Eucophylline, a Tetracyclic Vinylquinoline Alkaloid from Leuconotis eugenifolius

Eucophylline (1), a new tetracyclic vinylquinoline alkaloid, was isolated from the bark of Leuconotis eugenifolius together with leucophyllidine (2). The structure and absolute configuration of 1 were elucidated on the basis of 2D NMR correlations and simulated CD analysis. Leucophyllidine (2) showed iNOS inhibitory activity and decreased the iNOS protein expression dose-dependently.