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从落叶松[Larix gmelini (Rupr.)Rupr.]树皮中分离、鉴定了三种黄烷-3-醇,即(-)表阿夫儿茶素,(+)儿茶素和(-)表儿茶素。以乙酰衍生物形式分离出四种二聚黄烷-3-醇(二聚原花青定)B1—B4,并通过与标样薄层共层析及其核磁共振氢谱进行了鉴定。对可溶于甲醇的多聚黄烷-3-醇(多聚原花青定)用甲苯-α-硫醚和醋酸进行了化学分解。根据分解产物确定, 落叶松树皮含有分别以(+)儿茶素和(-)表儿茶素为终端单元之多聚黄烷-3-醇,其延伸单元亦由2,3反式和2,3-顺式3,5,7,3′,4′黄烷五醇所组成。用高效液相色谱定量测定了上述化学分解产物,并在此基础上得出该多聚黄烷-3-醇之平均聚合度为6-7,相应数均分子量为1700—2000。
Three flavan-3-ols were isolated and identified from the bark of Larch (Larix gmelini (Rupr.) Rupr.), namely (-) epiavitacin, (+) catechin and (-) Epicatechin. The four dimeric flavan-3-ols (dimer procyanidin) B1 to B4 were isolated in the form of acetylated derivatives and identified by com- plemental thin layer chromatography and nuclear magnetic resonance spectroscopy. Methanol-soluble polyflavan-3-ol (poly-procyanidin) was chemically decomposed with toluene-α-thioether and acetic acid. According to the decomposition products, the larch bark contains polyflavan-3-ol terminated with (+) catechin and (-) epicatechin, respectively, and its extension units are also 2, 3 trans and 2 ,3-cis 3,5,7,3’,4’flavanpentaol. The above-mentioned chemical decomposition products were quantitatively determined by high performance liquid chromatography, and on the basis thereof, the average degree of polymerization of the polyflavan-3-ol was 6-7, and the corresponding number average molecular weight was 1700-2000.