飛揚草地上部暨野牡丹莖部之成分研究

Abstract

中文摘要 本論文分兩部分，第一部分為飛揚草地上部成分之研究，飛揚草為‎大戟科(Euphorbiaceae) 地錦草屬(Chamaesyce) 植物，是一種生長在台灣的藥用植物，除了具有抗菌，止瀉和利尿作用外，還抗焦慮，鎮痛，鎮靜，解熱和抗發炎等。此外，亞洲其他地區飛揚草之成分在過去已被研究，故本研究擬針對台灣飛揚草地上部之較高極性部分進行探討。 本植物地上部之乙醇萃取物，經極性分割得到乙酸乙酯可溶部分、正丁醇可溶部分和水可溶部分。正丁醇可溶部分經由凝膠管柱層析和逆相低壓管柱層析分離後，共得到八個化合物，包括三個黃酮醇糖苷：myricetin 3-O-α-L-rhamnoside (1)、quercetin 3-O-α-L-rhamnoside (2)、quercetin 3-O-β-D-glucuronide (4) ，三個苯丙烯酸類: chlorogenic acid (3) 、caffeic acid (5) 和 ferulic acid (8), 及 shikimic acid (6) 和n-docosanoic acid (7)。化合物的結構藉由分析核磁共振譜和電灑游離質譜而確認。其中化合物 (1、2及4) 被報導具抗發炎、抗氧化、抗瘧疾與止瀉等作用。 第二部分為野牡丹莖部成分之研究，野牡丹為野牡丹科(Melastomataceae) 野牡丹屬(Melastoma) 的植物，在台灣用於消除瘀滯，與毒素；外傷及細菌性痢疾等疾病。研究證實了野牡丹除對單胺氧化酶B有抑制作用外，還具有抗高血壓和抗菌作用。其葉子的化學成分已被研究，然而莖部之成分尚未被探討；故本研究擬針對野牡丹莖部之成分進行探討。 本植物莖部之乙醇萃取物，經極性分割得到二氯甲烷、乙酸乙酯、正丁醇和水可溶部分。正丁醇可溶部分經由凝膠管柱層析，逆相低壓管柱層析和矽膠柱層析分離後，共得到七個化合物，包括一個黃酮醇糖：quercetin 3-O-β-D-glucoside (9)，一個黃酮類(2R, 3S)-catechin (10)，和三個單寧類casuarinin (11)，pendunculagin (12) 和castalagin (13) 及 shikimic acid (14) 和γ-aminobutyric acid (15)。化合物的結構藉由解析核磁共振譜和電灑游離質譜而確認。 本研究為第一個探討野牡丹莖部較高極性之成分，實驗結果證明melastoma屬植物富含黃酮類和單寧類化合物，其中化合物 (11、12和13) 被報導具有抗發炎、抗氧化、抗病毒和抗癌等活性。化合物14 更是被用於合成oseltamivir 的起始物，其化合物在正丁醇可溶部分含量較高(正丁醇層的7.47%)，故以HPLC分析及建立其化合物在水層之含量(ca. 0.72%, w/w)。

Abstract This thesis contains two parts. Part I. Chemical constituents from the aerial parts of Euphorbia hirta L. Euphorbia hirta L. (Euphorbiaceae) is a medicinal herb that grows throughout Taiwan. This folk medicine has been used to treat anxiety, pain and inflammation diseases, besides its antibacterial, antidiarrheal and diuretic effects. Although chemical constituents of E. hirta from other areas have been reported, those distributed in Taiwan have not been explored yet. This study was dedicated to find out whether geographic factors will influence the content of its chemical constituents. The n-BuOH soluble fraction of the EtOH extract of Euphorbia hirta was repeatedly chromatographed on Sephadex LH-20 and Lobar Rp-18 columns, and semi-preparative HPLC. These efforts led to the isolation of eight compounds, including three flavonol glycosides, i.e., myricetin 3-O-α-L-rhamnoside (1), quercetin 3-O-α-L-rhamnoside (2), and quercetin 3-O-β-D-glucuronide (4), three phenylpropanoids, i.e., chlorogenic acid (3), caffeic acid (5) and ferulic acid (8), and two others, i.e., shikimic acid (6), and n-docosanoic acid (7). Their structures were elucidated on the basis of NMR spectroscopic analysis and ESI-MS data. Flavonol glycosides isolated in this study, compounds (1, 2 and 4), has been reported to possess anti-oxidant, anti-malarial, anti-diarrheal, and anti-inflammatory activities. Part.II Chemical constituents from the stem of Melastoma candidum D. Don Melastoma candidum D. Don (Melastomataceae) has been used as folk medicine to detoxify the serum, treat injuries, diarrhea, leucorrhoea, and dysentery. It has been demonstrated to possess antihypertensive, antibacterial, and anti-monoamine oxidase B activities. Chemical constituents of its leaves have been reported, but not those of its stem. Thus, this research focused on chemical investigation of the stem part, especially those of higher polarity. The n-BuOH soluble fraction of the EtOH extract of its stem was repeatedly chromatographed on Sephadex LH-20, silica gel and Lobar Rp-18 columns, and semi-preparative HPLC. These efforts led to the isolation of seven compounds, including a flavonol glycoside, i.e., quercetin 3-O-β-D-glucoside (9), a flavanol, i.e., (2R, 3S)-catechin (10), and three ellagitannin, i.e., casuarinin (11), pedunculagin (12), and castalagin (13), and two others, i.e., shikimic acid (14) and γ-aminobutyric acid (15). Their structures were elucidated on the basis of NMR spectroscopic analysis and ESI-MS data. Compounds 11, 12 and 13 was reported to possess anti-oxidant, anti-viral, anti-inflammatory, and anti-cancer effects. Moreover, compound 14 is used as starting material in the synthesis of oseltamivir, because of its high content in the BuOH soluble layer (7.47% of the BuOH soluble layer), the content of 14 in H2O soluble layer was also explored by HPLC analysis, (ca. 0.72%, w/w, H2O soluble layer).