Two new isoflavanones from the roots of Erythrina variegata.

Two new isoflavanones, eryvarins Y (1) and Z (2), together with three known compounds (3-5) were isolated from the roots of Erythrina variegata. The structures of 1 and 2 were established on the basis of spectroscopic data The new compounds are peculiar isoflavanones, possessing both a 3-methylbut-2-en-1-yl group and a 2-hydroxy-3-methylbut-3-en-1-yl group. Among the isolates, orientanol E (5) exhibited potent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) strains.