【作者】 范华；

【导师】 杨光忠；

【作者基本信息】 中南民族大学 ， 药物化学， 2011， 硕士

【摘要】 人面果(Garcinia xanthochymus)、黑皮跌打藤茎(Fissistigma polyanthum)和布渣叶(Microcos paniculata L.)均是我国传统民族药物,药用历史悠久。在以往对这三种植物的研究中,发现其含有二苯甲酮衍生物、黄酮类、口山酮类、三萜类、以及生物碱类等多种化学成分,并具有抗炎、抗溃疡、抗肿瘤、抗细胞毒素、中枢抑制等多种药理活性,但是对上述三种植物的抗氧化及抗菌活性研究甚少。本文即主要对从人面果、黑皮跌打藤茎以及布渣叶中提取分离出的共36个化合物进行了抗氧化活性及抗菌活性进行了系统研究。在抗氧化活性的研究中,我们分别采用了三种体外模型(DPPH分光光度法、TEAC法和鲁米诺-过氧化氢-钴盐(Ⅱ)-EDTA流动注射化学发光法)对受试化合物的抗氧化能力进行了综合评价。其中,DPPH分光光度法和TEAC法对受试化合物的总抗氧化能力进行了有效测定,而鲁米诺-过氧化氢-钴盐(Ⅱ)-EDTA流动注射化学发光法则针对受试化合物清除羟基自由基的能力进行了准确分析。经研究发现:人面果显示出较强的抗氧化能力,可以作为天然的抗氧化剂。在DPPH评价中,化合物8(garcinexanthone F)和21(garcinexanthone B)清除DPPH自由基的IC50值达到7.95μg/mL和7.35μg/mL;而在化学发光评价中,化合物4(1, 3, 5, 6-tetrahydroxy-8-(3-methylbut-2-enyl)-xanthone; garcinexanthone C)和20(2,6-dihydroxy-1,5-dimethoxyxanthone)清除羟基自由基的IC50值则达到0.33μg/mL和0.10μg/mL。与人面果相比,黑皮跌打藤茎和布渣叶则显示出了较为一般的抗氧化能力,仅从布渣叶中提取分离的化合物2(epicatechin)具有较强的抗氧化能力(与阳性对照抗坏血酸即Vc相似),其分别清除DPPH自由基和羟基自由基的IC50值为2.83μg /mL和0.18μg /mL,TEAC值达到1.38,可以作为潜在的抗氧化剂。此外,我们还将受试化合物的化学结构与其抗氧化能力进行了构效关系分析,分析结果显示:受试化合物的抗氧化能力与化合物结构中所含羟基(尤其是酚羟基)的数目、羟基在苯环上的取代位置、共轭系统以及其他影响因素密切相关。在抗菌活性的研究中,我们采用了微稀释液体培养法对受试化合物的抗菌活性进行了有效评价,并最终确定了各个受试化合物的最低抑菌浓度。实验结果显示,人面果具有较好的抗菌能力:相对三种受试细菌,化合物5(Symphoxanthone)和1(41,5,6,5′-tetrahydroxy-7,8–di(3-methyl-2-butenyl )-6′, 6′-di- methylpyrano(2′, 3′: 3,4) xanthone)表现出了较强的抑制作用。而相对于两种受试真菌,受试化合物对热带念珠球菌的敏感性显著高于白色念珠球菌。抗白色念珠球菌能力最强的化合物6(Garcinenone D)、22(Garcinexanthone E)、25(2-methylbutyryl phloroglucinol)、29(1,4-Dihydroxy-6′,6′-dimethylpyrano (2′,3′:5,6) xanthone)、30(1-dihydroxy-4,5-methoxyxanthone)对其的MIC值均为31.25μg/mL,而化合物14(1,5,6,5′-tetrahydroxy-7,8–di(3-methyl-2-butenyl)-6′, 6′-dimethylpyrano(2′,3′:3,4) xanthone)和18(Subelliptenone H)对热带念珠球菌的MIC值达到3.91μg/mL。更多还原

【Abstract】 Garcinia xanthochymus, Fissistigma polyanthum and Microcos paniculata L. are traditional Dai medicines which have been used to prepare herbal medicines for a long time. Previous phytochemical investigations revealed the presence of benzophenones, flavones, xanthones, triterpenes and alkaloids in these three plants; and it has been reported that they not only have anti-inflammatory and antiulcer activities, but also exert antitumour, antihepatotoxic and CNS depressant effects. While a limited number of reports concerning the antioxidant and antibacterial activities of them have appeared in the literature. The objective of this study was to elucidate the antioxidant and antibacterial activities of the 36 compounds isolated from Microcos paniculata L.,Fissistigma polyanthum and Garcinia xanthochymus.The antioxidant activities of the tested compounds were evaluated through three in vitro model systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2’-azino- bis(3-ethylbenzothiazoline-6-sulfnate) (ABTS) and Co (Ⅱ) EDTA-induced luminol chemiluminescence by flow injection. Among them, the total antioxidant capacities of the antioxidants were assessed by the DPPH and TEAC test, and the scavenging activities of the antiodants towards Hydroxyl radical was measured by Co (Ⅱ) EDTA-induced luminol chemiluminescence by flow injection test. The results showed that Garcinia xanthochymus with strong antioxidant capacity can be expected as a promising natural antioxidant. Compounds 8 (garcinexanthone F) and 21 (garcinexanthone B) exhibited potent antioxidant activities in the DPPH and TEAC test with IC50 value of 7.95μg/mL and 7.35μg/mL, respectively; while Compounds 4(1, 3, 5, 6-tetrahydroxy-8-(3-methylbut-2-enyl)-xanthone; garcinexanthone C) and 20 (2,6-dihydroxy-1,5-dimethoxyxanthone) were the most effective hydroxyl radical scavengers with IC50 value of 0.33μg/mL and 0.10μg/mL in the chemiluminescence by flow injection test. Compared with Garcinia xanthochymus, Fissistigma polyanthum and Microcos paniculata L. showed moderate antioxidant effects, while compound 2 (epicatechin) isolated from Microcos paniculata L. displayed significant antioxidant activity which is similar to that of standard antioxidant ascorbic acid (VC) and therefore may be a promising natural antioxidant. Epicatechin exhibited powerful scavenging activities against DPPH and hydroxyl radicals with IC50 values of 2.83μg /mL and 0.18μg /mL, respectively, and the ABTS scavenging activity of 2 (TEAC = 1.38±0.05) was found to significantly higher than that of Trolox.The antibacterial activities and the MICs (minimal inhibitory concentration) of the tested compounds were determined through broth microdilution method. It was found that Garcinia xanthochymus exhibited strong antibacterial capacity. Compounds 5 (Symphoxanthone) and 14 (1,5,6,5′-tetrahydroxy-7,8–di(3-methyl-2-butenyl)-6′, 6′-di- methylpyrano(2′,3′:3,4) xanthone) showed effective inhibitory activities against three bacteria strains (S. aereus, B. subtilis and B. mucilaginosus). And obviously, the antibacterial activities of the tested compounds were more sensitive to C. tropicalis than C. albicans. The compounds 6 (Garcinenone D), 22 (Garcinexanthone E), 25 (2-methylbutyryl phloroglucinol), 29 (1,4-Dihydroxy-6′,6′-dimethylpyrano (2′,3′:5,6) xanthone), 30 (1-dihydroxy-4,5-methoxyxanthone) showed the strongest activities against C. albicans with MIC value of 31.25μg/mL, and both the MIC value of compounds 14 (1,5,6,5′-tetrahydroxy-7,8–di(3-methyl-2-butenyl)-6′, 6′-dimethylpyra- no(2′,3′:3,4) xanthone) and 18(Subelliptenone H) against C. tropicalis was 3.91μg/mL.更多还原