Three new monoterpene glycosides from oil peony seed cake

A phytochemical investigation of oil peony seed cake led to the isolation and identification of three new monoterpene glycosides called paeonirockosides A (1), B (2), and C (5), together with 21 known monoterpene glycosides. Their structures were elucidated through the extensive application of one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR) spectroscopy and a comparison with authentic standards. The inhibitory activity of the isolated compounds against nitric oxide (NO) production was evaluated on lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. Compounds mudanpioside F (3), benzoylpaeoniflorin (11), benzoyloxypaeoniflorin (12), oxypaeonidanin (18) and pyrindylpaeoniflorin (22) and the 70% aqueous ethanol extract (AEE) exhibited potent inhibitory activity against NO production with IC50 values of 18.65, 23.32, 25.14, 40.8, 28.61 and 36.42 μM, respectively. Monoterpene glycosides from peony seed cake can be developed into a promising immunosuppressive drug.