Acarbose: safe and effective for lowering postprandial hyperglycaemia and improving cardiovascular outcomes

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.

The Anti-Diabetic Effects of Medicinal Plants Belonging to the Liliaceae Family: Potential Alpha Glucosidase Inhibitors

Background

Diabetes mellitus is a complex metabolic disorder that has an enormous impact on people's quality of life and health. Although there is no doubt about the effectiveness of oral hypoglycemic agents combined with lifestyle management in controlling diabetes, no individual has ever been reported to have been completely cured of the disease. Globally, many medicinal plants have been used for the management of diabetes in various traditional systems of medicine. A deep look in the literature has revealed that the Liliaceae family have been poorly investigated for their antidiabetic activity and phytochemical studies. In this review, we summarize medicinal plants of Liliaceae utilized in the management of type II diabetes mellitus (T2DM) by inhibition of α-glucosidase enzyme and phytochemical content.

Methods

The literature search was conducted using databases including PubMed, ScienceDirect, and Google Scholar to find the significant published articles about Liliaceae plants utilized in the prevention and treatment of antidiabetics. Data were filtered to the publication period from 2013 to 2023, free full text and only English articles were included. The keywords were Liliaceae OR Alliaceae OR Amaryllidaceae AND Antidiabetic OR α-glucosidase.

Results

Six medicinal plants such as Allium ascalonicum, Allium cepa, Allium sativum, Aloe ferox, Anemarrhena asphodeloides, and Eremurus himalaicus are summarized. Phytochemical and α-glucosidase enzymes inhibition by in vitro, in vivo, and human studies are reported.

Conclusion

Plants of Liliaceae are potential as medicine herbs to regulating PPHG and prevent the progression of T2DM and its complication. In silico study, clinical application, and toxicity evaluation are needed to be investigated in the future.

Evaluation of antidiabetic and antioxidant effects of Polygonum cognatum Meisn. and phytochemical analysis of effective extracts

Polygonum cognatum Meisn. (Polygonaceae) is used both as food and as a folk medicine to treat diabetes. This study aimed to evaluate the effect of the extracts, along with isolated compounds, from P. cognatum aerial parts on diabetes. In vitro studies were conducted using an α-glucosidase inhibitory assay, while in vivo antidiabetic studies were carried out on streptozotocin-induced diabetic rats. Effective extracts were subjected to isolation studies, and structures of the compounds were elucidated by spectroscopic methods. The ethyl acetate and n-butanol extracts had the highest effect in both in vitro and in vivo experiments. They also decreased aspartate transaminase, alanine transaminase and malondialdehyde levels, while increasing glutathione and superoxide dismutase activity in rats. From the active extracts, 11 phenolic compounds were isolated and characterized. Among the isolated compounds, quercetin was found to be the most active according to α-glucosidase inhibitory activity studies. This study provided scientific evidence for the traditional use of P. cognatum as a folk medicine for treating diabetes. The findings suggest that the ethyl acetate and n-butanol extracts, as well as quercetin, have the potential for development as antidiabetic agents.

The effect of acarbose on inflammatory cytokines and adipokines in adults: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Although a large number of trials have observed an anti-inflammatory property of acarbose, the currently available research remains controversial regarding its beneficial health effects. Hence, the purpose of this study was to examine the effect of acarbose on inflammatory cytokines and adipokines in adults.

METHODS

PubMed, Web of Science, and Scopus were systematically searched until April 2023 using relevant keywords. The mean difference (MD) of any effect was calculated using a random-effects model. Weighted mean difference (WMD) and 95% confidence intervals (CIs) were calculated via the random-effects model.

RESULTS

The current meta-analysis of data comprised a total of 19 RCTs. Meta-analysis showed that acarbose significantly decreased tumor necrosis factor-alpha (TNF-α) (weighted mean difference [WMD]) = - 4.16 pg/ml, 95% confidence interval (CI) - 6.58, - 1.74; P = 0.001) while increasing adiponectin (WMD = 0.79 ng/ml, 95% CI 0.02, 1.55; P = 0.044). However, the effects of acarbose on TNF-α concentrations were observed in studies with intervention doses ≥ 300 mg/d (WMD = - 4.09; 95% CI - 7.00, - 1.18; P = 0.006), and the adiponectin concentrations were significantly higher (WMD = 1.03 ng/ml, 95%CI 0.19, 1.87; P = 0.016) in studies in which the duration of intervention was less than 24 weeks. No significant effect was seen for C-reactive protein (CRP; P = 0.134), interleukin-6 (IL-6; P = 0.204), and leptin (P = 0.576).

CONCLUSION

Acarbose had beneficial effects on reducing inflammation and increasing adiponectin. In this way, it may prevent the development of chronic diseases related to inflammation. However, more studies are needed.

Inhibitory effect of acarbose on tyrosinase: application of molecular dynamics integrating inhibition kinetics

Due to its clinical and cosmetic applications, investigators have paid attention to tyrosinase (TYR) inhibitor development. In this study, a TYR inhibition study with acarbose was investigated to gain insights into the regulation of the catalytic function. Biochemical assay results indicated that acarbose was turned to be an inhibitor of TYR in a reversible binding manner and probed as a distinctive mixed-type inhibitor via measurement of double-reciprocal kinetic (Ki = 18.70 ± 4.12 mM). Time-interval kinetic measurement indicated that TYR catalytic function was gradually inactivated by acarbose in a time-dependent behavior displaying with a monophase process that was evaluated by semi-logarithmic plotting. Spectrofluorimetric measurement by integrating with a hydrophobic residue detector (1-anilinonaphthalene-8-sulfonate) showed that the high dose of acarbose derived a conspicuous local structural deformation of the TYR catalytic site pocket. Computational docking simulation showed that acarbose bound to key residues such as HIS61, TYR65, ASN81, HIS244, and HIS259. Our study extends an understanding of the functional application of acarbose and proposes that acarbose is an alternative candidate drug for a whitening agent via direct retardation of TYR catalytic function and it would be applicable for the relevant skin hyperpigmentation disorders concerning the dermatologic clinical purpose.Communicated by Ramaswamy H. Sarma.

Finding structural requirements of structurally diverse α-glucosidase and α-amylase inhibitors through validated and predictive 2D-QSAR and 3D-QSAR analyses

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by hyperglycemic state. The α-glucosidase and α-amylase are considered two major targets for the management of Type 2 DM due to their ability of metabolizing carbohydrates into simpler sugars. In the current study, cheminformatics analyses were performed to develop validated and predictive models with a dataset of 187 α-glucosidase and α-amylase dual inhibitors. Separate linear, interpretable and statistically robust 2D-QSAR models were constructed with datasets containing the activities of α-glucosidase and α-amylase inhibitors with an aim to explain the crucial structural and physicochemical attributes responsible for higher activity towards these targets. Consequently, some descriptors of the models pointed out the importance of specific structural moieties responsible for the higher activities for these targets and on the other hand, properties such as ionization potential and mass of the compounds as well as number of hydrogen bond donors in molecules were found to be crucial in determining the binding potentials of the dataset compounds. Statistically significant 3D-QSAR models were developed with both α-glucosidase and α-amylase inhibition datapoints to estimate the importance of 3D electrostatic and steric fields for improved potentials towards these two targets. Molecular docking performed with selected compounds with homology model of α-glucosidase and X-ray crystal structure of α-amylase largely supported the interpretations obtained from the cheminformatic analyses. The current investigation should serve as important guidelines for the design of future α-glucosidase and α-amylase inhibitors. Besides, the current investigation is entirely performed by using non-commercial open-access tools to ensure easy accessibility and reproducibility of the investigation which may help researchers throughout the world to work more on drug design and discovery.

Geroprotector drugs and exercise: friends or foes on healthy longevity?

Physical activity and several pharmacological approaches individually combat age-associated conditions and extend healthy longevity in model systems. It is tantalizing to extrapolate that combining geroprotector drugs with exercise could extend healthy longevity beyond any individual treatment. However, the current dogma suggests that taking leading geroprotector drugs on the same day as exercise may limit several health benefits. Here, we review leading candidate geroprotector drugs and their interactions with exercise and highlight salient gaps in knowledge that need to be addressed to identify if geroprotector drugs can have a harmonious relationship with exercise.

Impact of ultrasonication on the contents, profiles and biofunctional properties of free and bound phenolics from white desert truffle (Tirmania nivea) and its protein fractions

The molecular and biofunctional properties of protein and phenolic fractions in edible truffles remain largely unknown. This study examined the effect of ultrasonication on the contents, profiles, and bioactive properties of free and bound phenolics (FP and BP) from desert truffle (Tirmania nivea) and its protein fractions. Protein fractions from the Osborne extraction scheme were biochemically and structurally characterized. The albumin fraction showed the highest abundance (16.8%) and yield (35.8%). Total phenolic contents were the highest in non-sonicated samples (3.5-34.1 mg/g), particularly in the albumin fraction and in whole truffle. FP extracted at 30 °C (FP-30 °C) accounted for the largest proportion of total phenolics in all protein fractions, whereas BP-30 °C and FP-60 °C were predominant in non-sonicated and sonicated truffle, respectively. The highest antioxidant activity was obtained with FP-30 °C extracts from non-sonicated albumins, globulins and truffle (91.9, 72.7 and 30.0%), followed by BP-30 °C from non-sonicated albumins (25.4%) and FP-60 °C from sonicated glutelins-1 (24.2%). High inhibition of α-amylase was evidenced in several extracts, including FP-30 °C from non-sonicated glutelins-1 (99.2%) and FP-30 °C from sonicated globulins (72.4%). Several extracts also displayed high inhibition of angiotensin I-converting enzyme (ACE), including FP-60 °C from non-sonicated glutelins-1 (65.1%) and sonicated glutelins-1 (71.1%) and globulins (64.7%). Most extracts were rich in epicatechin, gallic acid, chlorogenic acid and catechin. Correlations between phenolic content, antioxidant activity, anti-α-amylase and anti-ACE activities were influenced by sonication. Sonication reduced the particle size of the proteins and modified their structural characteristics. These findings demonstrate that white desert truffle proteins co-occur with bioactive phenolics whose functionalities can be tailored by protein fractionation and sonication.

The effect of acarbose on lipid profiles in adults: a systematic review and meta-analysis of randomized clinical trials

PURPOSE

Dyslipidemia, characterized by elevated levels of triglycerides (TG), low-density lipoprotein (LDL), total cholesterol (TC), and reduced levels of high-density lipoprotein (HDL), is a major risk factor for cardiovascular diseases (CVD). Several studies have shown the potential of acarbose in improving serum lipid markers. However, there have been conflicting results on the topic in adults. Therefore, a comprehensive systematic review and meta-analysis was conducted to assess the impact of acarbose on lipid profiles.

METHODS

The random-effects approach was used to combine the data, and the results were provided as weighted mean difference (WMD) with 95% confidence intervals (CI).

RESULTS

Our meta-analysis included a total of 74 studies with a combined sample size of 7046 participants. The results of the analysis showed that acarbose resulted in a reduction in levels of TG (WMD = - 13.43 mg/dl, 95% CI: - 19.20, - 7.67; P < 0.001) and TC (WMD = - 1.93 mg/dl, 95% CI: - 3.71, - 0.15; P = 0.033), but did not affect other lipid markers. When conducting a nonlinear dose-response analysis, we found that acarbose was associated with an increase in levels of HDL (coefficients = 0.50, P = 0.012), with the highest increase observed at a dosage of 400 mg/d. Furthermore, our findings suggested a non-linear relationship between the duration of the intervention and TC (coefficients = - 18.00, P = 0.032), with a decline observed after 50 weeks of treatment.

CONCLUSION

The findings of this study suggest that acarbose can reduce serum levels of TG and TC. However, no significant effects were observed on LDL or HDL levels.

Sex Differences in the Preventive Effect of Cardiovascular and Metabolic Therapeutics on Dementia

Dementia is a clinical syndrome characterized by progressive impairment of cognitive and functional abilities. As currently applied treatments for dementia can only delay the progression of dementia and cannot fundamentally cure it, much attention is being paid to reducing its incidence by preventing the associated risk factors. Cardiovascular and metabolic diseases are well-known risk factors for dementia, and many studies have attempted to prevent dementia by treating these risk factors. Growing evidence suggests that sex-based factors may play an important role in the pathogenesis of dementia. Therefore, a deeper understanding of the differences in the effects of drugs based on sex may help improve their effectiveness. In this study, we reviewed sex differences in the impact of therapeutics targeting risk factors for dementia, such as cardiovascular and metabolic diseases, to prevent the incidence and/or progression of dementia.

Plants of the Rubiaceae Family with Effect on Metabolic Syndrome: Constituents, Pharmacology, and Molecular Targets

Metabolic syndrome (MetS) predisposes individuals to chronic non-communicable diseases (NCDs) like type 2 diabetes (T2D), non-alcoholic fatty liver disease, atherosclerosis, and cardiovascular disorders caused by systemic inflammation, intestinal dysbiosis, and diminished antioxidant ability, leading to oxidative stress and compromised insulin sensitivity across vital organs. NCDs present a global health challenge characterized by lengthy and costly pharmacological treatments. Complementary and alternative medicine using herbal therapies has gained popularity. Approximately 350,000 plant species are considered medicinal, with 80% of the world's population opting for traditional remedies; however, only 21,000 plants are scientifically confirmed by the WHO. The Rubiaceae family is promissory for preventing and treating MetS and associated NCDs due to its rich content of metabolites renowned for their antioxidative, anti-inflammatory, and metabolic regulatory properties. These compounds influence transcription factors and mitigate chronic low-grade inflammation, liver lipotoxicity, oxidative stress, and insulin resistance, making them a cost-effective non-pharmacological approach for MetS prevention and treatment. This review aims to collect and update data that validate the traditional uses of the Rubiaceae family for treating MetS and associated NCDs from experimental models and human subjects, highlighting the mechanisms through which their extracts and metabolites modulate glucose and lipid metabolism at the molecular, biochemical, and physiological levels.

Harnessing the Bioactive Potential of Limonium spathulatum (Desf.) Kuntze: Insights into Enzyme Inhibition and Phytochemical Profile

This study assessed the halophyte species Limonium spathulatum (Desf.) as a possible source of natural ingredients with the capacity to inhibit enzymes related to relevant human health disorders and food browning. Extracts using food-grade solvents such as water and ethanol were prepared by maceration from dried L. spathulatum leaves. They were evaluated for in vitro inhibition activity of enzymes such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), α-glucosidase, tyrosinase and lipase, related to Alzheimer's disease, type-2-diabetes mellitus, skin hyperpigmentation, and obesity, respectively. These extracts were also appraised for in vitro acute toxicity on tumoral and non-tumoral cell lines and their chemical composition by high-performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI-MS/MS). The extracts were more effective towards BChE than AChE. The best results were obtained with the hydroethanolic and water extracts, with IC50 values of 0.03 mg/mL and 0.06 mg/mL, respectively. The hydroethanolic extract had the highest capacity to inhibit α-glucosidase (IC50: 0.04 mg/mL), higher than the positive control used (acarbose, IC50 = 3.14 mg/mL). The ethanol extract displayed the best inhibitory activity against tyrosinase (IC50 = 0.34 mg/mL). The tested samples did not inhibit lipase and exhibited low to moderate cytotoxic activity against the tested cell lines. The hydroethanolic extract had a higher diversity of compounds, followed by the ethanol and water samples. Similar molecules were identified in all the extracts and were mainly hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids. Taken together, these results suggest that L. spathulatum should be further explored as a source of bioactive ingredients for the food, cosmetic, and pharmaceutical industries.

Exploring the interactive mechanism of acarbose with the amylase SusG in the starch utilization system of the human gut symbiont Bacteroides thetaiotaomicron through molecular modeling

The α-amylase, SusG, is a principal component of the Bacteroides thetaiotaomicron (Bt) starch utilization system (Sus) used to metabolize complex starch molecules in the human gastrointestinal (GI) tract. We previously reported the non-microbicidal growth inhibition of Bt by the acarbose-mediated arrest of the Sus as a potential therapeutic strategy. Herein, we report a computational approach using density functional theory (DFT), molecular docking, and molecular dynamics (MD) simulation to explore the interactive mechanism between acarbose and SusG at the atomic level in an effort to understand how acarbose shuts down the Bt Sus. The docking analysis reveals that acarbose binds orthosterically to SusG with a binding affinity of -8.3 kcal/mol. The MD simulation provides evidence of conformational variability of acarbose at the active site of SusG and also suggests that acarbose interacts with the main catalytic residues via a general acid-base double-displacement catalytic mechanism. These results suggest that small molecule competitive inhibition against the SusG protein could impact the entire Bt Sus and eliminate or reduce the system's ability to metabolize starch. This computational strategy could serve as a potential avenue for structure-based drug design to discover other small molecules capable of inhibiting the Sus of Bt with high potency, thus providing a holistic approach for selective modulation of the GI microbiota.

α-amylase inhibition and in silico studies of novel naphtho[2,3-d]imidazole-4,9-dione linked N-acyl hydrazones

Aim: To enrich the pool of α-amylase inhibitors to manage Type 2 diabetes. Methods: Synthesis, conformational study, α-amylase inhibitory action and various in silico studies of novel N'-(arylbenzylidene)-2-(4,9-dioxo-4,9-dihydro-1H-naphtho[2,3-d]imidazol-1-yl)acetohydrazides carried out. Results: Compound H6 demonstrated the highest activity (IC50 = 0.0437 μmol mL-1) among the tested compounds. Structure-activity relationship study suggested that variable substitution at the aryl ring has a pivotal role in determining the inhibitory action of tested compounds. Docking simulations of the most active compound (H6) confirmed its interaction potential with active site residues of A. oryzae α-amylase. The root-mean-square deviation fluctuations substantiated the stability of protein-ligand complex. Absorption, distribution, metabolism and excretion prediction revealed optimal values for absorption, distribution, metabolism and excretion parameters. Conclusion: The developed molecules could be beneficial for the development of novel α-amylase inhibitors to treat Type 2 diabetes.

DNA protection ability, antihyperglycemic potential and in-vivo toxicity assessment of arrowleaf tearthumb (Persicaria sagittata L.), a neglected aquatic plant species of Eastern Asia

Persicaria sagittata L. (common name arrowleaf tearthumb, American) is an herbaceous edible plant with characteristics sessile leaves mainly found in wetland areas of North America and Eastern Asia. In Eastern Himalayan Region of India, the ethnic communities consumed this plant as vegetables. The present investigation suggests the plant is endowed with bioactive compounds having potential DNA protection ability and antihyperglycemic activity. The DNA nicking assay revealed that the methanolic extract of this plant has the potential to protect plasmid DNA against hydroxyl damage. The α-glucosidase and α-amylase inhibitory assay of this methanolic extract suggest more effectiveness in inhibition of α-amylase than the α-glucosidase. Further, proximate composition, micronutrient, total phenolic and flavonoid content of this underutilised aquatic plant was determined. And lastly the in-vivo cytotoxicity study of Persicaria sagittata L. plant extract suggest that the plant is less toxic to in-vivo system.

The effects of acarbose treatment on cardiovascular risk factors in impaired glucose tolerance and diabetic patients: a systematic review and dose-response meta-analysis of randomized clinical trials

Acarbose (ACB) seems to be an effective drug in the management of cardiovascular risk factors. However, no previous meta-analysis of randomized controlled trials (RCTs) has been done to evaluate the effects of ACB on cardiovascular risk factors on impaired glucose tolerance (IGT), type 2 diabetes mellitus (T2D), and type 1 diabetes mellitus (T1D). We comprehensively searched electronic databases including Scopus, Web of Science, and PubMed for RCTs for related keywords up to September 2022. A random-effects model was used to estimate the weighted mean difference (WMD) and 95% confidence interval (CI). The pooled analysis demonstrated that ACB treatment had a significant effect on fasting blood glucose (FBG) (WMD = -3.55 mg/dL; 95%CI: -6.29, -0.81; p = 0.011), fasting insulin (WMD = -6.73 pmoL/L; 95%CI: -10.37, -3.10; p < 0.001), HbA1c [WMD = -0.32%; 95%CI: -0.45, -0.20; p < 0.001], body weight (WMD = -1.25 kg; 95%CI: -1.79, -0.75; p < 0.001), body mass index (BMI) (WMD = -0.64 kg/m2; 95%CI: -0.92, -0.37; p < 0.001), tumor necrosis factor-alpha (TNF-α) (WMD = -2.70 pg/mL, 95%CI: -5.25, -0.16; p = 0.037), leptin (WMD = -1.58 ng/mL; 95%CI: -2.82, -0.35; p = 0.012), alanine transaminase (ALT) (WMD = 0.71 U/L; 95%CI: -0.31, 1.85; p = 0.164), triglyceride (TG) (WMD = -13.89 mg/dL; 95%CI: -20.69, -7.09; p < 0.001), total cholesterol (TC) (WMD = -2.26 mg/dL; 95%CI: -4.18, -0.34; p = 0.021), systolic blood pressure (SBP) (WMD = -1.29 mmHg; 95%CI: -2.44, -0.15; p = 0.027), and diastolic blood pressure (DBP) (WMD = 0.02 mmHg; 95%CI: -0.41, 0.45; p = 0.925) in an intervention group, compared with a placebo group. The non-linear dose-response analysis showed that ACB reduces the TC in trial duration by >50 weeks, and 180 mg/day is more effective for the decrement of CRP. ACB can improve lipid profiles, glycemic indices, anthropometric indices, and inflammatory markers in T2D, T1D, and IGT patients.

Acarbose Mitigates Age-Dependent Alterations in Erythrocyte Membrane Transporters During Aging in Rats

Acarbose (ACA), a well-studied and effective inhibitor of α-amylase and α-glucosidase, is a postprandial-acting antidiabetic medicine. The membrane of the erythrocyte is an excellent tool for analyzing different physiological and biochemical activities since it experiences a range of metabolic alterations throughout aging. It is uncertain if ACA modulates erythrocyte membrane activities in an age-dependent manner. As a result, the current study was conducted to explore the influence of ACA on age-dependent deteriorated functions of transporters/exchangers, disrupted levels of various biomarkers such as lipid hydroperoxides (LHs), protein carbonyl (PCO), sialic acid (SA), total thiol (-SH), and erythrocyte membrane osmotic fragility. In addition to a concurrent increase in Na+/H+ exchanger activity and concentration of LH, PCO, and osmotic fragility, we also detected a considerable decrease in membrane-linked activities of Ca2+-ATPase (PMCA) and Na+/K+-ATPase (NKA), as well as concentrations of SA and -SH in old-aged rats. The aging-induced impairment of the activities of membrane-bound ATPases and the changed levels of redox biomarkers were shown to be effectively restored by ACA treatment.

Assessments of Alpha-Amylase Inhibitory Potential of Tagetes Flavonoids through In Vitro, Molecular Docking, and Molecular Dynamics Simulation Studies

Diabetes is a chronic fast-growing metabolic disorder that is characterized by high blood glucose levels. Tagetes minuta L. has been used as a traditional remedy for various illnesses for many years, and, furthermore, its oil is used in the perfume and flavor industries. T. minuta contains various metabolites, such as flavonoids, thiophenes, terpenes, sterols, and phenolics, with varied bioactivities. Flavonoids can inhibit carbohydrate-digesting enzymes, such as alpha-amylase, which is a convenient dietary strategy for controlling hyperglycemia. In the current investigation, the isolated flavonoids quercetagetin-6-O-(6-O-caffeoyl-β-D-glucopyranoside), quercetagetin-7-O-β-D-glucopyranoside, quercetagetin-6-O-β-D-glucopyranoside, minutaside A, patuletin-7-O-β-D-glucopyranoside, quercetagetin-7-methoxy-6-O-β-D-glucopyranoside, tagenols A and B, quercetagetin-3,7-dimethoxy-6-O-β-D-glucopyranoside, patuletin, quercetin-3,6-dimethyl ether, and quercetin-3-methyl ether from T. minuta were assessed for their alpha-amylase inhibition (AAI) efficacy using an in vitro assay, as well as molecular docking, dynamics simulation, and ADMET analyses. Our findings show that quercetagetin-6-O-(6-O-caffeoyl-β-D-glucopyranoside) (1), quercetagetin-7-O-β-D-glucopyranoside (2), quercetagetin-6-O-β-D-glucopyranoside (3), minutaside A (4), patuletin-7-O-β-D-glucopyranoside (5), and quercetagetin-7-methoxy-6-O-β-D-glucopyranoside (6) had a notable AAI capacity (IC₅₀s ranged from 7.8 to 10.1 μM) compared to acarbose (IC₅₀ 7.1 μM). Furthermore, these compounds with the highest binding affinity among the tested flavonoids revealed high docking scores for AA (ranging from -12.171 to 13.882 kcal/mol) compared to that of acarbose (-14.668 kcal/mol). In MDS, these compounds were observed to show maximum stability and the greatest binding free energy, suggesting that they may contend with native ligands. In addition, the ADMET analysis showed that these active compounds had a broad span of drug-like, pharmacokinetic, and physicochemical features and did not possess any considerable undesired effects. The current results suggest the potential of these metabolites as AAI candidates. However, further in vivo and mechanistic studies are warranted to specify the efficacy of these metabolites.

Inhibitory Potential of Synthetic Amino Acid Derivatives against Digestive Enzymes as Promising Hypoglycemic and Anti-Obesity Agents

Over the last decades, the increased incidence of metabolic disorders, such as type two diabetes and obesity, has motivated researchers to investigate new enzyme inhibitors. In this study, the inhibitory effects of synthetic amino acid derivatives (PPC80, PPC82, PPC84, PPC89, and PPC101) on the activity of digestive enzymes were assessed using in vitro assays. The inhibitory effect was determined by the inhibition percentage and the 50% inhibitory concentration (IC50), and the mechanism of action was investigated using kinetic parameters and Lineweaver-Burk plots. PPC80, PPC82, and PPC84 inhibited pancreatic lipase (IC50 of 167-1023 µM) via competitive or mixed mechanisms. The activity of pancreatic α-amylase was suppressed by PPC80, PPC82, PPC84, PPC89, and PPC101 (IC50 of 162-519 µM), which acted as competitive or mixed inhibitors. Finally, PPC84, PPC89, and PPC101 also showed potent inhibitory effects on α-glucosidase (IC50 of 51-353 µM) as competitive inhibitors. The results suggest that these synthetic amino acid derivatives have inhibitory potential against digestive enzymes and may be used as therapeutic agents to control metabolic disorders.

Acarbose suppresses symptoms of mitochondrial disease in a mouse model of Leigh syndrome

Mitochondrial diseases represent a spectrum of disorders caused by impaired mitochondrial function, ranging in severity from mortality during infancy to progressive adult-onset disease. Mitochondrial dysfunction is also recognized as a molecular hallmark of the biological ageing process. Rapamycin, a drug that increases lifespan and health during normative ageing, also increases survival and reduces neurological symptoms in a mouse model of the severe mitochondrial disease Leigh syndrome. The Ndufs4 knockout (Ndufs4^-/-) mouse lacks the complex I subunit NDUFS4 and shows rapid onset and progression of neurodegeneration mimicking patients with Leigh syndrome. Here we show that another drug that extends lifespan and delays normative ageing in mice, acarbose, also suppresses symptoms of disease and improves survival of Ndufs4^-/- mice. Unlike rapamycin, acarbose rescues disease phenotypes independently of inhibition of the mechanistic target of rapamycin. Furthermore, rapamycin and acarbose have additive effects in delaying neurological symptoms and increasing maximum lifespan in Ndufs4^-/- mice. We find that acarbose remodels the intestinal microbiome and alters the production of short-chain fatty acids. Supplementation with tributyrin, a source of butyric acid, recapitulates some effects of acarbose on lifespan and disease progression, while depletion of the endogenous microbiome in Ndufs4^-/- mice appears to fully recapitulate the effects of acarbose on healthspan and lifespan in these animals. To our knowledge, this study provides the first evidence that alteration of the gut microbiome plays a significant role in severe mitochondrial disease and provides further support for the model that biological ageing and severe mitochondrial disorders share underlying common mechanisms.

Effects of an Extract of the Brown Seaweed Ascophylum nodosum on Postprandial Glycaemic Control in Healthy Subjects: A Randomized Controlled Study

The effects of the consumption of an extract of the brown seaweed Ascophyllum nodosum (BSW) on postprandial glucose and insulin responses to white bread were investigated in an acute, randomized, double-blind, three-arm, crossover, controlled trial in healthy, normoglycemic subjects. Sixteen subjects were administered either control white bread (50 g total digestible carbohydrates) or white bread with 500 mg or 1000 mg of BSW extract. Biochemical parameters were measured in venous blood over 3 h. Significant inter-individual variation in the glycaemic response to white bread was observed. Analysis of the responses of all subjects to either 500 mg or 1000 mg of BSW extract versus control revealed no significant effects of treatments. The variation in response to the control was used to classify individuals into glycaemic responders and non-responders. In the sub-cohort of 10 subjects with peak glucose levels after white bread above 1 mmol/L, we observed a significant decrease in maximum levels of plasma glucose after the intervention meal with 1000 mg of extract compared with the control. No adverse effects were reported. Further work is warranted to define all factors that determine "responders" to the effects of brown seaweed extracts and identify the cohort that would benefit the most from their consumption.

Therapeutic potential of multifunctional myricetin for treatment of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by chronic hyperglycemia, insulin resistance, and insufficient insulin secretion. It is considered that chronic hyperglycemia causes serious problems due to diabetic complications such as retinopathy, nephropathy, and neuropathy. Primarily, treatment in T2DM is pharmacologically tried by using drugs that are insulin sensitizers, insulin secretagogues, α-glucosidase inhibitors, and glucose transporter inhibitors. However, long-term application of these drugs frequently induces various harmful side effects, suggesting that the importance of taking advantage of natural products like phytochemicals. Accordingly, flavonoids, a group of phytochemicals, have attracted attention as components of natural products which are effective in the treatment of several diseases containing T2DM and are strongly recommended as food supplements to ameliorate T2DM-related complications. Several well-studied flavonoids such as quercetin and catechin are known to have anti-diabetic, anti-obesity, and anti-hypertensive actions, although a huge number of flavonoids are still under investigation and their actions are not fully understood. In this situation, myricetin is being shown to be a multiple bioactive compound to prevent and/or suppress hyperglycemia through inhibiting digestion and uptake of saccharides and enhancing insulin secretion as a possible GLP-1 receptor agonist, and to ameliorate T2DM-related complications by protecting endothelial cells from oxidative stress induced by hyperglycemia. In this review, we summarize the multiple effects of myricetin on the targets of T2DM treatment, comparing with different flavonoids.

Insights on the Hypoglycemic Potential of Crocus sativus Tepal Polyphenols: An In Vitro and In Silico Study

Post-prandial hyperglycemia typical of diabetes mellitus could be alleviated using plant-derived compounds such as polyphenols, which could influence the activities of enzymes involved in carbohydrate digestion and of intestinal glucose transporters. Here, we report on the potential anti-hyperglycemic effect of Crocus sativus tepals compared to stigmas, within the framework of valorizing these by-products of the saffron industry, since the anti-diabetic properties of saffron are well-known, but not those of its tepals. In vitro assays showed that tepal extracts (TE) had a greater inhibitory action than stigma extracts (SE) on α-amylase activity (IC50: TE = 0.60 ± 0.09 mg/mL; SE = 1.10 ± 0.08 mg/mL; acarbose = 0.051 ± 0.07) and on glucose absorption in Caco-2 differentiated cells (TE = 1.20 ± 0.02 mg/mL; SE = 2.30 ± 0.02 mg/mL; phlorizin = 0.23 ± 0.01). Virtual screening performed with principal compounds from stigma and tepals of C. sativus and human pancreatic α-amylase, glucose transporter 2 (GLUT2) and sodium glucose co-transporter-1 (SGLT1) were validated via molecular docking, e.g., for human pancreatic α-amylase, epicatechin 3-o-gallate and catechin-3-o-gallate were the best scored ligands from tepals (-9.5 kcal/mol and -9.4 kcal/mol, respectively), while sesamin and episesamin were the best scored ones from stigmas (-10.1 kcal/mol). Overall, the results point to the potential of C. sativus tepal extracts in the prevention/management of diabetes, likely due to the rich pool of phytocompounds characterized using high-resolution mass spectrometry, some of which are capable of binding and interacting with proteins involved in starch digestion and intestinal glucose transport.

A Comprehensive Review on Weight Loss Associated with Anti-Diabetic Medications

Obesity is a complex metabolic condition that can have a negative impact on one's health and even result in mortality. The management of obesity has been addressed in a number of ways, including lifestyle changes, medication using appetite suppressants and thermogenics, and bariatric surgery for individuals who are severely obese. Liraglutide and semaglutide are two of the five Food and Drug Administration (FDA)-approved anti-obesity drugs that are FDA-approved agents for the treatment of type 2 diabetes mellitus (T2DM) patients. In order to highlight the positive effects of these drugs as anti-obesity treatments, we analyzed the weight loss effects of T2DM agents that have demonstrated weight loss effects in this study by evaluating clinical studies that were published for each agent. Many clinical studies have revealed that some antihyperglycemic medications can help people lose weight, while others either cause weight gain or neutral results. Acarbose has mild weight loss effects and metformin and sodium-dependent glucose cotransporter proteins-2 (SGLT-2) inhibitors have modest weight loss effects; however, some glucagon-like peptide-1 (GLP-1) receptor agonists had the greatest impact on weight loss. Dipeptidyl peptidase 4 (DPP-4) inhibitors showed a neutral or mild weight loss effect. To sum up, some of the GLP-1 agonist drugs show promise as weight-loss treatments.

Quinazolinone-1,2,3-triazole-acetamide conjugates as potent α-glucosidase inhibitors: synthesis, enzyme inhibition, kinetic analysis, and molecular docking study

In this study, new hybrids of quinazolinone-1,2,3-triazole-acetamide were designed, synthesized, and screened for their α-glucosidase inhibitory activity. The results obtained from the in vitro screening indicated that all analogs exhibited significant inhibitory activity against α-glucosidase (IC50 values ranging from 4.8-140.2 μM) in comparison to acarbose (IC50 = 750.0 μM). The limited structure-activity relationships suggested the variation in the inhibitory activities of the compounds affected by different substitutions on the aryl moiety. The enzyme kinetic studies of the most potent compound 9c, revealed that it inhibited α-glucosidase in a competitive mode with a K i value of 4.8 μM. In addition, molecular docking studies investigated the structural perturbation and behavior of all derivatives inside the α-glucosidase active site. Next, molecular dynamic simulations of the most potent compound 9c, were performed to study the behavior of the 9c-complex during the time. The results showed that these compounds can be considered as potential antidiabetic agents.

Early or Late-Life Treatment With Acarbose or Rapamycin Improves Physical Performance and Affects Cardiac Structure in Aging Mice

Pharmacological treatments can extend the life span of mice. For optimal translation in humans, treatments should improve health during aging, and demonstrate efficacy when started later in life. Acarbose (ACA) and rapamycin (RAP) extend life span in mice when treatment is started early or later in life. Both drugs can also improve some indices of healthy aging, although there has been little systematic study of whether health benefits accrue differently depending on the age at which treatment is started. Here we compare the effects of early (4 months) versus late (16 months) onset ACA or RAP treatment on physical function and cardiac structure in genetically heterogeneous aged mice. ACA or RAP treatment improve rotarod acceleration and endurance capacity compared to controls, with effects that are largely similar in mice starting treatment from early or late in life. Compared to controls, cardiac hypertrophy is reduced by ACA or RAP in both sexes regardless of age at treatment onset. ACA has a greater effect on the cardiac lipidome than RAP, and the effects of early-life treatment are recapitulated by late-life treatment. These results indicate that late-life treatment with these drugs provide at least some of the benefits of life long treatment, although some of the benefits occur only in males, which could lead to sex differences in health outcomes later in life.

Structure-based approach: molecular insight of pyranocumarins against α-glucosidase through computational studies

α-glucosidase is an enzyme that catalyzes the release of α-glucose molecules through hydrolysis reactions. Regulation of this enzyme can increase sugar levels in type-2 diabetes mellitus (DM) patients. Pyranocoumarin derivatives have been identified as α-glucosidase inhibitors. Through an in silico approach, this work studied the inhibition of three pyranocoumarin compounds against the α-glucosidase at the molecular level. Molecular docking and molecular dynamics simulation were performed to understand the dynamics behavior of pyranocoumarin derivatives against α-glucosidase. The prediction of free binding energy (ΔG _bind) using the Quantum Mechanics/Molecular Mechanics-Generalized Born (QM/MM-GBSA) approach for each system had the following results, PC1-α-Glu: -13.97 kcal mol^-1, PC2-α-Glu: -3.69 kcal mol^-1, and PC3-α-Glu: -13.68 kcal mol^-1. The interaction energy of each system shows that the grid score, ΔG _bind, and ΔG _exp values had a similar correlation, that was PC1-α-Glu > PC3-α-Glu > PC2-α-Glu. Additionally, the decomposition energy analysis (ΔG ^residue _bind) was carried out to find out the contribution of the key binding residue. The results showed that there were 15 key binding residues responsible for stabilizing pyranocumarin binding with criteria of ΔG ^residue _bind < -1.00 kcal mol^-1. The evaluation presented in this work could provide information on the molecular level about the inhibitory efficiency of pyranocoumarin derivatives against a-glucosidase enzyme based on computational studies.

Synthetic benzofuran-linked chalcones with dual actions: a potential therapeutic approach to manage diabetes mellitus

Background: Identification of molecules having dual capabilities to reduce postprandial hyperglycemia and oxidative stress is one of the therapeutic approaches to treat diabetes mellitus. In this connection, a library of benzofuran-linked chalcone derivatives were evaluated for their dual action. Methods: A series of substituted benzofuran-linked chalcones (2-33) were synthesized and tested for α-amylase inhibitory as well as 2,2-diphenylpicrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities. Results: All compounds showed α-amylase inhibitory activity ranging from IC₅₀ = 12.81 ± 0.03 to 87.17 ± 0.15 μM, compared with the standard acarbose (IC₅₀ = 13.98 ± 0.03 μM). Compounds also demonstrated radical scavenging potential against DPPH and ABTS radicals. Conclusion: The identified compounds may serve as potential leads for further advanced research.

Optimisation of alpha-amylase inhibitor production in solid state fermentation

Though not a known producer of alpha-amylase inhibitor, the potential of Streptomyces xinghaiensis AAI-2 to produce this important metabolite was assessed and the process optimised in solid substrate using response surface methodology. The isolate was grown in an inoculum medium, inoculated into wheat bran and supplemented with a basal medium for production of alpha amylase inhibitor. Optimum conditions were determined by Response Surface Methodology. The extract was recovered using sodium phosphate buffer at refrigerated temperature and assay for the presence of alpha-amylase inhibitor was carried out by Dinitrosalicylic acid method. Based on the results of the experimental trials and iteration with those values, it was predicted that optimal pH for alpha-amylase inhibitor production using S. xinghaiensis in solid culture of wheat bran was pH 6.4-6.9 while optimal moisture content and incubation time were predicted as 71%-73% and 9-12 days respectively.

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.

Metagenomic analysis reveals crosstalk between gut microbiota and glucose-lowering drugs targeting the gastrointestinal tract in Chinese patients with type 2 diabetes: a 6 month, two-arm randomised trial

AIMS/HYPOTHESIS

The use of oral glucose-lowering drugs, particularly those designed to target the gut ecosystem, is often observed in association with altered gut microbial composition or functional capacity in individuals with type 2 diabetes. The gut microbiota, in turn, plays crucial roles in the modulation of drug efficacy. We aimed to assess the impacts of acarbose and vildagliptin on human gut microbiota and the relationships between pre-treatment gut microbiota and therapeutic responses.

METHODS

This was a randomised, open-labelled, two-arm trial in treatment-naive type 2 diabetes patients conducted in Beijing between December 2016 and December 2017. One hundred participants with overweight/obesity and newly diagnosed type 2 diabetes were recruited from the Pinggu Hospital and randomly assigned to the acarbose (n=50) or vildagliptin (n=50) group using sealed envelopes. The treatment period was 6 months. Blood, faecal samples and visceral fat data from computed tomography images were collected before and after treatments to measure therapeutic outcomes and gut microbiota. Metagenomic datasets from a previous type 2 diabetes cohort receiving acarbose or glipizide for 3 months were downloaded and processed. Statistical analyses were applied to identify the treatment-related changes in clinical variables, gut microbiota and associations.

RESULTS

Ninety-two participants were analysed. After 6 months of acarbose (n=44) or vildagliptin (n=48) monotherapy, both groups achieved significant reductions in HbA_1c (from 60 to 46 mmol/mol [from 7.65% to 6.40%] in the acarbose group and from 59 to 44 mmol/mol [from 7.55% to 6.20%] in the vildagliptin group) and visceral fat areas (all adjusted p values for pre-post comparisons <0.05). Both arms showed drug-specific and shared changes in relative abundances of multiple gut microbial species and pathways, especially the common reductions in Bacteroidetes species. Three months and 6 months of acarbose-induced changes in microbial composition were highly similar in type 2 diabetes patients from the two independent studies. Vildagliptin treatment significantly enhanced fasting active glucagon-like peptide-1 (GLP-1) levels. Baseline gut microbiota, rather than baseline GLP-1 levels, were strongly associated with GLP-1 response to vildagliptin, and to a lesser extent with GLP-1 response to acarbose.

CONCLUSIONS/INTERPRETATION

This study reveals common microbial responses in type 2 diabetes patients treated with two glucose-lowering drugs targeting the gut differently and acceptable performance of baseline gut microbiota in classifying individuals with different GLP-1 responses to vildagliptin. Our findings highlight bidirectional interactions between gut microbiota and glucose-lowering drugs.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02999841 FUNDING: National Key Research and Development Project: 2016YFC1304901.

Inhibition of α-Glucosidase and Pancreatic Lipase Properties of Mitragyna speciosa (Korth.) Havil. (Kratom) Leaves

Kratom (Mitragyna speciosa (Korth.) Havil.) has been used to reduce blood sugar and lipid profiles in traditional medicine, and mitragynine is a major constituent in kratom leaves. Previous data on the blood sugar and lipid-altering effects of kratom are limited. In this study, phytochemical analyses of mitragynine, 7-hydroxymitragynine, quercetin, and rutin were performed in kratom extracts. The effects on α-glucosidase and pancreatic lipase activities were investigated in kratom extracts and mitragynine. The LC-MS/MS analysis showed that the mitragynine, quercetin, and rutin contents from kratom extracts were different. The ethanol extract exhibited the highest total phenolic content (TPC), total flavonoid content (TFC), and total alkaloid content (TAC). Additionally, compared to methanol and aqueous extracts, the ethanol extract showed the strongest inhibition activity against α-glucosidase and pancreatic lipase. Compared with the anti-diabetic agent acarbose, mitragynine showed the most potent α-glucosidase inhibition, with less potent activity of pancreatic lipase inhibition. Analysis of α-glucosidase and pancreatic lipase kinetics revealed that mitragynine inhibited noncompetitive and competitive effects, respectively. Combining mitragynine with acarbose resulted in a synergistic interaction with α-glucosidase inhibition. These results have established the potential of mitragynine from kratom as a herbal supplement for the treatment and prevention of diabetes mellitus.

Antidiabetic potential of Lysiphyllum strychnifolium (Craib) A. Schmitz compounds in human intestinal epithelial Caco-2 cells and molecular docking-based approaches

Background

Lysiphyllum strychnifolium (Craib) A. Schmitz, a traditional Thai medicinal plant, is mainly composed of polyphenols and flavonoids and exhibits several pharmacological activities, including antioxidant, anticancer, antimicrobial, and antidiabetic activities. However, the mechanism by which pure compounds from L. strychnifolium inhibit glucose catalysis in the small intestine and their effect on the glucose transporter remain unknown.

Methods

The objectives of this research were to examine the effect of 3,5,7-trihydroxychromone-3-O-𝛼-L-rhamnopyranoside (compound 1) and 3,5,7,3’,5’-pentahydroxy-flavanonol-3-O-𝛼-L-rhamnopyranoside (compound 2) on the inhibition of α-amylase and α-glucosidase, as well as glucose transporters, such as sodium-glucose cotransporter 1 (SGLT1), glucose transporter 2 (GLUT2), and glucose transporter 5 (GLUT5), using Caco-2 cells as a model of human intestinal epithelial cells. Additionally, the binding affinity and interaction patterns of compounds against two receptor proteins (SGLT1 and GLUT2) were determined for the first time utilizing a molecular docking approach.

Results

In the α-amylase inhibition assay, a concentration-dependent inhibitory response was observed against the enzyme. The results indicated that compound 1 inhibited α-amylase activity in a manner similar to that of acarbose (which exhibit IC50 values of 3.32 ± 0.30 µg/mL and 2.86 ± 0.10 µg/mL, respectively) in addition to a moderate inhibitory effect for compound 2 (IC50 = 10.15 ± 0.53 µg/mL). Interestingly, compounds 1 and 2 significantly inhibited α-glucosidase and exhibited better inhibition than that of acarbose, with IC50 values of 5.35 ± 1.66 µg/mL, 510.15 ± 1.46 µg/mL, and 736.93 ± 7.02 µg/mL, respectively. Additionally, α-glucosidase activity in the supernatant of the Caco-2 cell monolayer was observed. In comparison to acarbose, compounds 1 and 2 inhibited α-glucosidase activity more effectively in Caco-2 cells without cytotoxicity at a concentration of 62.5 µg/mL. Furthermore, the glucose uptake pathways mediated by SGLT1, GLUT2, and GLUT5- were downregulated in Caco-2 cells treated with compounds 1 and 2. Additionally, molecular modeling studies revealed that compounds 1 and 2 presented high binding activity with SGLT1 and GLUT2.

Conclusion

In summary, our present study was the first to perform molecular docking with compounds present in L. strychnifolium extracts. Our findings indicated that compounds 1 and 2 reduced glucose uptake in Caco-2 cells by decreasing the expression of glucose transporter genes and inhibiting the binding sites of SGLT1 and GLUT2. Therefore, compounds 1 and 2 may be used as functional foods in dietary therapy for postprandial hyperglycemia modulation of type 2 diabetes.

Design, synthesis, and molecular docking studies of diphenylquinoxaline-6-carbohydrazide hybrids as potent α-glucosidase inhibitors

A novel series of diphenylquinoxaline-6-carbohydrazide hybrids 7a-o were rationally designed and synthesized as anti-diabetic agents. All synthesized compounds 7a-o were screened as possible α-glucosidase inhibitors and exhibited good inhibitory activity with IC50 values in the range of 110.6 ± 6.0 to 453.0 ± 4.7 µM in comparison with acarbose as the positive control (750.0 ± 10.5 µM). An exception in this trend came back to a compound 7k with IC50 value > 750 µM. Furthermore, the most potent derivative 7e bearing 3-fluorophenyl moiety was further explored by kinetic studies and showed the competitive type of inhibition. Additionally, the molecular docking of all derivatives was performed to get an insight into the binding mode of these derivatives within the active site of the enzyme. In silico assessments exhibited that 7e was well occupied in the binding pocket of the enzyme through favorable interactions with residues, correlating to the experimental results.

Combination therapy of bioactive compounds with acarbose: A proposal to control hyperglycemia in type 2 diabetes

Type 2 diabetes (T2D) is a chronic metabolic disease with a high impact on public health and social welfare. Hyperglycemia is a characteristic of T2D that leads to different complications. Acarbose (ACB) reduces hyperglycemia by inhibiting α-amylase (AMY) and α-glucosidase (GLU) enzymes. However, ACB causes low adherence to treatment by patients with diabetes due to its side effects. Consequently, reducing the side effects produced by ACB without compromising its efficacy is a challenge in treating T2D. Bioactive compounds (BC) are safe and could decrease the side effects compared to antidiabetic drugs such as ACB. Nevertheless, their efficacy alone concerning that drug is unknown. The scientific advances have been directed toward searching for new approaches, such as combination therapies between BC and ACB. This review analyzes the combined therapy of BC (extracts or isolates) with ACB in inhibiting AMY and GLU as a proposal to control hyperglycemia in T2D. PRACTICAL APPLICATION: Postprandial hyperglycemia is one most typical signs of type 2 diabetes, and it can have significant consequences, including cardiovascular problems. Acarbose has side effects that lead to the abandonment of treatment. Bioactive compounds in extracts or isolated forms have become a viable option for controlling hyperglycemia without side effects, but their administration alone is insufficient. The scientific advances of acarbose/bioactive compound combination therapy as a proposal for controlling hyperglycemia in T2D were analyzed. The findings suggested that bioactive compounds combined with acarbose are effective when they function synergistically or additively; however, they are not recommended in therapy when they have an antagonistic effect.

Can gallic acid potentiate the antihyperglycemic effect of acarbose and metformin? Evidence from streptozotocin-induced diabetic rat model

This study investigated the influence of dietary phenolic acid- Gallic acid (GA) on the antihyperglycemic properties of acarbose (ACA) and metformin (MET). Streptozotocin-induced diabetic rats were treated (p.o) with ACA, MET, GA and their combinations for 14 days. The effects of the treatments on blood glucose and insulin levels, pancreas α-amylase and intestinal α-glucosidase activities, as well as thiobarbituric acid reactive species (TBARS), thiol and reactive oxygen species (ROS) levels, including antioxidant enzyme activities were investigated. A significant increase in blood glucose, insulin, ROS and TBARS levels, and impaired antioxidant status, as well as elevation in the activities of α-amylase and α-glucosidase observed in diabetic rats were ameliorated in the treatment groups. Hpwever, GA had varying effects on the antidiabetic properties of the drugs. Nevertheless, GA showed more potentiating effects on the antidiabetic effect of MET and these effects were better observed at the lower dose of GA.

Antioxidant activity and α-glucosidase inhibitability of Distichochlamys citrea M.F. Newman rhizome fractionated extracts: in vitro and in silico screenings

Distichochlamys citrea M.F. Newman (commonly known as “Black Ginger”) is an endemic plant to Vietnam and has been extensively exploited by folk medication for treatments of infection-related diseases and diabetes. In this work, its rhizomes were subjected to fractionated extraction, phytochemical examination, evaluation of antioxidant effect by DDPH free radical neutralization, and inhibitory activity toward α-glucosidase. The compositional components were subjected to in silico screening, including density functional theory calculation, molecular docking simulation, physicochemical analysis, and pharmacokinetic regression. In the trials, EtOAc fraction is found as the bioactive part of most effectiveness, regarding both antioxidant effect (IC₅₀ = 90.27 µg mL⁻¹) and α-glucosidase inhibitory activity (IC₅₀ = 115.75 μg mL⁻¹). Chemical determination reveals there are 13 components of its composition. DFT-based calculations find no abnormal constraints in their structures. Docking-based simulation provides order of inhibitory effectiveness: 3-P53341 > 12-P53341 > 7-P53341 > 4-P53341 > 11-P53341 > 10-P53341. QSARIS-based investigations implicate their biocompatibility. ADMET-based regressions indicate that all candidates are generally safe for medicinal applications. The findings would contribute to the basis for further studies on the chemical compositions of Distichochlamys citrea and their biological activities.

Enterocyte HKDC1 Modulates Intestinal Glucose Absorption in Male Mice Fed a High-fat Diet

Hexokinase domain containing protein-1, or HKDC1, is a widely expressed hexokinase that is genetically associated with elevated 2-hour gestational blood glucose levels during an oral glucose tolerance test, suggesting a role for HKDC1 in postprandial glucose regulation during pregnancy. Our earlier studies utilizing mice containing global HKDC1 knockdown, as well as hepatic HKDC1 overexpression and knockout, indicated that HKDC1 is important for whole-body glucose homeostasis in aging and pregnancy, through modulation of glucose tolerance, peripheral tissue glucose utilization, and hepatic energy storage. However, our knowledge of the precise role(s) of HKDC1 in regulating postprandial glucose homeostasis under normal and diabetic conditions is lacking. Since the intestine is the main entry portal for dietary glucose, here we have developed an intestine-specific HKDC1 knockout mouse model, HKDC1Int-/-, to determine the in vivo role of intestinal HKDC1 in regulating glucose homeostasis. While no overt glycemic phenotype was observed, aged HKDC1Int-/- mice fed a high-fat diet exhibited an increased glucose excursion following an oral glucose load compared with mice expressing intestinal HKDC1. This finding resulted from glucose entry via the intestinal epithelium and is not due to differences in insulin levels, enterocyte glucose utilization, or reduction in peripheral skeletal muscle glucose uptake. Assessment of intestinal glucose transporters in high-fat diet-fed HKDC1Int-/- mice suggested increased apical GLUT2 expression in the fasting state. Taken together, our results indicate that intestinal HKDC1 contributes to the modulation of postprandial dietary glucose transport across the intestinal epithelium under conditions of enhanced metabolic stress, such as high-fat diet.

Recent advances on discovery of enzyme inhibitors from natural products using bioactivity screening

The essence of enzymes is to keep the homeostasis and balance of human by catalyzing metabolic responses and modulating cell. Suppression of enzyme slows the progress of some diseases, making it a therapeutic target. Therefore, it is important to develop enzyme inhibitors by proper bioactivity screening strategies for the future treatment of some major diseases. In this review, we summarized the recent (2015-2020) applications of several screening strategies (electrophoretically mediated microanalysis, enzyme immobilization, affinity chromatography, and affinity ultrafiltration) in finding enzyme inhibitors from certain species of bioactive natural compounds of plant origin (flavonoids, alkaloids, phenolic acids, saponins, anthraquinones, coumarins). At the same time, the advantages and disadvantages of each strategy were also discussed, and the future possible development direction in enzyme inhibitor screening has prospected. To sum up, it is expected to help readers select suitable screening strategies for enzyme inhibitors and provide useful information for the study of the biological of specific kinds of natural products. This article is protected by copyright. All rights reserved.

Different Interactive Effects of Metformin and Acarbose With Dietary Macronutrient Intakes on Patients With Type 2 Diabetes Mellitus: Novel Findings From the MARCH Randomized Trial in China

Antidiabetic oral agents and nutrition management are frequently used together as first-line therapies for type 2 diabetes mellitus (T2DM). However, less is known about their interaction. The interactive effect of two classic antidiabetic medications, namely, acarbose and metformin, with dietary intakes of macronutrients on glycemic control and cardiometabolic risk factors was investigated in the metformin and acarbose in Chinese as the initial hypoglycemic treatment (MARCH) randomized clinical trial. The patients with newly diagnosed T2DM from China were included in the trial. Participants were randomized to receive either metformin or acarbose monotherapy as the initial treatment, followed by a 24-week treatment phase, during which add-on therapy was used if necessary. Dietary intakes of carbohydrate, protein, fat, and total energy were calculated by a 24-h food diary recall method. Linear mixed-effect models combined with a subgroup analysis were used to investigate independent and interactive effects of drugs and diet on clinical outcomes. A data analysis was performed on 551 of the 788 patients randomly assigned to treatment groups. Metformin therapy was independently associated with higher triglycerides (TGs, β = 0.471, P = 0.003), 2 h postprandial plasma glucose (2hPPG, β = 0.381, P = 0.046) but lower low-density lipoprotein cholesterol (LDL-C, β = −0.149, P = 0.013) compared with acarbose therapy. Higher carbohydrates and lower fat intakes were independently associated with poorer glycemic control, less weight loss, and greater insulin secretion. Higher total energy intake was also independently associated with higher fasting (β = 0.0002, P = 0.001) and postprandial blood glucose (β = 0.0004, P = 0.001). Interaction and subgroup analyses demonstrated that glucagon-like peptide-1 (GLP-1) was positively related to total energy (β = 0.268, P = 0.033), carbohydrates intake, and insulin secretion (β = 2,045.2, P = 0.003) only in the acarbose group, while systolic blood pressure (SBP) was negatively related to protein intake in the metformin group (β = 23.21, P = 0.014). The results of this study showed that metformin and acarbose mainly exerted different interactive effects with dietary energy, carbohydrate, and protein intakes on GLP-1 secretion, insulin release, and SBP. The interaction between drug therapy and nutrition intervention in glycemia highlights the complexity of combination therapy.

2022 update to the position statement by Primary Care Diabetes Europe: a disease state approach to the pharmacological management of type 2 diabetes in primary care

Type 2 diabetes and its associated comorbidities are growing more prevalent, and the complexity of optimising glycaemic control is increasing, especially on the frontlines of patient care. In many countries, most patients with type 2 diabetes are managed in a primary care setting. However, primary healthcare professionals face the challenge of the growing plethora of available treatment options for managing hyperglycaemia, leading to difficultly in making treatment decisions and contributing to treatment and therapeutic inertia. This position statement offers a simple and patient-centred clinical decision-making model with practical treatment recommendations that can be widely implemented by primary care clinicians worldwide through shared-decision conversations with their patients. It highlights the importance of managing cardiovascular disease and elevated cardiovascular risk in people with type 2 diabetes and aims to provide innovative risk stratification and treatment strategies that connect patients with the most effective care.

Reprofiling of approved drugs against SARS-CoV-2 main protease: an in-silico study

Given the COVID-19 pandemic, currently, there are many drugs in clinical trials against this virus. Among the excellent drug targets of SARS-CoV-2 are its proteases (Nsp3 and Nsp5) that plays vital role in polyprotein processing giving rise to functional nonstructural proteins, essential for viral replication and survival. Nsp5 (also known as Mpro) hydrolyzes replicase polyprotein (1ab) at eleven different sites. For targeting Mpro, we have employed drug repurposing approach to identify potential inhibitors of SARS-CoV-2 in a shorter time span. Screening of approved drugs through docking reveals Hyaluronic acid and Acarbose among the top hits which are showing strong interactions with catalytic site residues of Mpro. We have also performed docking of drugs Lopinavir, Ribavirin, and Azithromycin on SARS-CoV-2 Mpro. Further, binding of these compounds (Hyaluronic acid, Acarbose, and Lopinavir) is validated by extensive molecular dynamics simulation of 500 ns where these drugs show stable binding with Mpro. We believe that the high-affinity binding of these compounds will help in designing novel strategies for structure-based drug discovery against SARS-CoV-2.Communicated by Ramaswamy H. Sarma.

Geroprotectors and Skeletal Health: Beyond the Headlines

Osteoporosis and osteoarthritis are the most common age-related diseases of the musculoskeletal system. They are responsible for high level of healthcare use and are often associated with comorbidities. Mechanisms of ageing such as senescence, inflammation and autophagy are common drivers for both diseases and molecules targeting those mechanisms (geroprotectors) have potential to prevent both diseases and their co-morbidities. However, studies to test the efficacy of geroprotectors on bone and joints are scant. The limited studies available show promising results to prevent and reverse Osteoporosis-like disease. In contrast, the effects on the development of Osteoarthritis-like disease in ageing mice has been disappointing thus far. Here we review the literature and report novel data on the effect of geroprotectors for Osteoporosis and Osteoarthritis, we challenge the notion that extension of lifespan correlates with extension of healthspan in all tissues and we highlight the need for more thorough studies to test the effects of geroprotectors on skeletal health in ageing organisms.

Magnolol and Luteolin Inhibition of α-Glucosidase Activity: Kinetics and Type of Interaction Detected by In Vitro and In Silico Studies

Magnolol and luteolin are two natural compounds recognized in several medicinal plants widely used in traditional medicine, including type 2 diabetes mellitus. This research aimed to determine the inhibitory activity of magnolol and luteolin on α-glucosidase activity. Their biological profile was studied by multispectroscopic methods along with inhibitory kinetic analysis and computational experiments. Magnolol and luteolin decreased the enzymatic activity in a concentration-dependent manner. With 0.075 µM α-glucosidase, the IC₅₀ values were similar for both compounds (~ 32 µM) and significantly lower than for acarbose (815 μM). Magnolol showed a mixed-type antagonism, while luteolin showed a non-competitive inhibition mechanism. Thermodynamic parameters suggested that the binding of magnolol was predominantly sustained by hydrophobic interactions, while luteolin mainly exploited van der Waals contacts and hydrogen bonds. Synchronous fluorescence revealed that magnolol interacted with the target, influencing the microenvironment around tyrosine residues, and circular dichroism explained a rearrangement of the secondary structure of α-glucosidase from the initial α-helix to the final conformation enriched with β-sheet and random coil. Docking studies provided support for the experimental results. Altogether, the data propose magnolol, for the first time, as a potential α-glucosidase inhibitor and add further evidence to the inhibitory role of luteolin.