16 Eudistoma種のホヤより単離したβ-カルボリン化合物の構造と生物活性

抄録

During our studies on bioactive metabolites from marine organisms, we have examined pharmacological effects of extracts of various tunicates. A series of β-carboline compounds with specific activities has been isolated from tunicates of Eudistoma species. They are eudistomin A〜Q isolated from the Caribbean tunicate Eudistoma olivaceum and eudistomidin-A isolated from the Okinawan tunicate Eudistoma glaucus. These structures were assigned on the basis of the spectral data including ^1H and ^<13>C NMR, as simple β-carbolines (eudistomin D, J, N and O), 1-pyrrolinyl-β-carbolines (eudistomin G, H, I, P, Q and eudistomidin-A), 1-pyrrolyl-β-carbolines (eudistomine A and M) and tetrahydro-β-carbolines containing a novel oxathiazepine ring (eudistomin C, E, F, K and L), respectively. Antiviral activity in vitro was found for endistomin C〜E, H, I, K and L, while eudistomin A, D and J induced Ca^<2+> release from sarcoplasmic reticulum like caffeine. Bromoeudistomin D (BED), a monobrominated derivative of eudistomin D, was 400 times more potent than caffeine in the Ca^<2+>-releasing activity. Eudistomidin-A exhibited potent calmodulin antagonistic activity to be 15 times more potent than W-7, a well-known calmodulin antagonist. The structures of these β-carboline tunicate metabolites will be discussed in relation to their pharmacological activities.