薏仁麩皮乙醇萃取物正己烷區分層之成分分析與純化鑑定

Abstract

薏苡 (adlay) 為禾本科一年生草本植物，學名 Coix lachrymal-jobi L. var. ma-yuen Stapf。根據本草綱目記載薏苡籽實薏仁為藥食兼備的食材，於中國與日本自古就在傳統醫學與民間療法中被廣泛的使用。近年學者也陸續發表薏仁萃取物、薏仁油脂、薏仁加工食品均具有抑制癌細胞生長、轉移和抗腫瘤之功效，且帶有麩皮的薏仁較精白薏仁效果為佳。中國大陸學者使用超臨界二氧化碳萃取薏苡籽實所得的油狀萃取物，以針劑 (康萊特注射劑) 方式施打於實驗動物後發現，可有效抑制腫瘤生長並延長其壽命，具有抗腫瘤與抗惡質化之效用，該學者更進一步發現，此油狀萃取物之主要成分為三酸甘油酯，推測薏仁中之有效抗癌成分可能來自於富含油脂的麩皮。薏仁麩皮油脂含量高達25% (Wt%)，但除少數文獻外，鮮少研究其組成分、物理化學特性以及生理功效，因此本實驗以薏仁麩皮萃取物之低極性區分層 (薏仁麩皮乙醇萃取物正己烷區分層) 為材料，以氣相層析質譜儀分析進行成分之定性分析並使用管柱層析以分離純化合物。 氣相層析質譜分析共可得32個化合物，7個植物固醇(phytosterol)；3個單酸甘油酯 (monoglyceride)；7個脂肪酸與其酯化物 (free fatty acid & ester)；1個醯胺 (amide)；1個醇類 (alcohol)；1烯類 (alkene)；7個醛類 (aldehyde)；5個其他類化合物 (others)。另外經分離純化鑑定所得之化合物為3-O-feruloyl-5beta-sitostan-3-ol、stigmasterol、beta-sitosterol與1,2-、1,3-diglyceride混合物。以文獻搜索探討薏仁麩皮乙醇萃取物正己烷區分層之機能性，推測植物固醇、單酸甘油酯以及脂肪酸醯胺為其可能之活性成分。

Adlay (Coix lachrymal-jobi L. var. ma-yuen Stapf) is an one year grass crop that has long been used as traditional Chinese medicine and a nourishing food. Recent studies have shown the effects of adlay are benefit to treat tumor and inflammation. Furthermore, the dehulled adlay has higher activity than polished adlay, especially in the adlay bran. In China, adlay seed was extracted with supercritical CO2 to get the oily extract that is formulated into an emulsion for injection (Kanglaite injection (KLT)). KLT injection showed the antitumor proliferation and life extension in animal tumor models. It demonstrated the potential for antitumor and anti-cachexia activity of the low polarity fraction of adlay seed. The adlay bran contain about 25% crude fat (Wt%), however, there are less research results shown the characteristic of the low polarity fraction of adlay seed or bran. Therefore the aim of this study is to analyze the composition in the n-hexane fraction of adlay bran ethanolic extract by gas chromatography / mass spectrometer (GC / MS).And column chromatography were employed to afford pure compounds. The study results revealed that there are 32 components identified in the GC / MS analysis, including 7 phytosterol; 3 monoglyceride; 7 free fatty acid & its ester; 1 amide; 1 alcohol; 1 alkene; 7 aldehyde; 5 other species of components. In addition, 3 pure compounds are isolated and identified: stigmasterol, beta-sitosterol, 3-O-feruloyl-5beta-sitostan-3-ol, and 1, 2-, 1, 3-diglyceride mixture. According to the literature review, the possible active components in the n-hexane fraction of adlay bran ethanolic extractare are phytosterol, monoglyceride, and fatty acid amide.