地榆中酚类成分及其Nrf2激动活性研究

Phenolic constituents of Sanguisorba officinalis and their Nrf2 agonistic effect

采用大孔树脂、硅胶、ODS、Sephadex LH-20、半制备HPLC等多种色谱技术从地榆饮片(Sanguisorbae Radix)的95%乙醇提取物中分离纯化得到31个酚类化合物,通过理化性质、波谱数据(MS、NMR)、电子圆二色谱(ECD)等技术确定化合物的结构,分别鉴定为3-methoxyl-2S,3S-epoxyflavanone(1a)、3-methoxyl-2R,3R-epoxyflavanone(1b)、longifoin B(2)、longifoin C(3)、圣草酚(4)、柚皮素(5)、甘草素(6)、5,3?-二羟基-7,4?-二甲氧基二氢黄酮(7)、柚皮素-7-O-β-D-葡萄糖苷(8)、二氢槲皮素(9)、二氢山柰酚(10)、(-)-garbanzol(11)、(2R,3R)-4-methoxyl-distylin(12)、山柰酚(13)、槲皮素(14)、α,4,2′,4′-tetrahydroxydihydrochalcone(15)、phloretin(16)、(+)-儿茶素(17)、ethyl(+)-cyanidan-3-ol-8-carboxylate(18)、phyllocoumarin(19)、methyl 3-methoxy-4,5-dihydroxybenzoate(20)、4,5-dimethoxy-3-hydroxybenzoicacidmethylester(21)、3,4′-di-O-methylellagicacid(22)、3,4,3′-三甲基逆没食子酸(23)、3,3?,4?-Otrimethylellagic acid-4-O-β-D-xyloside(24)、(3R)-thunberginol C(25)、resveratrol(26)、1-hydroxypinoresinol(27)、(7S,8S)-3-methoxy-3′,7-epoxy-8,4′-oxyneoligna-4,9,9′-triol(28)、大黄素-8-O-β-D-葡萄糖苷(29)、phloracetophenone(30)和4-(4′-hydroxyphenyl)-butan-2-one(31)。其中化合物1a和1b为一对新的2,3-环氧黄酮对映异构体,化合物2和3为一对新的差向异构体,化合物4、5、6、9、10、13、16和26为首次从该植物中分离得到,化合物7、8、27、30和31为首次从该属植物中分离得到,化合物11、12、15、18、19、25、28和29为首次从蔷薇科植物中分离得到。通过双荧光素酶报告基因实验在293T细胞中测定化合物1~24对核因子-红细胞2相关因子2(nuclear factor erythroid 2-related factor 2,Nrf2)的激动活性,结果表明,化合物4、6~10、12、14、17、19、20和22~24对Nrf2在25μmol·L-1下表现出显著的促转录活性,为该类化合物的抗氧化活性研究提供参考。

Thirty-one phenolic constituents were isolated and purified from the 95%ethanol extract of Sanguisorbae Radix by using various chromatographic techniques,including macroporous resin,silica gel,ODS,Sephadex LH-20 and semi-preparative HPLC.Their structures were elucidated by physicochemical properties,spectroscopic data(MS and NMR)and electronic circular dichroism(ECD)spectra,and identified as 3-methoxyl-2S,3Sepoxyflavanone(1a),3-methoxyl-2R,3R-epoxyflavanone(1b),longifoin B(2),longifoin C(3),eriodictyol(4),naringenin(5),liquiritigenin(6),5,3ʹ-dihydroxy-7,4ʹ-dimethoxyflavanone(7),naringenin-7-O-β-D-glucopyranoside(8),dihydroquercetin(9),dihydrokaempferol(10),(−)-garbanzol(11),(2R,3R)-4-methoxyl-distylin(12),kaempferol(13),quercetin(14),α,4,2′,4′-tetrahydroxydihydrochalcone(15),phloretin(16),(+)-catechin(17),ethyl(+)-cyanidan-3-ol-8-carboxylate(18),phyllocoumarin(19),methyl 3-methoxy-4,5-dihydroxybenzoate(20),4,5-dimethoxy-3-hydroxybenzoic acid methyl ester(21),3,4′-di-O-methylellagic acid(22),3,4,3′-O-trimethylellagic acid(23),3,3ʹ,4ʹ-O-trimethylellagic acid-4-O-β-D-xyloside(24),(3R)-thunberginol C(25),resveratrol(26),1-hydroxypinoresinol(27),(7S,8S)-3-methoxy-3′,7-epoxy-8,4′-oxyneoligna-4,9,9′-triol(28),emodin-8-O-β-Dglucoside(29),phloracetophenone(30)and 4-(4′-hydroxyphenyl)-butan-2-one(31).Among them,compound 1a and 1b is a pair of new flavonoid enantiomers,compounds 2 and 3 are a pair of new epimers,while compounds 4,5,6,9,10,13,16 and 26 were obtained from S.officinalis for the first time,compounds 7,8,27,30 and 31 were isolated for the first time from the S.officinalis genus,and compounds 11,12,15,18,19,25,28 and 29 were isolated for the first time from the Rosaceae.The antioxidant activities of compounds 1−24 were evaluated by activating the Nrf2 transcriptional pathway,which were measured by the dual-luciferase reporter gene assay in 293T cells.Compounds 4,6−10,12,14,17,19,20 and 22−24 showed significant Nrf2 agonistic effect compared with the control group at 25μmol·L-1,which provided reference for the research of their antioxidant activity.