Wiesneth Stefan, Aas Gregor, Heilmann Jörg, Jürgenliemk Guido
Institute of Pharmaceutical Biology, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany.
Ecological-Botanical Gardens, University of Bayreuth, D-95440 Bayreuth, Germany.
Phytochemistry. 2018 Jan;145:26-39. doi: 10.1016/j.phytochem.2017.10.001. Epub 2017 Oct 20.
Flavonoids, proanthocyanidins (PAs) and salicylic alcohol derivatives are the main groups of ingredients in Salix needed as defensive tools and signal molecules, but have also pharmaceutical importance. The present study investigated total PA content, complete PA pattern, the oligomeric/total PAs quotient and the contents of catechin and epicatechin during one growing-season for the leaves and this year's sprouts in ten willows (Salix pentandra L. ♂, S. alba L. ♂, S. fragilis L. ♀, S. caprea L. ♂ & ♀, S. cinerea L. ♂, S. caprea x cinerea ♂, S. daphnoidesVill. ♂ & ♀ and S. purpurea L. ♀; all Salicaceae). Comparison of the different species revealed distinct seasonal fluctuations of the oligomeric and polymeric PA fractions, but the contents of both groups always developed in the same direction. All willows prefer the synthesis of PAs with DP-2 - DP-4 within the oligomeric fraction (DP-2 - DP-10) and species with rather low PA contents like S. purpurea (0.1-2.6 mg/g) as well as species with rather high PA contents like S. alba (3.8-14.7 mg/g) were found. Only slight gender specific differences could be observed for both sexes of S. daphnoides and S. caprea. The PA pattern of the hybrid S. caprea x cinerea seems to be influenced by both parents. Thus, the accumulation of the oligomeric PAs accorded to S. caprea and the polymeric PAs matched S. cinerea resulting in an overall depression of PAs in the sprouts and a varying seasonal trend in the leaves. In contrast, the content of catechin remained high and seemed to be not influenced in the hybrid. Although only one individual of each Salix species could be considered in this screening study, the present results demonstrate the variability of the flavan-3-ol pattern within the genus Salix but also some preliminary correlations could be observed. Future studies with more Salix species will provide more insights into chemotaxonomic correlations.
黄酮类化合物、原花青素（PAs）和水杨醇衍生物是柳树中作为防御工具和信号分子所需的主要成分组，但也具有药用价值。本研究调查了10种柳树（紫柳♂、白柳♂、脆柳♀、欧洲山杨♂和♀、灰柳♂、欧洲山杨×灰柳♂、黄杞柳♂和♀、紫枝柳♀；均为杨柳科）叶片和当年嫩枝在一个生长季节中的总PA含量、完整PA模式、低聚体/总PAs商以及儿茶素和表儿茶素的含量。不同物种的比较显示，低聚体和聚合体PA组分存在明显的季节性波动，但两组的含量始终朝着相同方向变化。所有柳树都倾向于在低聚体组分（DP-2 - DP-10）中合成DP-2 - DP-4的PAs，发现了PA含量较低的物种，如紫枝柳（0.1 - 2.6毫克/克）以及PA含量较高的物种，如白柳（3.8 - 14.7毫克/克）。在黄杞柳和欧洲山杨的两性中仅观察到轻微的性别特异性差异。杂交种欧洲山杨×灰柳的PA模式似乎受到双亲的影响。因此，低聚体PAs的积累符合欧洲山杨，而聚合体PAs与灰柳匹配，导致嫩枝中PAs总体下降，叶片中季节性趋势各异。相比之下，儿茶素含量保持较高，且在杂交种中似乎不受影响。尽管在这项筛选研究中每种柳树仅考虑了一个个体，但目前的结果表明了柳属内黄烷-3-醇模式的变异性，同时也观察到了一些初步的相关性。未来对更多柳树物种的研究将提供更多关于化学分类学相关性的见解。
