Suppression of nitric oxide production on LPS/IFN-γ-stimulated RAW264.7 macrophages by a novel catechin, pilosanol N, from Agrimonia pilosa Ledeb.

A novel catechin, pilosanol N (1), was isolated from Agrimonia pilosa Ledeb and its structure was determined by (1)H, (13)C NMR and HRESI-MS analyses. Compound 1 inhibited nitric oxide (NO) production in LPS/IFN-γ -induced RAW264.7 macrophages, and then the iNOS gene expression and its protein production with LPS/IFN-γ treatment cells were also suppressed in the presence of 1. In addition, compound 1 scavenged NO or nitrogen radicals generated from NOR3 (4-ethyl-2-hydroxyamino-5-nitro-3-hexenamide) as an NO donor. These results indicated that pilosanol N can decrease the level of NO through a mechanism that involved both a decrease in the NO production and NO scavenging.