【作者】 夏威；

【导师】 锁然；

【作者基本信息】 河北农业大学 ， 食品工程， 2012， 硕士

【摘要】 白藜芦醇苷是中药虎杖中的主要有效成分之一,具有抑制心肌细胞收缩、控制血小板聚集、降血脂、抗脂质过氧化、抗休克等作用,可广泛应用于医药、保健品、食品添加剂和化妆品等领域,具有广泛的应用开发价值。但由于白藜芦醇苷在水中溶解度较小,在紫外照射下发生异构化,不稳定,导致体内生物利用度低,其应用受到严重限制。因此,开发白藜芦醇苷相关产品,提高其水溶性及稳定性,有利于拓宽其应用范围,促进其应用推广,对充分利用我国中草药资源、提高中草药附加值、实现中草药现代化具有现实意义。本研究通过制备白藜芦醇苷的环糊精(β-CD和HP-β-CD)分子包合物,显著提高了白藜芦醇苷在水溶液中的溶解度,并在一定程度上提高了其稳定性。(1)采用冷冻干燥法制备了白藜芦醇苷的环糊精(β-CD和HP-β-CD)分子包合物。利用紫外-可见光谱法、红外光谱法、X射线衍射法和核磁共振法对分子包合物的物相进行了鉴定,试验结果证明了分子包合物的形成。(2)通过相溶解度法研究了环糊精(β-CD和HP-β-CD)在水溶液中对白藜芦醇苷的包合和增溶作用,以及包合过程中热力学参数的变化结果。试验结果表明,在水溶液中,白藜芦醇苷与环糊精(β-CD和HP-β-CD)均可自发形成摩尔比1:1可溶性包合物,相溶解图均呈AL型;同时,白藜芦醇苷与环糊精(β-CD和HP-β-CD)在包合过程的吉布斯自由能变化(ΔG)、焓变(ΔH)和熵变(ΔS)均为负值。(3)对白藜芦醇苷的环糊精分子包合物的包合比进行了分析。通过等摩尔系列法测定了包合物的包合比,试验结果表明,白藜芦醇苷与环糊精(β-CD和HP-β-CD)均以摩尔比1:1包合,这与相溶解度法的测定结果一致。(4)采用DPPH和FRAP两种方法测定了白藜芦醇苷及其分子包合物的抗氧化性。试验结果表明,白藜芦醇苷-β-环糊精分子包合物、白藜芦醇苷-羟丙基-β-环糊精分子包合物及白藜芦醇苷均具有一定清除DPPH·和还原TPTZ的能力。在DPPH方法中,三者的抗氧化活性相差不大(IC50分别为:346.09mg/L、337.40mg/L、363.46mg/L);在FRAP方法中,白藜芦醇苷-β-环糊精分子包合物、白藜芦醇苷-羟丙基-β-环糊精分子包合物及白藜芦醇苷的EC1分别为431.15mg/L、405.07mg/L和463.88 mg/L,三者的还原能力也相差不大,这与DPPH法测定的结果一致。(5)研究了在紫外光照射条件下,分子包合物中白藜芦醇苷的稳定性。实验结果表明,β-环糊精包合物与羟丙基-β-环糊精包合物中的白藜芦醇苷表现出了近似的变化情况,说明这两种环糊精包合物对紫外光具有近似的稳定性;而没有包合的白藜芦醇苷与环糊精包合物相比,其稳定性较差,在紫外光照条件下损失率要高20%左右,说明环糊精包合物中白藜芦醇苷的稳定性得到了一定程度的提高。更多还原

【Abstract】 Polydatin is a main effective component in Polygonum cuspidatum, and its functions contain restraining cardiac muscle cell, moderating platelet aggregation, diminishing blood fat, resisting lipid oxidation and preventing shock. Thus, polydatin, with high development potential, is widely applied in clinical, medical and healthy areas, as well as fortified in food additives and cosmetics. However, due to its low solubility in water and isomerization tendency under ultraviolet radiation, polydatin is comparatively unstable, which declines its bioavailability and restricts its utilization. As a consequence, exploring polydatin and its products-enhancing its solubility and stability is very beneficial for its application and marketing, and also shows great significance for improving exploitation of Chinese herbal resources, increasing their added value and modernizing Chinese herbal medicine industry.The present study remarkably raised water-solubility of polydatin by manufacturing its cyclodextrin (β-CD and HP-β-CD) inclusion complexes, and advanced its stability to some extent.(1) The polydatin cyclodextrin (β-CD and HP-β-CD) inclusion complexes were prepared by freeze-drying method. Meanwhile, the inclusion complexes were identified by UV-visible spectra (UV-vis), infrared spectrometry (IR), X-ray diffraction (XRD), and nuclear magnetic resonance (NMR), respectively. It was identified that the polydatin cyclodextrin (β-CD and HP-β-CD) inclusion complexes were formed.(2) The intermolecular reaction between the host and the guest agents, soluble effects of cyclodextrins (β-CD and HP-β-CD) on polydatin in aqueous solution and changes of thermodynamic parameters in the complexation were determined by phase solubility method. The results indicated: the significant reactions between the host and the guest molecules in aqueous solution were confirmed, and polydatin could form inclusion compounds (1:1) with the two cyclodextrins derivates (β-CD and HP-β-CD). The solubility of polydatin in aqueous solution was linearly escalated with the increased concentration ofβ-CD and HP-β-CD, showing a plot of the typical AL type phase solubility. All three thermodynamic parametersΔG,ΔH andΔS in the complexation gave negative values.(3) Inclusion ratios of polydatin cyclodextrin inclusion complexes were analyzed by equimolar series method. The results revealed that polydatin included by both of the two cyclodextrins (β-CD and HP-β-CD) at the ratio of 1:1(molar/molar), which was in consistent with the results of phase solubility method tests.(4) DPPH and FRAP were employed to evaluate the antioxidant activities of polydatin and its inclusion complexes. Through the data, we discovered that polydatin-β-cyclodextrin, polydatin-hydroxypropyl-β-cyclodextrin and polydatin all showed some ability of eliminating DPPH·free radical and reducing TPTZ. Observed by DPPH, the above 3 compounds did not display much difference in antioxidation capability, as their IC50 were 346.09mg/L, 337.40mg/L and 363.46mg/L, separately. And FRAP determined EC1 values of polydatin-β-cyclodextrin, polydatin-hydroxypropyl-β-cyclodextrin and polydatin as 431.15 mg/L, 405.07 mg/L and 463.88 mg/L; hence, reducing capacity of the 3 compounds did not present much distinction either, which accorded with results from DPPH method.(5) Stability of polydatin in inclusion complexes under ultraviolet radiation was investigated. Among the results, polydatin-β-cyclodextrin and polydatin-hydroxypropyl-β-cyclodextrin altered similarly, which indicated the 2 compounds had similar stability under UV condition; however, polydatin which had not been included by cyclodextrin was unsteady, the loss ratio was 20% higher under ultraviolet radiation, illustrating stability of polydatin was elevated in cyclodextrin inclusion complexes.更多还原