In the search for novel antirheumatics: Re-discovery of a secoiridoid aglycone in Chinese ethnomedicine Radix Gentiana macrophylla Pall.

Abstract: Rheumatoid arthritis (RA) is a chronic, inflammatory, autoimmune disease that although systemic, mainly affects the synovium of the joints. Currently, remission is the goal of RA treatment. Research efforts are however targeted towards finding a cure. Radix Gentiana macrophylla Pall. (秦艽, Pinyin: Qinjiao) has been used for a long time in several prescriptions in the Chinese herbal medicinal tradition to treat, among others, rheumatic conditions. In this study, compounds from Radix G. macrophylla Pall. were extracted by maceration, isolated by NP-SPE followed by RP-HPLC-UV, identified by LRESIMS(+), 1D and 2D-NMR and finally prepared for in vitro screening (NF-κB downregulation activity). The method used was adapted from the NCI Program for Natural Product Discovery (NPNPD). This resulted in the identification of six known compounds. The secoiridoid aglycone (-)-swermusic acid B, known only in Swertia mussotii Franch., was however for the first time isolated from a Gentiana species.