Structures and radical-scavenging activities of phenolic constituents from the bark of Picea jezoensis var. jezoensis

The MeOH extract of the bark of Picea jezoensis var. jezoensis was found to show scavenging activity for the DPPH radical. Bioassay-guided fractionation led to the isolation of two new flavonostilbenes named jezonocinols A (1) and B (2) and one nor-flavonostilbene named jezonocinol C (3) together with six known phenolic compounds. Their structures were elucidated by spectroscopic methods, and the absolute configurations of jezonocinols A (1) and B (2) were determined by Mosher's method, CD, and NOESY data.