【作者】 付伟；

【导师】 阮金兰；

【作者基本信息】 华中科技大学 ， 药理学， 2011， 博士

【摘要】 中日金星蕨Parathelypteris nipponica (Franch.et Sav.) Ching系蕨类植物门水龙骨目金星蕨科(Thelypteridaceae)金星蕨属植物。中日金星蕨以全草入药,在民间被广泛用于治疗烧伤、烫伤、出血、急性炎症等疾病,但是目前少见有关其化学成分和生物活性的研究报道。为了探讨中日金星蕨的药效学物质基础,进一步揭示其生物活性,我们对中日金星蕨的化学成分和药理活性进行了研究,初步探讨了其抗氧化、抗炎、肝保护作用的相关活性物质和作用机制,以其为中日金星蕨的民间应用提供系统以及科学的依据。通过各种色谱技术从中日金星蕨全草乙醇提取物中分离得到16个化合物：3’-甲基-4’,6’-二羟基-2’-甲氧基-查耳酮(1),3’,5’-二甲基-一4’,6’-二羟基-2’-甲氧基-查耳酮(2),高良姜素(3),黄芩素(4),山柰酚(5),山柰素-3-O-β-D-芸香糖苷(6),槲皮素(7),槲皮素-3-O-β-D-葡萄糖苷(8),芦丁(9),莽草酸(10),3,4-二羟基苯甲酸(11),正二十六烷醇(12),十六烷酸(13),β-香树素(14),β-谷甾醇(15),β-胡萝卜苷(16)。其中黄酮类成分9个,表明黄酮类成分在中日金星蕨化学成分中占据主要地位,是其特征性成分,对于中日金星蕨的相关药理作用可能起着关键的作用。在体外抗氧化活性研究中,中日金星蕨乙醇提取物在体外还原力、脂质过氧化、DPPH自由基清除、超氧阴离子自由基清除、羟基自由基清除及H2O2清除方面均表现出很强的抗氧化能力,且作用效果在一定范围内呈剂量依赖性；在体内CCl4诱导大鼠肝损伤模型中,中日金星蕨乙醇提取物表现出一定的肝保护作用,能有效逆转CCl4导致的肝损伤,使各项生化指标趋于正常。中日金星蕨的保肝作用可能与其良好的抗氧化能力有关。在抗炎实验中,证实中日金星蕨乙醇提取物具有明显的抗炎作用,其作用机制可能与减少炎性组织中PGE2的生成,抑制组织炎症中脂质过氧化产物形成,降低NO及NOS的活力有关。金星蕨苷(Parathelypteriside, PG)是本实验室前期从金星蕨科金星蕨属的另一种植物金星蕨中提取得到的新的芪类化合物。近年来研究表明,芪类化合物具有广泛的药理活性,尤其是在抗氧化、抗肿瘤和抗脑缺血等方面。本实验室在前期的药理筛选过程中,发现其有较强的抗氧化和清除自由基的作用。为了发掘其潜在的药理活性,本文进一步研究了PG对神经细胞氧化损伤的保护作用,并利用动物模型对PG可能的抗老年痴呆作用进行了验证。细胞实验结果表明金星蕨苷可以显著减轻过氧化氢对PC12细胞造成的氧化损伤。动物实验采用了D-半乳糖致小鼠衰老的模型,行为学测试结果证实金星蕨苷能够改善D-半乳糖造成的小鼠学习记忆障碍,生化指标测定表明金星蕨苷能提高小鼠脑内抗氧化酶的水平。此外,小鼠脑片电生理实验表明,金星蕨苷可在一定程度上对抗D-半乳糖造成的长时程增强(LTP)下降,其机制可能与改善D-半乳糖所致小鼠海马CREB磷酸化障碍有关。最后本文还对天然产物抗氧化研究进展进行了系统的综述,为合理有效的开发蕨类植物的抗氧化成分提供了理论支持。更多还原

【Abstract】 Parathelypteris nipponica (Franch. et Sav.) Ching is a member of the family Dryopteridaceae which distributed in the southern provinces of China. Its entire plants have been used in folk medicine to treat inflammation, burn scald and haemorrhage. In spite of the very wide-spread use of Parathelypteris nipponica (Franch. et Sav.) Ching, few studies were carried out to support its ethnopharmacological use. Therefore, we did the investigation on the chemical constituents, antioxidant, free radical scavenging, anti-inflammatory and hepatoprotective activity of the extract from Parathelypteris nipponica (Franch. et Sav.) Ching.Sixteen compounds were isolated from the whole plant of Parathelypteris nipponica (Franch. et Sav.) Ching by normal and reverse phase silica gel and Sephadex LH-20 gel column chromatography, and these compounds were identified as 4’,6’-Dihydroxy-2’-methoxy-3’-methylchalcone (1),4’,6’-Dihydroxy-3’, 5’-dimethyl-2’-methoxychalcone (2), Galangin (3), Baicalein (4), Kaempferol (5), Kaempferol-3-O-β-D-rutinoside (6), Quercetin (7), Quercetin-3-O-β-D-glucoside (8), Rutin (9), Shikimic acid (10),3,4-Dihydroxyhenzoic acid (11), Hexacosyl alcohol (12), Hexadecanoic acid (13),β-amyrin (14),β-sitosterol (15),β-daucosterol (16), respectively, on the basis of physicochemical properties and spectral analysis. It were 9 flavonoids among these compounds, which shows that flavonoids occupy a major position in this herb, and it was play a key role in the pharmacological effects.In vitro test, the ethanol extract of Parathelypteris nipponica (Franch. et Sav.) Ching showed strong activities on reducing power, lipid peroxidation, DPPH radicals, superoxide anion radicals, hydroxyl radicals and hydrogen peroxide, and the activity in dose-dependent manner. In vivo study, the extract was evaluated for the hepatoprotective activity using hepatotoxicity induced by CCl4 in rat model and the extract was observed to exhibit hepatoprotective effect as demonstrated by a significant decrease in AST, ALT, ALP, and total bilirubin concentrations, and by preventing liver histopathological changes in rats. Moreover, the extract enhanced the activities of antioxidant enzymes (SOD, CAT, GPx) and diminished the amount of lipid peroxide against the CCl4-induced hepatotoxicity in these animals. In assessing anti-inflammatory activity the carrageenan-induced rat paw oedema test was used, the extract reduced carrageenan-induced rat paw oedema in dose-dependent manner, achieving high degree of anti-inflammatory activity. In addition, the extract reduced the content of PGE2, MDA, NO and NOS in rats inflammatory tissue.In conclusion, the present study revealed that complementary activities of antioxidant activities, anti-hepatotoxic and anti-inflammatory of the ethanolic extract of Parathelypteris nipponica (Franch. et Sav.) Ching, may be related and mediated through its anti-inflammatory and antioxidant activities.Parathelypteriside (PG) is a stilbenoid compound extracted from Parathelypteris glanduligera (kze.) ching that has been widely used in the Orient as folk medicine to treat inflammation and burn scald. Stilbenoid compounds are mostly found in plants and many foods such as red wine, grape, peanut, mulberry. In the past 20 years, these natural stilbenoid compounds have received a great deal of attention owing to their biological properties, including antioxidative, radical scavenging, immunoregulation, anti-inflammatory, and anticancer effects. In previous research, we found PG showed a marked anti-oxidant and radical scavenging activities. Therefore, the neuroprotective effects of PG in PC12 cells exposed to H2O2 and animal models were investigated in this study. We found PG showed a marked cytoprotective effect in PC 12 cells exposed to H2O2, and our results demonstrated that PG increased the activities of antioxidant enzymes and reduced the level of lipid peroxidation in the hippocampus of D-galactose (D-gal)-treated mouse. Furthermore, the activation of CREB implicated in the development LTP might be involved in PG induced neuroprotection. Several studies showed that age-related LTP impairments in hippocampal area CA1 have been also attributed in part to this increase in ROS levels. Therefore, further studies should be done to elucidate their interaction in LTP between ROS and phosphorylation of CREB.In addition, recent advances in the research of antioxidant activities of natural products were reviewed with 93 references.更多还原