Objective:To investigate the relationship between triterpenoid saponin content and antioxidant,antimicrobial,and α-glucosidase inhibitory activities of 70%ethanolic,butanolic,aqueous,supernate and precipitate extract...Objective:To investigate the relationship between triterpenoid saponin content and antioxidant,antimicrobial,and α-glucosidase inhibitory activities of 70%ethanolic,butanolic,aqueous,supernate and precipitate extracts of Juglans regia leaves.Methods:Triterpenoid saponins of different Juglans regia leaf extracts were measured by the vanillin method.Antioxidant activity was evaluated against DPPH and ABTS free radicals.We also assessed α-glucosidase inhibitory and antimicrobial activities of the leaf extracts.Pearson’s correlation coefficient was evaluated to determine the correlation between the saponin content and biological activities.Results:The butanolic extract was most effective against DPPH with an IC50of 6.63μg/mL,while the aqueous extract showed the highest scavenging activity against ABTS free radical with an IC50of 42.27μg/mL.Pearson’s correlation analysis indicated a strong negative correlation (r=-0.956) between DPPH radical scavenging activity (IC50) and the saponin content in the samples examined.In addition,the aqueous extract showed the best α-glucosidase inhibitory activity compared with other extracts.All the extracts had fair antibacterial activity against Bacillus subtilis,Escherichia coli,and Klebsiella pneumoniae except for the aqueous extract.Conclusions:Juglans regia extracts show potent antioxidant,antimicrobial,and α-glucosidase inhibitory activities.There is a correlation between saponin levels in Juglans regia leaf extracts and the studied activities.However,additional research is required to establish these relationships by identifying the specific saponin molecules responsible for these activities and elucidating their mechanisms of action.展开更多
Objective:α-Glucosidase inhibitors can be used as a new class of antidiabetic drug.By competitively inhibiting glycosidase activity,these inhibitors help to prevent the fast breakdown of sugars and thereby control th...Objective:α-Glucosidase inhibitors can be used as a new class of antidiabetic drug.By competitively inhibiting glycosidase activity,these inhibitors help to prevent the fast breakdown of sugars and thereby control the blood sugar level.This study provides a wealth of information aboutα-glucosidase inhibitors isolated from medicinal plants;this knowledge will be useful in finding more potent antidiabetic candidates from the natural resources for the clinical development of antidiabetic therapeutics.Results:411 compounds exhibitingα-glucosidase inhibitory activity were summarized and isolated them from medicinal plants.The compound classes isolated include:terpenes(61)from 14 genus,alkaloids(37)from 11 genus,quinines(49)from 4 genus,flavonoids(103)from 24 genus,phenols(37)from 9 genus,phenylpropanoids(73)from 20 genus,sterides(8)from 5 genus,and other types of compounds(43).Conclusion:Compounds withα-glucosidase inhibitory activity are abundant in nature and can be obtained from several sources.They have highα-glucosidase inhibitory potential,and can be clinically developed for treating diabetes mellitus.展开更多
Background:To explore the differences of 14 batches of Citri Reticulatae Pericarpium from different regions.Methods:The main aim of this study was to develop a high-performance liquid chromatography method-photodiode ...Background:To explore the differences of 14 batches of Citri Reticulatae Pericarpium from different regions.Methods:The main aim of this study was to develop a high-performance liquid chromatography method-photodiode array detection for determining the contents of five flavonoids and the chromatographic fingerprints of Citri Reticulatae Pericarpium from different regions.Theα-glucosidase inhibitory activities and antioxidant properties of Citri Reticulatae Pericarpium,based on free-radical scavenging assays against 1,1-diphenyl-2-picrylhydrazyl,2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),and hydroxyl radicals,were estimated and compared.Results:Among the tested compounds,the content of hesperidin(13.386-68.235 mg/g)was the highest and that of hesperitin(0.045-0.277 mg/g)was the lowest.In comparing different sources of Citri Reticulatae Pericarpium,the contents of narirutin in Citri Reticulatae Pericarpium from Guangdong(0.824-0.851 mg/g)and Sichuan(1.069-1.204 mg/g)provinces of China were lower than in other provinces.In contrast,nobiletin(8.429-12.237 mg/g)and tangeretin(3.947-4.613 mg/g)were most abundant in Guangdong sources of Citri Reticulatae Pericarpium,followed by samples from Sichuan Province(nobiletin:6.761-7.658 mg/g;tangeretin:3.422-3.933 mg/g).Correlation analysis showed that nobiletin and tangeretin were the main contributors to the antioxidant capacity,and narirutin was the main active component inhibiting theα-glucosidase activity of Citri Reticulatae Pericarpium.Conclusion:This work revealed that the intrinsic quality of Citri Reticulatae Pericarpium was affected by different growing regions,which provides a scientific basis for controlling the quality of Citri Reticulatae Pericarpium and rationally developing and utilizing Citri Reticulatae Pericarpium.展开更多
Xylariaceae sp.QGS 01,an endophytic fungus isolated from the stem of Quercus gilva Blume showed high-glucosidase inhibitory activity.α-Glucosidase inhibitor have the role as one of carbohydrate-hydrolyzing enzymes to...Xylariaceae sp.QGS 01,an endophytic fungus isolated from the stem of Quercus gilva Blume showed high-glucosidase inhibitory activity.α-Glucosidase inhibitor have the role as one of carbohydrate-hydrolyzing enzymes to postpone absorption of glucose in the digestive organs.The α-glucosidase inhibitor constituents were isolated from the ethyl acetate extract of the mycellium of endophytic fungi Xylariaceae sp.QGS 01 using a bioassay-guided fractionation technique.Further separation and purification of the active fraction led to the isolation of constituents with strong inhibitory activities against-glucosidase:8-hydroxy-6,7-dimethoxy-3-methylisocoumarine(1)with inhibitory concentration(IC50)values against-glucosidase from Saccharomyces cerevisiae of 41.75μg/mL,while quercetin as the standard had an IC50 value of 4.80g/mL.The results of the present study showed that the endophytic fungus Xylariaceae sp.QGS 01 is potentially a rich source of antidiabetic medicine.展开更多
Ten cucurbitane-type triterpene glycosides,including five new compounds named charantosides H(1),J(2),K(3),momor-characoside A(4),goyaglycoside-l(5),and five known compounds(6-10),were isolated from the EtOAc extract ...Ten cucurbitane-type triterpene glycosides,including five new compounds named charantosides H(1),J(2),K(3),momor-characoside A(4),goyaglycoside-l(5),and five known compounds(6-10),were isolated from the EtOAc extract of Momor-dica charantia fruits.The chemical structures of these compounds were identified by 1D and 2D NMR and HRESIMS spectroscopic analyses.Configurations of new compounds were determined by ROESY correlations and comparison of their 13C NMR data with literature reported values.All compounds were evaluated for their inhibition againstα-glucosidase,in which compounds 2,5,7,8,9 showed moderate inhibitory activities with IC50 values ranging from 28.40 to 63.26μM comparing with the positive control(acarbose,IC5087.65±6.51μM).展开更多
Objective: To isolate and investigate antioxidant and α-glucosidase inhibitor compounds in the leaves of Quercus gilva Blume(Q. gilva).Methods: Dry leaves of Q. gilva were extracted with methanol and the methanolic e...Objective: To isolate and investigate antioxidant and α-glucosidase inhibitor compounds in the leaves of Quercus gilva Blume(Q. gilva).Methods: Dry leaves of Q. gilva were extracted with methanol and the methanolic extract was further separated by silica gel column chromatography using several solvents with increasing polarity. The antioxidant activities of the isolated compounds were evaluated using various in vitro assays: 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, hydrogen peroxide radical scavenging activity, β-carotene bleaching assay, and reducing power assay. The α-glucosidase inhibitory assay was conducted against α-glucosidase from Saccharomyces cerevisiae.Results: Three compounds were isolated and their structures were identii ed as catechin(1), epicatechin(2), and tiliroside(3) using an instrumental analysis. Compound 2 had higher antioxidant activity with inhibitory concentrations(IC50) of(22.55 ± 2.23) μmol/L than that of quercetin, which was used as the standard, with an IC50 of(28.08 ± 2.39) μmol/L, followed by compound 1 with IC50 of(40.86 ± 3.45) μmol/L. On the other hand, compound 3 had the lowest antioxidant activity with an IC50 of(160.24 ± 8.15) μmol/L. However, compound 3 had the highest α-glucosidase inhibitory activity with an IC50 of(28.36 ± 0.11) μmol/L, followed by compounds 1 and 2 with(168.60 ± 5.15) and(920.60 ± 10.10) μmol/L, respectively.Conclusions: The results obtained for the antioxidant activities and α-glucosidase inhibitory activities in a methanolic extract from the leaves of Q. gilva coni rmed the potential of this plant as a source of natural antioxidants and antidiabetic medicine.展开更多
α-Glucosidase inhibitors are used therapeutically to treat type-2 diabetes mellitus. Through a bioassay-guided fractionation technique, three carotenoids,(all-E)-lutein,(all-E)-zeaxanthin and(9-Z)-zeaxanthin, were pu...α-Glucosidase inhibitors are used therapeutically to treat type-2 diabetes mellitus. Through a bioassay-guided fractionation technique, three carotenoids,(all-E)-lutein,(all-E)-zeaxanthin and(9-Z)-zeaxanthin, were purified from the green alga Chlorella ellipsoidea, in which(all-E)-lutein and(9-Z)-zeaxanthin had potent α-glucosidase inhibitory activity. IC_(50) values of(all-E)-lutein and(9-Z)-zeaxanthin were 70 and 53.5 μmol L^(-1) against Saccharomyces cerevisiae α-glucosidase, respectively, with non-competitive inhibition. In addition, IC_(50) values of(9-Z)-zeaxanthin against Bacillus stearothermophilus and rat-intestinal α-glucosidase were 805.1 and 671.2 μmol L^(-1), respectively. The K_i values of(all-E)-lutein and(9-Z)-zeaxanthin against S. cerevisiae α-glucosidase were 78.1 and 16.5 μmol L^(-1), respectively. Therefore, C. ellipsoidea carotenoids might be utilized as a novel candidate to prevent type-2 diabetes mellitus related disorders in food and medical industry.展开更多
The present study used in vitro and in silico techniques, as well as the metabolomics approach to characterise α-glucosidase inhibitors from different fractions of Clinacanthus nutans. C. nutans is a medicinal plant ...The present study used in vitro and in silico techniques, as well as the metabolomics approach to characterise α-glucosidase inhibitors from different fractions of Clinacanthus nutans. C. nutans is a medicinal plant belonging to the Acanthaceae family, and is traditionally used to treat diabetes in Malaysia. nHexane, n-hexane: ethyl acetate(1:1, v/v), ethyl acetate, ethyl acetate: methanol(1:1, v/v), and methanol fractions were obtained via partitioning of the 80% methanolic crude extract. The in vitro α-glucosidase inhibitory activity was analyzed using all the fractions collected, followed by profiling of the metabolites using liquid chromatography combined with mass spectrometry. The partial least square(PLS) statistical model was developed using the SIMCA P^+14.0 software and the following four inhibitors were obtained:(1) 4,6,8-Megastigmatrien-3-one;(2) N-Isobutyl-2-nonen-6,8-diynamide;(3) 1′,2′-bis(acetyloxy)-3′,4′-didehydro-2′-hydro-β, ψ-carotene; and(4) 22-acetate-3-hydroxy-21-(6-methyl-2,4-octadienoate)-olean-12-en-28-oic acid. The in silico study performed via molecular docking with the crystal structure of yeast isomaltase(PDB code: 3 A4 A) involved a hydrogen bond and some hydrophobic interactions between the inhibitors and protein. The residues that interacted include ASN259, HID295, LYS156, ARG335,and GLY209 with a hydrogen bond, while TRP15, TYR158, VAL232, HIE280, ALA292, PRO312, LEU313,VAL313, PHE314, ARG315, TYR316, VAL319, and TRP343 with other forms of bonding.展开更多
Larger-leaf yellow tea(LYT)is a characteristic type of Chinese tea produced in Huoshan County,Anhui Province,which is made by mature leaves with stems.According to recent report,LYT showed competitive effects in anti-...Larger-leaf yellow tea(LYT)is a characteristic type of Chinese tea produced in Huoshan County,Anhui Province,which is made by mature leaves with stems.According to recent report,LYT showed competitive effects in anti-hyperglycemia in comparison to other teas such as green or black tea.However,the bioactive compounds of LYT are still undiscovered so far.For this purpose,5 fractions of LYT were prepared by sequential extraction.The in vitro bioassay results indicated that the ethyl acetate fraction of LYT had the strongest inhibitory effects onα-glucosidase andα-amylase.Fluorescence-quenching analysis and proteinbinding test revealed that the compounds of ethyl acetate fraction could inhibitα-glucosidase andα-amylase activities through binding to enzymes or other mechanisms.All chromatographic peaks of high-performance liquid chromatography(HPLC)of ethyl acetate fraction were separated and collected.The purified compounds were identified by liquid chromatography-mass spectrometry(LC-MS),and subsequently screened by calculating their inhibition ratio onα-glucosidase at the real concentration in LYT infusion.The results showed that(-)-epigallocatechin gallate,(-)-gallocatechin gallate,caffeine,N-ethyl-2-pyrrolidone-substituted flavan-3-ols were effective inhibitors forα-glucosidase.展开更多
Objective The Morus alba root bark is a well-known Chinese herbal medicine called Sang-Bai-Pi and has often been used to relieve the hyperglycemic symptom of diabetes patients.The current work aims to further explore ...Objective The Morus alba root bark is a well-known Chinese herbal medicine called Sang-Bai-Pi and has often been used to relieve the hyperglycemic symptom of diabetes patients.The current work aims to further explore its bioactive constituents with α-glucosidase inhibitory activity for the potential treatment of diabetes.Methods A combination of different separating techniques including routine column chromatograph and HPLC especially on chiral columns were applied for the isolation of target molecules,while comprehensive spectroscopic experiments comprising MS,NMR,ECD,etc.were carried out to complete the structural assignment.The anti-hyperglycemic property of the isolates was evaluated by an in vitro α-glucosidase inhibitory bioassay.Results Two pairs of new flavanone-monoterpene hybrid enantiomers were isolated and identified,and an interesting phenomenon of mutual transformation between these cometabolites were detected,which resulted in their regio-isomerization and enantiomerization.The bioassay results revealed remarkable α-glucosidase inhibitory activity for these fascinating molecules.Conclusions The Morus alba root bark is a rich source of bioactive flavonoid derivatives and deserves further investigations to develop new potential chemotherapies for diabetes control and treatment.展开更多
α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia,which play crucial roles in the management of type 2 diabetes.Protocatechuic acid(PCA)is one of phenolic acids existing not only in var...α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia,which play crucial roles in the management of type 2 diabetes.Protocatechuic acid(PCA)is one of phenolic acids existing not only in various plant foods but also as a major microbial metabolite of dietary anthocyanins in the large colon.The present study investigated the inhibitory mechanism of PCA on a-glucosidase in vitro and examined its effect on postprandial blood glucose levels in vivo.Results from in vitro experiments demonstrated that PCA was a mix-type inhibitor of a-glucosidase.Driven by hydrogen bonds and van der Waals interactions,PCA reversibly bound withα-glucosidase to form a stable a-glucosidase-PCA complex in a spontaneous manner.The computational simulation found that PCA could insert into the active cavity of a-glucosidase and establish hydrogen bonds with catalytic amino acid residues.PCA binding aroused the steric hindrance for substrates to enter active sites and caused the structural changes of interacted catalytic amino acid residues.PCA also exhibited postprandial hypoglycemic capacity in diabetic mice.This study may provide the theoretical basis for the application of PCA as an active ingredient of functional foods in dietary management of diabetes.展开更多
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 propert...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 sampsonii was 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 IC_(50) values ranging from 0.050±0.0016 to 366.70±11.08μg·mL^(-1).Notably,compound 5(0.050±0.0016μg·mL^(-1))was identified as the most potential α-glucosidase inhibitor,with an inhibitory effect about 6900 times stronger than the positive control,acarbose(IC_(50)=346.63±15.65μg·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.展开更多
Objective To study the chemical constituents of Bombycis Feculae.Methods Chemical constituents were isolated by HPLC-ELSD.The structures of the isolated compounds were determined by spectral means.Results Two compound...Objective To study the chemical constituents of Bombycis Feculae.Methods Chemical constituents were isolated by HPLC-ELSD.The structures of the isolated compounds were determined by spectral means.Results Two compounds were isolated and identified as 1-deoxynojirimycin(1)and(2R,3R,5R)-2-(hydroxymethyl) piperidine-3,5-diol,named as 1,3-dideoxygalatonojirimycin(2).Conclusion Compound 2 is a new alkaloid.The extract of Bombycis Feculae,compound 1 and compound 2 show inhibitory activities againstα-glucosidase.展开更多
A series of novel pyrano[2,3-d]trizaole compounds were synthesized and theirα-glucosidase inhibitory activities were evaluated by in vitro enzyme assay.The experimental data demonstrated that compound 10 f showed up ...A series of novel pyrano[2,3-d]trizaole compounds were synthesized and theirα-glucosidase inhibitory activities were evaluated by in vitro enzyme assay.The experimental data demonstrated that compound 10 f showed up to 10-fold higher inhibition(IC5074.0±1.3μmol·L-1)than acarbose.The molecular docking revealed that compound 10 f could bind toα-glucosidase via the hydrophobic,π-πstacking,and hydrogen bonding interactions.The results may benefit further structural modifications to find new and potentα-glucosidase inhibitors.展开更多
Severalα-glucosidase inhibitory constituents were isolated from the methanolic extract of the leaves of Quercus phillyraeoides A.Gray(Q.phillyraeoides)using a bioassay-guided fractionation technique.Further separatio...Severalα-glucosidase inhibitory constituents were isolated from the methanolic extract of the leaves of Quercus phillyraeoides A.Gray(Q.phillyraeoides)using a bioassay-guided fractionation technique.Further separation and purification of the methanol-soluble fraction led to the isolation of constituents with moderate and strong inhibitory activities againstα-glucosidase:α-sitosterol-d-glucoside(1)and condensed tannin fractions(2,3,4,5,and 6).Compound 1 and fractions 2-6 had inhibitory concentration(IC50)values againstm-glucosidase from Saccharomyces cerevisiae of 118.8,2.79,2.78,3.10,2.60,and 3.14μg/mL,respectively,while quercetin as the standard had an IC50 value of 4.80mg/mL.Furthermore,the significant antioxidant activities were evaluated using several assays,such as the DPPH radical scavenging,hydrogen peroxide radical scavenging,reducing power,andβ-carotene-linoleate bleaching assays,and the results suggested that the isolated constituents showed their possible application for treating the hyperglycemia-induced oxidative stress.The results of the present study showed the potential of Q.phillyraeoides as a rich source of natural antidiabetic medicine.展开更多
Tsaokols A(1)and B(2),two complicated flavanol-monoterpenoid hybrids,were isolated from the dried fruits of Amomum tsao-ko under the guidance of LCMS and bioassay.Their structures were determined by extensive spectros...Tsaokols A(1)and B(2),two complicated flavanol-monoterpenoid hybrids,were isolated from the dried fruits of Amomum tsao-ko under the guidance of LCMS and bioassay.Their structures were determined by extensive spectroscopic analyses and electronic circular dichroism(ECD)calculations.Compounds 1 and2 shared a flavanol backbone fused with 5/7 and 5/6 bicyclic monoterpenoid scaffolds,which were biogenetically condensed by Michael addition and acetalization.Compounds 1 and 2 exhibited significantα-glucosidase inhibitory activity with IC_(50)values of 18.8 and 38.6μmol/L(acarbose,IC_(50)=213μmol/L).Docking study supported the strong interactions of 1 and 2 bonding with enzyme by mainly hydrophobic and hydrogen-bond effects.Compounds 1 and 2 could be fast distinguished by the diagnostic ions at m/z 289 and 313 in negative MS^(2)experiments.展开更多
The roasting process of pyrogallol,a polyphenol compound distributed in coffee beverages,significantly enhanced itsα-glucosidase inhibitory activity.In this study,a bioassay-guided isolation of the thermal reaction p...The roasting process of pyrogallol,a polyphenol compound distributed in coffee beverages,significantly enhanced itsα-glucosidase inhibitory activity.In this study,a bioassay-guided isolation of the thermal reaction products of pyrogallol led to the identification of two potentα-glucosidase inhibitors,4-4′dimer of pyrogallol(4,4′-DP)and 4-5′dimer of pyrogallol(4,5′-DP).Theirα-glucosidase inhibitory activity was higher than that of pyrogallol,as evidenced by comparing the IC_(50)values(206.2±1.2μM for 4,4′-DP,187.6±2.6μM for 4,5′-DP,2660±60.1μM for pyrogallol).And the roasting products were more potentα-glucosidase inhibitors compared to acarbose(IC_(50)=695±12.7μM).Enzyme kinetics demonstrated that 4,4′-DP and 4,5′-DP inhibitedα-glucosidase in an uncompetitive and a non-competitive manner,respectively.Docking simulations revealed that the main interaction forces between these two compounds andα-glucosidase were hydrogen bonding and hydrophobic effect.These results suggested that a simple roasting process might increase theα-glucosidase inhibitory activity of pyrogallol-containing foods such as coffee beverages.展开更多
A pair of alkaloid enantiomers possessing a novel 1-oxaspiro[4.4]non-3-ene-2,7-dione skeleton,trichodermotin A(1),was obtained from the fungus Trichoderma asperellum.Spectroscopic data,X-ray diffraction,and ECD calcul...A pair of alkaloid enantiomers possessing a novel 1-oxaspiro[4.4]non-3-ene-2,7-dione skeleton,trichodermotin A(1),was obtained from the fungus Trichoderma asperellum.Spectroscopic data,X-ray diffraction,and ECD calculations were used to establish its structure and absolute configuration.(−)-1 showed significantα-glucosidase inhibitory activity(IC_(50)=10.1μmol/L vs.60.1μmol/L of positive control).A plausible biosynthetic pathway originating from L-β-phenylalanine was proposed,and a facile total synthesis was further accomplished.The key reaction of our synthetic strategy was a domino aza-Michael/lactonization in one pot,leading to the pivotal 4-amino-oxaspiro[4.4]octane scaffold.展开更多
Inhibition ofα-glucosidase activity is an important strategy in lowering the concentration of blood sugar.In this paper,using domestic and foreign characteristic food-derived substances as the sources of lactobacillu...Inhibition ofα-glucosidase activity is an important strategy in lowering the concentration of blood sugar.In this paper,using domestic and foreign characteristic food-derived substances as the sources of lactobacillus,the performance of them were evaluated by measuring the strains’α-glucosidase inhibitory ability.Finally,the cell-free extracellular supernatants(CFS)of Lactobacillus rhamnosus LB1lac10 was determined to have the highest α-glucosidase inhibition ability.Based on the Nanopore third-generation sequencing technology platform,the genome of LB1lac10 was sequenced and functional gene annotation was performed.After that,the biological activity and structural composition of the exopolysaccharide produced by L.rhamnosus LB1lac10 were studied.The purified exopolysaccharide EPS1-1 also showed efficientα-glucosidase inhibitory ability.The structure and conformation characteristics of EPS1-1 were further analyzed.The EPS1-1 from L.rhamnosus LB1lac10 had a molecular weight of 88,650 Da,and it was mainly composed of mannose,glucuronic acid,glucose,xylose,galactose,and arabinose.From the FT-IR and NMR analyses,EPS1-1 had functional groups of a typical polysaccharide structure and contained two types of glycosidic bonds with α-configuration pyranose.The main glycosidic bond corresponded to→4)-α-D-Glcp-(1→,which might be an important reason why EPS1-1 could inhibit α-glycosidase.Thermodynamic studies showed that EPS1-1 had high heat resistance to meet the needs of food processing.The results suggested that L.rhamnosus LB1lac10 could be used as a potential probiotic to lower blood sugar,and the EPS1-1 has the potential to serve as a naturalα-glycosidase inhibitor to regulate the concentration of blood glucose.展开更多
Postprandial hyperglycemia is an early indication of type 2 diabetes and the target of many anti-diabetic and anti-obesity studies.α-Glucosidase and α-amylase are the crucial factors in regulating starch digestion a...Postprandial hyperglycemia is an early indication of type 2 diabetes and the target of many anti-diabetic and anti-obesity studies.α-Glucosidase and α-amylase are the crucial factors in regulating starch digestion and glucose absorption,making them key targets for many studies to treat postprandial hyperglycemia.We studied the inhibitory activities of microalgal fucoxanthin against rat-intestinalα-glucosidase and pancreaticα-amylase along with the antidiabetic eff ect to induce diff erentiation in 3T3-L1 pre-adipocytes using Oil Red-O staining.Fucoxanthin displayed strong hindrance activities towardα-amylase in a concentration-dependent manner,with an IC50 value of 0.68mmol/L,whereas weak inhibitory activity against α-glucosidase,with an IC 50 value of 4.75 mmol/L.Fucoxanthin also considerably elevated glucose oxidase activity in 3T3-L1 cells by 31.3%at 5μmol/L.During adipocyte differentiation,fucoxanthin showed lipid accumulation in 3T3-L1 cells with no cytotoxicity up to 20μmol/L.However,fucoxanthin had no inhibitory activity on glucose-6-phosphate dehydrogenase.These results suggest that fucoxanthin might be useful for the prevention of obesity or diabetes by inhibiting carbohydrate-hydrolyzing enzymes and lipid accumulation and be utilized as an ingredient for a functional food or dietary supplement.展开更多
基金supported by the Deanship of Scientific Research at Umm Al-Qura University(Grant code:22UQU4331128DSR77).
文摘Objective:To investigate the relationship between triterpenoid saponin content and antioxidant,antimicrobial,and α-glucosidase inhibitory activities of 70%ethanolic,butanolic,aqueous,supernate and precipitate extracts of Juglans regia leaves.Methods:Triterpenoid saponins of different Juglans regia leaf extracts were measured by the vanillin method.Antioxidant activity was evaluated against DPPH and ABTS free radicals.We also assessed α-glucosidase inhibitory and antimicrobial activities of the leaf extracts.Pearson’s correlation coefficient was evaluated to determine the correlation between the saponin content and biological activities.Results:The butanolic extract was most effective against DPPH with an IC50of 6.63μg/mL,while the aqueous extract showed the highest scavenging activity against ABTS free radical with an IC50of 42.27μg/mL.Pearson’s correlation analysis indicated a strong negative correlation (r=-0.956) between DPPH radical scavenging activity (IC50) and the saponin content in the samples examined.In addition,the aqueous extract showed the best α-glucosidase inhibitory activity compared with other extracts.All the extracts had fair antibacterial activity against Bacillus subtilis,Escherichia coli,and Klebsiella pneumoniae except for the aqueous extract.Conclusions:Juglans regia extracts show potent antioxidant,antimicrobial,and α-glucosidase inhibitory activities.There is a correlation between saponin levels in Juglans regia leaf extracts and the studied activities.However,additional research is required to establish these relationships by identifying the specific saponin molecules responsible for these activities and elucidating their mechanisms of action.
基金This research was supported by Key Project in Science and Technology Agency of Henan Province(Nos.132102310261 and 142102310147)Natural Science Project in Department of Education of Henan Province(Nos.13B360981 and 14B360011)+1 种基金Henan Province Department of Education Teachers,the backbone of Youth Fund(2013GGJS-220)and Key Project in Science and Technology Agency of Zhengzhou City(No.120140790).
文摘Objective:α-Glucosidase inhibitors can be used as a new class of antidiabetic drug.By competitively inhibiting glycosidase activity,these inhibitors help to prevent the fast breakdown of sugars and thereby control the blood sugar level.This study provides a wealth of information aboutα-glucosidase inhibitors isolated from medicinal plants;this knowledge will be useful in finding more potent antidiabetic candidates from the natural resources for the clinical development of antidiabetic therapeutics.Results:411 compounds exhibitingα-glucosidase inhibitory activity were summarized and isolated them from medicinal plants.The compound classes isolated include:terpenes(61)from 14 genus,alkaloids(37)from 11 genus,quinines(49)from 4 genus,flavonoids(103)from 24 genus,phenols(37)from 9 genus,phenylpropanoids(73)from 20 genus,sterides(8)from 5 genus,and other types of compounds(43).Conclusion:Compounds withα-glucosidase inhibitory activity are abundant in nature and can be obtained from several sources.They have highα-glucosidase inhibitory potential,and can be clinically developed for treating diabetes mellitus.
基金supported by the National Natural Science Foundation of China(No.81872956)National Key R&D Program of China(No.2019YFC1710604)+1 种基金Key Project at Central Government Level(No.2060302)the Science and Technology Project of Tianjin(No.18ZXXYSY00080).
文摘Background:To explore the differences of 14 batches of Citri Reticulatae Pericarpium from different regions.Methods:The main aim of this study was to develop a high-performance liquid chromatography method-photodiode array detection for determining the contents of five flavonoids and the chromatographic fingerprints of Citri Reticulatae Pericarpium from different regions.Theα-glucosidase inhibitory activities and antioxidant properties of Citri Reticulatae Pericarpium,based on free-radical scavenging assays against 1,1-diphenyl-2-picrylhydrazyl,2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),and hydroxyl radicals,were estimated and compared.Results:Among the tested compounds,the content of hesperidin(13.386-68.235 mg/g)was the highest and that of hesperitin(0.045-0.277 mg/g)was the lowest.In comparing different sources of Citri Reticulatae Pericarpium,the contents of narirutin in Citri Reticulatae Pericarpium from Guangdong(0.824-0.851 mg/g)and Sichuan(1.069-1.204 mg/g)provinces of China were lower than in other provinces.In contrast,nobiletin(8.429-12.237 mg/g)and tangeretin(3.947-4.613 mg/g)were most abundant in Guangdong sources of Citri Reticulatae Pericarpium,followed by samples from Sichuan Province(nobiletin:6.761-7.658 mg/g;tangeretin:3.422-3.933 mg/g).Correlation analysis showed that nobiletin and tangeretin were the main contributors to the antioxidant capacity,and narirutin was the main active component inhibiting theα-glucosidase activity of Citri Reticulatae Pericarpium.Conclusion:This work revealed that the intrinsic quality of Citri Reticulatae Pericarpium was affected by different growing regions,which provides a scientific basis for controlling the quality of Citri Reticulatae Pericarpium and rationally developing and utilizing Citri Reticulatae Pericarpium.
文摘Xylariaceae sp.QGS 01,an endophytic fungus isolated from the stem of Quercus gilva Blume showed high-glucosidase inhibitory activity.α-Glucosidase inhibitor have the role as one of carbohydrate-hydrolyzing enzymes to postpone absorption of glucose in the digestive organs.The α-glucosidase inhibitor constituents were isolated from the ethyl acetate extract of the mycellium of endophytic fungi Xylariaceae sp.QGS 01 using a bioassay-guided fractionation technique.Further separation and purification of the active fraction led to the isolation of constituents with strong inhibitory activities against-glucosidase:8-hydroxy-6,7-dimethoxy-3-methylisocoumarine(1)with inhibitory concentration(IC50)values against-glucosidase from Saccharomyces cerevisiae of 41.75μg/mL,while quercetin as the standard had an IC50 value of 4.80g/mL.The results of the present study showed that the endophytic fungus Xylariaceae sp.QGS 01 is potentially a rich source of antidiabetic medicine.
基金supported by a program of the National Natural Science Foundation of China(Nos.31872675 and 81373288)the cooperation program between Chinese Academy of Sciences and Guangdong Province(2013B09110011).
文摘Ten cucurbitane-type triterpene glycosides,including five new compounds named charantosides H(1),J(2),K(3),momor-characoside A(4),goyaglycoside-l(5),and five known compounds(6-10),were isolated from the EtOAc extract of Momor-dica charantia fruits.The chemical structures of these compounds were identified by 1D and 2D NMR and HRESIMS spectroscopic analyses.Configurations of new compounds were determined by ROESY correlations and comparison of their 13C NMR data with literature reported values.All compounds were evaluated for their inhibition againstα-glucosidase,in which compounds 2,5,7,8,9 showed moderate inhibitory activities with IC50 values ranging from 28.40 to 63.26μM comparing with the positive control(acarbose,IC5087.65±6.51μM).
文摘Objective: To isolate and investigate antioxidant and α-glucosidase inhibitor compounds in the leaves of Quercus gilva Blume(Q. gilva).Methods: Dry leaves of Q. gilva were extracted with methanol and the methanolic extract was further separated by silica gel column chromatography using several solvents with increasing polarity. The antioxidant activities of the isolated compounds were evaluated using various in vitro assays: 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, hydrogen peroxide radical scavenging activity, β-carotene bleaching assay, and reducing power assay. The α-glucosidase inhibitory assay was conducted against α-glucosidase from Saccharomyces cerevisiae.Results: Three compounds were isolated and their structures were identii ed as catechin(1), epicatechin(2), and tiliroside(3) using an instrumental analysis. Compound 2 had higher antioxidant activity with inhibitory concentrations(IC50) of(22.55 ± 2.23) μmol/L than that of quercetin, which was used as the standard, with an IC50 of(28.08 ± 2.39) μmol/L, followed by compound 1 with IC50 of(40.86 ± 3.45) μmol/L. On the other hand, compound 3 had the lowest antioxidant activity with an IC50 of(160.24 ± 8.15) μmol/L. However, compound 3 had the highest α-glucosidase inhibitory activity with an IC50 of(28.36 ± 0.11) μmol/L, followed by compounds 1 and 2 with(168.60 ± 5.15) and(920.60 ± 10.10) μmol/L, respectively.Conclusions: The results obtained for the antioxidant activities and α-glucosidase inhibitory activities in a methanolic extract from the leaves of Q. gilva coni rmed the potential of this plant as a source of natural antioxidants and antidiabetic medicine.
基金a part of the project titled ‘Future Marine Technology Development’ funded by the Ministry of Oceans and Fisheries,Republic of Korea
文摘α-Glucosidase inhibitors are used therapeutically to treat type-2 diabetes mellitus. Through a bioassay-guided fractionation technique, three carotenoids,(all-E)-lutein,(all-E)-zeaxanthin and(9-Z)-zeaxanthin, were purified from the green alga Chlorella ellipsoidea, in which(all-E)-lutein and(9-Z)-zeaxanthin had potent α-glucosidase inhibitory activity. IC_(50) values of(all-E)-lutein and(9-Z)-zeaxanthin were 70 and 53.5 μmol L^(-1) against Saccharomyces cerevisiae α-glucosidase, respectively, with non-competitive inhibition. In addition, IC_(50) values of(9-Z)-zeaxanthin against Bacillus stearothermophilus and rat-intestinal α-glucosidase were 805.1 and 671.2 μmol L^(-1), respectively. The K_i values of(all-E)-lutein and(9-Z)-zeaxanthin against S. cerevisiae α-glucosidase were 78.1 and 16.5 μmol L^(-1), respectively. Therefore, C. ellipsoidea carotenoids might be utilized as a novel candidate to prevent type-2 diabetes mellitus related disorders in food and medical industry.
基金the Ministry of Agriculture of Malaysia for NKEA Research Grant Scheme fund (NRGS SP15-0600182)International Islamic University Malaysia for Publication Research Initiative Grant fund (PRIGS18-027-0027)
文摘The present study used in vitro and in silico techniques, as well as the metabolomics approach to characterise α-glucosidase inhibitors from different fractions of Clinacanthus nutans. C. nutans is a medicinal plant belonging to the Acanthaceae family, and is traditionally used to treat diabetes in Malaysia. nHexane, n-hexane: ethyl acetate(1:1, v/v), ethyl acetate, ethyl acetate: methanol(1:1, v/v), and methanol fractions were obtained via partitioning of the 80% methanolic crude extract. The in vitro α-glucosidase inhibitory activity was analyzed using all the fractions collected, followed by profiling of the metabolites using liquid chromatography combined with mass spectrometry. The partial least square(PLS) statistical model was developed using the SIMCA P^+14.0 software and the following four inhibitors were obtained:(1) 4,6,8-Megastigmatrien-3-one;(2) N-Isobutyl-2-nonen-6,8-diynamide;(3) 1′,2′-bis(acetyloxy)-3′,4′-didehydro-2′-hydro-β, ψ-carotene; and(4) 22-acetate-3-hydroxy-21-(6-methyl-2,4-octadienoate)-olean-12-en-28-oic acid. The in silico study performed via molecular docking with the crystal structure of yeast isomaltase(PDB code: 3 A4 A) involved a hydrogen bond and some hydrophobic interactions between the inhibitors and protein. The residues that interacted include ASN259, HID295, LYS156, ARG335,and GLY209 with a hydrogen bond, while TRP15, TYR158, VAL232, HIE280, ALA292, PRO312, LEU313,VAL313, PHE314, ARG315, TYR316, VAL319, and TRP343 with other forms of bonding.
基金supported by Natural Science Foundation of China(32072633,32072634,31201335)earmarked fund for China Agriculture Research System(CARS-19)+1 种基金Anhui Key research and development plan(1804b06020367,202004b11020004)Young Elite Scientist Sponsorship Program by National CAST(2016QNRC001)。
文摘Larger-leaf yellow tea(LYT)is a characteristic type of Chinese tea produced in Huoshan County,Anhui Province,which is made by mature leaves with stems.According to recent report,LYT showed competitive effects in anti-hyperglycemia in comparison to other teas such as green or black tea.However,the bioactive compounds of LYT are still undiscovered so far.For this purpose,5 fractions of LYT were prepared by sequential extraction.The in vitro bioassay results indicated that the ethyl acetate fraction of LYT had the strongest inhibitory effects onα-glucosidase andα-amylase.Fluorescence-quenching analysis and proteinbinding test revealed that the compounds of ethyl acetate fraction could inhibitα-glucosidase andα-amylase activities through binding to enzymes or other mechanisms.All chromatographic peaks of high-performance liquid chromatography(HPLC)of ethyl acetate fraction were separated and collected.The purified compounds were identified by liquid chromatography-mass spectrometry(LC-MS),and subsequently screened by calculating their inhibition ratio onα-glucosidase at the real concentration in LYT infusion.The results showed that(-)-epigallocatechin gallate,(-)-gallocatechin gallate,caffeine,N-ethyl-2-pyrrolidone-substituted flavan-3-ols were effective inhibitors forα-glucosidase.
基金Financial support is from the Natural Science Foundation of Shandong Province for Distinguished Young Scholars(No.JQ201721).
文摘Objective The Morus alba root bark is a well-known Chinese herbal medicine called Sang-Bai-Pi and has often been used to relieve the hyperglycemic symptom of diabetes patients.The current work aims to further explore its bioactive constituents with α-glucosidase inhibitory activity for the potential treatment of diabetes.Methods A combination of different separating techniques including routine column chromatograph and HPLC especially on chiral columns were applied for the isolation of target molecules,while comprehensive spectroscopic experiments comprising MS,NMR,ECD,etc.were carried out to complete the structural assignment.The anti-hyperglycemic property of the isolates was evaluated by an in vitro α-glucosidase inhibitory bioassay.Results Two pairs of new flavanone-monoterpene hybrid enantiomers were isolated and identified,and an interesting phenomenon of mutual transformation between these cometabolites were detected,which resulted in their regio-isomerization and enantiomerization.The bioassay results revealed remarkable α-glucosidase inhibitory activity for these fascinating molecules.Conclusions The Morus alba root bark is a rich source of bioactive flavonoid derivatives and deserves further investigations to develop new potential chemotherapies for diabetes control and treatment.
基金supported by the General Research Fund of Hong Kong (14105820)。
文摘α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia,which play crucial roles in the management of type 2 diabetes.Protocatechuic acid(PCA)is one of phenolic acids existing not only in various plant foods but also as a major microbial metabolite of dietary anthocyanins in the large colon.The present study investigated the inhibitory mechanism of PCA on a-glucosidase in vitro and examined its effect on postprandial blood glucose levels in vivo.Results from in vitro experiments demonstrated that PCA was a mix-type inhibitor of a-glucosidase.Driven by hydrogen bonds and van der Waals interactions,PCA reversibly bound withα-glucosidase to form a stable a-glucosidase-PCA complex in a spontaneous manner.The computational simulation found that PCA could insert into the active cavity of a-glucosidase and establish hydrogen bonds with catalytic amino acid residues.PCA binding aroused the steric hindrance for substrates to enter active sites and caused the structural changes of interacted catalytic amino acid residues.PCA also exhibited postprandial hypoglycemic capacity in diabetic mice.This study may provide the theoretical basis for the application of PCA as an active ingredient of functional foods in dietary management of diabetes.
基金supported by the National Natural Science Foundation of China(No.32270413,U1812403)the Science and Technology Department of Guizhou Province(No.QKH 2020-1Z076)+5 种基金the 13th batch of Outstanding Young Scientific and Technological Talents in Guizhou Province(No.QKHPTRC[2021]5633)Cultivation project of National Natural Science Foundation of Guizhou Medical University(No.19NSP003)the Education Department of Guizhou Province(No.QJH KY[2021]189)the Natural Science Foundation of Guizhou Province(No.QKHZYD[2022]4015)High-level Innovative Talents in Guizhou Province(Thousand Levels of Talent for Chunmao Yuan in 2018)“Light of the West”Talent Cultivation Program of Chinese Academy of Sciences for Chunmao Yuan(No.RZ[2020]82).
文摘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 sampsonii was 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 IC_(50) values ranging from 0.050±0.0016 to 366.70±11.08μg·mL^(-1).Notably,compound 5(0.050±0.0016μg·mL^(-1))was identified as the most potential α-glucosidase inhibitor,with an inhibitory effect about 6900 times stronger than the positive control,acarbose(IC_(50)=346.63±15.65μg·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.
基金Key National Science & Technology Specific Projects(2009ZX09103-363)
文摘Objective To study the chemical constituents of Bombycis Feculae.Methods Chemical constituents were isolated by HPLC-ELSD.The structures of the isolated compounds were determined by spectral means.Results Two compounds were isolated and identified as 1-deoxynojirimycin(1)and(2R,3R,5R)-2-(hydroxymethyl) piperidine-3,5-diol,named as 1,3-dideoxygalatonojirimycin(2).Conclusion Compound 2 is a new alkaloid.The extract of Bombycis Feculae,compound 1 and compound 2 show inhibitory activities againstα-glucosidase.
基金the National Key R&D Program of China(No.2018YF-A0507602)the National Natural Science Foundation of China(Nos.81821004 and21738001)。
文摘A series of novel pyrano[2,3-d]trizaole compounds were synthesized and theirα-glucosidase inhibitory activities were evaluated by in vitro enzyme assay.The experimental data demonstrated that compound 10 f showed up to 10-fold higher inhibition(IC5074.0±1.3μmol·L-1)than acarbose.The molecular docking revealed that compound 10 f could bind toα-glucosidase via the hydrophobic,π-πstacking,and hydrogen bonding interactions.The results may benefit further structural modifications to find new and potentα-glucosidase inhibitors.
文摘Severalα-glucosidase inhibitory constituents were isolated from the methanolic extract of the leaves of Quercus phillyraeoides A.Gray(Q.phillyraeoides)using a bioassay-guided fractionation technique.Further separation and purification of the methanol-soluble fraction led to the isolation of constituents with moderate and strong inhibitory activities againstα-glucosidase:α-sitosterol-d-glucoside(1)and condensed tannin fractions(2,3,4,5,and 6).Compound 1 and fractions 2-6 had inhibitory concentration(IC50)values againstm-glucosidase from Saccharomyces cerevisiae of 118.8,2.79,2.78,3.10,2.60,and 3.14μg/mL,respectively,while quercetin as the standard had an IC50 value of 4.80mg/mL.Furthermore,the significant antioxidant activities were evaluated using several assays,such as the DPPH radical scavenging,hydrogen peroxide radical scavenging,reducing power,andβ-carotene-linoleate bleaching assays,and the results suggested that the isolated constituents showed their possible application for treating the hyperglycemia-induced oxidative stress.The results of the present study showed the potential of Q.phillyraeoides as a rich source of natural antidiabetic medicine.
基金supported by the Yunnan Wanren Project(Nos.YNWR-KJLJ-2019-002 and YNWR-QNBJ-2018-061)the Yunnan Science Fund for Excellent Young Scholars(No.2019FI017)+1 种基金the Program of Yunling Scholar,the Youth Innovation Promotion Association,CAS(No.Y201756)the Reserve Talents of Young and Middle-aged Academic and Technical Leaders in Yunnan Province。
文摘Tsaokols A(1)and B(2),two complicated flavanol-monoterpenoid hybrids,were isolated from the dried fruits of Amomum tsao-ko under the guidance of LCMS and bioassay.Their structures were determined by extensive spectroscopic analyses and electronic circular dichroism(ECD)calculations.Compounds 1 and2 shared a flavanol backbone fused with 5/7 and 5/6 bicyclic monoterpenoid scaffolds,which were biogenetically condensed by Michael addition and acetalization.Compounds 1 and 2 exhibited significantα-glucosidase inhibitory activity with IC_(50)values of 18.8 and 38.6μmol/L(acarbose,IC_(50)=213μmol/L).Docking study supported the strong interactions of 1 and 2 bonding with enzyme by mainly hydrophobic and hydrogen-bond effects.Compounds 1 and 2 could be fast distinguished by the diagnostic ions at m/z 289 and 313 in negative MS^(2)experiments.
基金This work was supported by the National Natural Science Foundation of China[grant number 82003650]TCM Science and Technology Project of Shandong Province,China[grant number 2020Q050].
文摘The roasting process of pyrogallol,a polyphenol compound distributed in coffee beverages,significantly enhanced itsα-glucosidase inhibitory activity.In this study,a bioassay-guided isolation of the thermal reaction products of pyrogallol led to the identification of two potentα-glucosidase inhibitors,4-4′dimer of pyrogallol(4,4′-DP)and 4-5′dimer of pyrogallol(4,5′-DP).Theirα-glucosidase inhibitory activity was higher than that of pyrogallol,as evidenced by comparing the IC_(50)values(206.2±1.2μM for 4,4′-DP,187.6±2.6μM for 4,5′-DP,2660±60.1μM for pyrogallol).And the roasting products were more potentα-glucosidase inhibitors compared to acarbose(IC_(50)=695±12.7μM).Enzyme kinetics demonstrated that 4,4′-DP and 4,5′-DP inhibitedα-glucosidase in an uncompetitive and a non-competitive manner,respectively.Docking simulations revealed that the main interaction forces between these two compounds andα-glucosidase were hydrogen bonding and hydrophobic effect.These results suggested that a simple roasting process might increase theα-glucosidase inhibitory activity of pyrogallol-containing foods such as coffee beverages.
基金supported by the Program for Changiiang Scholars of Ministry of Education of the People's Republic of China(No.T2016088)the National Natural Science Foundation for Distinguished Young Scholars(No.81725021)+5 种基金the National Natural Science Foundation for Excellent Young Scholars(No.81922065)the Innovative Research Groups of the National Natural Science Foundation of China(No.81721005)the National Natural Science Foundation of China(No.81903461)the Science and Technology Major Project of Hubei Province(No.2021ACA012)the Research and Development Program of Hubei Province(No.2020BCA058)the Fundamental Research Funds for the Centural Universities(No.2019kfyXJJS168).
文摘A pair of alkaloid enantiomers possessing a novel 1-oxaspiro[4.4]non-3-ene-2,7-dione skeleton,trichodermotin A(1),was obtained from the fungus Trichoderma asperellum.Spectroscopic data,X-ray diffraction,and ECD calculations were used to establish its structure and absolute configuration.(−)-1 showed significantα-glucosidase inhibitory activity(IC_(50)=10.1μmol/L vs.60.1μmol/L of positive control).A plausible biosynthetic pathway originating from L-β-phenylalanine was proposed,and a facile total synthesis was further accomplished.The key reaction of our synthetic strategy was a domino aza-Michael/lactonization in one pot,leading to the pivotal 4-amino-oxaspiro[4.4]octane scaffold.
基金financially supported by the Research and Development Plan in Key Areas of Guangdong Province(grant number 2018B020205002)the Science and Technology Planning Project of Tianjin City(grant number TSBICIP-KJGG-006-21)+1 种基金the Science and Technology Planning Project of Guangzhou City(grant number 202002030207)the core technology project of Foshan city(grant number 1920001000824).
文摘Inhibition ofα-glucosidase activity is an important strategy in lowering the concentration of blood sugar.In this paper,using domestic and foreign characteristic food-derived substances as the sources of lactobacillus,the performance of them were evaluated by measuring the strains’α-glucosidase inhibitory ability.Finally,the cell-free extracellular supernatants(CFS)of Lactobacillus rhamnosus LB1lac10 was determined to have the highest α-glucosidase inhibition ability.Based on the Nanopore third-generation sequencing technology platform,the genome of LB1lac10 was sequenced and functional gene annotation was performed.After that,the biological activity and structural composition of the exopolysaccharide produced by L.rhamnosus LB1lac10 were studied.The purified exopolysaccharide EPS1-1 also showed efficientα-glucosidase inhibitory ability.The structure and conformation characteristics of EPS1-1 were further analyzed.The EPS1-1 from L.rhamnosus LB1lac10 had a molecular weight of 88,650 Da,and it was mainly composed of mannose,glucuronic acid,glucose,xylose,galactose,and arabinose.From the FT-IR and NMR analyses,EPS1-1 had functional groups of a typical polysaccharide structure and contained two types of glycosidic bonds with α-configuration pyranose.The main glycosidic bond corresponded to→4)-α-D-Glcp-(1→,which might be an important reason why EPS1-1 could inhibit α-glycosidase.Thermodynamic studies showed that EPS1-1 had high heat resistance to meet the needs of food processing.The results suggested that L.rhamnosus LB1lac10 could be used as a potential probiotic to lower blood sugar,and the EPS1-1 has the potential to serve as a naturalα-glycosidase inhibitor to regulate the concentration of blood glucose.
基金a part of the project titled ’Future Marine Technology Development’ funded by the Ministry of Oceans and Fisheries, Republic of Korea
文摘Postprandial hyperglycemia is an early indication of type 2 diabetes and the target of many anti-diabetic and anti-obesity studies.α-Glucosidase and α-amylase are the crucial factors in regulating starch digestion and glucose absorption,making them key targets for many studies to treat postprandial hyperglycemia.We studied the inhibitory activities of microalgal fucoxanthin against rat-intestinalα-glucosidase and pancreaticα-amylase along with the antidiabetic eff ect to induce diff erentiation in 3T3-L1 pre-adipocytes using Oil Red-O staining.Fucoxanthin displayed strong hindrance activities towardα-amylase in a concentration-dependent manner,with an IC50 value of 0.68mmol/L,whereas weak inhibitory activity against α-glucosidase,with an IC 50 value of 4.75 mmol/L.Fucoxanthin also considerably elevated glucose oxidase activity in 3T3-L1 cells by 31.3%at 5μmol/L.During adipocyte differentiation,fucoxanthin showed lipid accumulation in 3T3-L1 cells with no cytotoxicity up to 20μmol/L.However,fucoxanthin had no inhibitory activity on glucose-6-phosphate dehydrogenase.These results suggest that fucoxanthin might be useful for the prevention of obesity or diabetes by inhibiting carbohydrate-hydrolyzing enzymes and lipid accumulation and be utilized as an ingredient for a functional food or dietary supplement.