【作者】 李霞；

【导师】 高文远；

【作者基本信息】 天津大学 ， 应用化学， 2010， 博士

【摘要】 平贝母是百合科(Liliaceae)贝母属(Fritillaria)植物的干燥鳞茎,大量研究表明生物碱、皂苷等是其主要活性成分,但对于含量高达40%~60%的淀粉研究却很少,为了更全面地开发利用该植物资源,本文在对原淀粉研究的基础上,采用不同方法对其改性并进行系统表征。本文首次制备了平贝母羧甲基淀粉(CMS)、乙酰化淀粉、酸水解和酶解淀粉,并使用红外光谱(FT-IR)、扫描电子显微镜(SEM)、X-射线衍射(XRD)、激光散射粒度分布(PSD)、差示扫描量热(DSC)和热失重分析(TGA)等方法对四种变性淀粉进行了系统的表征(包括基本的理化性质,颗粒微观形态,颗粒尺寸分布,晶体学性质及热学性质等),同时比较了原淀粉和变性淀粉的各种性质差异。基本理化性质实验结果显示CMS冷水可溶且溶液透明度高;乙酰化淀粉比原淀粉具有较高的膨胀度和溶解性,而酸水解和酶解程度较高的淀粉吸水性好。SEM结果显示完整、光滑呈卵圆形或椭圆形的平贝母原淀粉经羧甲基化和乙酰化后原淀粉颗粒被严重腐蚀,出现了凝结成块的现象,并且表面出现了蜂窝状的小孔;原淀粉经酸水解时,其表面首先被酸腐蚀成孔穴,继而颗粒内部被水解,最终分裂成碎块,而经糖化酶水解时,表面只出现小的裂缝,颗粒内部首先被水解。X-射线衍射结果表明平贝母原淀粉晶体结构呈B型,经羧甲基化和乙酰化后结晶区域随着取代度的增大而减少;而酸水解和酶解时,淀粉的晶体构型变化不大,但结晶度相对增大。DSC结果显示羧甲基淀粉和酶解淀粉熔融温度降低,热塑性增加,乙酰化淀粉降低了凝胶化转变温度和热焓值(ΔHgel),增加其热塑性和热成形性。热重分析(TGA)结果显示CMS较原淀粉具有较低的分解温度;而乙酰化淀粉和酶解淀粉分解温度升高,热稳定性增强。现代药理研究表明,平贝母能抑制血小板聚集,提示其可能具有抗炎作用,因此,本文还对平贝母各提取物进行抗炎、抗氧化作用研究,并对其抗炎机理进行了初步探讨,结果表明,平贝母总黄酮和总皂苷在一定剂量下具有很好的抗炎、抗氧化活性,且总黄酮作用较强。抗炎机理实验证明平贝母抗炎作用可能与通过抑制炎性液中PGE2和MDA的形成有关,还可能通过抑制自由基攻击机体细胞,减少细胞损伤,从而降低炎症反应程度,此外,抑制NO的生成也可能是其抗炎作用的另一机制。更多还原

【Abstract】 Fritillaria ussurensis Maxim. is derived from the bulbs of the genus Fritillaria of the Liliaceae. A lots of studies indicated that alkaloid,saponin and other chemical ingredients are the major active components. However, there are few works on the starch which was r esponsible f or t he m ian c omponents of F. ussurensis Maxim. occupying approximately 40-60%. In order to understand the medicinal plant better for the development and utilization of the starch, different modified starches were prepared and their properties were investigated sufficiently.The essential physicochemical, morphological, crystalline and thermal properties of native and modified F. ussurensis Maxim. starches were researched using Fourier transform i nfrared (FT-IR), scanning electron microscope (SEM), X -ray diffractometry (XRD), pa rticle s ize di stribution (PSD), differential s canning calorimetry (DSC) and thermogravimetry analysis (TGA) in this thesis.These results indi cated tha t C MS possessed any unique properties such as solubility in unheated water, less retrogradation and well light transmittance, while the acetylated starch has improved swelling capacity and solubility. Water absorption capacity increased after acid and enzyme hydrolysis. The SEM results revealed that carboxymethylation and acetylation process no t onl y a ffected t he s urface of t he granules but also the internal part,and the structural arrangement of starch granules was destroyed and many alveolate holes could be seen on t he granule surface. In addition, t he external s tructure was at tacked firstly by acid, w here the i nternal fractions were hydrolyzed easily by glucoamylase. From t he X RD, a pr onounced reduction in crystallinity of CMS and the starch acetates was obs erved. The DSC results s howed that af ter carboxymethylation or enzyme hydrolyztion, the thermoplastic property was improved and the starch acetates showed lower transition gelatinization temperature and enthalpy values than native starch. From the TGA, the melting temperature of the starch decreased and at a lower decomposition speed after modified by acetyl group and glucoamylase.Modern pharmacological studies have shown that Fritillaria ussuriensis Maxim. inhibits platelet aggregation, suggesting that it ma y have anti-inflammatory effect. Therefore the ant i-inflammatory and antioxidant activities of all the extracts from Fritillaria ussuriensis Maxim. were i nvesgated. The mechanisms of anti-inflammatory actions of the ethanol extract were also explored. The antioxidant activity of the t hree extracts de creased in the order: flavonoids e xtract> saponin extract> ethanol ex tract. All the a dministered gr oups pr oduced s ignificant anti-inflammatory effects on the three animal models. The results demonstrated that the different fractions of Fritillaria ussurensis Maxim. have different responses with different antioxidant methods and anti-inflammation animal models. The flavonoids extract showed the best antioxidant and anti-inflammatory activities and the saponin extract and the e thanol followed. The results of anti-inflammatory mechanisms revealed that the effect may be related to reduce the content of PGE2 and MDA in the exudates. Moreover, it relevented to decrease t he l evel of i nflammatory reaction through i nhibitin t he attack of cel lular caus ed by free r adical and alleviated the cellular damage. Moreover, the administrated groups had good preventive action of the level of NO in the serum, which is also an action mechanism.更多还原