A new skeleton flavonoid and a new lignan from Portulaca oleracea L. and their activities

A new skeleton flavonoid, identified as (5aR)-10-hydroxy-8-methoxy-5aH,11H-chromeno[2,3-b]chromen-11-one (1), named oleracone G, and a new lignan, confirmed as 8-(4-hydroxy-3-methoxyphenyl)-3-methoxynaphthalen-2-ol (2), named oleralignan B, were isolated from Portulaca oleracea L., and the structures of them were determined using spectroscopic methods including UV, IR, 1D NMR, 2D NMR, and UHPLC-ESI-QTOF/MS. In addition, compounds 1-2 were applied to investigate the anti-inflammatory activities on lipopolysaccharide-stimulated macrophages and scavenging effects in 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical. The results showed that the two compounds at 10 μM and 20 μM could dose-dependently decrease the secretion of interleukin 1β in RAW 264.7 cells by enzyme-linked immunosorbent assay, moreover, presented remarkable antioxidant activities with IC₅₀ values of 27.57, 20.12 μM, respectively.