OBJECTIVETo study the inhibitory activity of Aeschynanthus maculatus on alpha-glucosidase.

METHODThe inhibilitory model of in vitro alpha-glucosidase was established. Active extracts of A. maculatus were isolated and identified bymultiple chromatographic methods, and their molecular structures were identifiied by spectral techniques.

RESULTSeven coumpounts were isolated from A. maculatus and isolated as lupeol(1), stigmasterol(2), ursolic acid(3), stigmast-5,22(E)-diene-3beta-ol(4), beta-daucosterol(5), 3-hydroxy-12-taraxasten-28-oic-acid(6) and oleanic acid(7). Compounds 1 (IC50 25.41 mg x L(-1)),3(IC0 4.42 mg L(-1)),4(IC50 11.50 mg x L(-1)),6(IC50 14.17 mg x L(-1)) and 7(IC50 2.88 mg x L(-1)) had higher inhibitory activities than that of acarbose (IC50 1103.01 mg x L(-1)) as the positive control drug.

CONCLUSIONCompound 1-7 were isolated from this plant for the first time. Compound 6 was isolated from Gesneriaceae family for the first time. Compound 7 was isolated from Aeschynanthus genus for the first time.

Enzyme Inhibitors ; chemistry ; pharmacology ; Ferns ; chemistry ; Glycoside Hydrolase Inhibitors ; Plant Exudates ; chemistry ; pharmacology

This study employed the α-glucosidase inhibitory activity model as an anti-diabetic assay and implemented a bioactivity-guided isolation strategy to identify novel natural compounds with potential therapeutic properties. Hypericum sampsoniiwas investigated, leading to the isolation of two highly modified seco-polycyclic polyprenylated acylphloroglucinols (PPAPs) (1 and 2), eight phenolic derivatives (3-10), and four terpene derivatives (11-14). The structures of compounds 1 and 2, featuring an unprecedented octahydro-2H-chromen-2-one ring system, were fully characterized using extensive spectroscopic data and quantum chemistry calculations. Six compounds (1, 5-7, 9, and 14) exhibited potential inhibitory effects against α-glucosidase, with IC₅₀ values ranging from 0.050 ± 0.0016 to 366.70 ± 11.08 μg·mL^-1. Notably, compound 5 (0.050 ± 0.0016 μg·mL^-1) was identified as the most potential α-glucosidase inhibitor, with an inhibitory effect about 6900 times stronger than the positive control, acarbose (IC₅₀ = 346.63 ± 15.65 μg·mL^-1). A docking study was conducted to predict molecular interactions between two compounds (1 and 5) and α-glucosidase, and the hypothetical biosynthetic pathways of the two unprecedented seco-PPAPs were proposed.
Molecular Structure ; Hypericum/chemistry* ; alpha-Glucosidases ; Magnetic Resonance Spectroscopy ; Glycoside Hydrolase Inhibitors/pharmacology*

Diabetes is a common metabolic disorder characterized by abnormally increased plasma glucose levels. Postprandial hyperglycemia plays an essential role in development of type-2 diabetes. Inhibitors of carbohydrate-hydrolyzing enzymes (such as α-glucosidase and α-amylase) offer an effective strategy to regulate/prevent hyperglycemia by controlling starch breakdown. Natural α-amylase and α-glucosidase inhibitors, as well as antioxidants from plant-based sources, offer a source of dietary ingredients that affect human physiological function in order to treat diabetes. Several research studies have investigated the effectiveness of plant-based inhibitors of α-amylase and α-glucosidase, as well as their antioxidant activity. The aim of this review is to summarize the antidiabetic and antioxidant properties of several medicinal plants around the world. Half inhibitory concentration (IC50, for enzyme suppression) and half effective concentration (EC50, for antioxidant activity) values of less than 500 μg/mL were defined as the most potent plant-based inhibitors (in vitro) and are expected to provide interesting candidates for herbal treatment of diabetes, as foods, supplements, or refined drugs.
Antioxidants ; pharmacology ; Glycoside Hydrolase Inhibitors ; pharmacology ; Humans ; Hypoglycemic Agents ; pharmacology ; Plant Extracts ; pharmacology ; Plants, Medicinal ; alpha-Amylases ; antagonists & inhibitors

Six compounds were isolated from the aerial part of cultivated Clerodendranthus spicatus in Hainan with various chromatographic techniques,and their structures were determined as:1-dehydroxy-1-oxo-rupestrinol(1),N-trans-feruloyltyramine(2),methyl 3,4-dihydroxyphenyllactate(3),caffein acid(4),methyl caffeate(5) and ethyl caffeate(6),via analysis of physicochemical properties and spectroscopic evidence.Compound 1 was a new compound,while compounds 2 and 3 were isolated from C.spicatus for the first time.Biological activity results showed that compounds 2-4 exhibited α-glucosidase inhibitory activity with different inhibition ratio.
China ; Glycoside Hydrolase Inhibitors ; isolation & purification ; pharmacology ; Lamiaceae ; chemistry ; Molecular Structure ; Phytochemicals ; isolation & purification ; pharmacology ; Sesquiterpenes, Eudesmane ; isolation & purification ; pharmacology

OBJECTIVETo search alpha-glucosidase inhibitors from Rubia cordifolia.

METHODThe alpha-glucosidase inhibitors were isolated by the column chromatographic techniques and the bioassay-guided method in vitro. A combination of MS and NMR spectroscopy was used to identify the chemical structures. The inhibitory kinetics of the inhibitors were also investigated.

RESULTThe chloroform extract showed high inhibitory activity, and three active compounds were isolated and identified as 1,3-dihydroxy-2-methylanthraquinone (1), 1-hydroxy-2-methylanthraquinone (2) and 1,2-dihydroxyanthraquinone (3). The IC5o values of compound 1-3 were all lower than that of acarbose. Compound 1 and 2 shown competitive type manner on alpha-glucosidase, whereas compound 3 shown noncompetitive type model.

CONCLUSIONCompounds 1-3 as strong inhibitors of alpha-glucosidase were reported for the first time.

Binding, Competitive ; Enzyme Inhibitors ; analysis ; metabolism ; pharmacology ; Glycoside Hydrolase Inhibitors ; Inhibitory Concentration 50 ; Kinetics ; Rubia ; chemistry ; alpha-Glucosidases ; metabolism

OBJECTIVETo investigate the effects of Xanthium sibiricum Patrin ex Widder water extracts (CEW) on α-glucosidase activity (AG) and blood sugar in mice.

METHODSThe inhibition of AG by CEW was studied with enzyme-inhibitor screening external model with acarbose as control drug. The normal mice were administrated by gavage with 40.0g*kg(-1), or 10.0 g*kg(-1) of CEW, 0.375 g*kg(-1) of acarbose, and 0.3ml of normal saline, respectively in successive 5 days; then the animals were loaded with 2.0 g*kg(-1) of glucose, 4.0 g*kg(-1) of sucrose, and 2.0 g*kg(-1) of starch and blood sugar levels were measured within 15, 30, 60, and 120min. Diabetes was induced by injection of streptozotocin (STZ) in mice, then 40.0 g*kg(-1), or 10.0 g*kg(-1) of CEW was given to diabetic mice in successive 2 weeks and 4 weeks, then the blood sugar levels were measured.

RESULTSIn the enzyme inhibition test, when the concentration of CEW was between 0.3125 g*L(-1)-10.00 g*L(-1), the inhibition rate was 55.42%-92.73% when the concentration of acarbose was 1.5625 g*L(-1)-25.00 g*L(-1), the inhibition rate was 9.28%-64.87%. In the sugar tolerance test, the blood sugar value in starch-loaded mice decreased sharply (P<0.01), followed by sucrose-loaded group (P<0.05), and there was no change in glucose-loaded group (P>0.05). In diabetic mice CEW-40 and CEW-10 groups showed significant blood sugar lowering effect (P<0.01 or P<0.05).

CONCLUSIONCEW has stronger effect in inhibition of AG activity than acarbose. CEW can increase the sugar tolerance in normal mice and decrease the blood sugar level in diabetic mice..

Animals ; Blood Glucose ; drug effects ; metabolism ; Diabetes Mellitus, Experimental ; drug therapy ; Enzyme Inhibitors ; pharmacology ; Female ; Glycoside Hydrolase Inhibitors ; Male ; Mice ; Plant Extracts ; pharmacology ; Xanthium ; chemistry ; alpha-Glucosidases ; metabolism

Alpha-glucosidase inhibitor can reduce the postprandial hyperglycemia and have good effect on preventing and treating the diabetes and diabetic complication. Along with the application of acarbose which is a kind of alpha-glucosidase inhibitor, many research groups pay attention to the crude alpha-glucosidase inhibitor screened from the medicinal herbs in order to find new, safe, and effective medicine. The development of alpha-glucosidase inhibitor screened from the medicinal herbs and its evaluation in vivo and vitro as well as the varieties of the medicinal herbs that contain alpha-glucosidase inhibitor in recent 30 years were summarized in this paper.
Cell Line ; Drug Evaluation, Preclinical ; Enzyme Inhibitors ; isolation & purification ; pharmacology ; Glycoside Hydrolase Inhibitors ; Humans ; Plant Extracts ; isolation & purification ; pharmacology ; Plants, Medicinal ; chemistry

The incidence of diabetes has increased considerably, and become the third serious chronic disease following cancer and cardiovascular diseases. Though acarbose, metformin, and 1-deoxynojirimycin have good efficacy for clinical application as hypoglycemic drugs, their expensive costs and some degree of side effects have limited their clinical application. Recently, increasing attention has concentrated on the polysaccharides from natural plant and animal sources for diabetes. In order to illustrate the pharmaceutical activity of polysaccharides as natural hypoglycemic agents, polysaccharides isolated from Astragalus, oyster mushroom, and Yacon were evaluated for their inhibitory effects on α-glucosidase. Polysaccharides were extracted and purified from Astragalus, Oyster mushroom, and Yacon with hot water at 90 °C for 3 h, respectively. The total sugar content of the polysaccharide was determined by the phenol-sulfuric acid method. The α-glucosidase inhibitory activity was measured by the glucose oxidase method. The results exhibited that the inhibitory effects on α-glucosidase were in decreasing order, Astragalus > oyster mushroom > Yacon. The α-glucosidase inhibition percentage of Astragalus polysaccharide and oyster mushroom polysaccharide were over 40% at the polysaccharide concentration of 0.4 mg·mL(-1). The IC50 of Astragalus polysaccharide and oyster mushroom polysaccharide were 0.28 and 0.424 mg·mL(-1), respectively. The information obtained from this work is beneficial for the use polysaccharides as a dietary supplement for health foods and therapeutics for diabetes.
Asteraceae ; chemistry ; Astragalus Plant ; chemistry ; Diabetes Mellitus ; enzymology ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Glycoside Hydrolase Inhibitors ; chemistry ; pharmacology ; Humans ; Pleurotus ; chemistry ; Polysaccharides ; chemistry ; pharmacology ; alpha-Glucosidases ; chemistry

In the present study, two new compounds from Ipomoea cairica were identified and demonstrated to have α-glucosidase inhibitory activity. They were isolated by column chromatography on silica gel and sephadex LH-20 and finally purified by prep-HPLC, with their structures being elucidated by spectroscopic methods, such as 1D- and 2D-NMR and HR-TOF-MS, and chemical methods. Compounds 1 and 2, named cairicoside A and cairicoside B, were evaluated for α-glucosidase inhibitory activity by the MTT method, with the IC50 values being 25.3 ± 1.6 and 28.5 ± 3.3 μmol·L(-1), respectively.
Glycoside Hydrolase Inhibitors ; isolation & purification ; pharmacology ; Ipomoea ; chemistry ; Molecular Structure ; Plant Extracts ; pharmacology ; Resins, Plant ; isolation & purification ; pharmacology ; Spectrum Analysis ; alpha-Glucosidases

In order to develop potent antidiabetic agents that have inhibitory effect to a-glucosidase, twelve β-acetamido ketone derivatives such as N-{[(substituted-4-oxo-thiochroman-3-yl)phenyl]-methyl}acetamide are designed and synthesized through one-pot Dakin-West reaction. Their chemical structures are confirmed by 1H NMR, 13C NMR, IR and HR-MS. In vitro α-glucosidase inhibition assays of compounds 4a-41 were carried out using glucose oxidase method. The result indicated that most of them possess inhibitory activity in vitro. Compound 4k showed the most potent inhibitory activity with 87.3% inhibition of α-glucosidase at the concentration of 5.39 mmol x L(-1). The structure-activity relationship of these β-acetamido ketone derivatives was discussed preliminarily. Moreover, the molecular docking method was used to study the interaction mode of compound 4k and α-glucosidase. Our results will be helpful for designing of α-glucosidase inhibitors in the future.
Acetamides ; Glycoside Hydrolase Inhibitors ; chemical synthesis ; pharmacology ; Hypoglycemic Agents ; chemical synthesis ; pharmacology ; Molecular Docking Simulation ; Structure-Activity Relationship ; alpha-Glucosidases ; metabolism