Lignans with NO inhibitory activity from Tinospora sinensis

Two new lignan glucosides, tinsinlignans A and B ( 1 and 2 ), two new oxyneolignans, tinsinlignans C and D ( 3 and 4 ), along with one known analogue ( 5 ), were isolated from the stems of Tinospora sinensis. The structures of the new compounds were elucidated based on analysis of spectroscopic data, and the absolute configuration of 1 was determined through electronic circular dichroism (ECD) calculation based on the time-dependent density functional theory (TD-DFT). Compounds 1 − 4 were evaluated for their inhibitory effects on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in murine RAW264.7 macrophage cells and compounds 1 and 2 exhibited moderate inhibitory activities with IC₅₀ values of 18.5 ± 2.0 and 28.8 ± 1.2 μmol·L⁻¹, respectively.