Chemical composition of Erycibe schmidtii and antiproliferative activity of scopoletin on immature dendritic cells

Immature dendritic cells (iDCs) play very important roles in the pathological process of rheumatoid arthritis (RA). Therefore, it is urgent to search for natural products with antiproliferative activity on iDCs for anti-RA drug discovery. Erycibe schmidtii, a traditional Chinese medicine, has been used to treat RA in China. Its bioactive ingredients on RA are still unclear. In this study, twenty compounds including a new caffeoylquinic acid derivative, 3-O-caffeoyl-4-O-syringoylquinic acid methyl ester (16), were isolated from E. schmidtii. Their structures were elucidated by NMR and mass spectroscopic analysis, and comparison with literature data. Seventeen compounds were obtained from this plant for the first time, and ten were first found from the genus Erycibe. Scopoletin (1, 5.0 μM) functionally reduced proliferation level of bone marrow immature dendritic cells (BM-iDCs) more than 50%, relative to vehicle. However, scopoletin (1) exhibited no effect on the phagocytosis or survival of BM-iDCs in vitro.