金蟬花及蓬萊同蕊草葉部化學成分之研究

Abstract

第一部分：金蟬花之活性成分大量及量少化合物研究 金蟬花為中國傳統中藥材，早在魏晉南北朝時期即有食療方面的記載，由於金蟬花功效多，不遜於冬蟲夏草，因此有多方學者針對金蟬花的功效展開深入的研究，包含生物活性成分、藥理作用和保健功能，且因為對於腎病的改善頗有見效，在臨床應用研究方面也多著重於此。 本實驗室先前利用水萃取金蟬花 (1.2 Kg)，欲仿效民間炮製和食療多以水為主，將不溶物部分使用乙醇萃取後，再使用氯仿、正丁醇、水三種溶劑做極性分割，氯仿可溶層再進一步使用乙腈和己烷進行液相-液相萃取，藉以將大量的脂肪類化合物從乙腈可溶層分離。接下來藉由Sephadex LH-20、silica gel 230-400 mesh、Lobar pre-packed column 和半製備正相高效層析進行分離，得到 14 個化合物。 鑑於前次的分離得知目的化合物 Beauvericin (10) 主要存於乙腈可溶層中，因此本次實驗直接利用氯仿萃取大量金蟬花 (15 Kg)，再利用乙腈和己烷進行液相-液相萃取，接者使用silica gel與Sephadex LH-20分離純化得到約8 g的Beauvericin (10)。另外也藉由此次大量實驗，分離出7個含量較少之化合物，包括三個擬環雙肽、三個環雙肽與一個擬環四肽化合物以及一個由Hiv (2-hydroxyisovalerate)生合成之化合物，分別為 (3S,6R)-bassiatin (19)、(3S,6R)-7-hydroxybassiatin (20)、(3S,6S)-bassiatin (21)、cyclo(L-Pro-L-Pro) (22)、cyclo(L-Pro-L-Val) (23)、cyclo(L-Pro-L-Leu) (24)、cyclo(N-Me-Phe-D-Hiv-N-Me-Phe-D-Hiv) (25)和2,2,4-trimethyl-1,3-pentanediol diisobutyrate (26)；其中除了化合物 19 之外，其餘皆為第一次從金蟬花中分離得到，可見金蟬花成分之多元性。 第二部分：蓬萊同蕊草葉部化學成分研究 苦苣苔科植物蓬萊同蕊草(Rhynchotechum formosanum)為一年生草本植物，是台灣北部低海拔森林中常見的物種之一，目前這個植物之化學成分尚未被任何研究報導，故本實驗室擬進行其葉部之成分研究。 經過萃取和極性分割後，利用CPC、Sephadex LH-20、Lobar-A分離，得到9個化合物，分別為4個核苷酸，uracil (1)、deoxyuridine (2)、thymidine (3)、adenosine、thymine、4-hydroxy-2-methoxypyrimidine (4)；2個長鏈脂肪酸，methyl icosanoate (5)和icosanoic acid (8)；2個固醇類化合物混合物，β-sitosterol (6) 和stigmasterol (7)；以及1個苯丙烯酸化合物，p-coumaric acid (9)。此成分研究可充當爾後化學分類之參考資料。

Part. I. Comprehensive chemical investigation of Isaria cicadae. Isaria cicadae, a traditional Chinese herbal medicine. Its application can be traced back to the Wei and Jin Dynasties. Because its effect is not inferior to Ophiocordyceps sinensis, many intensive researches have been conducted on exploration of its, including bioactive components, pharmacologic effects and health applications. In the clinical use, more attention was raised on its improvement on kidney disease. Smaller scale chemical investigation has been undertaken in our lab, the active constituent, beauvericin (10), was yielded via conventional approach. The ethanol extract was divided into fractions soluble in chloroform, n-butanol, and water. Chloroform-soluble layer was divided into fractions soluble in acetonitrile and hexane. The MeCN-soluble fraction was separated by Sephadex LH-20, silica gel, RP-Lobar column chromatography and semi-prepared HPLC to yield 14 compounds. The current study was aimed to isolate enough amount of beauvericin (10) for animal study. Thus, large scale extraction of I. cicadae (15 Kg) was undertaken. The CHCl3-extract was partitioned between acetonitrile and hexanes to eliminate the interference of lipids (hexanes layer). The MeCN-soluble part was chromatographed on silica gel and Sephadex LH-20 column to yield beauvericin. In this study, additional seven minor compounds were also isolated. Four of them are cyclodepsipeptides, including (3S,6R)-bassiatin (19), (3S,6R)-7-hydroxybassiatin (20), (3S,6S)-bassiatin (21), cyclo(N-Me-Phe-D-Hiv-N-Me-Phe-D-Hiv) (25), and the rest three are cyclodipeptides, i.e. cyclo(L-Pro-L-Pro) (22), cyclo(L-Pro-L-Val) (23), cyclo(L-Pro-L-Leu) (24). The last one is 2,2,4-trimethyl-1,3-pentadiol diisobutyrate (26). Except for compound 19, the other seven compounds are separated for the first time from the I. cicadae. Part. II. Chemical investigation of Rhynchotechum formosanum leaves. Rhynchotechum formosanum Hatus., a herbaceous plant, is one of the most common species in North Taiwan low-altitude forests. Up to the present study, the chemical constituents of this plant have not been reported yet. Therefore, this study was aimed to disclose this part from its leaves. Through CPC, Sephadex LH-20 and Lobar-A column, 11 compounds were isolated from the EtOH extract. They are six nucleosides, uracil (1), deoxyuridine (2), thymidine (3), adenosine, thymine and 4-hydroxy-2-methoxypyrimidine (4); 2 long-chain fatty acids, methyl icosanoate (5) and icosanoic acid (8); two inseparate steroids, mixture of β-sitosterol (6) and stigmasterol (7); and one phenylpropenoic acid compound, p-coumaric acid (9). This study will be useful for chemotaxonomy of the Rhynchotechum plants.