Coumarin Constituents of the Juice Oil from Citrus hassaku and Their Spasmolytic Activity

Abstract

Ten 7-hydroxycoumarin derivatives (4-13), containing two newly identified compounds (8 and 9), were isolated from the juice oil of fruits of Citrus hassaku, along with aurapten (1), (+)-epoxyaurapten (2), and (+)-marmin (3), and their structures were absolutely determined by spectroscopic and chemical methods. The spasmolytic activity of the isolated compounds was measured by the Magnus method, using guinea pig ileums. Three compounds (4, 7, and 11) showed higher activity than that of aurapten (1). The other compounds showed no activity under these conditions. The structure and activity relationship is discussed.