Brem Brigitte, Seger Christoph, Pacher Thomas, Hartl Markus, Hadacek Franz, Hofer Otmar, Vajrodaya Srunya, Greger Harald
Comparative and Ecological Phytochemistry Department, Institute of Botany, University of Vienna, Rennweg 14, A-1030 Wien, Austria.
Phytochemistry. 2004 Oct;65(19):2719-29. doi: 10.1016/j.phytochem.2004.08.023.
From the roots of various Stemona species four new dehydrotocopherols (chromenols) were isolated and their structures and stereochemistry elucidated by spectroscopic methods. The double bond between C-3 and C-4 proved to be a typical chemical character of the genus found in most of the species. Various C-methylations of the aromatic ring reflect differences in methyltransferase activities and agreed with the current species delimitations showing an exclusive accumulation of dehydro-delta-tocopherol for the Stemona tuberosa group, whereas different provenances of Stemona curtisii were characterized by dehydro-gamma-tocopherol accompanied by small amounts of dehydro-alpha-tocopherol. From Stemona collinsae all four tocopherols were isolated with a clear preponderance of dehydro-delta-tocopherol accompanied by smaller amounts of the rare dehydro-beta-tocopherol. Stemona burkillii and a group of unidentified species showed a weak accumulation trend towards dehydro-alpha-tocopherol, whereas Stemona cochinchinensis and especially Stemona kerrii clearly differed by a preponderance of chromanol derivatives. In Stemona cf. pierrei no tocopherols could be detected at all. Based on TLC tests and microplate assays with the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH*) the antioxidant capacities of all chromenol derivatives were comparable with that of alpha-tocopherol showing no significant differences among each other, except for a more rapid kinetic behaviour of the 5,7,8-methylated dehydro-alpha-tocopherol.
从多种百部属植物的根中分离出了四种新的脱氢生育酚（色满醇），并通过光谱方法阐明了它们的结构和立体化学。C-3和C-4之间的双键被证明是该属在大多数物种中发现的典型化学特征。芳香环的各种C-甲基化反映了甲基转移酶活性的差异，并且与当前的物种划分一致，显示出百部块根组中脱氢δ-生育酚的独特积累，而不同来源的柯氏百部的特征是脱氢γ-生育酚并伴有少量脱氢α-生育酚。从柯氏百部中分离出了所有四种生育酚，其中脱氢δ-生育酚明显占优势，同时伴有少量稀有的脱氢β-生育酚。百部和一组未鉴定的物种对脱氢α-生育酚表现出较弱的积累趋势，而越南百部，尤其是长叶百部明显不同，以色满醇衍生物占优势。在拟百部中根本检测不到生育酚。基于TLC测试和使用自由基2,2-二苯基-1-苦基肼（DPPH*）的微孔板测定，所有色满醇衍生物的抗氧化能力与α-生育酚相当，彼此之间没有显著差异，除了5,7,8-甲基化的脱氢α-生育酚具有更快的动力学行为。
