Carotinoide aus marinen Schwämmen ( Porifera ): Isolierung und Struktur von sieben Hauptcarotinoiden aus Agelas schmidtii

Carotenoids from Marine Sponges (Porifera) : Isolation and Structure of the Seven Main Carotenoids from Agelas schmidtii The following carotenoids were identified in the marine sponge Agelas schmidtii : α‐carotene ((6′ R )‐β, ε‐carotene ( 1 )), isorenieratene (φ,φ‐carotene ( 2 )), trikentriorhodin (3,8‐dihydroxy‐κ,χ‐caroten‐6‐one ( 3 )) and zeaxanthin ((3 R , 3′ R )‐β, β‐carotene‐3, 3′‐diol ( 4 )). In addition, three previously unknown carotenoids called agelaxanthin A, B and C were isolated. Spectroscopical and chemical structure elucidation showed agelaxanthin A to be (3 R )‐β, φ‐caroten‐3‐ol ( 6 ) and agelaxanthin C to be a methoxy‐19,3′,8′‐trihydroxy‐7,8‐didehydro‐β, κ‐caroten‐6′‐one ( 7 ) with the methoxy group at C (2), C (3) or C (4). The limited data on age‐laxanthin B were compatible with the structure of a 19‐ O ‐methyl derivative of agelaxanthin C.