Department of Chemistry, The Technical University of Denmark, DK-2800, Lyngby, Denmark.
J Nat Prod. 2010 Sep 24;73(9):1593-6. doi: 10.1021/np100366k.
From Veronica longifolia were isolated three chlorinated iridoid glucosides, namely, asystasioside E (6) and its 6-O-esters 6a and 6b, named longifoliosides A and B, respectively. The structures of 6a and 6b were proved by analysis of their spectroscopic data and by conversion to the catalpol ester verproside (5a) or to catalpol (5), respectively. The configuration of the previously known vanilloyl analogue, urphoside B, was shown to be the 6β-epimer (6c) of the structure originally reported. Longifoliosides A (6a) and B (6b) were found to exhibit radical-scavenging activity against nitric oxide, superoxide, and 2,2-diphenyl-1-picrylhydrazyl radicals.
从 Veronica longifolia 中分离得到三种氯化环烯醚萜苷，分别为 asystasioside E（6）及其 6-O-酯 6a 和 6b，分别命名为 longifoliosides A 和 B。通过分析其光谱数据以及分别转化为 catalpol 酯 verproside（5a）或 catalpol（5），证明了 6a 和 6b 的结构。先前已知的香草酰类似物 urphoside B 的构型被证明为最初报道的结构的 6β-差向异构体（6c）。发现 longifoliosides A（6a）和 B（6b）具有清除一氧化氮、超氧自由基和 2,2-二苯基-1-苦基肼自由基的活性。
