hmC) levels by affecting activity of 10-11 translocation enzymes (TETs). Therefore, we hypothesized that EA prevents diabetic cardiac dysfunction by modulating DNA 5hmC levels. C57BL/6J mice were fed a high-fat diet to induce diabetes and treated with EA (100 mg kg^-1 day^-1) for 8 weeks. Serum concentrations of glucose, insulin, and triglyceride and aspartate transaminase and creatine kinase activities were significantly lower in the EA group than the diabetes mellitus (DM) group. DNA 5hmC levels of mice hearts were significantly higher in the EA group than the DM group. The protein levels of TET, complexes I/III/V were significantly higher in the EA group than the DM group. The results shows that EA has a preventive effect on diabetic cardiac dysfunction, which may be achieved by upregulating TET activity through improving the TCA cycle, to reshape DNA 5hmC levels of mice hearts.

Combined treatment of sinapic acid and ellagic acid attenuates hyperglycemia in streptozotocin-induced diabetic rats

In the present study, we aimed to investigate the effect of individual and combined treatment of sinapic acid (SA) and ellagic acid (EA) in streptozotocin (STZ)-induced diabetic rats. Rats were divided into eight groups (n = 7): Normal Control, Diabetic Control, Diabetic + Sinapic Acid, Diabetic + Ellagic Acid, Diabetic + Sinapic Acid + Ellagic Acid, Sinapic Acid, Ellagic Acid and Sinapic Acid + Ellagic Acid. Diabetic groups were injected with a single dose of 50 mg/kg STZ intraperitoneally. Rats received 20 mg/kg/day SA and 50 mg/kg/day EA intragastrically for 28 days. The numerical density of immunopositive β-cells and volume density of pancreatic islets were calculated. Additionally, glucose and insulin levels in serum, MDA, GSH, and CAT levels of pancreatic tissue were measured. While serum glucose levels increased, serum insulin levels decreased in STZ-induced diabetic rats. But these changes in glucose and insulin were restored by individual and combined treatments of SA and EA. Also, individual and combined treatments of SA and EA increased insulin expression of β-cells in STZ-induced diabetic rats. Moreover, these compounds improved deteriorating oxidative stress parameters in STZ-induced diabetic rats. Our study indicates that SA and EA, especially their combined treatments, can be used as an antihyperglycemic agent in diabetes.

Plants Secondary Metabolites as Blood Glucose-Lowering Molecules

Recently, significant advances in modern medicine and therapeutic agents have been achieved. However, the search for effective antidiabetic drugs is continuous and challenging. Over the past decades, there has been an increasing body of literature related to the effects of secondary metabolites from botanical sources on diabetes. Plants-derived metabolites including alkaloids, phenols, anthocyanins, flavonoids, stilbenoids, saponins, tannins, polysaccharides, coumarins, and terpenes can target cellular and molecular mechanisms involved in carbohydrate metabolism. In addition, they can grant protection to pancreatic beta cells from damage, repairing abnormal insulin signaling, minimizing oxidative stress and inflammation, activating AMP-activated protein kinase (AMPK), and inhibiting carbohydrate digestion and absorption. Studies have highlighted many bioactive naturally occurring plants' secondary metabolites as candidates against diabetes. This review summarizes the current knowledge compiled from the latest studies published during the past decade on the mechanism-based action of plants-derived secondary metabolites that can target various metabolic pathways in humans against diabetes. It is worth mentioning that the compiled data in this review will provide a guide for researchers in the field, to develop candidates into environment-friendly effective, yet safe antidiabetics.