Iridoids from the Roots of Patrinia scabra and Their Inhibitory Potential on LPS-Induced Nitric Oxide Production

An activity-guided fractionation procedure of the 70% aqueous EtOH extract from the roots of Patrinia scabra led to the isolation and characterization of five new iridoids, patriscabrins A–E (1–5), along with 13 known compounds. The structures of 1–5 were determined by interpretation of spectroscopic data, particularly by 1D and 2D NMR, ECD, and VCD studies. Thereafter, isolates were evaluated for their inhibitory effects on lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells. Of these, the new iridoids 2 and 5 and the known lignan patrineolignan B (6) exhibited IC50 values of 14.7 to 17.8 μM.