Isonitenin and Acetylhomoagmatine new Metabolites from the SpongesSpongia OfficinalisandCliona celatacollected at the Galician Coast (NW Spain)

Abstract
Isonitenin (1), a new C-21 difuranoterpene and the new alkaloid acetylhomoagmatine (4) were isolated from Spongia officinalis and Cliona celata. respectively. The absolute stereochemistry of isonitenin (1) was proposed as 9R and that of dihydronitenin (3) as 7R and 9R.