A new apocarotenoid from the sea hare Aplysia kurodai

Abstract 1. 1. The carotenoids in the viscera, muscle and gonad of the sea hare Aplysia kurodai were investigated. 2. 2. A new apocarotenoid α-citraurinol [3 R , 6 R )-8′-apo- ϵ -carotene-3,8′-diol]( 1 ) has been isolated from the sea hare. A series of known apocarotenoids; 8′-apo-β-caroten-8′-al( 2 ), 8′-apo-β-caroten-8′-ol( 3 ), α-citraurin [(3 R ,6 R )-3-hydroxy-8′-apo- ϵ -caroten-8′-al]( 4 ), β-citraurin [(3 R )-3-hydroxy-8′-apo- β -caroten-8′-al]( 5 ) and β -citraurinol(3 R )-8′-apo- β -carotene-3,8′-diol]( 6 ) has further been isolated. Besides, β-carotene, (3 R )- β -cryptoxanthin, lutein A, (3 R ,3′ R )-zeaxanthin, diatoxanthin, fucoxanthin and fucoxanthiol were obtained. 3. 3. This is the first report of the isolation of ( 3 ) from nature. The isolation of ( 2 ), ( 4 ), ( 5 ) and ( 6 ) from the sea hare is the first from the animal kingdom. The absolute configurations of ( 4 ) and ( 6 ) were determined. 4. 4. Based on the experimental results, the possible metabolic pathways of β-carotene, lutein A and (3 R ,3′ R )-zeaxanthin in the sea hare have been proposed.