The inhibition of superoxide anion generation by neutrophils from Viscum articulactum.

Two new flavanones, (2S)-pinocembrin 7-O-[beta-D-apiosyl(1-->2)]-beta-D-glucoside (1), and (2S)-pinocembrin 7-O-[cinnamoyl(1-->5)-beta-D-apiosyl(1-->2)]-beta-D-glucoside (2) together with eighteen known compounds, which include five known flavanones, nine benzenoids, one inositol and three triterpenoids, were isolated and characterized from fresh Viscum articulactum. Structures of new compounds were determined by spectral analysis. Among them, oleanolic acid (18) showed a significant inhibition effect on superoxide anion generation by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP).