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AbstractAstragalus membranaceus is a traditional Chinese medicine with multiple pharmacological activities. Modern pharmacological research has found that Astragalus membranaceus extract has an inhibitory effect on α-glucosidase, however, which component can inhibit the activity of α-glucosidase and its degree of inhibition are unknown. To address this issue, this study used affinity ultrafiltration screening combined with UPLC-ESI-Orbitrap-MS technology to screen α-glucosidase inhibitors in Astragalus membranaceus. Using affinity ultrafiltration technology, we obtained the active components, and using UPLC-ESI-Orbitrap-MS technology, we quickly analyzed and identified them. As a result, a total of 8 ingredients were selected as α-glucosidase inhibitors. [ABSTRACT FROM AUTHOR]

Diabetes mellitus is a multi-systematic chronic metabolic disorder and life-threatening disease resulting from impaired glucose homeostasis. The inhibition of glucosidase, particularly α-glucosidase, could serve as an effective methodology in treating diabetes. Attributed to the catalytic function of glucosidase, the present research focuses on the synthesis of sulfonamide-based acyl pyrazoles (5a-k) followed by their in vitro and in silico screening against α-glucosidase. The envisaged structures of prepared compounds were confirmed through NMR and FTIR spectroscopy and mass spectrometry. All compounds were found to be more potent against α-glucosidase than the standard drug, acarbose (IC50 = 35.1 ± 0.14 µM), with IC50 values ranging from 1.13 to 28.27µM. However, compound 5a displayed the highest anti-diabetic activity (IC50 = 1.13 ± 0.06 µM). Furthermore, in silico studies revealed the intermolecular interactions of most potent compounds (5a and 5b), with active site residues reflecting the importance of pyrazole and sulfonamide moieties. This interaction pattern clearly manifests various structure-activity relationships, while the docking results correspond to the IC50 values of tested compounds. Hence, recent investigation reveals the medicinal significance of sulfonamide-clubbed pyrazole derivatives as prospective therapeutic candidates for treating type 2 diabetes mellitus (T2DM). [ABSTRACT FROM AUTHOR]

Ethnobotanically in Indonesia, Diospyros celebica Bakh is recognized as having antidiabetic activity. This study aimed to isolate antidiabetic compounds from the leaves of Eboni (Diospyros celebica). D. celebica leaves were dried and extracted with 96% ethanol, then fractionated and purified guided by antioxidant activity test, a-glucosidase inhibitory test, and dipeptidyl peptidase-4 (DPP-4) inhibitory test until bioactive isolates were obtained. The isolates were identified and their structures were determined based on NMR 1H, 13C, 2D, and LCMS/MS spectroscopic data. Extracts and fractions have potential antioxidant (DPPH), glucosidase inhibitor, and DPP-4 inhibitor activities as well as containing flavonoids and polyphenols. From the ethyl acetate fraction, isolate 26a-2 namely 3,5-digalloyl-(-)- epiafzelechin was obtained which was active as a DPPH scavenger, glucosidase inhibitor, and DPP4 inhibitor. The extracts, fractions, and flavonoid compounds in D. celebica leaves have the potential for antidiabetic drug candidates. [ABSTRACT FROM AUTHOR]

Type 2 diabetes mellitus is a metabolic dreadful disease caused by an uncontrolled glucose level in the bloodstream, particularly high after a meal. Inhibitors of glucosidases, involved in the digestion of carbohydrates, can regulate this post‐prandial increase in glucose concentration. The traditional drugs act as competitive inhibitors of both pancreatic α‐amylase and α‐glucosidases and this unselective inhibition is behind severe gastrointestinal side effects related to the concomitant inhibition of α‐amylase. We described herein some perglycosylated cyclodextrins as efficient and selective inhibitors of α‐glucosidase with low micromolar IC50 (3.64‐7.98 μM) compared to the acarbose (IC50 212 μM), clinically used for patients suffering from type 2 diabetes. On the other hand, they do not inhibit α‐amylase (IC50>500 μM). Structure/activity relationship rationalization suggests multiple interactions between the described inhibitors and α‐glucosidase, which support the existence of both active site and allosteric interactions. [ABSTRACT FROM AUTHOR]

Two libraries of quinoline‐based hybrids 1‐(7‐chloroquinolin‐4‐yl)‐1H‐pyrazolo[3,4–d]pyrimidin‐4‐amine and 7‐chloro‐N‐phenylquinolin‐4‐amine were synthesized and evaluated for their α‐glucosidase inhibitory and antioxidant properties. Compounds with 4‐methylpiperidine and para‐trifluoromethoxy groups, respectively, showed the most promising α‐glucosidase inhibition activity with IC50=46.70 and 40.84 μM, compared to the reference inhibitor, acarbose (IC50=51.73 μM). Structure‐activity relationship analysis suggested that the cyclic secondary amine pendants and para‐phenyl substituents account for the variable enzyme inhibition. Antioxidant profiling further revealed that compounds with an N‐methylpiperazine and N‐ethylpiperazine ring, respectively, have good DPPH scavenging abilities with IC50=0.18, 0.58 and 0.93 mM, as compared to ascorbic acid (IC50=0.05 mM), while the best DPPH scavenger is NO2‐substituted compound (IC50=0.08 mM). Also, compound with N‐(2‐hydroxyethyl)piperazine moiety emerged as the best NO radical scavenger with IC50=0.28 mM. Molecular docking studies showed that the present compounds are orthosteric inhibitors with their quinoline, pyrimidine, and 4‐amino units as crucial pharmacophores furnishing α‐glucosidase binding at the catalytic site. Taken together, these compounds exhibit dual potentials; i. e., potent α‐glucosidase inhibitors and excellent free radical scavengers. Hence, they may serve as structural templates in the search for agents to manage Type 2 diabetes mellitus. Finally, in preliminary assays investigating the anti‐tubercular potential of these compounds, two pyrazolopyrimidine series compounds and a 7‐chloro‐N‐phenylquinolin‐4‐amine hybrid showed sub‐10 μM whole‐cell activities against Mycobacterium tuberculosis. [ABSTRACT FROM AUTHOR]

Type 2 diabetes is common and involves α‐glucosidase inhibition to regulate glucose. We synthesized twenty E‐arylidene steroids with hydroxy and methoxy groups on the aromatic ring. Compounds 3 a, 5 a, 5 b, and 5 d showed notable inhibition, with IC50 values ranging from 1.84±0.28 to 9.25±2.53 μM. Key features for bioactivity include ortho methoxy and α‐hydroxy. Various inhibition mechanisms were observed. In silico studies elucidate the possible binding modes of E‐arylidene steroids, confirming their enzymatic mechanisms of non/un‐competitive inhibitors. Allosteric site 2 emerges as a potential binding site for compounds 3 a, 5 a, and 5 b. Compound 5 d holds promise as a potent α‐glucosidase inhibitor compared to acarbose at the orthosteric receptor binding site. [ABSTRACT FROM AUTHOR]

In a search for novel nonsugar α‐glucosidase inhibitors for diabetes treatment, a series of N‐(phenylsulfonyl)thiazole‐2‐carboxamide derivatives were designed and synthesized, the α‐glucosidase inhibitory activities were then evaluated. Several compounds with promising α‐glucosidase inhibitory effects were identified. Among these, compound W24 which shows low cytotoxicity and good α‐glucosidase inhibitory activity with an IC50 value of 53.0 ± 7.7 μM, is more competitive compared with the commercially available drug acarbose (IC50 = 228.3 ± 9.2 μM). W24 was identified as a promising candidate in the development of α‐glucosidase inhibitors. Molecular docking studies and molecular dynamics simulation were also performed to reveal the binding pattern of the active compound to α‐glucosidase, and the binding free energy of the best compound W24 was 36.3403 ± 3.91 kcal/mol. [ABSTRACT FROM AUTHOR]

Cellular stress, notably oxidative, inflammatory, and endoplasmic reticulum (ER) stress, is implicated in the pathogenesis of cardiovascular disease. Modifiable risk factors for cardiovascular disease such as diabetes, hypercholesterolemia, saturated fat consumption, hypertension, and cigarette smoking cause ER stress whereas currently known cardioprotective drugs with diverse pharmacodynamics share a common pleiotropic effect of reducing ER stress. Selective targeting of oxidative stress with known antioxidative vitamins has been ineffective in reducing cardiovascular risk. This "antioxidant paradox" is partially attributed to the unexpected aggravation of ER stress by the antioxidative agents used. In contrast, some of the contemporary antihyperglycemic drugs inhibit both oxidative stress and ER stress in human coronary artery endothelial cells. Unlike sulfonylureas, meglitinides, α glucosidase inhibitors, and thiazolidinediones, metformin, glucagon-like peptide 1 receptor agonists, and sodium-glucose cotransporter 2 inhibitors are the only antihyperglycemic drugs that reduce ER stress caused by pharmacological agents (tunicamycin) or hyperglycemic conditions. Clinical trials with selective ER stress modifiers are needed to test the suitability of ER stress as a therapeutic target for cardiovascular disease. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) is one of the chronic non-communicable diseases and has been rapidly increasing globally. Alpha glucosidase is an important enzyme that hydrolyzes polysaccharides into monosaccharides before being absorbed into the bloodstream. The alpha glucosidase inhibitors, such as acarbose are expensive and have several adverse effects. The use of herbal products to prevent or treatment of disease is becoming popular. There are many herbal products that can reduce blood sugar levels. However, taking herbal products with anti-DM medicines may cause herb-drug interactions that affect either the pharmacokinetics or pharmacodynamics of the drugs, leading to adverse effects or ineffective treatment. The aim of this study is to examine the effect of herbal extracts on alpha-glucosidase activity and the level of cytochrome P450 3A4 (CYP3A4) by using HepaRG as a model. Three herbs that reported blood glucose-lowering activity were selected including Moringa oleifera, Momordica charantia, and Morus alba. All herbs were extracted with 95% ethanol and tested for their in vitro alpha glucosidase inhibitory activity. The results showed that M. alba extract exhibits the highest activity (IC50= 83.75 µg/mL). Then, the extracts were evaluated for their cytotoxicity on the HepaRG cell line. All extracts showed no cytotoxicity at concentrations up to 250 µg/mL. The sub-cytotoxic concentration of each extract was selected to test for the effect on the CYP3A4 enzyme. The results showed that only M. alba extract elevated the level of CYP3A4, while the others slightly reduce the level of CYP3A4. However, this is a preliminary study that the major compounds of each extract must be isolated and evaluated in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Five pairs of novel merosesquiterpenoid enantiomers were isolated and identified. • Dauresorcinol A (1) possesses an unprecedented methyl-shifted merosesquiterpenoid carbon skeleton. • Dauresorcinol B (2) bears a novel caged merosesquiterpenoid carbon skeleton. • (+)/(−)- 1 and 3 − 5 showed more potent α -glucosidase inhibitory activity than acarbose. • The structure−activity relationships of isolates were discussed. Five pairs of new merosesquiterpenoid enantiomers, named dauresorcinols A−E (1 − 5), were isolated from the leaves of Rhododendron dauricum. Their structures were elucidated by comprehensive spectroscopic data analysis, quantum chemical calculations, Rh 2 (OCOCF 3) 4 -induced ECD, and single-crystal X-ray diffraction analysis. Dauresorcinols A (1) and B (2) possess two new merosesquiterpene skeletons bearing an unprecedented 2,6,7,10,14-pentamethyl-11-oxatetracyclo[8.8.0.02,7.012,17]octadecane and a caged 15-isohexyl-1,5,15-trimethyl-2,10-dioxatetracyclo[7.4.1.111,14.03,8]pentadecane motif, respectively. Plausible biosynthetic pathways of 1 − 5 are proposed involving key oxa-electrocyclization and Wagner−Meerwein rearrangement reactions. (+)/(−)- 1 and 3 − 5 showed potent α -glucosidase inhibitory activity, 3 to 22 times stronger than acarbose, an antidiabetic drug targeting α -glucosidase. Docking results provide a basis to design and develop merosesquiterpenoids as potent α -glycosidase inhibitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flavonoids with hypoglycemic activity from the waste leaves of Rheum tanguticum were studied for the first time. • Extraction and enrichment process of active flavonoids were optimized based on an activity-oriented strategy. • Thirty-six flavonoids in the fraction with best α-glycosidase inhibition activity were identified by UPLC-QTOF-MS/MS. • Six flavonoids with higher α-glycosidase inhibition activity were screened by molecular docking and in vitro validation. • The interaction mechanism between six flavonoids and protein was investigated using multispectral approaches. In the present study, an efficient strategy has been established for rapid screening of potential α-glucosidase inhibitors from the waste leaves of Rheum tanguticum by activity-oriented extraction and enrichment optimization, UPLC-QTOF-MS/MS, molecular docking, and in vitro validation. With α-glucosidase inhibitory activity as the evaluation index, the extraction process was optimized by response surface methodology and the enrichment process by macroporous resins was optimized by adsorption and desorption experiments. The active flavonoids yield was 8.85 mg/g under the optimized extraction conditions. After AB-8 macroporous resins enrichment, the active flavonoids purity increased from 2.89 % to 47.6 %, a 17-fold increase, while the IC 50 of α-glucosidase reduced from 13.97 mg/mL to 412 μg/mL, a 33.9-fold reduction. Thirty-six flavonoids in the active flavonoids fraction were identified by UPLC-QTOF-MS/MS. Molecular docking screening, in vitro activity assay and multispectral approaches verification confirmed the potential of six flavonoids as novel α-glucosidase inhibitors. [ABSTRACT FROM AUTHOR]

• Pleurospermum candollei possess high inhibition activity against DPPH radicals and alpha glucosidase enzyme. • P. candollei can reduce the diabetic effects of streptozotocin. • P. candollei can normalize the production of antioxidant enzymes and free radicals in rat kidney. • P. candollei can regulate the inhibition of inflammatory, and apoptotic mediators. • P. candollei can be used as potent drug against diabetes induced nephropathy. Pleurosepermum candollei is a local vegetable that is traditionally used to cure abdominal problems, pain, and infertility. The purpose of this study was to evaluate the therapeutic potential of P. candollei ethanolic extract against T2DM through modulation of renal genetic markers. Biochemical composition of extract was investigated through high performance liquid chromatography and quantitative phytochemical analyses. In rats, T2DM was induced by injecting streptozotocin (STZ), and P. candollei ethanol extract was administered for 21 days. Antioxidant enzymes and renal biomarkers were assessed in homogenized kidney samples of treated groups. qRT-PCR analysis of isolated RNA was performed for estimation of inflammatory and apoptotic markers. These biochemical analyses revealed that plant extract significantly normalized the levels of catalase (CAT), superoxide dismutase (SOD), and reduced glutathione (GSH) after 21 days of treatment. However, high dose of plant extract (300 mg/kg) exhibited more prominent results in restoring the inflammatory (IL-6, IL-β1, and TNF-α) and apoptotic markers than low dose (150 mg/kg). Similarly, histological studies also revealed that there was minor inflammation and necrosis in kidney of plant treated rats. Generally, the present study showed that administration of P. candollei extract exhibits renal protective, anti-hyperglycemic, and anti-glycation properties. However, further research is required to assess the mechanism of action of PCE at clinical level. [Display omitted] [ABSTRACT FROM AUTHOR]

Identifying medicinally relevant compounds from natural resources generally involves the tedious work of screening plants for the desired activity before capturing the bioactive molecules from them. In this work, we created a paper-based ligand fishing platform to vastly simplify the discovery process. This paper-based method exploits the enzymatic cascade reaction between α -glucosidase (GAA), glucose oxidase (GOx), and horseradish peroxidase (HRP), to simultaneously screen the plants and capture the GAA inhibitors from them. The designed test strip could capture ligands in tandem with screening the plants, and it features a very simply operation based on direct visual assessment. Multiple acylated flavonol glycosides from the leaves of Quercus variabilis Blume were newly found to possess GAA inhibitory activities, and they may be potential leads for new antidiabetic medications. Our study demonstrates the prospect of the newly discovered GAA ligands as potential bioactive ingredients as well as the utility of the paper-based ligand fishing method. [Display omitted] • Test strip (GDTS) built on enzyme cascade reaction and dopamine-paper was newly set. • GDTS can screen bioactive plants and concurrently capture α -glucosidase inhibitors. • Four plants were screened by GDTS as targets from fourteen plants. • Twenty-two inhibitors were acquired from target plants via GDTS. • Acylated flavonol glucosides in Quercus variabilis were new GAA inhibitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • New indol-fused pyrano-[2,3- d ]pyrimidines 11a-l were designed and synthesized. • The plausible mechanism for formation of compounds 11a-l was described. • Their α-glucosidase and acetylcholinesterase inhibitory activities were evaluated. • α-Glucosidase inhibitors 11d , e were around 93-fold more potent than acarbose. • Product 11 k exhibited good acetylcholinesterase inhibitory activity. In this study, new indol-fused pyrano[2,3- d ]pyrimidines were designed and synthesized. These products were obtained in moderate to good yields and their structures were assigned by NMR, MS, and IR analysis. Afterwards, the biological important of the products was highlighted by evaluating in vitro for α-glucosidase inhibitory activity as well as acetylcholinesterase (AChE) inhibitory activity. Eleven products revealed substantial inhibitory activity against α-glucosidase enzyme, among which, two most potent products 11d,e were approximately 93-fold more potent than acarbose as a standard antidiabetic drug. Besides that, product 11 k exhibited good AChE inhibition. The substituents on the 5-phenyl ring, attached to the pyran ring, played a critical role in inhibitory activities. The biological potencies have provided an opportunity to further investigations of indol-fused pyrano[2,3- d ]pyrimidines as potential anti-diabetic agents. [ABSTRACT FROM AUTHOR]