Iridoid glucosides and a C13-norisoprenoid from Lamiophlomis rotata and their effects on NF-κB activation

Four new iridoid glucosides, 7-dehydroxyzaluzioside (1), 6′-O-syringylphlorigidoside C (2), barlerin-6″-hydroxy-2″,6″-dimethylocta-2″,7″-dienate ester (3), 6β-n-butoxy-7,8-dehydropenstemonoside (4), and a new C13-norisoprenoid derivative, 5β,6α-dihydroxy-3β-(β-d-glucoyranosyloxy)-7-megastigmen-9-one (5), together with 16 known iridoid glucosides, were isolated from Lamiophlomis rotata. The structures of these new compounds were elucidated by HRMS, 1D and 2D NMR spectroscopy. A stable nuclear factor kappaB (NF-κB)-luciferase-expressing human embryonic kidney 293 cell line was used in the luciferase assay for monitoring the anti-inflammatory activity of the compounds. It was found that 6β-n-butoxy-7,8-dehydropenstemonoside (4) and two known compounds (8-epi-7-deoxyloganin and 7,8-dehydropenstemonoside) had a significant inhibitory effect on lipopolysaccharide-stimulated NF-κB activation.