桑椹果及洛神葵中花青素之分離與純化

Abstract

本研究從新鮮桑椹果實及乾燥的洛神葵花萼粉末中萃取分離出花青素，並進行抗氧化活性測定。將樣品之甲醇粗萃取物經由快速液相層析儀(Flash chromatograph)作初步分離，以25%甲醇(含1%醋酸)及50%甲醇(含1%醋酸)溶離，再利用HPLC作定性定量分析，進一步以HPLC-PDA、LC/MS、NMR鑑定花青素之結構。鑑定結果顯示，桑椹中含有cyanidin 3-glucoside、cyanidin-3-rutinoside及pelargonidin 3- rutinoside，其中cyanidin 3-glucoside、cyanidin-3-rutinoside含量為237.0±14.26mg (100g FW)-1、158.8±8.80mg (100g FW)-1，因此每100克新鮮桑椹果實可分離出395.8±14.26mg，而乾燥洛神葵花萼粉末中，可得到花青素8.7±0.05mg/g Dry Wt.。抗氧化活性測定方面，以FRAP(Ferric Reducing Ability of Plasma)及抑制H2O2誘發老鼠腦漿脂質過氧化(Lipid peroxidation)等方法，評估甲醇粗萃取物及快速層析儀分離出的色層之抗氧化活性。在抑制脂質過氧化表現上，F1-25及F1-50的ID50(μg)為2.0、1.7，相較於Trolox的ID50 4.3μg，抑制效果相當顯著。

This work focuses on the separation, purification and identification of anthocyanins, mulberry (Morus spp.) and roselle (Hibiscus Sabdariffa L.) grown in Taiwan. Their antioxidative activities were also determined and compared. Extracts from the fruit samples were fractionated by flash chromatography using 25 and 50% methanol (with 1% acetic acid each). Qualitatative and quantitative analysis of fractionated products were carried out by using HPLC and identified the structures by employing HPLC-PDA, LC-Mass as well as NMR. The results showed that the mulberry contained cyanidin 3-glucoside (237.0±14.26mg/100g FW), cyanidin 3-rutinoside (158.8±8.80mg/100g FW) and a trace amount of plargonidin 3-rutinoside. 8.7±0.05mg/g DW of anthocyanins were isolated form the dried roselle. The method of Ferric Reducing Ability of Plasma (FRAP) and the inhibition of H2O2-induced lipid peroxidation in the rat brain homogenates were employed to assess their antioxidant activities. The ID 50 values of F1-25 and F1-50 were 2.0 and 1.7 μg, respectively. Comparing to the Trolox (ID 50 4.3μg), the inhibition capability of lipid peroxidation of mulberry was remarkable