Anti-allergic flavones from Arthraxon hispidus.

Bioactivity-guided fractionation for an EtOAc-soluble fraction of methanolic extract of Arthraxon hispidus, using primary cell assay with bone marrow-derived mast cells (BMMC), led to an isolation of six new flavones and nine known compounds. The structures of the new compounds were established by one dimensional (1D)- and 2D-NMR spectroscopic data, as luteolin 8-C-β-kerriopyranoside (1), luteolin 8-acetic acid methyl ester (2), 7-methyl-luteolin 8-C-β-(6-deoxyxylo-3-uloside) (3), apigenin 8-C-α-fucopyranoside (4), apigenin 8-C-β-fucopyranoside (5) and luteolin 8-C-β-fucopyranoside (6). All the isolates were evaluated for inhibitory activities on interleukin-6 release in the primary cultures using BMMC. Of the tested compounds, compounds 2, 3 and 10 were found to inhibit interleukin-6 release. Furthermore, compound 2 displayed inhibitory activity against prostaglandin D2, leukotriene C4, and β-hexosaminidase releases.