ISOLATION OF TOXIC AND POTENTIALLY TOXIC SESQUITERPENES AND MONOTERPENES FROM THE TROPICAL GREEN SEAWEED CAULERPA-TAXIFOLIA WHICH HAS INVADED THE REGION OF CAP MARTIN AND MONACO

The green seaweed Caulerpa taxifolia (VAHL) C. AGARDH (Caulerpales), which, after its recent accidental introduction, is growing in the region of Cap Martin much more vigorously than in the tropics, is shown to contain the known sesquiterpenic toxins caulerpenyne (1) in larger amounts than in tropical Caulerpales and oxytoxin 1 (2). Novel, potentially toxic products isolated in small amounts from this seaweed include the sesquiterpenes taxifolial A (= (5E)-6,10-dimethyl-2-[(E)2-oxoethylidene]undeca-5,9-dien-7-yne-1,3-diyl diacetate; 3), taxifolial B (= (1E, 6E, 10E)-3-[(Z)-acetoxymethylidene]-7,11-dimethyl-12-oxododeca-1,6, 10-trien-8-yne-1,4-diyl diacetate: 4), 10,11-epoxycaulerpenyne (= (1E,6E)-3-[(Z)-acetoxymethylidene]-10,11-epoxy-7,11-dimethyldodeca-1,6-dien-8-yne-1,4-diyl diacetate; 1:1 diastereoisomer mixture: 5), and taxifolial C (= (2Z,6E)-3-formyl-7,11-dimethyldodeca-2,6,10-trien-8-yne-1,1,4-triyl triacetate; 6), besides. as the first example of a monoterpene from the Caulerpales, taxifolial D(2Z)-3,7-dimethylocta-2,6-dien-4-ynal; 7).