Rare phenolic structures found in the aerial parts of Eriosema laurentii De Wild

• Published in: Phytochemistry (Oxford) 2016-08, Vol.128, p.5-11
• Main Authors: Ateba, Sylvin Benjamin, Njamen, Dieudonné, Gatterer, Claus, Scherzer, Tamara, Zehl, Martin, Kählig, Hanspeter, Krenn, Liselotte
• Format: Article
• Language: English
• Subjects: 1-[2,4-dihydroxy-3-(2-hydroxy-3-methylbut-3-en-1-yl) phenyl]-3-phenylpropan-1-one; 1-[2,4-dihydroxy-3-(2-hydroxy-3-methylbut-3-en-1-yl)phenyl]-3-(4-methoxyphenyl)-propan-1-one; 3,4′,6,8-tetrahydroxyflavanone-7-C-glucoside; 3,4′,6,8-tetrahydroxyflavone-7-C-glucoside; Eriosema laurentii De Wild; Fabaceae - chemistry; Flavonoids; Glucosides - chemistry; Glucosides - isolation & purification; Hydroxybenzoic acids; Leguminosae; Medicine, African Traditional; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Phenols - chemistry; Phenols - isolation & purification; Plant Components, Aerial - chemistry; Plant Extracts - chemistry
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2016.03.020

Recent pharmacological and toxicological investigations of Eriosema laurentii (Leguminosae) have underlined the plausibility of the use of this plant in traditional African medicine. A very complex pattern of phenolic compounds was detected in the tested extracts. Based on these preceding results a detailed phytochemical study was performed and resulted in the isolation and identification of eleven compounds. All are reported in this plant for the first time and four of those are previously undescribed secondary metabolites: 3,4′,6,8-tetrahydroxyflavanone-7-C-glucoside and 3,4′,6,8-tetrahydroxyflavone-7-C-glucoside with an extremely rare substitution pattern as well as 1-[2,4-dihydroxy-3-(2-hydroxy-3-methylbut-3-en-1-yl)phenyl]-3-phenylpropan-1-one and 1-[2,4-dihydroxy-3-(2-hydroxy-3-methylbut-3-en-1-yl)phenyl]-3-(4-methoxyphenyl)-propan-1-one. Their structures were elucidated unambiguously by extensive MS- and NMR-experiments. [Display omitted] •First in-depth investigation of phenolics in Eriosema laurentii.•Identification of 11 substances by NMR, MS and LC-MS analyses.•Two previously undescribed flavonoids with unusual substitution pattern.•3,4′,6,8-Tetrahydroxyflavanone- and 3,4′,6,8-tetrahydroxyflavone-7-C-glucoside.•First proof of previously undescribed dihydrochalcones in Eriosema laurentii.