Placidenes C-F, novel a-pyrone propionates from the Mediterranean Sacoglossan Placida dendritica

Four new a pyrone-containing propionates and an unprecedented hydroperoxide have been isolated from the mantle extract of Placida dendritica, a Mediterranean sacoglossan that lives upon the green alga Bryopsis plumosa. The new metabolites co-occur with other known compounds that have been described in previous studies of the mollusc. The presence of hdroperoxide derivative opens intriguing perspectives on the ecological role of placidenes. This paper reports the isolation and structural elucidation of the new compounds.