Iridoid and phenylethanol glycosides from Scrophularia umbrosa with inhibitory activity on nitric oxide production

Abstract

Three new iridoid glycosides, namely umbrosides A–C (1–3); ten known iridoid glycosides (4–8 and 16–20); and seven known phenylethanoid glycosides (9–15) were isolated from Scrophularia umbrosa Dumortier, and their structures were established through spectroscopic methods including 1D and 2D NMR experiments and ESIMS analysis. The inhibitory activities of the isolated compounds on LPS-stimulated nitric oxide (NO) production in RAW 264.7 cells were investigated. Compounds 1–3, 7, 9–10, 13–16, and 19–20 inhibited NO production, with IC50 values ranging from 9.0 to 40.3 μM. Their structure–activity relationships are preliminarily discussed in this paper.