Yezo'otogirins D-H, Acylphloroglucinols and Meroterpenes from Hypericum yezoense.

Investigation of the methanolic extract from the aerial parts of Hypericum yezoense resulted in the isolation of three new acylphloroglucinols, yezo'otogirins D-F (1-3), and two new meroterpenes, yezo'otogirins G (4) and H (5). The structures of 1-5 were assigned on the basis of spectroscopic data. Yezo'otogirin D (1) is an acylphloroglucinol with a monoterpene moiety linked through an ether bond, while yezo'otogirins E (2) and F (3) are polyprenylated acylphloroglucinols possessing a tricyclic core. Yezo'otogirins G (4) and H (5) are linear meroterpenes with an enolized β-diketone moiety. Yezo'otogirin E (2) exhibited antimicrobial activity against Escherichia coli and Staphylococcus aureus.