Dactyloditerpenol acetate, a new prenylbisabolane-type diterpene from Aplysia dactylomela with significant in vitro anti-neuroinflammatory activity

A new regular diterpene possessing an unusual 1,6-anti-3-methylcyclohex-2-en-1-ol ring system, dactyloditerpenol acetate (1), has been extracted from the tropical sea hare Aplysia dactylomela and its stereostructure elucidated by spectroscopic methods. The absolute configuration of 1 was determined as 1S, 6S, 7R, 10S, and 11R by application of Kishi's method for the assignment of absolute configuration of alcohols. The new diterpene potently inhibited in vitro thromboxane B2 (TXB2) (IC50 0.4 μM) and superoxide anion (O2-) (IC50 1 μM) generation from Escherichia coli lipopolysaccharide (LPS)-activated rat neonatal microglia, with concomitant low short-term toxicity.