白益母草中酚苷类化合物的分离鉴定及其体外抗氧化活性评价

目的 分离鉴定白益母草中抗氧化活性成分。方法 采用常规回流提取法先以二氯甲烷对白益母草脱脂，然后药渣用乙酸乙酯提取得到其提取物。乙酸乙酯提取物利用硅胶、葡聚糖凝胶柱色谱及HPLC进行分离，分离得到化合物经波谱学数据分析，确定其结构式。同时，利用1，1-二苯基-2-三硝基苯肼（DPPH）法测定分离得到化合物的抗氧化活性。结果 从白益母草乙酸乙酯提取物中分离得到4个酚苷类化合物，分别为毛蕊花苷（1），5，7，4'-三羟基黄酮-7-O-（6″-O-[E]-香豆酰基）-β-葡萄糖苷（2），5，7，4'-三羟基黄酮-7-O-（6″-O-[E]-咖啡酰基）-β-葡萄糖苷（3）和5，7，4'-三羟基黄酮-7-O-（6″-O-[E]-二香豆酰基）-β-葡萄糖苷（4）。化合物1~4表现出较好的抗氧化活性，其EC₅₀平均值分别为（19.5±1.81），（26.2±3.4），（22.9±2.7），（24.4±3.1）。结论 化合物1~4均为首次从该药材中分离得到，可作为天然抗氧化剂。

Isolation and Identification of Phenolic Glycosides from Panzeria Alashanica Kupr. and Evaluation of Their Antioxidant Activities in Vitro

OBJECTIVE To isolate and identify the antioxidant components from Panzeria alashanica Kupr.. METHODS Panzeria alashanica Kupr. was degrease by dichloromethane with reflux, then the residue was extracted with ethyl acetate to obtain its extract. The ethyl acetate extract was separated by silica gel, Sephadex gel column chromatography and HPLC. The structures of the compounds were determined by spectral data analysis. At the same time, the antioxidant activity of the compounds was determined by DPPH method. RESULTS Four phenolic glycosides were isolated from the ethyl acetate extract of Panzeria alashanica Kupr., namely verbascoside(1), 5,7,4'-trihydroxyflavone-7-O-(6″-O-[E]-coumaroyl)-β-glucopyranoside(2), 5,7,4'-trihydroxyflavone-7-O-(6″-O-[E]-caffeyl)-β-glucopyranoside(3) and 5,7,4'-trihydroxyflavone-7-O-(2″,6″-O-[E]- dicoumaroyl)-β-glucopyranoside(4). Compounds 1-4 demonstrated good antioxidant activity. The average values of EC₅₀ were (19.5±1.8), (26.2±3.4), (22.9±2.7), (24.4±3.1)μg·mL^-1 for compounds 1-4 respectively. CONCLUSION Compounds 1-4 are isolated for the first time from the medicinal materials and can be used as natural antioxidants.