Kayano Shin-Ichi, Kikuzaki Hiroe, Fukutsuka Naoko, Mitani Takahiko, Nakatani Nobuji
Research and Development Institute, MIKI Corporation, 12-4 Naruohama 3, Nishinomiya 663-8142, Japan.
J Agric Food Chem. 2002 Jun 19;50(13):3708-12. doi: 10.1021/jf0200164.
Ethanol extract of prune was separated into hexane-soluble and H(2)O-soluble fractions, and the H(2)O-soluble fraction was further separated into a methanol (MeOH) eluate and an H(2)O eluate by Diaion HP-20 column chromatography. The MeOH eluate exhibited the strongest antioxidant activity among the separated fractions evaluated by oxygen radical absorbance capacity (ORAC). Further purification of the MeOH eluate led to isolation of a novel compound, 4-amino-4-carboxychroman-2-one, together with four known compounds (p-coumaric acid, vanillic acid beta-glucoside, protocatechuic acid, and caffeic acid), structures of which were identified by NMR and MS analyses. The ORAC values of these isolated compounds showed 0.15-1.43 units (micromol of Trolox equiv)/micromol, and the new compound showed a remarkable synergistic effect on caffeoylquinic acid isomers. The antioxidant activity of the MeOH eluate was highly dependent on the major prune components, caffeoylquinic acid isomers, with a contribution from the new synergist.
李子乙醇提取物被分离为己烷可溶部分和水可溶部分，水可溶部分通过Diaion HP - 20柱色谱进一步分离为甲醇（MeOH）洗脱液和水洗脱液。通过氧自由基吸收能力（ORAC）评估，甲醇洗脱液在分离出的部分中表现出最强的抗氧化活性。对甲醇洗脱液进一步纯化，得到一种新化合物4 - 氨基 - 4 - 羧基色满 - 2 - 酮，以及四种已知化合物（对香豆酸、香草酸β - 葡萄糖苷、原儿茶酸和咖啡酸），其结构通过核磁共振（NMR）和质谱（MS）分析确定。这些分离出的化合物的ORAC值显示为0.15 - 1.43单位（微摩尔Trolox当量）/微摩尔，新化合物对咖啡酰奎尼酸异构体表现出显著的协同效应。甲醇洗脱液的抗氧化活性高度依赖于李子的主要成分咖啡酰奎尼酸异构体，并受到新协同剂的影响。
