Four new acridone-coumarin dimers, neoacrimarines-H (1), -I (2), -J (3
) and -K (4), were isolated from the roots of Marsh grapefruit (Citrus
paradisi MACF.). The structures of these new compounds were elucidate
d by spectral analysis especially using heteronuclear multiple-bond co
rrelation (HMBC) and nuclear Overhauser effect experiments.