The structural analogues of cumambrin B (1, 2, 3, 4) were isolated fro
m the flower of Chrysanthemum boreale Makino. The structures of compou
nds were determined by two-dimensional H-1-H-1 COSY and C-13-H-1 COSY
spectra with the aid of homonuclear and heteronuclear double resonance
experiment. The stereochemistry of compounds has been verified from s
ingle crystal X-ray diffraction oi cumambrin A (2). The antimicrobial
activities of these guaianolides have been studied.