New flavonoids from Portulaca oleracea L. and their activities
Résumé
Three new compounds, identified as (3S)-5-hydroxy-3-(2-hydroxybenzyl)-7methoxychroman-4-one, oleracone C (1), 5-hydroxy-3-(2-hydroxybenzyl)-7-methoxy-4Hchromen-4-one, oleracone D (2), and 1-(2-hydroxy-4,6-dimethoxyphenyl)-3-(2hydroxyphenyl)propan-1-one, oleracone E (4), together with one new natural product, 5,7dimethoxy-4-O-2′-cycloflavan (3) already known from synthesis, and two known compounds, (2S)-5,2′-dihydroxy-7-methoxyflavanone (5) and 2′,4′-dihydroxy-4,6′dimethoxychalcone (6) were isolated from the Portulaca oleracea L. for the first time. Their structures were elucidated using spectroscopic methods, including one-and twodimensional nuclear magnetic resonance, high-resolution electrospray ionization time-offlight mass spectrometry and circular dichroism spectrometry. Oleracone C (1), D (2) and E (4) presented scavenging activities in 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical quenching assay, with IC 50 values of 23.27, 11.73, 13.17 μM, respectively and anticholinesterase activities with IC 50 values ranging between 59.55 and 78.85 μM.
Domaines
Chimie
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