Novel secoeunicellins produced by an octocoral Cladiella sp

Two novel 6,7-secoeunicellins, cladieunicellins W (1) and X (2), along with a known eunicellin, klymollin Y (3), were isolated from an octocoral identified as Cladiella sp. The structures of secoeunicellins 1 and 2 were elucidated by spectroscopic methods. 1 is the first secoeunicellin possessing a gamma-lactone ring and 2 represents the first secoeunicellin possessing two tetrahydrofuran moieties. Secoeunicellin 2 displayed significant inhibitory effects on the generation of superoxide anions and the release of elastase. These results implied that the methoxy group at C-6 in 2 plays an important role in determining the activity of these compounds. (C) 2019 Elsevier Ltd. All rights reserved.