近年來,天然產物在營養(yǎng)、保健、化妝品、飼料和藥品等領域受到越來越多的關注。茶葉是世界上消費量第二大的飲料,它在亞洲的應用歷史悠久,特別是在中國和日本。根據不同的發(fā)酵程度,茶葉主要分為三大類:綠茶(未發(fā)酵)、烏龍茶(半發(fā)酵)和紅茶(全發(fā)酵)。茶葉的化學成分非常復雜,包括(1)碳水化合物:如多糖、纖維素、果膠、葡萄糖、果糖;(2)多酚:包括兒茶素、花色苷、黃酮類等;(3)蛋白質;(4)氨基酸:如茶氨酸、色氨酸、甘氨酸;(5)維生素(B,C,E);(6)生物堿類:如咖啡因和茶堿;還有脂肪類、揮發(fā)性成分、礦物質和微量元素等。其中,茶葉中的活性成分主要是茶多糖(TPS)和茶多酚,這兩者是茶葉發(fā)揮抗氧化、抗癌、免疫調節(jié)和抗糖尿病等藥用價值的兩個重要成分,其中表沒食子兒茶素沒食子酸酯(EGCG)是茶多酚的主要組成成分。食物和口服藥在人體內的消化起始于口腔的咀嚼和唾液酶的作用,然后進入到胃腸,消化道環(huán)境的溫度、pH值、胃蛋白酶、胰酶和其他消化酶、腸道菌群等能夠影響物質在體內的消化和吸收,這些因素可能改變物質的理化性質、穩(wěn)定性、生物利用度和生物活性等。多糖的分子量、化學成分、結構和構象的變化能夠影響其生...

【文章頁數(shù)】：86 頁

【學位級別】：碩士

【文章目錄】：
摘要
abstract
Chapter 1 General introduction
    1.1 An overview of tea
        1.1.1 Chemical components of tea
        1.1.2 Tea polysaccharides
        1.1.3 Tea polyphenols
    1.2 Research progress on digestion and fermentation of polysaccharides
    1.3 Antidiabetic mechanisms related to T2DM
        1.3.1 α-amylase and α-glucosidase inhibitory effects
        1.3.2 Targeting β cell dysfunction
        1.3.3 Targeting signal pathways
        1.3.4 Modulation of gut microbiota
    1.4 Research progress on protein-polyphenols-polysaccharides interaction in drugdelivery system
        1.4.1 Interaction between protein and polyphenols
        1.4.2 Interaction between protein and polysaccharides
        1.4.3 Interaction between polyphenols and polysaccharides
        1.4.4 Protein-polyphenols-polysaccharides nanoparticles
    1.5 Significance of the study
Chapter 2 In vitro simulated digestion of tea polysaccharides
    2.1 Introduction
    2.2 General experimental procedures
    2.3 Methods
        2.3.1 TPS preparation
        2.3.2 Simulated digestion in vitro
        2.3.3 UV-vis spectrophotometric measurement of TPS
        2.3.4 IR fingerprint experiment of TPS
        2.3.5 Morphological properties of TPS
        2.3.6 Determination of molecular weight distribution of TPS
        2.3.7 Determination of reducing sugar
        2.3.8 Determination of monosaccharide changes of TPS
        2.3.9 α-amylase inhibitory effects of TPS
        2.3.10 Statistical analysis
    2.4 Results and Discussion
        2.4.1 UV-vis spectra fingerprint of TPS before and after simulated digestion in vitro
        2.4.2 IR spectra of TPS before and after simulated digestion in vitro
        2.4.3 Morphological properties of TPS before and after simulated digestion in vitro
        2.4.4 Molecular weight changes of TPS after simulated digestion in vitro
        2.4.5 Changes of the contents of reducing sugar
        2.4.6 Monosaccharide composition changes of TPS after gastric and intestinaldigestion
        2.4.7 α-amylase inhibitory effects of TPS before and after the simulated digestion
    2.5 Conclusion
Chapter 3 Interaction of EGCG with α-glucosidase and in vitro evaluation ofantidiabetic activity
    3.1 Introduction
    3.2 General experimental procedures
    3.3 Methods
        3.3.1 Inhibitory effects of EGCG on α-glucosidase
        3.3.2 Fluorescence spectroscopy analysis
        3.3.3 FI-IR spectra analysis
        3.3.4 Molecular docking analysis
        3.3.5 Cell culture
        3.3.6 Cell viability
        3.3.7 Glucose uptake
        3.3.8 Oil red o staining
        3.3.9 Statistical analysis
    3.4 Results and discussion
        3.4.1 α-Glucosidase inhibition studies
        3.4.2 Fluorescence quenching of α-glucosidase by EGCG
        3.4.3 FT-IR measurements
        3.4.4 Molecular docking analysis
        3.4.5 Glucose uptake
        3.4.6 Oil red o staining
    3.5 Conclusion
Chapter 4 Encapsulation of EGCG in BSA/Tea Polysaccharides nanoparticles
    4.1 Introduction
    4.2 General experimental procedures
    4.3 Methods
        4.3.1 TPS-2 (30-80 KDa) preparation
        4.3.2 Nanoparticle preparation
        4.3.3 Characterization of nanoparticles
        4.3.4 In vitro release of EGCG from nanoparticles
        4.3.5 Antioxidant activities
        4.3.6 Statistical analysis
    4.4 Results and discussion
        4.4.1 Loading efficiency and loading capacity
        4.4.2 Characterization of nanoparticles
        4.4.3 In vitro release of EGCG from nanoparticles
        4.4.4 Antioxidant activities
    4.5 Conclusion
Chapter 5 Conclusions and prospect
References
Appendix
Publications and participation in scientific research
Acknowledgement



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