Stereochemistry of 16a-Hydroxyfriedelin and 3-Oxo-16-methylfriedel-16-ene Established by 2D NMR Spectroscopy

Abstract

Friedelin (1), 3β-friedelinol (2), 28-hydroxyfriedelin (3), 16α-hydroxyfriedelin (4), 30-hydroxyfriedelin (5) and 16α,28-dihydroxyfriedelin (6) were isolated through fractionation of the hexane extract obtained from branches of Salacia elliptica. After a week in CDCl3 solution, 16α-hydroxyfriedelin (4) reacted turning into 3-oxo-16-methylfriedel-16-ene (7). This is the first report of a dehydration followed by a Nametkin rearrangement of a pentacyclic triterpene in CDCl3 solution occurring in the NMR tube. These seven pentacyclic triterpenes was identified through NMR spectroscopy and the stereochemistry of compound 4 and 7 was established by 2D NMR (NOESY) spectroscopy and mass spectrometry (GC-MS). It is also the first time that all the 13C-NMR and 2D NMR spectral data are reported for compounds 4 and 7.

Chemical constituents of Salacia elliptica (Celastraceae)

“…However, this compound was previously described as a constituent of the Antidesma menasu Miq.ex.Tul 24 and the 2D NMR (HSQC, HMBC, COSY and NOESY) data of this PCTT were recently published. 25 The xanthone glucoside mangiferin (13) has been commonly found in species of the genus Salacia. 17,26,27 This compound correspond to one constituent which was associated to the antidiabetic effect of Salacia reticulata.…”

Produtos Naturais Como Potenciais Alternativas No Tratamento Da Diabetes Melito: Uma Revisão Sistemática De Patentes (2016- 2022)

“…Pelo menos neste modelo experimental, a FC se mostrou a mais potente em termos de redução de glicação da ASB. DUARTE et al, 2009;KOGA et al, 2013;SULAIMAN et al, 2014;YOSHIKAWA et al, 2008;YOSHINO et al, 2009). Destes compostos isolados da Salacia, tanto para os triterpenos como para os polifenóis várias atividades farmacológicas já foram caracterizadas (GAO et al, 2010;KOGA et al, 2013;LEE et al, 2013;SELLAMUTHU et al, 2013;SOMWONG et al, 2011;YOSHIKAWA et al, 2002).…”

Ciências da saúde: conceitos e tendências

“…Pelo menos neste modelo experimental, a FC se mostrou a mais potente em termos de redução de glicação da ASB. DUARTE et al, 2009;KOGA et al, 2013;SULAIMAN et al, 2014;YOSHIKAWA et al, 2008;YOSHINO et al, 2009). Destes compostos isolados da Salacia, tanto para os triterpenos como para os polifenóis várias atividades farmacológicas já foram caracterizadas (GAO et al, 2010;KOGA et al, 2013;LEE et al, 2013;SELLAMUTHU et al, 2013;SOMWONG et al, 2011;YOSHIKAWA et al, 2002).…”