蓝花参甲醇提取物保肝作用及化学成分

Hepatoprotective activity and chemical constituents of the aqueous methanol extract of Wahlenbergia marginata

关键词:  蓝花参, 甲醇提取物, 急性肝损伤, 保肝活性, 化学成分, Wahlenoside D

Key words:  Wahlenbergia marginata, aqueous methanol extract, acute liver injury, hepatoprotective activity, chemical constituents, Wahlenoside D

摘要:

蓝花参为桔梗科蓝花参属植物蓝花参的根或全草,具有益气健脾、祛痰止咳等功效。临床实践中蓝花参被用于肝病治疗,效果较好,但目前未见其保肝活性的相关报道。该研究采用80%甲醇冷浸提取蓝花参全草,提取液浓缩后经冷冻干燥得到蓝花参提取物。对以刀豆蛋白A造模的急性肝损伤小鼠分别给予联苯双酯及不同剂量的蓝花参提取物灌胃,测定血清中 ALT/AST 活性,HE 染色观察肝组织病理形态学的改变。结果表明:蓝花参提取物可以降低急性肝损伤小鼠血清中 ALT/AST 水平,且对减轻肝脏病理组织损伤有积极作用。进一步利用多种现代色谱学方法从蓝花参甲醇提取物的水溶性部位分离单体化合物,经过波谱学分析(MS、1D-NMR、2D-NMR等)并结合文献数据对比,鉴定了5个化合物的结构。其中化合物1为新化合物,命名为Wahlenoside D。其它4个已知化合物分别为demethyl syringin(2)、3,5-dihydroxyphenethyl alcohol-3-O-β-D-glucopyranoside(3)、芦丁(4)、异牡荆素(5),其中化合物3-5为首次从该植物中分离得到。该研究结果为蓝花参的保肝作用提供了科学依据,同时促进了蓝花参药材资源的进一步开发与利用。

Abstract:

Lanhuashen is the roots or herbs of Wahlenbergia marginata(Campanulaceae). This medicinal plant is useful in clinic for the treatment of heptatis, but there was no report about its hepatoprotective activity. The objective of this study is to explore the active components of W. marginata and to investigate the effects of its aqueous methanol extract against acute liver injury of mice. The whole plant of W. marginata was extracted by aqueous methanol(80%)at room temperature, and the concentrate was freeze-dried to afford a solid extract. An acute liver injury model of mice induced by Concanavalin A was established. The model mice were given bifendatatum and the extract of W. marginata respectively. The ALT/AST in blood serum were determined,and the morphology changes of hepatic tissue were observed by HE. The results showed that the extract of W. marginata reduced the activity of ALT/AST in blood serum of acute liver injury of mice, and relieved the damage of liver pathological tissue. In order to find out the active components, the water-soluble part of the extract was studied primarily, and five compounds were obtained by repeated column chromatography over silica gel, RP-C₁₈, MCI and Sephadex LH-20. Their structures were elucidated on the basis of extensive spectral analysis including 1D and 2D NMR spectrum, as well as comparison with literature data. Compound 1 was elucidated to be a new natural product and named wahlenoside D. The known compounds were identified as demethyl syringin(2), 3,5-dihydroxyphenethyl alcohol 3-O-β-D-glucopyranoside(3),rutin(4)and isovitexin(5), in which, compounds 3-5 were isolated from this plant for the first time. This work provides a scientific evidence for the hepatoprotective activity of W. marginata, and the mechanism would be studied further in future.