Screening alpha-glucosidase and alpha-amylase inhibitors from natural compounds by molecular docking in silico

Synthesis, molecular modelling, and biological evaluation of novel quinoxaline derivatives for treating type II diabetes

Quinoxalines are benzopyrazine derivatives with significant therapeutic impact in the pharmaceutical industry. They proved to be useful against inflammation, bacterial, fungal, viral infection, diabetes and other applications. Very recently, in January 2024, the FDA approved new quinoxaline containing drug, erdafitinib for treatment of certain carcinomas. Despite the diverse biological activities exhibited by quinoxaline derivatives and the role of secretory phospholipase A2 (sPLA2) in diabetes-related complications, the potential of sPLA2-targeting quinoxaline-based inhibitors to effectively address these complications remains unexplored. Therefore, we designed novel sPLA2- and α-glucosidase-targeting quinoxaline-based heterocyclic inhibitors to regulate elevated post-prandial blood glucose linked to patients with diabetes-related cardiovascular complications. Compounds 5a-d and 6a-d were synthesised by condensing quinoxaline hydrazides with various aryl sulphonyl chlorides. Biological screening revealed compound 6a as a potent sPLA2 inhibitor (IC50 = 0.0475 µM), whereas compound 6c most effectively inhibited α-glucosidase (IC50 = 0.0953 µM), outperforming the positive control acarbose. Moreover, compound 6a was the best inhibitor for both enzymes. Molecular docking revealed pharmacophoric features, highlighting the importance of a sulfonohydrazide moiety in the structural design of these compounds, leading to the development of potent sPLA2 and α-glucosidase inhibitors. Collectively, our findings helped identify promising candidates for developing novel therapeutic agents for treating diabetes mellitus.

Evaluating the antidiabetes and antioxidant activities of halogenated Schiff bases derived from 4-(diethylamino)salicylaldehyde: in vitro antidiabetes, antioxidant and computational investigation

Six Schiff bases with general name 5-(diethylamino)-2-(((halophenyl)imino)methyl)phenol (where halo = 4-fluoro (H1), 2-fluoro (H2), 2-bromo (H3), 4-bromo (H4), 4-chloro (H5) and 3-chloro-4-fluoro (H6)) were prepared by the condensation reaction between 4-(diethylamino)salicylaldehyde and suitable halogenated aromatic amines. The six halogenated Schiff bases were elucidated using different spectroscopic techniques and the structure of H3 and H6 were confirmed using single-crystal X-ray crystallography. The bond lengths of C7-N1, C7-C8 and C8-C9 obtained from structural analysis for both compounds depicted their enol-tautomeric characteristic form. The Hirshfeld analysis revealed that H‧‧‧H intermolecular contacts contributed most towards the Hirshfeld surfaces of both H3 (47.6%) and H6 (39.9%). Quantum chemical calculation studies showed that H1 and H2 have the highest and lowest energy band gap (∆E = 3.80 eV for H1 and ∆E = 3.73 eV for H2), depicting H2 and H1 as the most and least chemically reactive respectively among all the compounds. α-Amylase and α-glucosidase assay were used to evaluate the antidiabetes prowess of the synthesized compounds. All the compounds exhibited lower IC50 values than acarbose (reference drug) in α-amylase assay experiments and H5 with lowest IC50 value of 63.54 μM could be suggested to have the highest α-amylase inhibitory potential among the test samples. For α-glucosidase assay, H1-H6 displayed good antidiabetic potential. However, none of the compounds outshined acarbose with H6 having highest α-glucosidase inhibitory potential when compared to others i.e., IC50 of H6 = 60.89 μM and IC50 of acarbose = 51.42 μM. We measured the antioxidant potential of H1-H6 exploring 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and ferric reducing ability power (FRAP) assays. The DPPH as well as NO radical scavenging assay showed that all the compounds exhibited excellent antioxidant results with some of the compounds surpassing catechin (reference drug). Compound H5 with IC50 values of 30.32 mM and 31.73 mM outshined catechin with IC50 values of 31.17 mM and 140.62 mM for DPPH and NO assays respectively. All the compounds fell within the threshold of Lipinski's Ro5 projecting them as orally bioavailable and less toxic future therapeutics.

Insights into Catechin-Copper Complex Structure and Biologic Activity Modulation

Compounds of natural origin found in varying quantities in plant-based products constitute a highly significant category, possessing structural significance as well as the capacity to regulate oxidative processes. The activity of these compounds may be modulated by the composition of the biological environment in which they operate, the pH of the environment, or the presence of metal cations in plants or plant extracts. A successful complexation reaction was mainly confirmed by FT-IR, observing the shift from the original transmittance of catechin bonds, especially O-H ones. This work shows the synthetic methodology and the optimization process that took place to synthesize a catechin-copper complex, which demonstrated antioxidant activity. It was tested for iron chelation ability, hydroxyl radicals, and the inhibition of lipoxygenase (15-LOX). An antidiabetic assay was performed by determining the inhibition of alpha-amylase and alpha-glucosidase, finding that the synthesized complex had similar inhibitory potential as pure catechin. The antibacterial tests showed results against Staphylococcus aureus and the antifungal properties of the complex against Candida albicans.

The in vitro and in silico investigations on the α-amylase inhibitor derived from Leptadenia lanceolata (Poir.) Goyder leaf extract

An attempt has been made to assess the α-amylase inhibitory activity of a phytochemical compound extracted and purified from the leaf extract of Leptadenia lanceolata. The total yield of the crude leaf extract was 11.42% and among the different solvents involved in this study, hexane and ethyl acetate at 7:3 was effective in the separation of phytochemical compounds. Hexane and ethyl acetate at 25:75% ratios (elution S4) were found greater in inhibiting α-amylase enzyme (83%). The most abundant compound found was Phytol (3,7,11,15-tetramethyl-2-hexadecen-1-ol) and its derivatives. It resulted that the binding energy for acarbose and phytol were -8.1 kcal/mol and -5.9 kcal/mol respectively. However, the binding affinity was greater in the case of acarbose than phytol and the binding sites are different for both the ligands. Therefore, this study adds scientific evidence of the α-amylase inhibitory activity of phytol derived from the leaf extract of L. lanceolata.

Suppression of the postprandial hyperglycemia in patients with type 2 diabetes by a raw medicinal herb powder is weakened when consumed in ordinary hard gelatin capsules: A randomized crossover clinical trial

INTRODUCTION

Contradictory claims about the efficacy of several medicinal plants to promote glycemic control in patients with type 2 diabetes mellitus (T2DM) have been explained by divergences in the administration form and by extrapolation of data obtained from healthy individuals. It is not known whether the antidiabetic effects of traditional herbal medicines are influenced by gelatin capsules. This randomized crossover trial aimed to evaluate the acute effect of a single dose of raw cinnamon consumed orally either dissolved in water as a beverage or as ordinary hard gelatin capsules on postprandial hyperglycemia (>140 mg/dL; >7.8 mmol/L) in T2DM patients elicited by a nutritionally-balanced meal providing 50 g of complex carbohydrates.

METHODS

Fasting T2DM patients (n = 19) randomly ingested a standardized meal in five experimental sessions, one alone (Control) and the other after prior intake of 3 or 6 g of crude cinnamon in the form of hard gelatin capsules or powder dissolved in water. Blood glucose was measured at fasting and at 0.25, 0.5, 0.75, 1, 1.5 and 2 hours postprandially. After each breakfast, its palatability scores for visual appeal, smell and pleasantness of taste were assessed, as well as the taste intensity sweetness, saltiness, bitterness, sourness and creaminess.

RESULTS

The intake of raw cinnamon dissolved in water, independently of the dose, decreased the meal-induced large glucose spike (peak-rise of +87 mg/dL and Δ1-hour glycemia of +79 mg/dL) and the hyperglycemic blood glucose peak. When cinnamon was taken as capsules, these anti-hyperglycemic effects were lost or significantly diminished. Raw cinnamon intake did not change time-to-peak or the 2-h post-meal glycaemia, but flattened the glycemic curve (lower iAUC) without changing the shape that is typical of T2DM patients.

CONCLUSIONS

This cinnamon's antihyperglycemic action confirms its acarbose-like property to inhibit the activities of the carbohydrate-digesting enzymes α-amylases/α-glucosidases, which is in accordance with its exceptionally high content of raw insoluble fiber. The efficacy of using raw cinnamon as a diabetes treatment strategy seems to require its intake at a specific time before/concomitantly the main hyperglycemic daily meals. Trial registration: Registro Brasileiro de Ensaios Clínicos (ReBEC), number RBR-98tx28b.

Study of the antidiabetic mechanism of berberine compound on FOXO1 transcription factor through molecular docking and molecular dynamics simulations

CONTEXT

Diabetes mellitus (DM) is a metabolic disorder disease that causes hyperglycemia conditions and associated with various chronic complications leading to mortality. Due to high toxicity of conventional diabetic drugs, the exploration of natural compounds as alternative diabetes treatments has been widely carried out. Previous in silico studies have highlighted berberine, a natural compound, as a promising alternative in antidiabetic therapy, potentially acting through various pathways, including the inhibition of the FOXO1 transcription factor in the gluconeogenesis pathway. However, the specific mechanism by which berberine interacts with FOXO1 remains unclear, and research in this area is relatively limited. Therefore, this study aims to determine the stability of berberine structure with FOXO1 based on RMSD, RMSF, binding energy, and trajectory analysis to determine the potential of berberine to inhibit the gluconeogenesis pathway. This research was conducted by in silico method with molecular docking using AutoDock4.2 and molecular dynamics study using Amber20, then visualized by VMD.

METHODS

Docking between ligand and FOXO1 receptor was carried out with Autodock4.2. For molecular dynamics simulations, the force fields of DNA.OL15, protein.ff14SB, gaff2, and tip3p were used.

Biogenic synthesis, characterization, and in vitro biological investigation of silver oxide nanoparticles (AgONPs) using Rhynchosia capitata

The current research aimed to study the green synthesis of silver oxide nanoparticles (AgONPs) using Rhynchosia capitata (RC) aqueous extract as a potent reducing and stabilizing agent. The obtained RC-AgONPs were characterized using UV, FT-IR, XRD, DLS, SEM, and EDX to investigate the morphology, size, and elemental composition. The size of the RC-AgONPs was found to be ~ 21.66 nm and an almost uniform distribution was executed by XRD analysis. In vitro studies were performed to reveal biological potential. The AgONPs exhibited efficient DPPH free radical scavenging potential (71.3%), reducing power (63.8 ± 1.77%), and total antioxidant capacity (88.5 ± 4.8%) to estimate their antioxidative power. Antibacterial and antifungal potentials were evaluated using the disc diffusion method against various bacterial and fungal strains, and the zones of inhibition (ZOI) were determined. A brine shrimp cytotoxicity assay was conducted to measure the cytotoxicity potential (LC50: 2.26 μg/mL). In addition, biocompatibility tests were performed to evaluate the biocompatible nature of RC-AgONPs using red blood cells, HEK, and VERO cell lines (< 200 μg/mL). An alpha-amylase inhibition assay was carried out with 67.6% inhibition. Moreover, In vitro, anticancer activity was performed against Hep-2 liver cancer cell lines, and an LC50 value of 45.94 μg/mL was achieved. Overall, the present study has demonstrated that the utilization of R. capitata extract for the biosynthesis of AgONPs offers a cost-effective, eco-friendly, and forthright alternative to traditional approaches for silver nanoparticle synthesis. The RC-AgONPs obtained exhibited significant bioactive properties, positioning them as promising candidates for diverse applications in the spheres of medicine and beyond.

Anti-Obesity and Anti-Diabetic Effects of Ostericum koreanum (Ganghwal) Extract

"Ganghwal" is a widely used herbal medicine in Republic of Korea, but it has not been reported as a treatment strategy for obesity and diabetes within adipocytes. In this study, we determined that Ostericum koreanum extract (OKE) exerts an anti-obesity effect by inhibiting adipogenesis and an anti-diabetic effect by increasing the expression of genes related to glucose uptake in adipocytes and inhibiting α-glucosidase activity. 3T3-L1 preadipocytes were differentiated for 8 days in methylisobutylxanthine, dexamethasone, and insulin medium, and the effect of OKE was confirmed by the addition of 50 and 100 µg/mL of OKE during the differentiation process. This resulted in a reduction in lipid accumulation and the expression of PPARγ (Peroxisome proliferator-activated receptor γ) and C/EBPα (CCAAT enhancer binding protein α). Significant activation of AMPK (AMP-activated protein kinase), increased expression of GLUT4 (Glucose Transporter Type 4), and inhibition of α-glucosidase activity were also observed. These findings provide the basis for the anti-obesity and anti-diabetic effects of OKE. In addition, OKE has a significant antioxidant effect. This study presents OKE as a potential natural product-derived material for the treatment of patients with metabolic diseases such as obesity- and obesity-induced diabetes.

A guide to the use of bioassays in exploration of natural resources

Bioassays are the main tool to decipher bioactivities from natural resources thus their selection and quality are critical for optimal bioprospecting. They are used both in the early stages of compounds isolation/purification/identification, and in later stages to evaluate their safety and efficacy. In this review, we provide a comprehensive overview of the most common bioassays used in the discovery and development of new bioactive compounds with a focus on marine bioresources. We present a comprehensive list of practical considerations for selecting appropriate bioassays and discuss in detail the bioassays typically used to explore antimicrobial, antibiofilm, cytotoxic, antiviral, antioxidant, and anti-ageing potential. The concept of quality control and bioassay validation are introduced, followed by safety considerations, which are critical to advancing bioactive compounds to a higher stage of development. We conclude by providing an application-oriented view focused on the development of pharmaceuticals, food supplements, and cosmetics, the industrial pipelines where currently known marine natural products hold most potential. We highlight the importance of gaining reliable bioassay results, as these serve as a starting point for application-based development and further testing, as well as for consideration by regulatory authorities.

In Vitro and in Silico Analysis of α -Amylase Inhibitory Activity of Ethanolic Extract of Adhatoda vasica Leaves

Objective

Diabetic individuals have a higher probability of suffering from illness and death due to small blood vessel-related problems such as retinopathy, neuropathy, nephropathy, and stroke than other complications. There are many synthetic anti-diabetic agents available, but these can be expensive and have undesirable pathological effects. The enzyme α-amylase (hydrolase), catalyzes the hydrolysis of starch to maltose and glucose via the cleavage of α-1,4-glucosidic linkages. Diabetes mellitus patients may benefit from a therapeutic strategy that involves slowing the hydrolysis of starch by inhibiting the activity of α-amylase. Thus, looking for cost-effective, natural, and safe antidiabetic agents is essential. This study aims to screen phytoconstituents and evaluate the in-vitro and in-silico α-amylase inhibitory activity of the ethanolic extract of Adhatoda vasica leaves.

Methods

The extraction of Adhatoda vasica leaves was performed using ethanol via the Soxhlet extraction process. Different concentrations (100 μg/mL to 1000 μg/mL) of ethanolic extract, Acarbose, and Sitagliptin, were prepared and evaluated for α-amylase inhibitory activity using the spectrophotometric method. Molecular docking (AutodockVina 1.2.0) and toxicity profiling (SToPToX web server) studies were performed.

Results

The ethanolic extract of Adhatoda vasica leaves showed the highest percentage inhibition against α-amylase (56.763 ± 0.0035) at a concentration of 1000 μg/mL. The in-silico study supported this inhibitory activity. Vasicoline (C5) and Quercetin (C9), the active constitute of Adhatoda vasica, showed the best binding energies of -8.3 and -8.0 Kcal/mol, respectively against α-amylase enzyme (PDBID: 4W93). A toxicity study revealed the safety profile of the plant extract.

Conclusion

It was concluded that Adhatoda vasica leaves possess some bioactive compounds that are responsible for controlling blood glucose levels, and their identification, purification, and isolation may lead to the development of new therapeutic agents with fewer side effects than the available drugs.

In-silico, in-vitro and in-vivo Biological Activities of Flavonoids for the Management of Type 2 Diabetes

In spite of the fact that many medicinal plants have been truly utilized for the management of diabetes all through the world, very few of them have been reported scientifically. Recently, a diverse variety of animal models have been established to better understand the pathophysiology of diabetes mellitus, and new medications to treat the condition have been introduced in the market. Flavonoids are naturally occurring substances that can be found in plants and various foods and may have health benefits in the treatment of neuropathic pain. Flavonoids have also been shown to have an anti-inflammatory impact that is significant to neuropathic pain, as indicated by a decrease in several pro-inflammatory mediators such TNF-, NF-B IL-6, and IL-1. Flavonoids appear to be a viable novel therapy option for macrovasular complications in preclinical models; however, human clinical data is still inadequate. Recently, several in silico, in-vitro and in-vivo aproaches were made to evaluate mechanisms associated with the pathogenesis of diabetes in a better way. Screening of natural antidiabetic agents from plant sources can be analysed by utilizing advanced in-vitro techniques and animal models. Natural compounds, mostly derived from plants, have been studied in diabetes models generated by chemical agents in the majority of research. The aim of this work was to review the available in silico, in-vitro and animal models of diabetes for screening of natural antidiabetic agents. This review contributes to the scientist's design of new methodologies for the development of novel therapeutic agents having potential antihyperglycemic activity.

Chia (Salvia hispanica L.), a Pre-Hispanic Food in the Treatment of Diabetes Mellitus: Hypoglycemic, Antioxidant, Anti-Inflammatory, and Inhibitory Properties of α-Glucosidase and α-Amylase, and in the Prevention of Cardiovascular Disease

Diabetes mellitus (DM) is considered one of the major health diseases worldwide, one that requires immediate alternatives to allow treatments for DM to be more effective and less costly for patients and also for health-care systems. Recent approaches propose treatments for DM based on that; in addition to focusing on reducing hyperglycemia, they also consider multitargets, as in the case of plants. Among these, we find the plant known as chia to be highlighted, a crop native to Mexico and one cultivated in Mesoamerica from pre-Hispanic times. The present work contributes to the review of the antidiabetic effects of chia for the treatment of DM. The antidiabetic effects of chia are effective in different mechanisms involved in the complex pathogenesis of DM, including hypoglycemic, antioxidant, and anti-inflammatory mechanisms, and the inhibition of the enzymes α-glucosidase and α-amylase, as well as in the prevention of the risk of cardiovascular disease. The tests reviewed included 16 in vivo assays on rodent models, 13 clinical trials, and 4 in vitro tests. Furthermore, chia represents advantages over other natural products due to its availability and its acceptance and, in addition, as a component of the daily diet worldwide, especially due to its omega-3 fatty acids and its high concentration of dietary fiber. Thus, chia in the present work represents a source of antidiabetic agents that would perhaps be useful in novel clinical treatments.

Evaluation of In Vitro Antioxidant, Anti-Obesity, and Anti-Diabetic Activities of Opuntia ficus Cladodes Gel and Its Application as a Preservative Coating for Shrimp during Refrigerated Storage

Opuntia ficus cladodes (OFC) are considered one of the wastes that result from opuntia cultivation, and their disposal by traditional methods results in many environmental problems. Therefore, this study was conducted with two aims. The first was the production of OFC gel, and the evaluation of its in vitro antioxidant (by two methods, DPPH and ABTS), anti-obesity, and anti-diabetic activities. The second was an investigation of the effects of different concentrations of this gel (0, 50, and 100%) as an edible coating on the quality of shrimp during 8 days of refrigerated storage. The results showed that this gel was characterised by a high content of ash (10.42%), total carbohydrates (75.17%), and total phenols (19.79 mg GAE/g). OFC gel contained six types of sugars: arabinose, xylose, galactose, rhamnose, glucose, and uronic acid, and the most abundant was xylose (36.72%). It is also clear from the results that the OFC gel had high antioxidant properties, which were higher against DPPH than ABTS at the same concentration. OFC gel showed a high inhibition activity against lipase, α-glycosidase, and α-amylase enzymes, and their IC50 values were 1.43 mg/mL, 0.78 mg/mL, and 0.57 mg/mL, respectively. The results also stated that shrimp coated with OFC gel had lower pH, drip loss, TVB-N, and TBA values through the days of refrigerated storage. Moreover, the shrimp coated with 100% OFC gel were better than those coated with 50% OFC gel. In conclusion, OFC gel showed high potency as active antioxidant, for its enzyme anti-activities, and as an edible coating for shrimp.

Eugenia sonderiana O. Berg leaves: Phytochemical characterization, evaluation of in vitro and in vivo antidiabetic effects, and structure-activity correlation

Several medicinal plants have drawn the attention of researchers by its phytochemical composition regarding their potential for treating chronic complications of diabetes mellitus. In this context, plants of the Myrtaceae family popularly used in Brazil for the treatment of diabetes mellitus, including Eugenia sonderiana, have shown beneficial effects due to the presence of phenolic compounds and saponins in their chemical constitution. Thus, the present work aimed to perform the phytochemical characterization of the hydroethanolic extract of E. sonderiana leaves using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS), along with in vitro and in vivo studies of antidiabetic activity. The chemical characterization revealed the presence of phenolic compounds, flavonoids, neolignans, tannins, and saponins. In addition, the extract exhibited minimum inhibitory concentrations of alpha-amylase and alpha-glycosidase higher than the acarbose in the in vitro tests. Also, the in vivo tests revealed a slight increase in body mass in diabetic rats, as well as a significant decrease in water and feed consumption provided by the extract. Regarding serum biochemical parameters, the extract showed significant activity in decreasing the levels of glucose, hepatic enzymes, and triglycerides, in addition to maintaining HDL cholesterol levels within normal ranges, protecting the cell membranes against oxidative damage. Thus, the extract of E. sonderiana leaves was considered promising pharmaceutical ingredient in the production of a phytotherapy medication.

Nutritional and medicinal plants as potential sources of enzyme inhibitors toward the bioactive functional foods: an updated review

Enzymes are biologically active complex protein molecules that catalyze most chemical reactions in living organisms, and their inhibitors accelerate biological processes. This review emphasizes medicinal food plants and their isolated chemicals inhibiting clinically important enzymes in common diseases. A mechanistic overview was investigated to explain the mechanism of these food bases enzyme inhibitors. The enzyme inhibition potential of medicinal food plants and their isolated substances was searched in Ovid, PubMed, Science Direct, Scopus, and Google Scholar. Cholinesterase, amylase, glucosidase, xanthine oxidase, tyrosinase, urease, lipoxygenase, and others were inhibited by crude extracts, solvent fractions, or isolated pure chemicals from medicinal food plants. Several natural compounds have shown tyrosinase inhibition potential, including quercetin, glabridin, phloretin-4-O-β-D-glucopyranoside, lupinalbin, and others. Some of these compounds' inhibitory kinetics and molecular mechanisms are also discussed. Phenolics and flavonoids inhibit enzyme activity best among the secondary metabolites investigated. Several studies showed flavonoids' significant antioxidant and anti-inflammatory activities, highlighting their medicinal potential. Overall, many medicinal food plants, their crude extracts/fractions, and isolated compounds have been studied, and some promising compounds depending on the enzyme have been found. Still, more studies are recommended to derive potential pharmacologically active functional foods.

Annona cherimola Miller and Its Flavonoids, an Important Source of Products for the Treatment of Diabetes Mellitus: In Vivo and In Silico Evaluations

The antihyperglycemic activity of ethanolic extract from Annona cherimola Miller (EEAch) and its products were evaluated using in vivo and in silico assays. An α-glucosidase inhibition was evaluated with oral sucrose tolerance tests (OSTT) and molecular docking studies using acarbose as the control. SGLT1 inhibition was evaluated with an oral glucose tolerance test (OGTT) and molecular docking studies using canagliflozin as the control. Among all products tested, EEAc, the aqueous residual fraction (AcRFr), rutin, and myricetin reduced the hyperglycemia in DM2 mice. During the carbohydrate tolerance tests, all the treatments reduced the postprandial peak such as the control drugs. In the molecular docking studies, rutin showed more affinity in inhibiting α-glucosidase enzymes and myricetin in inhibiting the SGLT1 cotransporter, showing ∆G values of -6.03 and -3.32 kcal/mol^-1, respectively, in α-glucosidase enzymes. In the case of the SGLT1 cotransporter, molecular docking showed ∆G values of 22.82 and -7.89 in rutin and myricetin, respectively. This research sorts in vivo and in silico pharmacological studies regarding the use of A. cherimola leaves as a source for the development of new potential antidiabetic agents for T2D control, such as flavonoids rutin and myricetin.

α-Glucosidase Inhibitors from Two Mangrove-Derived Actinomycetes

α-Glucosidase (AGS) inhibitors have been regarded as an ideal target for the management of type 2 diabetes mellitus (T2DM) since they can maintain an acceptable blood glucose level by delaying the digestion of carbohydrates and diminishing the absorption of monosaccharides. In the process of our endeavor in mining AGS inhibitors from natural sources, the culture broth of two mangrove-derived actinomycetes Streptomyces sp. WHUA03267 and Streptomyces sp. WHUA03072 exhibited an apparent inhibitory activity against AGS. A subsequent chemical investigation into the two extracts furnished 28 secondary metabolites that were identified by spectroscopic methods as two previously undescribed linear polyketides 1-2, four benzenoid ansamycins 3-6, fourteen cyclodipeptides 7-18, one prenylated indole derivative 19, two fusicoccane-type diterpenoids 20-21, two hydroxamate siderophore 22-23, and five others 24-28. Among all of the isolates, 11 and 24 were obtained from actinomycetes for the first time, while 20-21 had never been reported to occur in a marine-derived microorganism previously. In the in vitro AGS inhibitory assay, compounds 3, 8, 9, 11, 14, 16, and 17 exhibited potent to moderate activity with IC₅₀ values ranging from 35.76 ± 0.40 to 164.5 ± 15.5 μM, as compared with acarbose (IC₅₀ = 422.3 ± 8.4 μM). The AGS inhibitory activity of 3, 9, 14, 16, and 17 was reported for the first time. In particular, autolytimycin (3) represented the first ansamycin derivative reported to possess the AGS inhibitory activity. Kinetics analysis and molecular docking were performed to determine the inhibition types and binding modes of these inhibitors, respectively. In the MTT assay, 3, 8, 9, 11, 14, 16, and 17 exhibited no apparent cytotoxicity to the human normal hepatocyte (LO2) cells, suggesting satisfactory safety of these AGS inhibitors.

New Specific α-Glucosidase Inhibitor Flavonoid from Thymelaea tartonraira Leaves: Structure Elucidation, Biological and Molecular Docking Studies

The phytochemical investigation of Thymelaea tartonraira leaves led to the isolation and characterization of six compounds, including one new flavonoid glycoside identified as hypolaetin 8-O-β-D-galactopyranoside (4) along with five known compounds, daphnoretin (1), triumbelletin (2), genkwanin (3), tiliroside (5) and yuankanin (6). Their structures were established based on spectroscopic methods, such as UV, IR, NMR, and HR-ESI-MS. Triumbelletin (2) and tiliroside (5) were isolated for the first time from T. tartonraira leaves. The antioxidant property of all isolated compounds was tested based on DPPH, FRAP and total antioxidant capacity assays. Compound 4 displayed an antioxidant potency more interesting than vitamin C with an IC₅₀ =15.00±0.50 μg/ml, followed by compound 5. Furthermore, the both compounds 4 and 5 were tested for their α-amylase inhibitory activity in-vitro. Compound 4 displayed higher potency to inhibit α-amylase, with an IC₅₀ =46.49±2.32 μg/ml, than compound 5, with an IC₅₀ =184.2±9.2 μg/ml, while the reference compound acarbose presented the highest potency to inhibit α-amylase with an IC₅₀ =0.44±0.022 μg/ml. Compound 4 displayed a strong inhibitory ability of α-glucosidase activity approximately twice more than the reference compound, acarbose, with IC₅₀ values of 60.00±3.00 and 125.00±6.25 μg/ml, respectively. Thus, compound 4 exhibited a specific inhibitory activity for α-glucosidase. The molecular docking studies have supported our findings and suggested that compound 4 has been involved in various binding interactions within the active site of both enzymes α-amylase and α-glucosidase.

A Review of Fibraurea tinctoria and Its Component, Berberine, as an Antidiabetic and Antioxidant

Diabetes mellitus is a group of metabolic disorders characterized by hyperglycemia caused by resistance to insulin action, inadequate insulin secretion, or excessive glucagon production. Numerous studies have linked diabetes mellitus and oxidative stress. People with diabetes usually exhibit high oxidative stress due to persistent and chronic hyperglycemia, which impairs the activity of the antioxidant defense system and promotes the formation of free radicals. Recently, several studies have focused on exploring natural antioxidants to improve diabetes mellitus. Fibraurea tinctoria has long been known as the native Borneo used in traditional medicine to treat diabetes. Taxonomically, this plant is part of the Menispermaceae family, widely known for producing various alkaloids. Among them are protoberberine alkaloids such as berberine. Berberine is an isoquinoline alkaloid with many pharmacological activities. Berberine is receiving considerable interest because of its antidiabetic and antioxidant activities, which are based on many biochemical pathways. Therefore, this review explores the pharmacological effects of Fibraurea tinctoria and its active constituent, berberine, against oxidative stress and diabetes, emphasizing its mechanistic aspects. This review also summarizes the pharmacokinetics and toxicity of berberine and in silico studies of berberine in several diseases and its protein targets.

In Vitro α-Amylase and α-Glucosidase Inhibitory Activity of Green Seaweed Halimeda tuna Extract from the Coast of Lhok Bubon, Aceh

Seaweed belongs to marine biota and contains nutrients and secondary metabolites beneficial for health. This study aimed to determine the antidiabetic activity of extracts and fractions of green seaweed Halimeda tuna. The H. tuna sample was extracted with the maceration method using methanol and then partitioned using ethyl acetate and water to obtain ethyl acetate and water fractions. The methanol extract, ethyl acetate fraction, and water fraction of H. tuna were tested for their inhibitory activity against α-amilase and α-glucosidase. The methanol extract and the fractions with the highest inhibitory activity were phytochemically tested and analyzed using gas chromatography-mass spectrometry (GC-MS). The results showed that the ethyl acetate fraction (IC50 = 0.88 ± 0.20 mg/mL) inhibited α-amylase relatively similar to acarbose (IC50 = 0.76 ± 0.04 mg/mL). The methanol extract (IC50 = 0.05 ± 0.01 mg/mL) and the ethyl acetate fraction (IC50 = 0.01 ± 0.00 mg/mL) demonstrated stronger inhibitory activity against α-glucosidase than acarbose (IC50 = 0.27 ± 0.13 mg/mL). Phytochemical testing showed that the methanol extract and the ethyl acetate fraction contained secondary metabolites: alkaloids, flavonoids, steroids, and phenol hydroquinone. The compounds in methanol extract predicted to have inhibitory activity against α-amylase and α-glucosidase were Docosanol, Neophytadiene, Stigmasta-7,22-dien-3-ol,acetate,(3.beta.,5.alpha.,22E), Octadecanoic acid,2-oxo-,methyl ester, and phytol, while those in the ethyl acetate fraction were n-Nonadecane, Phytol, Butyl ester, 14-.Beta.-H-pregna, Octadecenoic acid, and Oleic acid.

The Effects of Carbon Dots from Hordei Fructus Germinatus Carbonisatus on Glycometabolism and α-Glycosidase Activity

Hordei Fructus Germinatus Carbonisatus (HFC), the carbonized malt known as Maiya-tan in China, has been used as an effective natural treatment to improve digestion for a long time. In this research, we separated and distinguished CDs (carbon dots) from HFC, which were prepared using traditional methods. The HFC CDs had a lattice spacing of 0.26 nm and an average size of 4.3 nm, according to morphology investigations, which revealed that they were nearly spherical. The significant elements in the HFC CDs were C, O, and N. These HFC CDs produced several emissive traps between π − π* states because they had functional groups including C–OH, –NH, C=O, and C–H on their surface, according to X-ray photoelectron spectroscopy investigation. Our results indicated that HFC CDs could effectively reduce postprandial blood glucose and inhibit α-glycosidase in vitro, which suggested that HFC CDs may affect aspects of carbohydrate metabolism. This work indicates that HFC CDs may have the potential to play a crucial clinical role in regulating blood sugar.

Bilosomes as a promising nanoplatform for oral delivery of an alkaloid nutraceutical: improved pharmacokinetic profile and snowballed hypoglycemic effect in diabetic rats

Diabetes mellitus is a life-threatening metabolic disease. At the moment, there is no effective treatment available to combat it. In this study, we aimed to develop berberine-loaded bilosomes (BER-BLS) to boost the oral bioavailability and therapeutic efficacy of berberine, a natural antidiabetic medication. The BER-BLS was fabricated using a thin-film hydration strategy and optimized using a central composite design (face-centered). The average vesicle size, entrapment efficiency, and surface charge of the optimized BER-BLS preparation were 196.5 nm, 89.7%, (−) 36.4 mV, respectively. In addition, it exhibited higher stability and better-sustained release of berberine than the berberine solution (BER-SOL). BER-BLS and BER-SOL were administered to streptozocin-induced diabetic rats. The optimized BER-BLS formulation had a significant hypoglycemic impact, with a maximum blood glucose decrease of 41%, whereas BER-SOL only reduced blood glucose by 19%. Furthermore, the pharmacological effect of oral BER-BLS and BER-SOL corresponded to 99.3% and 31.7%, respectively, when compared to subcutaneous insulin (1 IU). A pharmacokinetic analysis found a 6.4-fold rise in the relative bioavailability of berberine in BER-BLS when compared to BER-SOL at a dosage of 100 mg/kg body weight. Histopathological investigation revealed that BER-BLS is suitable for oral administration. Our data demonstrate that BLS is a potential nanocarrier for berberine administration, enhancing its oral bioavailability and antidiabetic activity.

Critical Assessment of In Vitro Screening of α-Glucosidase Inhibitors from Plants with Acarbose as a Reference Standard

Postprandial hyperglycemia is treated with the oral antidiabetic drug acarbose, an intestinal α-glucosidase inhibitor. Side effects of acarbose motivated a growing number of screening studies to identify novel α-glucosidase inhibitors derived from plant extracts and other natural sources. As "gold standard", acarbose is frequently included as the reference standard to assess the potency of these candidate α-glucosidase inhibitors, with many outperforming acarbose by several orders of magnitude. The results are subsequently used to identify suitable compounds/products with strong potential for in vivo efficacy. However, most α-glucosidase inhibitor screening studies use enzyme preparations obtained from nonmammalian sources (typically Saccharomyces cerevisiae), despite strong evidence that inhibition data obtained using nonmammalian α-glucosidase may hold limited value in terms of identifying α-glucosidase inhibitors with actual in vivo hypoglycemic potential. The aim was to critically discuss the screening of novel α-glucosidase inhibitors from plant sources, emphasizing inconsistencies and pitfalls, specifically where acarbose was included as the reference standard. An assessment of the available literature emphasized the cruciality of stating the biological source of α-glucosidase in such screening studies to allow for unambiguous and rational interpretation of the data. The review also highlights the lack of a universally adopted screening assay for novel α-glucosidase inhibitors and the commercial availability of a standardized preparation of mammalian α-glucosidase.

Multiprotein Inhibitory Effect of Dietary Polyphenol Rutin from Whole Green Jackfruit Flour Targeting Different Stages of Diabetes Mellitus: Defining a Bio-Computational Stratagem

The anti-diabetic potential of whole unripe jackfruit (peel with pulp, flake, and seed) was investigated using inhibitory assays for α-glucosidase, α-amylase, aldose reductase, and glycation at multiple stages. Using activity-guided repeated fractionation on a silica gel column chromatography, dietary flavonoid rutin with potent antihyperglycemic activity was extracted from the methanol extract of whole jackfruit flour (MJ). Rutin was found to inhibit both α-glucosidase (IC50: 7.86 µg/mL) and α-amylase (IC50: 22.00 µg/mL) in a competitive manner of inhibition with low Ki values. In addition, in vitro glycation experiments revealed that rutin prevented each stage of protein glycation as well as the production of intermediate molecules. Furthermore, rutin significantly inhibited aldose reductase (IC50: 2.75 µg/mL) in a non-competitive manner. During in silico studies, molecular docking and molecular dynamics simulation studies have suggested that rutin has a high binding affinity for the enzymes studied, which could explain its inhibitory effects. Rutin interacted with the key residues of the target enzymes’ inhibitor binding sites. Compared to the controls used, rutin had a higher binding efficiency as well as stability in the inhibitor binding pocket of the target enzymes. According to our findings, the presence of rutin is more likely to be associated with the potential of MJ in antihyperglycemic activity via inhibition of α-glucosidase and in anti-diabetic action via inhibition of the polyol pathway and protein glycation. The bio-computational study indicates rutin as a potential lead inhibitor of all the target enzymes used and could be used as an effective anti-diabetic drug in the near future.

Investigation of effective natural inhibitors for starch hydrolysing enzymes from Simaroubaceae plants by molecular docking analysis and comparison with in-vitro studies

The present study aims to find the effective natural enzyme inhibitors against alpha-amylase and alpha-glucosidase from the array of compounds identified in plants of the Simaroubaceae family using molecular docking and ADME/Toxicity studies. Among the 218 compounds docked against seven enzymes, buddlenol-A and citrusin-B showed the best binding energies (kcal/mol) of -7.830 and -7.383 against human salivary alpha-amylase and pancreatic alpha-amylase respectively. The other two compounds 9-hydroxycanthin-6-one and bruceolline-B had the best binding energy of -6.461 and -7.576 against N-terminal and C-terminal maltase glucoamylase respectively. Whereas the binding energy of prosopine (-6.499) and fisetinidol (-7.575) was considered as the best against N-terminal and C-terminal sucrase-isomaltase respectively. Picrasidine-X showed the best binding energy (-7.592) against yeast alpha-glucosidase. The study revealed that the seven compounds which showed the best binding energy against respective enzymes are considered as the 'lead hit compounds'. Even though the 'lead hit compounds' are not obeying all the laws of ADMET, the drug-likeness properties of 9-hydroxycanthin-6-one, fisetinidol, picrasidine-X, and prosopine were considerable. Also, kaempferol-3-O-pentoside was the recent compound identified from the Simarouba glauca plant extract found to be one among the top five lead hit compounds against four enzymes. This study provides valuable insight into the direction of developing natural compounds as potential starch hydrolysing enzyme inhibitors for managing type 2 diabetes.

Antihyperglycemic Effects of Salvia polystachya Cav. and Its Terpenoids: α-Glucosidase and SGLT1 Inhibitors

The antihyperglycemic activity of ethanolic extract from Salvia polystachya (EESpS) and its products was evaluated using in vivo, ex vivo and in silico assays; additionally, an acute toxicity assay was evaluated. EESpS was classified as a nontoxic class 5 drug. EESpS, ethyl acetate fraction (EtOAcFr), secondary-6-fraction (SeFr6), ursolic acid (UA), and oleanolic acid (OA) reduced the hyperglycemia in DM2 mice. α-glucosidase inhibition was evaluated with oral sucrose and starch tolerance tests (OSuTT and OStTT), an intestinal sucrose hydrolysis (ISH) assay and molecular docking studies using acarbose as control. SGLT1 inhibition was evaluated with oral glucose and galactose tolerance tests (OGTT and OGaTT), an intestinal glucose absorption (IGA) assay and molecular docking studies using canagliflozin as the control. During the carbohydrate tolerance tests, all the treatments reduced the postprandial peak, similar to the control drugs. During the ISH, IC₅₀ values of 739.9 and 726.3 µM for UA and OA, respectively, were calculated. During the IGA, IC₅₀ values of 966.6 and 849.3 for UA, OA respectively, were calculated. Finally, during the molecular docking studies, UA and OA showed ∆G values of -6.41 and -5.48 kcal/mol^-1, respectively, on α-glucosidase enzymes. During SGLT1, UA and OA showed ∆G values of -10.55 and -9.65, respectively.

Molecular Structure-Based Screening of the Constituents of Calotropis procera Identifies Potential Inhibitors of Diabetes Mellitus Target Alpha Glucosidase

Diabetes mellitus is a disorder characterized by higher levels of blood glucose due to impaired insulin mechanisms. Alpha glucosidase is a critical drug target implicated in the mechanisms of diabetes mellitus and its inhibition controls hyperglycemia. Since the existing standard synthetic drugs have therapeutic limitations, it is imperative to identify new potent inhibitors of natural product origin which may slow carbohydrate digestion and absorption via alpha glucosidase. Since plant extracts from Calotropis procera have been extensively used in the treatment of diabetes mellitus, the present study used molecular docking and dynamics simulation techniques to screen its constituents against the receptor alpha glucosidase. Taraxasterol, syriogenin, isorhamnetin-3-O-robinobioside and calotoxin were identified as potential novel lead compounds with plausible binding energies of −40.2, −35.1, −34.3 and −34.3 kJ/mol against alpha glucosidase, respectively. The residues Trp⁴⁸¹, Asp⁵¹⁸, Leu⁶⁷⁷, Leu⁶⁷⁸ and Leu⁶⁸⁰ were identified as critical for binding and the compounds were predicted as alpha glucosidase inhibitors. Structurally similar compounds with Tanimoto coefficients greater than 0.7 were reported experimentally to be inhibitors of alpha glucosidase or antidiabetic. The structures of the molecules may serve as templates for the design of novel inhibitors and warrant in vitro assaying to corroborate their antidiabetic potential.

Analysis of the Structure and Activity of Dipeptidyl Peptidase IV (DPP-IV) Inhibitory Oligopeptides from Sorghum Kafirin

Potential dipeptidyl peptidase IV (DPP-IV) inhibitory oligopeptides from sorghum kafirin were developed using in silico and in vitro methodologies for the management of diabetes. Twenty-eight peptides with 5-10 residues were identified from the papain hydrolysates of sorghum kafirin. Sixteen nontoxic DPP-IV inhibitory peptides were screened with a computer method based on molecular docking. Molecular docking revealed that LPFYPQ (LP6), GPVTPPILG (GP9), and LPFYPQGV (LP8) effectively inactivated DPP-IV by binding to its active sites with a low interaction energy. An in silico analysis of these three inhibitory oligopeptides indicated that they were all bound to the S1 and S2 active pockets of DPP-IV through hydrogen bonds and hydrophobic interactions. The in vitro inhibitory activity was also verified. The DPP-IV inhibitory activities of LP6 and LP8 decreased after gastric digestion and remained stable after intestinal digestion, and the GP9 inhibitory activity remained stable after gastrointestinal digestion. Experimental results from Caco-2 cells showed further inhibitory effects of oligopeptides on DPP-IV. The results are relevant to the exploration of biofunctional DPP-IV inhibitory peptides from sorghum as a treatment for patients with diabetes or in medical research.

Antidiabetic Activity and In Silico Molecular Docking of Polyphenols from Ammannia baccifera L. subsp. Aegyptiaca (Willd.) Koehne Waste: Structure Elucidation of Undescribed Acylated Flavonol Diglucoside

Chemical investigation of the aerial parts of Ammania aegyptiaca ethanol extract (AEEE) showed high concentrations of polyphenol and flavonoid content, with notable antioxidant activity. Undescribed acylated diglucoside flavonol myricetin 3-O-β-⁴C₁-(6″-O-galloyl glucopyranoside) 7-O-β-⁴C₁-glucopyranoside (MGGG) was isolated from the aerial parts of AEEE, along with four known polyphenols that had not been characterized previously from AEEE. The inhibitory effects of MGGG, AEEE, and all compounds against α-amylase, pancreatic lipase and β-glucosidase were assessed. In addition, molecular docking was used to determine the inhibition of digestive enzymes, and this confirmed that the MGGG interacted strongly with the active site residues of these enzymes, with the highest binding free energy against α-amylase (-8.99 kcal/mol), as compared to the commercial drug acarbose (-5.04 kcal/mol), thus justifying its use in the potential management of diabetes. In streptozotocin (STZ)-induced diabetic rats, AEEE significantly decreased high serum glucose, α-amylase activity and serum liver and kidney function markers, as well as increasing insulin blood level. Moreover, AEEE improved the lipid profile of diabetic animals, increased superoxide dismutase (SOD) activity, and inhibited lipid peroxidation. Histopathological studies proved the decrease in pancreas damage and supported the biochemical findings. These results provide evidence that AEEE and MGGG possess potent antidiabetic activity, which warrants additional investigation.

In Vivo and In Silico Assessment of Diabetes Ameliorating Potentiality and Safety Profile of Gynura procumbens Leaves

BACKGROUND

Diabetes mellitus is one of the most notable health dilemmas. Analyzing plants for new antidiabetic remedies has become an impressive territory for life science researchers. Gynura procumbens has long been used to treat diabetes. Thus, we strived to ascertain the hypoglycemic potentiality of extract of leaves of G. procumbens by in vivo and in silico approaches.

METHODS

Fresh leaves of G. procumbens were collected and shade-dried to prepare ethanolic extracts to evaluate pharmacological parameters. Diabetes was induced in rats via injecting alloxan through the intraperitoneal route at a dose of 150 mg/kg body weight. Humalyzer 3000 was used to perform a biochemical assay of collected samples from rats. Anti-hyperglycemic activity study along with overdose toxicity test was performed. The pharmacological activity of this plant was also evaluated through a molecular docking study. This in silico study investigated the binding affinity of natural ligands from G. procumbens against glycoside hydrolase enzymes.

RESULTS

We detected a peak plasma concentration of G. procumbens at 3 hours 45 minutes that is roughly similar to the peak plasma concentration of metformin. Again, in OGTT and anti-hyperglycemic tests, it has been ascertained that both plant extract and metformin can exert significant (P < 0.05) and highly significant (P < 0.01) hypoglycemic activity in a dose-dependent manner. Metformin exhibited better therapeutic efficacy than that of plant extract, but it possessed null statistical significance. Also, our safety profile expressed that, similar to metformin, the plant extract can restore the disturbed pathological state in a dose-oriented approach with a wide safety margin. In silico study also validated the potentialities of natural constituents of G. procumbens. Conclusion. This study suggested that G. procumbens can be considered as potential antidiabetic plant. Robust and meticulous investigation regarding plant chemistry and pharmacology in the future may bring about a new dimension that will aid in discovering antidiabetic drugs from this plant in the diabetes management system.

In Vitro Evaluation of the Anti-Diabetic Potential of Aqueous Acetone Helichrysum petiolare Extract (AAHPE) with Molecular Docking Relevance in Diabetes Mellitus

Diabetes mellitus (DM) is a chronic metabolic condition that can lead to significant complications and a high fatality rate worldwide. Efforts are ramping up to find and develop novel α-glucosidase and α-amylase inhibitors that are both effective and potentially safe. Traditional methodologies are being replaced with new techniques that are less complicated and less time demanding; yet, both the experimental and computational strategies are viable and complementary in drug discovery and development. As a result, this study was conducted to investigate the in vitro anti-diabetic potential of aqueous acetone Helichrysum petiolare and B.L Burtt extract (AAHPE) using a 2-NBDG, 2-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl) amino)-2-deoxy-d-glucose uptake assay. In addition, we performed molecular docking of the flavonoid constituents identified and quantified by liquid chromatography-mass spectrometry (LC-MS) from AAHPE with the potential to serve as effective and safe α-amylase and α-glucosidase inhibitors, which are important in drug discovery and development. The results showed that AAHPE is a potential inhibitor of both α-amylase and α-glucosidase, with IC₅₀ values of 46.50 ± 6.17 (µg/mL) and 37.81 ± 5.15 (µg/mL), respectively. This is demonstrated by a significant increase in the glucose uptake activity percentage in a concentration-dependent manner compared to the control, with the highest AAHPE concentration of 75 µg/mL of glucose uptake activity being higher than metformin, a standard anti-diabetic drug, in the insulin-resistant HepG2 cell line. The molecular docking results displayed that the constituents strongly bind α-amylase and α-glucosidase while achieving better binding affinities that ranged from ΔG = -7.2 to -9.6 kcal/mol (compared with acarbose ΔG = -6.1 kcal/mol) for α-amylase, and ΔG = -7.3 to -9.0 kcal/mol (compared with acarbose ΔG = -6.3 kcal/mol) for α-glucosidase. This study revealed the potential use of the H. petiolare plant extract and its phytochemicals, which could be explored to develop potent and safe α-amylase and α-glucosidase inhibitors to treat postprandial glycemic levels in diabetic patients.

Identification of Novel Potential Anti-Diabetic Candidates targeting Human Pancreatic ɑ-Amylase and Human ɑ-Glycosidase: An Exhaustive Structure-based Screening

Diabetes is a major health issue that half a billion people affected worldwide. It is a serious, long-term medical condition majorly impacting the lives and well-being of individuals, families, and societies at large. It is amongst the top 10 diseases responsible for the death amongst adults with an expected rise to 10.2% (578 million) by 2030 and 10.9% (700 million) by 2045. The carbohydrates absorbed into the body are hydrolyzed by pancreatic α-amylase and other enzymes, human α-glucosidase. The α-amylase and α-glucosidase are validated therapeutic targets in the treatment of Type II diabetes (T2DM) as they play a vital role in modulating the blood glucose post meal. Herein, we report novel and diverse molecules as potential candidates, with predicted affinity for α-amylase and α-glucosidase. These molecules have been identified via hierarchical multistep docking of small molecules database with the estimated binding free energies. A Glide XP Score cutoff −8.00 kcal/mol was implemented to filter out non potential molecules. Four molecules viz. amb22034702, amb18105639, amb17153304, and amb9760832 have been identified after an exhaustive computational study involving, evaluation of binding interactions and assessment of the pharmacokinetics and toxicity profiles. The in-depth analysis of protein– ligand interactions was performed using a 100ns molecular dynamics (MD) simulation to establish the dynamic stability. Furthermore MM-GBSA based binding free energies were computed for 1000 trajectory snapshots to ascertain the strong binding affinity of these molecules for α-amylase and αglucosidase. The identified molecules can be considered as promising candidates for further drug development through necessary experimental assessments.

Elucidating the Glucokinase Activating Potentials of Naturally Occurring Prenylated Flavonoids: An Explicit Computational Approach

Glucokinase activators are considered as new therapeutic arsenals that bind to the allosteric activator sites of glucokinase enzymes, thereby maximizing its catalytic rate and increasing its affinity to glucose. This study was designed to identify potent glucokinase activators from prenylated flavonoids isolated from medicinal plants using molecular docking, molecular dynamics simulation, density functional theory, and ADMET analysis. Virtual screening was carried out on glucokinase enzymes using 221 naturally occurring prenylated flavonoids, followed by molecular dynamics simulation (100 ns), density functional theory (B3LYP model), and ADMET (admeSar 2 online server) studies. The result obtained from the virtual screening with the glucokinase revealed arcommunol B (−10.1 kcal/mol), kuwanon S (−9.6 kcal/mol), manuifolin H (−9.5 kcal/mol), and kuwanon F (−9.4 kcal/mol) as the top-ranked molecules. Additionally, the molecular dynamics simulation and MM/GBSA calculations showed that the hit molecules were stable at the active site of the glucokinase enzyme. Furthermore, the DFT and ADMET studies revealed the hit molecules as potential glucokinase activators and drug-like candidates. Our findings suggested further evaluation of the top-ranked prenylated flavonoids for their in vitro and in vivo glucokinase activating potentials.

Multi-Mechanistic In Vitro Evaluation of Antihyperglycemic, Antioxidant and Antiglycation Activities of Three Phenolic-Rich Indian Red Rice Genotypes and In Silico Evaluation of Their Phenolic Metabolites

The study evaluated the antidiabetic potential of three traditional Indian red rice genotypes/RR (Kattuyanam/KA, Chennangi/CH & Karungkuruvai/KU) using a combination of in vitro, metabolomics (Quadrupole-Time of Flight-Liquid chromatography-Mass spectrometry/Q-TOF-LC-MS/MS), and in silico techniques. In terms of antihyperglycemic potential, KA exhibited the highest inhibitory activity against α-amylase; CH against α-glucosidase; and KU against DPPIV and PTP1B enzymes. KA exhibited the highest antioxidant activity (DPPH, FRAP, and ABTS) and greater inhibition of protein glycation compared to other RR indicating its potential to mitigate diabetic complications. The metabolomic analysis confirmed the presence of 99 phenolics in the sample extracts (KU-71, KA-70, CH-68). Molecular docking studies revealed seven metabolites to be good inhibitors of the four target enzymes and activators of insulin receptor substrate/IRS. The antihyperglycemic and oxidation-glycation reduction composite index revealed KA to have the highest overall antidiabetic potential. Hence, the RR could be utilized in functional foods with a multi-barrelled strategy for diabetes prevention/management.

Advanced Bioinformatics Tools in the Pharmacokinetic Profiles of Natural and Synthetic Compounds with Anti-Diabetic Activity

Diabetes represents a major health problem, involving a severe imbalance of blood sugar levels, which can disturb the nerves, eyes, kidneys, and other organs. Diabes management involves several synthetic drugs focused on improving insulin sensitivity, increasing insulin production, and decreasing blood glucose levels, but with unclear molecular mechanisms and severe side effects. Natural chemicals extracted from several plants such as Gymnema sylvestre, Momordica charantia or Ophiopogon planiscapus Niger have aroused great interest for their anti-diabetes activity, but also their hypolipidemic and anti-obesity activity. Here, we focused on the anti-diabetic activity of a few natural and synthetic compounds, in correlation with their pharmacokinetic/pharmacodynamic profiles, especially with their blood-brain barrier (BBB) permeability. We reviewed studies that used bioinformatics methods such as predicted BBB, molecular docking, molecular dynamics and quantitative structure-activity relationship (QSAR) to elucidate the proper action mechanisms of antidiabetic compounds. Currently, it is evident that BBB damage plays a significant role in diabetes disorders, but the molecular mechanisms are not clear. Here, we presented the efficacy of natural (gymnemic acids, quercetin, resveratrol) and synthetic (TAK-242, propofol, or APX3330) compounds in reducing diabetes symptoms and improving BBB dysfunctions. Bioinformatics tools can be helpful in the quest for chemical compounds with effective anti-diabetic activity that can enhance the druggability of molecular targets and provide a deeper understanding of diabetes mechanisms.

Mangosteen xanthone γ-mangostin exerts lowering blood glucose effect with potentiating insulin sensitivity through the mediation of AMPK/PPARγ

Diabetes mellitus (DM) is concomitant with significant morbidity and mortality and its prevalence is accumulative in worldwide. The conventional antidiabetic agents are known to mitigate the symptoms of diabetes; however, they may also cause side and adverse effects. There is an imperative necessity to conduct preclinical and clinical trials for the discovery of alternative therapeutic agents that can overcome the drawbacks of current synthetic antidiabetic drugs. This study aimed to investigate the efficacy of lowering blood glucose and underlined mechanism of γ-mangostin, mangosteen (Garcinia mangostana) xanthones. The results showed γ-Mangostin had a antihyperglycemic ability in short (2 h)- and long-term (28 days) administrations to diet-induced diabetic mice. The long-term administration of γ-mangostin attenuated fasting blood glucose of diabetic mice and exhibited no hepatotoxicity and nephrotoxicity. Moreover, AMPK, PPARγ, α-amylase, and α-glucosidase were found to be the potential targets for simulating binds with γ-mangostin after molecular docking. To validate the docking results, the inhibitory potency of γ-mangostin againstα-amylase/α-glucosidase was higher than Acarbose via enzymatic assay. Interestingly, an allosteric relationship between γ-mangostin and insulin was also found in the glucose uptake of VSMC, FL83B, C2C12, and 3T3-L1 cells. Taken together, the results showed that γ-mangostin exerts anti-hyperglycemic activity through promoting glucose uptake and reducing saccharide digestion by inhibition of α-amylase/α-glucosidase with insulin sensitization, suggesting that γ-mangostin could be a new clue for drug discovery and development to treat diabetes.

A phase 2, proof of concept, randomised controlled trial of berberine ursodeoxycholate in patients with presumed non-alcoholic steatohepatitis and type 2 diabetes

Non-alcoholic steatohepatitis is frequently associated with diabetes and may cause progressive liver disease. Current treatment options are limited. Here we report on a prospective, randomised, double-blind, placebo-controlled trial of two doses of HTD1801 (berberine ursodeoxycholate, an ionic salt of berberine and ursodeoxycholic acid), versus placebo that was conducted in 100 subjects with fatty liver disease and diabetes (NCT03656744). Treatment was for 18 weeks with a primary endpoint of reduction in liver fat content measured by magnetic resonance imaging proton density fat fraction. Key secondary endpoints included improvement in glycemic control, liver-associated enzymes and safety. The pre-specified primary endpoint was met. Thus, subjects receiving 1000 mg twice a day of berberine ursodeoxycholate had significantly greater reduction in liver fat content than in placebo recipients (mean absolute decrease -4.8% vs. -2.0% (p = 0.011). Compared to placebo, subjects receiving this dose also experienced significant improvement in glycemic control as well as reductions in liver-associated enzymes and significant weight loss. Diarrhea and abdominal discomfort were the most frequently reported adverse events. We conclude that berberine ursodeoxycholate has a broad spectrum of metabolic activity in patients with presumed NASH and diabetes. It is relatively well tolerated and merits further development as a treatment for NASH with diabetes.

A review on phytochemical and therapeutic potential of Iris germanica

Objectives

Iris germanica L. is a medicinal plant, which has a long history of uses, mainly in medieval Persia and many places worldwide for the management of a wide variety of diseases. In this study, we aimed to review ethnopharmacological applications in addition to phytochemical and pharmacological properties of I. germanica.

Key findings

Ethnomedical uses of I. germanica have been reported from many countries such as China, Pakistan, India, Iran and Turkey. The medicinal part of I. germanica is the rhizome and the roots. Based on phytochemical investigations, different bioactive compounds, including flavonoids, triterpenes, sterols, phenolics, ceramides and benzoquinones, have been identified in its medicinal parts. Current pharmacological studies represent that the plant possesses several biological and therapeutic effects, including neuroprotective, hypoglycaemic, hypolipidaemic, antimicrobial, antioxidant, antiproliferative, anti-inflammatory, antiplasmodial, antifungal, immunomodulatory, cytotoxic and antimutagenic effects.

Summary

Although the majority of preclinical studies reported various pharmacological activities of this plant, however, sufficient clinical trials are not currently available. Therefore, to draw a definitive conclusion about the efficacy and therapeutic activities of I. germanica and its bioactive compounds, further clinical and experimental studies are required. Moreover, it is necessary to focus on the pharmacokinetic and safety studies on the extracts of I. germanica.

In silico docking studies of α-amylase inhibitors from the anti-diabetic plant Leucas ciliata Benth. and an endophyte, Streptomyces longisporoflavus

In this investigation, potential inhibitors of α-amylase, one of the key regulatory enzymes in diabetes were characterized from the methanolic extract of Leucas ciliata Benth. (Lamiaceae), a traditional medicinal plant of the Western Ghats, southern India and the ethyl acetate extract of Streptomyces longisporoflavus (JX965948), an endophytic actinomycete isolated from the stem fragments of L. ciliata, by Gas Chromatography and Mass Spectroscopy (GC-MS) technique followed by molecular docking studies. Forty-four compounds were detected in the solvent extracts of the host plant and the endophyte, respectively. These compounds were selected as ligands for the receptor α-amylase in the molecular docking studies using PyRx software (0.8 V) for the inhibition of α-amylase activity. The ligands were ranked based on the binding energies ranging between - 3.1 and - 10.1 kcal/mol. Three ligands from the host plant extract, viz., Topotecan (PNo_7), Cathine (PNo_17) and 2,5-dimethoxy-4-(methylsulfonyl)amphetamine (PNo_18), depicted good binding energies of - 5.2 to - 7.8, respectively, whereas seven compounds from the endophyte extract showed binding energies in the range of - 4.7 to - 10.1, respectively. The standard α-amylase inhibitor Acarbose™ depicted binding energy of - 9.2 kcal/mol. All ligands were subjected to lead-likeliness property using Lipinski's rule of five. On the basis of the hydrogen bonding interactions with the receptor, and chemoinformatics analysis for drug-likeliness, one ligand, Topotecan (PNo_7) from the host plant was identified as the potential α-amylase inhibitor. This is the first attempt to identify alkaloid and flavonoid compounds as the α-amylase inhibitors from the host plant and its endophyte simultaneously. The molecular docking analyses presented in this study could lead to the development of potent α-amylase inhibitors helpful in the treatment of diabetes.

SUPPLEMENTARY INFORMATION

The online version of this article (10.1007/s13205-020-02547-0) contains supplementary material, which is available to authorized users.

Mixed Micelles with Galactose Ligands for the Oral Delivery of Berberine to Enhance Its Bioavailability and Hypoglycemic Effects

Diabetes mellitus (DM) has become an epidemic disorder that is an escalating public health risk. Currently, DM treatment is highly challenging due to temporary medical relief rather than a permanent cure. This article reports a ligand-anchored mixed micellar system formed by phospholipids and N -oleoyl-D-galactosamine aiming to enhance the oral bioavailability and hypoglycemic effects of berberine, an antidiabetic agent with poor absorption. Berberine-loaded mixed micelles (BBMMs) were prepared through a solvent diffusion technique. The resulting BB-MMs were characterized by particle size, potential, morphology, entrapment efficiency (EE) and in vitro release. The oral pharmacokinetics and hypoglycemic efficacy of BB-MMs were evaluated in rats and compared with a berberine suspension. As a result, BB-MMs prepared with the preferable formulation had a particle size of approximately 100 nm with an EE of over 85%. BB-MMs exhibited sustained drug release owing to the entrapment in the micelles. After oral administration, BB-MMs ameliorated the pharmacokinetic profile of berberine and significantly enhanced its oral bioavailability (317.17% relative to the suspension). The pharmacological effect (PE) of BB-MMs was approximately 3.44 times greater than that of the suspension. In addition, in situ single-pass intestinal perfusion and cellular testing results illustrated that BB-MMs had good intestinal permeability and cellular uptake. Our findings demonstrate that the oral bioavailability and hypoglycemic effects of berberine could be largely enhanced by encapsulation into mixed micelles with a galactose moiety. Thus, galactosylated micelles may be promising for developing berberine nanomedicines to fight DM.

In silico study of garlic (Allium sativum L.)-derived compounds molecular interactions with α-glucosidase

Diabetes mellitus is a metabolic syndrome characterized by elevated blood glucose. The α-glucosidase enzyme is responsible for the hydrolysis of carbohydrates. This in silico study aimed to evaluate the inhibitory effects of the isolated compounds from Allium sativum L. on α-glucosidase. At first, sulfur and phenolic compounds of A. sativum L. were obtained from PubChem database, and α-glucosidase enzyme structure was obtained from Protein Data Bank. Toxicity class of compounds and the Lipinski parameter were predicted by Toxtree and Protox II and the Swiss ADME tools, respectively. Finally, the molecular interaction analysis between α-glucosidase and compounds from A. sativum L. was performed by AutoDock 4.2.6. Molecular interactions were investigated using Discovery Studio Visulizer and Ligplot 2.1 program. All of the selected sulfur and phenolic compounds from A. sativum L. followed the Lipinski's rules, had an acceptable binding energy, and lacked toxicity; therefore, they were appropriate candidates for α-glucosidase inhibition. Among these compounds, methionol and caffeic acid showed the lowest binding energy, and the highest inhibitory effect on α-glucosidase enzyme with - 3.9 and - 4.8 kcal/mol, respectively. These compounds also indicated the lower binding energy than the standard inhibitor (miglitol). Among the sulfur and phenolic compounds in A. sativum L., methionol and caffeic acid were predicted to be the powerful inhibitors, due to having more hydrogen binds and hydrophobic interactions with the active site of α-glucosidase.

Antidiabetic Properties of Curcumin: Insights on New Mechanisms

Plant extracts have been used to treat a wide range of human diseases. Curcumin, a bioactive polyphenol derived from Curcuma longa L., exhibits therapeutic effects against diabetes while only negligible adverse effects have been observed. Antioxidant and anti-inflammatory properties of curcumin are the main and well-recognized pharmacological effects that might explain its antidiabetic effects. Additionally, curcumin may regulate novel signaling molecules and enzymes involved in the pathophysiology of diabetes, including glucagon-like peptide-1, dipeptidyl peptidase-4, glucose transporters, alpha-glycosidase, alpha-amylase, and peroxisome proliferator-activated receptor gamma (PPARγ). Recent findings from in vitro and in vivo studies on novel signaling pathways involved in the potential beneficial effects of curcumin for the treatment of diabetes are discussed in this review.

Curcumin-based Antioxidant and Glycohydrolase Inhibitor Compounds: Synthesis and In Vitro Appraisal of the Dual Activity Against Diabetes

BACKGROUND

Curcumin, as the substantial constituent of the turmeric plant (Curcuma longa), plays a significant role in the prevention of various diseases, including diabetes. It possesses ideal structure features as an enzyme inhibitor, including a flexible backbone, hydrophobic nature, and several available hydrogen bond (H-bond) donors and acceptors.

OBJECTIVE

The present study aimed at synthesizing several novel curcumin derivatives and further evaluation of these compounds for possible antioxidant and anti-diabetic properties along with inhibitory effect against two carbohydrate-hydrolyzing enzymes, α-amylase and α-glucosidase, as these enzymes are therapeutic targets for attenuation of postprandial hyperglycemia.

METHODS

Therefore, curcumin-based pyrido[2,3-d]pyrimidine derivatives were synthesized and identified using an instrumental technique like NMR spectroscopy and then screened for antioxidant and enzyme inhibitory potential. Total antioxidant activity, reducing power assay and 1,1-diphenyl-2- picrylhydrazyl (DPPH•) radical scavenging activity were done to appraise the antioxidant potential of these compounds in vitro.

RESULTS

Compounds L6-L9 showed higher antioxidant activity while L4, L9, L12 and especially L8 exhibited the best selectivity index (lowest α-amylase/α-glucosidase inhibition ratio).

CONCLUSION

These antioxidant inhibitors may be potential anti-diabetic drugs, not only to reduce glycemic index but also to limit the activity of the major reactive oxygen species (ROS) producing pathways.