New flavonoids from the underground parts of Eriosema laurentii

Publication date: December 2016 Source:Phytochemistry Letters, Volume 18 Author(s): Sylvin Benjamin Ateba, Dieudonné Njamen, Katrin Ukowitz, Martin Zehl, Hanspeter Kählig, Stefanie Hobiger, Alois Jungbauer, Liselotte Krenn Pharmacological, toxicological and phytochemical investigations of aerial parts of Eriosema laurentii De Wild. (Leguminosae), a plant used in traditional African medicine, showed a complex pattern of very rare and several new exceptional phenolic compounds. In continuation of the phytochemical work and based on the activity of an extract from the underground parts, the presented study showed the occurrence of a new pyranoisoflavone, named methyleriosemaone D, and a new highly prenylated (2S,3S)-6,8,3′-triprenyl-3,5,7,2′,4′-pentahydroxyflavanone in these parts of E. laurentii. In addition, the very rare pyranoisoflavone eriosemaone D was proven in this plant for the first time. All structures were elucidated unambiguously by extensive MS- and one and two-dimensional NMR-experiments. Detailed NMR spectra of eriosemaone D were included to rationalize the correction of some of the previously reported carbon signals in the 13C NMR spectrum. The estrogenic activity of the extract and isolated compounds was tested in an estrogen receptor α yeast transactivation assay. Graphical abstract

Source: Phytochemistry Letters - October 13, 2016 Category: Chemistry Source Type: research