New drug metabolism inhibitor of marine origin.

Dactylyne, an acetylenic dibromochloro ether, was isolated from the sea hare Aplysia dactylomela and characterized pharmacologically. It had no direct effect on the cardiovascular, respiratory, and central nervous systems of mice, rats, and guinea pigs. However, a 25-mg/kg ip dose of dactylyne prolonged pentobarbital sleep time in mice by more than 10 hr. This potentiation was subsequently determined to be due to the inhibition of pentobarbital metabolism by dactylyne since the elimination half-life of pentobarbital in the dactylyne-treated mice increased several folds. Dactylyne was nontoxic up to 200 mg/kg iv. The unique structure, high potency, and relatively nontoxic nature of dactylyne make it an interesting pharmacological substance of marine origin.