A new bioactive sterol glycoside, 3β-O-(3′,4′-di-O-acetyl-β-d-arabinopyranosyl) -25ξ-cholestane-3β,5α,6β,26-tetrol-26-acetate) (carijoside A, 1), was isolated from an octocoral identified as Carijoa sp. The structure of glycoside 1 was established by spectroscopic methods and by comparison with spectral data for the other known glycosides. Carijoside A (1) displayed significant inhibitory effects on superoxide anion generation and elastase release by human neutrophils and this compound exhibited moderate cytotoxicity toward DLD-1, P388D1, HL-60, and CCRF-CEM tumor cells.

Tunicates have been well-recognized as marine organisms containing large quantities of secondary metabolites that exhibit varying degrees of biological activities. 1,2) In connection with our continuing investigations of bioactive substances from marine organisms, a tunicate Eudistoma species (subphylum Urochordata, class Ascidiacea, order Enterogona, suborder Aplousobranchiata, family Polycitoridae) was selected for study, 3,4) as the EtOAc extract of this organism was found to exhibit cytotoxicity against MCF-7 (human breast cancer), NCI-H460 (human non-small cell lung cancer), and SF-268 (human CNS cancer) cells. In this paper, we report the isolation, structure elucidation, and biological activity of two hydroperoxysterols, 7b-hydroperoxycholesterol (1) and its stereoisomer 7a-hydroperoxycholesterol (2), from a Formosan tunicate identified as Eudistoma sp.

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Two new briarane-related diterpenoids, designated as excavatoids E (1) and F (2), were isolated from the cultured octocoral Briareum excavatum. The structures of compounds 1 and 2 were established on the basis of extensive spectral data analysis. Briaranes 1 and 2 were found to exhibit moderate inhibitory effects on elastase release by human neutrophils.