检索结果-南通市图书馆

α-glucosidase immobilization on functionalized Fe_3O_4 magnetic nanoparticles for screening of enzyme inhibitors

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2019年第3期30卷 656-659页

作者： Guorong Cheng Junpeng Xing Zifeng Pi Shu Liu Zhiqiang Liu Fengrui Song National Center of Mass Spectrometry in Changchun &Jilin Province Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry Changchun Institute of Applied Chemistry Chinese Academy of Sciences University of Science and Technology of China

Magnetic nanoparticles(MNPs) are widely used for the immobilization of enzyme owing to the unique properties such as good biocompatibility and rapid separation. Herein, we used Fe_3O_4 magnetic nanoparticles(Fe_3O_4 MNPs) as the carrier core with(3-aminopropyl)triethoxysilane(APTES)modification by our approach, in which a-glucosidase was stereoscopically immobilized on the surface of Fe_3O_4 MNPs via covalent binding. The result of immobilization was characterized by scanning electron microscope(SEM) and fourier transform-infrared spectroscopy(FT-IR). Then we optimized some key parameters of the immobilization reaction, including the ratio of MNPs to enzyme, GA concentration,crosslinking time and immobilization time. Moreover, under the optimal conditions, pH tolerance,thermo stability and reusability of the immobilized enzyme were investigated and compared with the free one. In order to evaluate the change of the affinity of the enzyme to its specific substrate after immobilization, the Michaelis-Menten constant(K_m) was also studied. Finally, the immobilized α-glucosidase combining with high performance liquid chromatography-tandem mass spectrometry technique(HPLC-MS/MS) was applied to screen and identify eight inhibitors from Polygonum cuspidatum extract. These results indicated that the established method had the broad prospects for biotechnological applications.

关键词： Magnetic nanoparticles(MNPs) α-glucosidase Immobilization HPLC-MS/MS Inhibitor screening Polygonum cuspidatum

A colorimetric method for α-glucosidase activity assay and its inhibitor screening based on aggregation of gold nanoparticles induced by specific recognition between phenylenediboronic acid and 4-aminophenyl-α-D- glucopyranoside

在线全文

学校读者我要写书评

暂无评论

Nano Research 2015年第3期8卷 920-930页

作者： Juan Zhang Ying Liu Jun Lv Genxi Li Laboratory of Biosensing Technology School of Life Sciences Shanghai University Shanghai 200444 China ing University Nanjing 210093 China

A colorimetric method has been established for a-glucosidase activity assay and its inhibitor screening. The method is based on the specific recognition between 1,4-phenylenediboronic acid （PDBA） and 4-aminophenyl-a-D-glucopyranoside （pAPG）, which may induce aggregation of pAPG-functionalized gold nano- particles （AuNPs） to achieve color change of the test solution. Because pAPG is the substrate of α-glucosidase, the aggregation of AuNPs will be influenced by α-glucosidase since there is no coordination reactivity between PDBA and 4-aminobenzene, the hydrolyzed product of pAPG catalyzed by the enzyme. Therefore, a simple and easily-operated colorimetric method for the assay of a-glucosidase activity can be developed. Under the optimized experimental conditions, the ratios of absorbance at a wavelength of 650 nm to that at 520 nm vary linearly with the α-glucosidase activity within a range from 0.05 to 1.1 U/mL with a lowest detection limit of 0.004 U/mL. Moreover, using the proposed method, the inhibition effect of gallic acid and quercetin on a-glucosidase activity can be tested with IC50 values of 1.16 mM and 1.82 μM, respectively. Thus, the method has a great potential not only for the detection of a-glucosidase activity, but also for the screening of its inhibitors.

关键词： α-glucosidase inhibitor screening 1 4-phenylenediboronicacid gold nanoparticles

Bioassay-guided isolation of α-glucosidase inhibitory constituents from Hypericum sampsonii

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Natural Medicines 2023年第6期21卷 443-453页

作者： TAO Linlan XU Shuangyu ZHANG Zizhen LI Yanan YANG Jue GU Wei YI Ping HAO Xiaojiang YUAN Chunmao State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical UniversityGuiyang 550014China School of Pharmaceutical Sciences Guizhou Medical UniversityGuiyang 550025China Natural Products Research Center of Guizhou Province Guiyang 550014China State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China

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 *** 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 *** 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.

关键词： Hypericum sampsonii Chemical constituents Structure elucidation α-glucosidase Molecular docking

α-glucosidase inhibitive diarylheptanoids from Ottelia acuminata ***,a traditional vegetable of Bai Nationality in Yunnan

在线全文

学校读者我要写书评

暂无评论

Natural Products and Bioprospecting 2022年第1期12卷 299-309页

作者： Hong-Xing Liu Jun-Zeng Ma Yan-Song Ye Jian-Jun Zhao Shi-Jie Wan Xin-Yue Hu Gang Xu State Key Laboratory of Phytochemistry and Plant Resources in West China and Yunnan Key Laboratory of Natural Medicinal Chemistry Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China University of Chinese Academy of Sciences Beijing 100049China

Diabetes is an urgent health issue characterized by ethnic and regional variations,and is inseparable from the differ-ent dietary *** is worthy to note that the incidence of diabetes in Bai nationality has been reported to be much lower than Han in *** a daily vegetable of Bai,the phytochemical and antidiabetic study of Ottelia acuminata *** had not been carried *** this study,41 metabolites with diverse diarylheptanoid(six new ones,Otteacumienes A-F),flavone,sesquiterpenoid,coumarin,lignan,polyacetylene,and alkaloid skeletons were charac-terized from *** *** them,the racemic nature of 3 was characterized by chiral resolution and calculated ECD *** biological study revealed diarylheptanoids showed significantα-glucosidase inhibi-tory activities with 5 as the most effective one(60-fold stronger than acarbose).Molecular docking studies indicated that these structures have different binding cavities with *** study demonstrated that *** *** might correlated with the low incidence diabetes of Bai and the diarylheptanoids may have potential therapeutic value for diabetes mellitus.

关键词： Ottelia acuminata var.acuminata Bai nationality Vegetable Diarylheptanoids α-glucosidase

Purification and characterization of α-glucosidase in Apis cerana indica

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Insect Science 2008年第3期15卷 217-224页

作者： Chanpen Chanchao Suwisa Pilalam Polkit Sangvanich Department of Biology Faculty of Science Chulalongkom University Bangkok Thailand Program of Biotechnology Faculty of Science Chulalongkom University Bangkok Thailand Department of Chemistry Faculty of Science Chulalongkom University Bangkok Thailand

Apis cerana indica foragers were used for the isolation of a full-length α- glucosidase cDNA, and for purification of the active nascent protein by low salt extraction of bee homogenates, ammonium sulphate precipitation and diethylaminoethyl-cellulose and Superdex 200 c hromatographies. The molecular mass of the purified protein was estimated by polyacrylamide gel electrophoresis resolution, and the pH, temperature, incubation, and substrate optima for enzymic activity were determined. Conformation of the purified enzyme as α-glucosidase was performed by BLAST software homology comparisons between matrix assisted laser desorption ionization time of flight mass spectroscopy analysed partial tryptic peptide digests of the purified protein with the predicted amino acid sequences deduced from the α-glucosidase cDNA sequence.

关键词： α-glucosidase Apis cerana indica cDNA chromatography purification

Identification of α-glucosidase inhibitors from Clinacanthus nutans leaf extract using liquid chromatography-mass spectrometry-based metabolomics and protein-ligand interaction with molecular docking

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Pharmaceutical Analysis 2019年第2期9卷 91-99页

作者： Suganya Murugesu Zalikha Ibrahim Qamar Uddin Ahmed Bisha Fathamah Uzir Nik Idris Nik Yusoff Vikneswari Perumal Faridah Abas Khozirah Shaari Alfi Khatib Department of Pharmaceutical Chemistry Kulliyyah of PharmacyInternational Islamic University Malaysia Department of Pharmaceutical Technology Faculty Pharmacy & Health SciencesUniversiti Kuala LumpurRoyal College of Medicine Perak Laboratory of Natural Products Institute of BioscienceUniversiti Putra Malaysia

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.

关键词： Clinacanthus nutans LC-MS-QTOF Metabolomics α-glucosidase inhibitors Diabetes Molecular docking

Expression and characterization of a-glucosidase III in the dwarf honeybee, Apis florea （Hymenoptera： Apoidea： Apidae）

在线全文

学校读者我要写书评

暂无评论

Insect Science 2007年第4期14卷 283-293页

作者： CHANPEN CHANCHAO RUMPALAI PADOONGSUPALAI POLKIT SANGVANICH DepartmentofBiology ProgramofBiotechnology DepartmentofChemistry FacultyofScienceChulalongkornUniversityBangkokThailand

Alpha-glucosidase is synthesized in the hypopharyngeal glands located in the head of worker bees including Apisflorea. To analyze the developmental stage-specific expression of the a-glucosidase gene ***, total RNA was isolated from eggs, and the heads of nurse and forager bees. By reverse transcription polymerase chain reaction （RT- PCR）, it was shown that the highest expression levels of the a-glucosidase Ⅲ gene, in the three examined developmental stadia, were found in forager bees, with much lower expression levels in nurse bees and no detectable expression in eggs. A complete aglucosidase III eDNA was obtained by RT-PCR and sequenced. The 1 701 bp eDNA nucleotide sequence and the predicted 567 amino acids it encodes were assayed by BLASTn, BLASTp and BLASTx programs and revealed a 95% and 94% similarity to the A. mellifera aglucosidase III gene at the DNA and amino acid sequence levels, respectively. For purification of the active encoded enzyme, forager bee heads were homogenized in sodium phosphate buffer solution and the crude extract （0.30 U/mg） sequentially precipitated with 95% saturated ammonium sulfate （0.18 U/mg）, and purified by DEAE cellulose ion exchange chromatography （0.17 U/mg）, and gel filtration on Superdex 200 （0.52 U/mg）. After resolution through sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a single enzymically active band （73 kDa） was identified from renatured substrate gels. Excision of this band, elution of the protein and tryptic peptide digestives identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry （MALDI-TOF MS） revealed six matching masses to the A. mellifera （Q17958） and predicted *** α glucosidase Ⅲ protein with 12% coverage, supporting the probable purification of the same α-glucosidase III protein as that encoded by the cloned cDNA.

关键词： α-glucosidase Apisflorea cDNA expression homology purification

Inhibitory activities of microalgal fucoxanthin againstα-amylase,α-glucosidase, and glucose oxidase in 3T3-L1cells linked to type 2 diabetes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2019年第3期37卷 928-937页

作者： KAWEE-AI Arthitaya KIM Aaron Taehwan KIM Sang Moo Department of Marine Food Science and Technology Gangneung-Wonju National UniversityGangneung 25457Republic of Korea Department of Biotechnology Chiang Mai UniversityChiang Mai 50200Thailand Department of Food Science and Biotechnology Kyung Hee UniversityYongin 17104Republic of Korea

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 *** 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 *** 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/*** also considerably elevated glucose oxidase activity in 3T3-L1 cells by 31.3%at 5μmol/*** adipocyte differentiation,fucoxanthin showed lipid accumulation in 3T3-L1 cells with no cytotoxicity up to 20μmol/***,fucoxanthin had no inhibitory activity on glucose-6-phosphate *** 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.

关键词： α-glucosidase amylase diabetes fucoxanthin glucose oxidase microalgae

Flavonoids from Litchi(Litchi chinensis Sonn.) Seeds and Their Inhibitory Activities on α-glucosidase

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2013年第4期29卷 682-685页

作者： REN Shen XU Duo-duo GAO Yang MA Yu-ting GAO Qi-pin Research and Development Center Changehun University of Traditional Chinese Medicine Changchun130117 P. R. China College of Traditional Chinese Medicine Jilin Agricultural University Changehun130118 P R. China

With the bioactivity-guided method,a new flavanone glycoside,together with nine known flavonoids were isolated from 50% aqueous ethanol of litchi（Litchi chinensis Sonn.） *** chemical structure of the new compound was elucidated via 1D and 2D nuclear magnetic resonance（NMR） techniques and mass spectrometry to be （2S）-pinocembrin-7-O-（6＂-O-α-L-arabinosyl-β-D-glucopyranoside）（1）,and the nine known compounds were determined to be quercetin（2）,phlorhizin（3）,pinocembrin-7-O-glucoside（4）,kaempferol-7-O-β-D-glucopyranoside（5）,onychin（6）,nairutin（7）,narcissin（8）,pinocembrin-7-O-[（6＂-O-β-D-glucopyranoside）-β-D-glucopyranoside]（9） and pinocembrin-7-O-[（2＂,6＂-di-O-α-L-rhamnopyranosyl）-β-D-glucopyranoside]（10）.Some of the isolated flavonoids were tested for their inhibitory effects on α-*** compounds 2 and 3 showed stronger inhibitory activity than positive control.

关键词： Litchi chinensis Sonn.seed Flavanoid Inhibitory activity α-glucosidase