艾草揮發性物質與抗氧化成分之初探

Abstract

艾草(Artemisia argyi Levl. et Vant.)具濃烈香氣，為常用之中國傳統中藥材，但民間使用之艾草種類繁多，相關的分類標準及品種鑑定資料較少，而環境因子對臺灣艾草的生長及功能性成分的影響，相關研究亦少。本試驗比較五種臺灣常見的艾草種類，由葉部型態特徵分類，並以GC-MS分析其揮發性化合物，初步建立各種類之化學指紋圖譜，並探討環境溫度對艾草生長、揮發性成分及DPPH自由基清除能力的影響。 五種供試艾草分別為寬葉艾、鴨掌艾、五月艾、野艾及艾，調查葉片形態之結果，五種艾草的葉片能以羽狀裂片的狀況、每側裂片數，裂片形狀，葉緣形狀及真假托葉作為鑑別艾草種類之標準。利用固相微萃取技術 (solid phase microextraction, SPME) 及氣相層技術析質譜儀(gas chromatography-mass spectrometry, GC-MS)分析五種艾草鮮葉揮發性有機化合物，共獲得22種可辨認之有機化合物，其中主要共同可測得之有機化合物為1,8-Cineole、α-Pinene、Thujoner、Caryophyllene及Myrcene，而以化合物類型做雷達圖分佈，寬葉艾之揮發性物質明顯與其他4者不同。 不同溫度處理對野艾生長量之影響，分別是以日夜溫30/25℃、25/20℃、 20/15℃及15/13℃進行。野艾在日夜溫30/25℃處理下株高最高。在日夜溫25/20℃生長的野艾有最多的葉片數。揮發性有機化合物方面，在日夜溫30/25℃溫度環境下，其α- Pinene 及Myrcene的所佔比例為各處理間最高，分別為54.69%及7.18%；在日夜溫15/13℃溫度處理下，β-Pinene、β-Ocimene相對容易生成，分別佔總化合物面積的21.54%及7.38%。功效性成分方面，野艾在日夜溫20/15℃溫度環境下，有最高的總酚含量33.49 mg/g，但在不同環境溫度下皆有75.47-77.96% DPPH自由基清除率。 整合艾草葉部型態特徵及化學指紋圖譜，可成為艾草之分類特徵。溫度處理對野艾生長量及酚類含量有明顯的影響，但不影響DPPH自由基清除率。

Artemisia argyi Levl. Et Vant. with strong aroma is a common Chinese traditional medicine. However, there are plenty similar species and the index of taxonomy is not clear. We compared 5 species of wormwood in Taiwan with the leaf morphology and volatile compounds by GC/MS analysis. With the results of volatiles compounds, we established the preliminary fingerprints for these 5 vareities. We also discussed the total phenolic contents and DPPH radical scavenging capacity of wormwood. The impact of temperature on volatile and its functional efficacy was to be evaluated. We investigated the leaf characters of 5 Artemisia argyi varieties and used solid phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS) to analyze the fresh leaf volatile constituents. The lobes of leaf, the leaf margin and the stipule were the major characteristics to distinguish 5 wormwood varieties. There were 27 volatile compounds identified. The main aroma components were 1,8-cineole, α-pinene, thujoner, caryophyllene and myrcene. Using the radar diagram for the distribution in kinds of volatile organic compound, the volatiles in wide-leaf wormwood showed the most different from others. The effect of the growth temperature on wild wormwood were investigated. The 4 temperate sets were day/night 30/25℃, 25/20℃, 20/15℃and 15/13℃, respectively. The wild wormwood showed the highest natural height in 30/25℃, and there were most leaf numbers of the wild wormwood in 25/20℃environment. The most relative contents of aroma components in fresh leaves were α-pinene (54.69%) and myrcene (7.18%) in 30/25℃environmen. In 15/13℃, the wild wormwood had more β-ocimene and β-pinene, and their relative contents were 7.38% and 21.54% respectively. The wild wormwood growing in 30/25℃ had 33.49 mg/g phenolic compounds content at 30/25℃environment , and it was the highest content in all treatments. The DPPH radical scavenging activities in all reattments were 75.47%-77.96%, and ther was no significant difference. Integrating the data of the leaf characters and chemical fingerprints of Artemisia argyi, it can be an useful classification tool. Growth temperatures had significant effects on the growth and phenol content of wild wormwood, but not on the DPPH radical scavenging capacity.