Anti-inflammatory iridoid glycosides from Paederia scandens (Lour.) Merrill

Eight previously undescribed iridoid glycosides together with 20 known congeners were isolated from the aerial parts of Paederia scandens (Lour.) Merrill (Rubiaceae). Their structures incorporating absolute configurations were elucidated based on the comprehensive analyses of NMR data, HR-ESI-MS spectrometry, and ECD data. The potential anti-inflammatory activities of the isolated iridoids were evaluated in lipopolysaccharide-stimulated RAW 264.7 macrophages. Compound 6 significantly inhibited the production of nitric oxide with an IC50 value of 15.30 μM. The results of immunoblotting, qPCR, and immunofluorescence staining assays revealed that compound 6 exhibited anti-inflammatory activity by suppressing nuclear translocation of NF-κB and reducing the expression of COX-2, iNOS, IL-1β, and IL-6. These results provide a basis for further development and utilization of P. scandens as a natural source of potential anti-inflammatory agents. Eight previously undescribed iridoid glycosides together with 20 known congeners were isolated from the aerial parts of Paederia scandens (Lour.) Merrill (Rubiaceae). [Display omitted] •Bioactive phytochemicals of Paederia scandens (Lour.) Merrill were conducted.•Eight previously undescribed and 20 known iridoids were isolated from P. scandens.•Some iridoid glucosides showed potent anti-inflammatory activities in vitro.•Compound 6 suppressed the nuclear translocation of NF-κB in RAW 264.7 cells.