台灣產蘆薈花主要抗氧化成分之分離與鑑定

Isolation and identification of the major antioxidant compounds in the flower of Aloe vera. cultivated in Taiwan.

李姿燕(Zih-Yang Li)

指導教授 ： 林昭田 ； 胡超群

中山醫學大學/健康管理學院/應用化學系碩士班/碩士(2018年)

摘要

蘆薈為Asphodeloideae科，蘆薈屬(Aloe)的植物，原產於地中海，現多分佈於非洲，四季皆有，為熱帶地區的經濟作物，其功用多用於葉肉的食用、藥用、保濕等功用，其中商用價值最佳的品種為費拉蘆薈(Aloe Barbadensis，又名Aloe Vera)。本研究目的找出蘆薈花的主要抗氧化成分。將不同年份的蘆薈花進行70℃熱風乾燥，並以不同溶劑萃取找出最佳的萃取條件，並且依次進行液液分離、矽膠管柱分離、LH-20管柱分離、HPLC分離，所得的區分物均進行抗氧化含量測定。在不同溶劑的萃取中乙醇萃出物抗氧化能力最佳，其中2015年蘆薈花抗氧化能力最佳，將乙醇粗萃物以四種溶劑進行液液分離其乙酸乙酯區分物氧化能力最佳;再經矽膠管柱分離純化得到16個區分，以第14~15區分物的抗氧化活性最佳，先將第14個區分物以HPLC進行分離純化，得到四個區分物，以第三個區分物抗氧化能力最佳，我們在第三的區分物中找到了抗氧化成分，並且以MASS以及NMR進行結構鑑定，確認蘆薈花主要抗氧化成分為sinapic acid，次要抗氧化成分為p-coumaric acid。
第15的區分物再進行sephadex LH-20管柱分離得到了五個次區分物，以第四個次區分物抗氧化成分以及能力皆為最好，再以HPLC分離純化得到四個樣品以第三個樣品中的抗氧化能力最好，並且以MASS以及NMR進行結構鑑定，確認蘆薈花的主要抗氧化成分為p-anisic acid。
定量後，烘乾蘆薈花sinapc含量為7.41 (mg/g of dry weight);p-anisic acid 的含量為5.41(mg/g of dry weight);p-coumaric acid 的含量為11.14(mg/g of dry weight)。

關鍵字

蘆薈花

並列摘要

Aloe (aloe vera) is a plant belonging to the Ashodeloidear family, Aloe genus which is native to the Mediterranean Sea and also found in many regions of Africa. It is a tropical economic crop and its most useful part for edible, medicine and moisturizing application is the leaf gel. Aloe barbadensis is the commercially valuable species among different kinds of aloe. In this study, our aim is to isolate and evaluate the major components in aloe guided by the antioxidant assays. The aloe flower harvested at different years were dried at 70 ℃ and then extracted by various solvent (hexane, butanol,ethyl acetate, water). In these extracts, the ethanolic extract had a notable level of polyphenols and prominent antioxidant capacity than the others.
The ethanolic extract was further separated through liquid-liquid partition, silica gel column chromatography and LH-20 column chromatography. The amount of phenolic acid and flavonoid of each fraction at every stage were determined and their antioxidant activities were also assayed with Trolox equivalent antioxidant capacity (TEAC), scavenging ability of 2,2-diphenyl-2-picryhydrazyl hydrate (DPPH) radical and inhibition of Cu2+-induced oxidation of human low density lipoprotein (LDL).
Sixteen fractions were obtain after the EA partition was subjected to the silica gel column chromatography which showed the highest levels of polyphenol as well as strongest antioxidant capacities than other partitions.
Four areas from fraction 14 by HPLC were obtained and there were two compounds in that sinapic acid and p-coumaric acid, being the major
antioxidant components in the aloe flower. The LH-20 column chromatography further separated fraction 15 into five sub-fractions that the fourth sub-fraction had the best antioxidant activities and highest levels of polyphenol than the other four sub-fractions , which the major compound , p-anisic acid , was isolated and identified by MASS and NMR.
After the separation , the content of major antioxidant compounds identified in the aloe flower were determine : sinapic acid 7.41 (mg / g of dry weight ) , p-anisic acid 5.41 (mg / g of dry weight ) and p-coumaric acid 11.14 (mg / g of dry weight ), respectively.

並列關鍵字

aloe flower

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