Bis(sulfato)-cyclosiphonodictyol A, a new disulfated sesquiterpene-hydroquinone from a deep water collection of the Marine sponge Siphonodictyon coralliphagum

Oxidative Coupling of (-)-Sclareol and Related Diols Leading to Oxepane Terpenoids

Treatment of (-)-sclareol and related compounds with lead tetraacetate affords tetracyclic compounds bearing a 2,8-dioxabicyclo[5.2.0]nonane moiety with complete regio- and stereoselectivity. This process, which is also applicable to 1,5-diols with a similar substitution pattern, facilitates the development of efficient syntheses toward oxepane terpenoids, such as aplysistatin derivatives.

New sesquiterpene hydroquinones from the Caribbean sponge Aka coralliphagum

Four new sulfated sesquiterpene hydroquinones siphonodictyals E1-E4 (1-4) and cyclosiphonodictyol A (5) were isolated from a sample of the Caribbean sponge Aka coralliphagum collected off the coast of San Salvador in the Bahamas. The structures of the new compounds were elucidated on the basis of mass spectrometric and NMR spectroscopic analysis. Compounds 1-4 are derivatives of siphonodictyal E (9). Siphonodictyal E4 (4) exhibited mild antiproliferation activity against L929 mouse fibroblast, KB-31 epidermoid carcinoma, and MCF-7 breast cancer cell lines, while siphondictyal E3 (3) and cyclosiphonodictyol A (5) showed moderate activity against Gram-positive bacteria.

Meroterpenes from marine invertebrates: structures, occurrence, and ecological implications

Meroterpenes are widely distributed among marine organisms; they are particularly abundant within brown algae, but other important sources include microorganisms and invertebrates. In the present review the structures and bioactivities of meroterpenes from marine invertebrates, mainly sponges and tunicates, are summarized. More than 300 molecules, often complex and with unique skeletons originating from intra- and inter-molecular cyclizations, and/or rearrangements, are illustrated. The reported syntheses are mentioned. The issue of a potential microbial link to their biosynthesis is also shortly outlined.

New Meroterpenoids from the Marine Sponge Aka coralliphaga

Three new sulfated meroterpenoids containing sesquiterpene and hydroquinone moieties, namely siphonodictyal A sulfate (1), akadisulfate A (2) and akadisulfate B (3), along with the known siphonodictyal B3 and bis(sulfato)-cyclosiphonodictyol A were isolated from the sponge Aka coralliphaga. Their structures were elucidated on the basis of spectroscopic data. Akadisulfate B and siphonodictyal B3 showed a radical-scavenging activity comparable with that of the known lipophylic antioxidant BHT.

Cytotoxic terpene quinones from marine sponges

The 1,4-benzoquinone moiety is a common structural feature in a large number of compounds that have received considerable attention owing to their broad spectrum of biological activities. The cytotoxic and antiproliferative properties of many natural sesquiterpene quinones and hydroquinones from sponges of the order Dictyoceratida, such as avarol, avarone, illimaquinone, nakijiquinone and bolinaquinone, offer promising opportunities for the development of new antitumor agents. The present review summarizes the structure and cytotoxicity of natural terpenequinones/hydroquinones and their bioactive analogues and derivatives.

Deep-sea natural products

This review covers the 390 novel marine natural products described to date from deep-water (>50 m) marine fauna, with details on the source organism, its depth and country of origin, along with any reported biological activity of the metabolites. Relevant synthetic studies on the deep-sea natural products have also been included.

New sesquiterpene quinols from a Micronesian sponge, Aka sp

Three new sesquiterpene quinols (1, 2, and 5) and two known ones (3 and 4) were isolated along with halistanol sulfate (6) from a marine sponge of the genus Aka collected from Yap Island, Federated States of Micronesia. Their structures were determined from spectral data, and the structure of siphonodictyal C (3) was revised. Sulfates 3 and 6 inhibit CDK4/cyclin D1 complexation, whereas 1 and 4 do not.

New prenylhydroquinone glycosides from Phagnalon rupestre

Three new hydroquinone glycosides were isolated from the MeOH extract of the aerial parts of Phagnalon rupestre. Their structures were elucidated as 1-O-beta-glucopyranosyl-1,4-dihydroxy-2-(3',3'-dimethylallyl)benzene (1), 1-O-beta-glucopyranosyl-1,4-dihydroxy-2-(3'-hydroxymethyl-3'-methylallyl)benzene (2), and 1-O-(4' '-O-caffeoyl)-beta-glucopyranosyl-1,4-dihydroxy-2-(3',3'-dimethylallyl)benzene (3) by spectroscopic methods.