【作者】 兰作平；

【导师】 侯长军；

【作者基本信息】 重庆大学 ， 药物化学， 2008， 硕士

【摘要】 葛根素(7,4’-二羟基-8-β-D-葡萄糖基异黄酮)为豆科葛属植物葛根提取的主要活性成分之一,有研究表明葛根素具有多种药理活性,如降低血管阻力,改善脑及冠脉循环,降低心肌耗氧量,调节NOS活性,抗氧化、抗癌及诱导癌细胞分化等作用,且有毒性小、代谢快等优点。但因异黄酮类化合物本身的结构特点,使葛根素的水溶性和脂溶性均较差,生物利用度不理想,制约了临床应用。为改善葛根素的上述缺点、提高生物利用度,本论文以葛根素为先导化合物,根据反应物结构和酰化反应特点,采用酰化法制备乳酸葛根素,然后用紫外光谱、红外光谱和核磁共振进行了结构确认。在工艺优化方面,本论文用均匀设计实验,优化了原料的配料比、溶剂用量、反应时间和温度等工艺条件,最后确定最佳的工艺条件为,原料的配料摩尔比1.4:1、反应温度:20℃、反应时间100min及吡啶用量1.0ml。对合成衍生物进行了理化性质及稳定性的初步研究。在稳定性方面,选择以外观及薄层色法谱鉴别、HPLC法测定含量、吸湿增重等为评价指标,对其温度、湿度、光线、空气中的氧气以及pH值等因素进行了考察,结果表明:衍生物对高温、高湿度、强光等均不稳定,对空气较敏感,在较强碱性的条件下也不稳定。在理化性质测定方面,将葛根素分子结构中的4’-酚羟基进行酰化后其理化性质发生了一定的变化。其中,衍生物熔点有所降低,旋光度值相对于葛根素有所增大,但都为右旋体,水中溶解度有所提高,脂/水分布系数增大,pKa值有一定的变化。说明经过结构修饰后的葛根素衍生物,与葛根素比较其水溶性和脂溶性都有一定的改善。抗心肌缺血的动物实验研究表明衍生物能明显对抗垂体后叶素所导致的大鼠心肌缺血;抗心率失常的动物实验发现衍生物能明显的对抗氯仿所致的小鼠心率失常;对高血脂症大鼠血液流变学的研究表明衍生物能显著改善急性高脂血症大鼠血液流变学的相关指标,以上三项研究都表明衍生物的作用均比葛根素的作用强或更显著。急性毒性实验的研究结果显示,通过对小鼠灌胃最大浓度的乳酸葛根素稠溶液和最大体积乳酸葛根素溶液后,观察小鼠的毒性反应,结果表明葛根素没有显著的毒性反应。综上所述,本论文基于葛根素分子结构所制备的衍生物乳酸葛根素,其理化性质、生物活性等方面均有一定程度的改善,达到了提高生物利用度,增强药理活性的目的,同时也为今后的制剂开发以及临床应用提供了一定的理论基础和数据支持。更多还原

【Abstract】 Puerarin (4’, 7-dihydroxy-8-C-β-D-gluco-isoflavone) is one of the important active components of pueraria lobato (Wild) Ohwi. Some research shows that puerarin has a variety of pharmacological activities, such as reducing vascular resistance, improving circulation of brain and coronary artery, reducing myocardial oxygen demand, regulating the activity of NOS, antioxidation, anticancer and inducing cancer cell differentiation. Moreover, it has the advantages of small toxicity and quick metabolism and so on.However, the isoflavones’own structural characteristics causes puerarin has the bad water-solubility and liposolubility, and its poor bioavailability. So the clinical application is restricted.To improve the above-mentioned shortcomings, we selected puerarin as the lead compound and the acylation synthetic process to prepare Lactic Acid puerarin according to the reagent’s structure and the reaction of acylation characteristics. Then we confirmed the derivates’structure by using UV, IR and NMR.In the process optimization aspect, finally, we determined the optimum conditions: The preparation of raw materials molar ratio is 1.4:1; The reaction temperature is 20℃; The reaction time is 100 min and the solvent dosage of Pyr. is 1.0 ml.We carried on the preliminary study on the physico-chemical property and stability of puerarin derivatives. We chose the appearance, TLC, HPLC and moisture absorption as evaluation index on the stability aspect. In the physico-chemical property study, we observated the effects of temperature, humidity, light, oxygen in the air and pH etc for puerarin derivatives. The results indicated that the derivatives were instable in the high temperature, high humidity and highlight. They were sensitive about the atmosphere. They were instable under the alkaline condition, too. When we acylated the 4’-phenolic hydroxyl group in the molecular structure of puerarin, the derivatives’physico-chemical properties had some changes. Their melting point was degraded, and the optical activity was increased by comparing with puerarin. But all of them were d-isomers. The solubility in water to some extent boosted; their lipoids/water distribution coefficient increased, and pKa had some change. Compared with puerain, it was demonstrated that water-solubility and liposolubility of the derivatives which had processed structural modification was improved in some extent.The Anti-myocardial ischemia animal experiments indicated that the derivatives can obviously antagonize the myocardial ischemia of rats caused by hypophysin. The derivatives can resist arrhythmia of mice induced by chloroform in the anti-arrhythmia animal experiments. In addition, it could apparently improve the hemorheological correlated index of acute hyperlipemia rats in the research about the hemorheology of hyperlipemia rats. All of the researches showed that the effects of the derivatives were more conspicuous than puerarin.The acute toxicity testing finding showed that after the mice were lavaged with maximum concentration and maximum capacity of lactic acid puerarin’s thick liquor, lactic acid puerarin didn’t have conspicuous toxic reaction.In summary, the properties of the derivatives which were synthesized based on the puerarin’s molecular structure, such as, physico-chemical properties and biological activity , and so on, have been improved. So they can improve their bioavailability and enhance pharmacological activity. At the same time, this paper also provides theoretical basis and useful data for praeparatum development and clinical application in future.更多还原