Furo-1,2-naphthoquinones from Crataegus pinnatifida with ICAM-1 expression inhibition activity.

Two new furo-1,2-naphthoquinones, crataequinones A (1) and B (2), were isolated from the fruits of Crataegus pinnatifida. The structures of two new compounds were determined as 11,12-dimethoxy-3,4-furo-1,2-naphthoquinone (1) and 11,12-dimethoxy-5-hydroxy-3,4-furo-1,2-naphthoquinone (2) by spectroscopic analysis. The two compounds 1 and 2 showed significant inhibitory activity with IC50 values of 33 and 90 microM, respectively, against the expression of intercellular adhesion molecule-1 (ICAM-1).