頭花香苦草葉部成分之研究及色原酮衍生物之製備

Abstract

本論文包括二個部分： 第一部分 頭花香苦草葉部成分之研究 唇形科（Labiatae）香苦草屬（Hyptis）的植物主要分布在全球熱帶以及亞熱帶地區。本研究以Hyptis rhomboids Mart. Gal.（頭花香苦草）葉部乙醇萃取成分是否具有抑制黃嘌呤氧化酵素的活性為研究方向，利用Sephadex LH-20管柱、矽膠管柱、低壓逆相層析管柱以及半製備高壓液相層析管柱進行分離。自乙醇萃取物中分離並鑑定出十一個化合物，其中包括caffeic acid、kaempferol 3-O-glucoside、rosmarinic acid、rosmarinic acid methyl ester、7-hydroxy-5,8,4'-trimethoxyflavone、genkwanin、nicotiflorin、ethyl caffeoate、nepetoidin A、nepetoidin B、 kaempferol 。活性結果顯示十一個化合物具有微弱的抑制效果，其中具有中等抑制活性的為caffeic acid (IC50 77.0 uM)，nepetoidin B (IC50 14.1 uM)及kampferol (IC50 7.1 uM)則有較佳抑制活性。 第二部分 色原酮衍生物之製備 黃酮類化合物根據文獻以及第一部分的研究結果顯示此類化合物的架構對黃嘌呤氧化酵素有弱抑制活性，接著以電腦分子模擬方式預測色原酮衍生物對於黃嘌呤氧化酵素有結合能力，因此以此系列化合物為合成目標，進行其結構與抑制黃嘌呤氧化酵素活性之探討。此系列化合物先以phloroglucinol為起始物，和丙醯氯在強路易士酸中進行Friedel-Craft反應，接著以不同碳數之酸酐進行酯化反應，再進行醇醛縮合及脫水而得在2號位置上具甲基-戊基取代的15a-e終產物。藥物活性測試結果顯示產物15a-e對於黃嘌呤氧化酵素有微弱的抑制效果。本部分研究結果中，色原酮在2號位置上接有5碳結構具有最好的抑制活性。 關鍵詞： 頭花香苦草、黃嘌呤氧化酵素、色原酮衍生物、Friedel-Craft反應

This dissertation includes two parts: Part 1. Chemical investigation of the leaves of Hyptis rhomboids Mart. Gal. The Hyptis（Labiatae）plants are mainly distributed in the tropical and subtropical regions. This research was aimed to discover the ingredients of the EtOH extract of Hyptis rhomboids (leaves) with the inhibitory activity against xanthine oxidase by chromatographic methods (Sephadex LH-20, silica gel, Lobar RP-18, semipreparative HPLC). Eleven compounds in total were isolated including caffeic acid, kaempferol 3-O-glucoside, rosmarinic acid, rosmarinic acid methyl ester, 7-hydroxy-5,8,4'-trimethoxyflavone, genkwanin, nicotiflorin, ethyl caffeoate, nepetoidin A, nepetoidin B and kaempferol. Bioassay of these isolates against xanthine oxidase revealed that only caffeic acid (IC50 77.0 uM), nepetoidin B (IC50 14.1 uM) and kaempferol (IC50 7.1 uM) possess moderate inhibitory activity.

Part 2. Preparation of chromone derivatives According to reference and the results of part 1 study, flavonoids appears to reveal the inhibitory activity against xanthine oxidase. Since the chromone derivatives were predicted to have moderate inhibitory activity against this enzyme by computer assisted docking study, this second part study was aimed to prepare such compounds and verify whether their activity is correlated well with that predicted. The Friedel-Craft acylation of phloroglucinol with propionyl chloride yielded the key intermediate, flopropione. Esterification of flopropione with various acid anhydride, followed by aldol condensation and dehydration, gave the final products 15a-e with different carbon number on C2 position. The results of the inhibitory activity of 15a-e against xanthine oxidase reveal weak activity. Of them, 15e with a pentyl substitution at the C-2 position shows the best inhibitory activity. Key words：Hyptis rhomboids Mart. Gal., xanthine oxidase, chromone derivatives, Friedel-Craft acylation