【作者】 朱立才；

【导师】 于淑娟；

【作者基本信息】 华南理工大学 ， 制糖工程， 2010， 博士

【摘要】 多酚类物质是植物的次生代谢产物,具有独特的化学性质和生理活性。快速有效地分离纯化植物中酚类物质进行结构鉴定是生物活性研究、合理组方和可再生资源高值化利用的必要前提。本文以低极性多酚—蒽醌苷元和高极性多酚—黄酮糖苷为分离目标,探讨了快速寻找植物多酚高速逆流色谱分离的方法步骤,建立了微波辅助提取/大孔树脂富集提取、高速逆流色谱分离、高效液相色谱做最终分离物纯度检测的高效、快速植物多酚分离纯化平台,并对代表性多酚单体的电喷雾串联质谱碎裂规律、晶体结构信息等特性进行了研究,以期通过本课题的研究能为同类其它植物多酚单体的分离纯化、结构鉴定及生物活性研究提供可借鉴的技术和理论依据。主要结果如下:（1）利用微波辅助从决明子中提取蒽醌类多酚的最优工艺为:乙醇浓度60%,料液比1: 4,在60°C下提取40 min,蒽醌类多酚的得率为0.275%。通过HPLC-ESI-MS联用技术,采用正、负离子扫描模式对提取物进行分析,初步鉴定了22种多酚成分。（2）通过HPLC测定分配系数来选择和优化两相溶剂系统,建立了低极性多酚—蒽醌苷元的高速逆流色谱分离纯化平台,利用该平台并结合半制备HPLC从决明子中分离得到5种纯度均超过97%蒽醌苷元。经UV、MS、¹H NMR等分析,它们分别为:橙黄决明素、钝叶决明素、1-去甲基钝叶决明素、甲基钝叶决明素、1-去甲基橙黄决明素。（3）通过SD 300大孔树脂吸附富集、乙醇洗脱从甘蔗榨汁中提取黄酮类多酚,并利用HPLC-ESI-MS负离子扫描模式初步鉴定了9种单体成分。同时建立了高极性多酚—黄酮糖苷的高速逆流色谱分离纯化平台,以乙酸乙酯-正丁醇-水（9:1:10, v/v/v）为两相溶剂体系,从250 mg样品中分离得到38.3 mg异荭草素-7, 3’-二甲基醚、19.7 mg当药黄素、8.5 mg麦黄酮-7-O-葡萄糖苷,HPLC峰面积归一法显示,这三种黄酮糖苷的纯度分别为98.3%、97.8%和97.2%。（4）运用电喷雾-离子阱质谱技术对橙黄决明素、钝叶决明素、甲基钝叶决明素、1-去甲基橙黄决明素、异荭草素-7, 3’-二甲基醚、麦黄酮-7-O-葡萄糖苷等4个蒽醌类和2个黄酮类多酚进行多级碰撞诱导解离分析（MS5-MS9）,归属了负离子模式下这些化合物的主要特征碎片离子,提出了它们的可能裂解途径,并总结了蒽醌、黄酮类化合物的主要碎裂规律。（5）利用单晶X-射线衍射分析了甲基钝叶决明素、茜素-1-甲醚、1, 2-二甲氧基-3-羟基蒽醌、咖啡酸和原儿茶酸五种酚酸的晶体结构。结果表明:此五种酚酸晶体分别属于单斜和三斜两大晶系;晶态下它们分别由氢键、π-π堆积等弱作用组装单个分子成具有二维层状结构的三维超分子网络。此外,单晶X-射线衍射结构分析也表明原儿茶酸与钾、钙离子发生配位反应的基团为3-、4-位羟基,配位后其羟基氢并未离去,晶体结构中每个钾、钙离子均与四分子配体作用,形成八配位的空间构型。原儿茶酸-钾、钙配合物分别属于三斜和正交晶系,主体结构化学计量式为K（C₇H₅O₄）（C₇H₆O₄）和Ca（C₇H₅O₄）₂（C₇H₆O₄）₂。（6）原儿茶酸、原儿茶酸-钾和原儿茶酸-钙对O^2-·、·OH均有较强的清除能力。原儿茶酸形成配合物后,由于K-O、Ca-O配位键的形成降低了羟基O-H间的电子云密度,增大了羟基氢的离去能力,从而使得其抗氧化能力升高,三者的抗氧化活性为原儿茶酸-钙﹥原儿茶酸-钾﹥原儿茶酸。抑菌实验表明原儿茶酸、原儿茶酸-钾、原儿茶酸-钙对大肠杆菌和金黄色葡萄球菌均有一定的抑制作用,但原儿茶酸形成配合物后不能改善其抑菌活性。更多还原

【Abstract】 Polyphenols are secondary metabolites in plants, which possess special chemical and physiological activities. Separation and purification of phenolic compounds from plants for molecule structure identification are key steps of their pharmacological activities, rational combination and high-value utilization of renewable resources. This paper first described the qualitative determination of phenolic compounds in Cassia tora L. and sugarcane by HPLC- ESI-MS. And then high-speed counter-current chromatography （HSCCC） was used to establish the rapid and high efficiency preparation platforms of phenolic compounds from Cassia tora L. and sugarcane. The characterizations of main phenolic compounds were also investigated. The main contents and results are as follows:（1） The extraction of anthraquinones in Cassia tora L. with microwave-assisted method was studied. The optimal condition was 60% ethanol （V:V）, the ratio of solid to liquid （1:4）, extraction 40 minutes at 60°C by orthogonal experiments.（2） The chemical components were analyzed by HPLC-ESI-MS in Cassia tora L., and 22 molecule structures were elucidated according to mass-to-charge （m/z） of quasi-molecule ion peak and reference. Five anthraquinones including aurantio-obtusin, 1-desmethylaurantio- obtusin, chryso-obtusin, obtusin, and 1-desmethylchryso-obtusin were isolated and purified by HSCCC and semi-HPLC from Cassia tora L. The purity of aurantio-obtusin, 1-desmethylaurantio-obtusin, chryso-obtusin, obtusin, and 1-desmethylchryso-obtusin was over 97% as determined by HPLC. The structures of five anthraquinones were identified by UV, MS, ¹H NMR.（3） HPLC-ESI-MS was utilized for the identification of nine flavonoid glycosides from sugarcane juice. Three flavonoid glycosides including swertisin, isoorientin-7, 3’-dimethyl ether, and tricin-7-O-glycoside were isolated and purified from sugarcane juice by HSCCC with a two-phase solvent system composed of ethyl acetate-n-butanol-water （9:1:10, v/v/v）. The isolation produced a total of 19.7 mg of swertisin, 38.3 mg of isoorientin-7, 3’-dimethyl ether, and 8.5 mg of tricin-7-O-glycoside from 250 mg of crude extract in one-step elution. The purity of each compound was over 97% as determine by HPLC. The chemical identities of these components were confirmed by UV, MS and ¹H NMR. （4） The muti-stage tandem collision-induced dissociation mass spectrum （MS⁵-MS⁹） of four anthraquinones （aurantio-obtusin, obtusin, chryso-obtusin, 1-desmethylaurantio-obtusin） and two flavonoid glycosides （isoorientin-7, 3’-dimethyl ether, tricin-7-O-glycoside） were investigated in negative mode by electrospray ionization-ion trap mass spectrometry （ESI-ITMS）. The fragmentation mechanisms of these compounds were explored according to some interesting losses. We also summarized the relationship between structural features of similar compounds and corresponding fragmentation behavior.（5） The crystals of five phenolic compounds were analyzed by single-crystal X-ray diffraction. The results showed that chryso-obtusin and caffeic acid crystallized in the monoclinic space group P2₁/n, and alizarin-1-methyl ether, 1,2-dimethoxy-3-hydroxy- anthraquinone and protocatechuic acid （PCA） crystallized in the triclinic space group P -1. It was one important feature of these crystals that their molecules were interconnected by themselves through hydrogen bonds,π···πstacking, and weak intermolecular interactions to form 3D supramolecular network. Single-crystal X-ray analysis revealed that, in the complexes K-protocatechuic acid （K-PCA） and Ca-protocatechuic acid （Ca-PCA）, the central metallic ions were coordinated to eight oxygen atoms from 3-OH and 4-OH of four PCA ligands, crystallizing in the triclinic space group P -1 and the orthorhombic space group P 2₁2₁2 respectively. The main chemical stoichiometry of complexes K-PCA and Ca-PCA were K（C₇H₅O₄）（C₇H₆O₄） and Ca（C₇H₅O₄）₂（C₇H₆O₄）₂.（6） The antioxidant activity of PCA, complexes K-PCA and Ca-PCA were investigated. The results demonstrated that the ligand and its complexes showed good ability for scavenging superoxide and hydroxyl free radicals, and the order of antioxidant activity was Ca-PCA > K-PCA > PCA. At the molecular level, we deduced that the formation of K-O and Ca-O coordination bonds reduced the electron density of 3-OH and 4-OH, and increased the departure ability of H. On the other hand, PCA and its complexs also were tested in vitro to evaluate their antibacterial activity against bacteria Escherichia coli and Staphylococcus aureus, but it was not found that Ca-PCA and K-PCA showed higher activity than PCA.更多还原