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目的分离纯化栝楼Trichosanthes kirilowii雄株茎叶中黄酮类化合物,并探究其清除1,1-二苯基-2-苦基肼(DPPH)自由基能力的构效关系。方法利用聚酰胺树脂柱、高速逆流色谱及高效液相色谱等手段对栝楼雄株茎叶黄酮类成分进行分离纯化,根据化合物光谱数据鉴定其结构;采用DPPH法测定7个黄酮单体的体外抗氧化活性。结果从栝楼雄株茎叶中分离得到7种黄酮类化合物,分别鉴定为木犀草素(1)、金圣草黄素(2)、木犀草素-7-O-β-D-葡萄糖苷(3)、柯伊利素-7-O-β-D-葡萄糖苷(4)、芹菜素-7-O-β-D-葡萄糖苷(5)、香叶木素-7-O-β-D-葡萄糖苷(6)、槲皮素-3-O-β-D-葡萄糖苷(7)。7种黄酮类化合物清除DPPH自由基能力(IC50)依次为1>3>7>2>4>6>5。结论化合物1、2、6和7为首次从栝楼茎叶中分离得到。7种黄酮类化合物均能有效清除DPPH自由基,化合物1、3、7的DPPH自由基清除能力明显强于其他4种黄酮,比较其结构发现,前3者均存在B环3′,4′邻二羟基;化合物4和6的DPPH清除活性明显弱于化合物3,而在结构上前两者较化合物3存在3′位或4′位羟基甲基化;化合物3清除DPPH自由基能力弱于化合物1,但在结构上仅在A环7位存在糖基取代,考虑糖基化增加了前者的化学位阻。
OBJECTIVE To isolate and purify the flavonoids from the stems and leaves of male Trichosanthes kirilowii from Trichosanthes kirilowii and to explore the structure-activity relationship of the ability to scavenge 1,1-diphenyl-2-picrylhydrazine (DPPH) free radicals. Methods The flavonoids from plant stems and leaves of Ziziphus mariquese were separated and purified by polyamide resin column, high-speed countercurrent chromatography and high performance liquid chromatography (HPLC). The structures of the flavonoids were identified according to the spectral data of the compounds. Antioxidant activity. Results Seven kinds of flavonoids were isolated from male plant stems and leaves of Chrysanthemum morifolium and identified as luteolin (1), rutin (2), luteolin-7-O-β-D-glucoside (4), apigenin-7-O-β-D-glucoside (5), geraniol -7-O-β-D - glucoside (6), quercetin -3-O-β-D-glucoside (7). Seven kinds of flavonoids scavenging DPPH free radical capacity (IC50) were 1> 3> 7> 2> 4> 6> 5. Conclusion Compounds 1, 2, 6 and 7 were isolated from the stems and leaves of Chrysanthemum morifolium for the first time. 7 kinds of flavonoids can effectively scavenge DPPH free radicals. The DPPH radical scavenging ability of compounds 1, 3 and 7 is obviously stronger than that of the other 4 flavonoids. Comparing the structure, DPPH scavenging activity of compounds 4 and 6 was weaker than that of compound 3, while the former two compounds were 3 ’or 4’ hydroxyl methylation in comparison with compound 3; and the DPPH scavenging ability of compound 3 was weaker than that of compound 3 Compound 1, but with glycosyl substitution only structurally at position 7 of ring A, considering that glycosylation increases the chemical steric hindrance of the former.