Chemical constituents from the aerial parts of Rubia cordifolia L. with their NO inhibitory activity

A new naphthoquinone derivative (1) together with twenty-three known compounds (2–24), were isolated from the aerial parts of Rubia cordifolia L. Their structures were elucidated on the basis of NMR and HR-ESIMS data. Compounds 1–13 were assessed for their inhibitory effects on NO production in LPS-stimulated RAW 264.7 macrophage cells. Compounds 2-6 exhibited significant inhibitory activities with IC50 values of 21.37, 13.81, 24.56, 20.32, and 30.08 μmol·L−1, respectively.