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Four new pregnane steroids, 3β,4β,16β-trihydroxypregna-5,17-diene-10,2-carbolactone (1), 16β-acetoxy-3β,4β-dihydroxypregna-5,17-diene-10,2-carbolactone (2), 12β-acetoxy-3β,4β,16β-trihydroxypregna-5,17-diene-10,2-carbolactone (3), and 12β,16β-diacetoxy-3β,4β-dihydroxypregna-5,17-diene-10,2-carbolactone (4) were isolated from an extract of an Epipolasis sp. marine sponge. The structures of the new compounds were determined by extensive NMR spectroscopic analysis and comparison with data from previously reported compounds.

Marine sponges (porifera) have proved to be a prolific source of unique bioactive secondary metabolites, among which the alkaloids occupy a special place in terms of unprecedented structures and outstanding biological activities. Identification of active cytotoxic alkaloids extracted from marine animals, particularly sponges, is an important strive, due to lack of knowledge on traditional experiential and ethnopharmacology investigations. In this report, a comprehensive survey of demospongian bioactive alkaloids in the range 1987–2020 had been performed with a special emphasis on the potent cytotoxic activity. Different resources and databases had been investigated, including Scifinder (database for the chemical literature) CAS (Chemical Abstract Service) search, web of science, Marin Lit (marine natural products research) database. More than 230 representatives of different classes of alkaloids had been reviewed and classified, different genera belonging to the phylum porifera had been shown to be a prolific source of alkaloidal molecules, including Agelas sp., Suberea sp., Mycale sp., Haliclona sp., Epipolasis sp., Monanchora sp., Crambe sp., Reniera sp., and Xestospongia sp., among others. The sufficient production of alkaloids derived from sponges is a prosperous approach that requires more attention in future studies to consider the constraints regarding the supply of drugs, attained from marine organisms.

Epipolasis tubulata sp. nov. Figures 115 a–g Material examined. Holotype RMNH Por. 9965 (larger specimen), Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station G56, 7.26°N 56.6667°W, depth 67–68 m, Agassiz trawl, 10 May 1966. Paratype RMNH Por. 10549 (smaller specimen), same data as holotype. Description. (Fig. 115 a) Sponge forms low thick-walled tubes, diameter of the larger tube 1.5 cm, height 2 cm. Largest tube opening 8 mm in diameter. Surface smooth, but irregular around the oscules. Color greyish brown. Consistency compressible. The smaller paratype (Fig. 115 a1) is similar. Skeleton. The surface (Fig. 115 b) is a halichondrioid tangential crust of intercrossing spicule tracts and single spicules, 2–10 spicules in diameter. This is carried by choanosomal spicule tracts (Fig. 115 c), likewise 2–10 spicules in cross section, surrounded by a largely confused mass of single spicules and numerous single raphides, partially arranged in thin trichodragmas. Spicules. (Figs 115 d–g) Oxeote styles, trichodragmas. Oxeotes, style-like, smooth, slightly fusiform, usually somewhat curved, with a faint subapical constriction, in two distinct size categories, (1) larger (Figs 115 d,d1), 462– 601 –618 x 12 – 16.3 –19 µm, and (2) smaller (Figs 115 e,e1), 192– 286 –324 x 5 – 7.4 –9 µm. Raphides, partially in thin trichodragmas (Fig. 115 f), but many raphides (Fig. 115 g) are strewn singly throughout the skeleton; provided with a lanceolate hook at both ends (Fig. 115 g1), 76– 87 –114 x 0.3–0.4 µm; trichodragmas up to 20 µm in diameter. Distribution and ecology. Guyana Shelf, at 67–68 m depth. Etymology. The name refers to the tubular shape of the sponge. Remarks. The genus assignment is tentative. At first the species was assigned to the axinellid genus Dragmaxia (cf. above), because of the combination of smooth stylote spicules with trichodragmas. However, the clear division into a larger and a smaller category of megascleres added to the tangential halichondrioid ectosomal skeleton, precludes membership of the genus Dragmaxia. So far, Epipolasis has been limited to species with large and small oxeas, although stylote modifications are reported in the type species, Spongosorites suluensis Wilson, 1925. There is one other Epipolasis in the Central West Atlantic, E. profunda Díaz, Pomponi & Van Soest, 1993, but this has much larger spicules (up to 1600 x 29 µm), which are predominantly proper oxeas; trichodragmas are only half as long as those of the new species., Published as part of Van, Rob W. M., 2017, Sponges of the Guyana Shelf, pp. 1-225 in Zootaxa 1 on pages 184-185, DOI: 10.5281/zenodo.272951, {"references":["Wilson, H. V. (1925) Silicious and horny sponges collected by the U. S. Fisheries Steamer ' Albatross' during the Philippine Expedition, 1907 - 10. In: Contributions to the biology of the Philippine Archipelago and adjacent regions. Bulletin of the United States National Museum, 100 (2, part 4), 273 - 532.","Diaz, M. C., Pomponi, S. A. & Van Soest, R. W. M. (1993) A systematic revision of the central West Atlantic Halichondrida (Demospongiae, Porifera). Part III: Description of valid species. In: Uriz, M. - J. & Rutzler, K. (Eds.), Recent Advances in Ecology and Systematics of Sponges. Scientia Marina, 57 (4), 283 - 306."]}

Spirastrellolides A (1) and B (3) have been isolated as free acids from a marine sponge Epipolasis sp. collected in the East China Sea. These compounds had been isolated from the Caribbean marine sponge Spirastrella coccinea after conversion to the methyl ester. We examined the cytotoxic activities of 1 and 3 and found that the activities of the free acids are comparable to those of the corresponding methyl esters.

Two new marine species of the family Halichondriidae, Ciocalypta sasuensis n. sp. and Epipolasis maraensis n. sp., are collected from Chujado Island and Jejudo Island, Korea during 2000–2005. Ciocalypta sasuensis n. sp. is closely related to C. penicillus (Bowerbank, 1864) in the type of shape and ectosomal skeleton. However, C. sasuensis n. sp. is larger than Ciocalypta penicillus. Epipolasis maraensis n. sp. is similar to E. suluensis (Wilson, 1925) in the type of skeleton, but is different in size of spicule and growth form. Its oxeas and raphide are smaller than E. suluensis's. The growth form of this new species is semispherical and massive, but E. suluensis is lamellated.

The antibacterial properties of organic extracts of 15 species of sponges collected from a depth of 30 m in the coastal waters off Gopalpur (Bay of Bengal) were tested against six virulent fish pathogens. The extracts of 11 sponges showed species-specific antibacterial activity. Four extracts exhibited broad antibacterial activity against three or more species. Epipolasis topsenti was active against all the six pathogens and showed the lowest minimum inhibitory concentration (MIC) value of 12.5 μg against three pathogens. Chromatographic fractionation of extracts yielded enriched fractions with increased activity and lower MIC values.

A new diterpene, umabanol, has been isolated from the sponge Epipolasis kushimotoensis and its structure determined by spectroscopic analysis. Umabanol possesses a new tetracyclic ring system related to verrucosane class diterpenes.

Two diterpenes, epipolone (1) and epipolol (3), produced by terpenoid pathways leading to a tricarbocyclic structure with an irregular "head to tail" isoprene configuration, have been isolated from the Caribbean marine sponge Epipolasis reiswigi collected in Puerto Rico. The structures of 1 and 3 were elucidated largely by 1D and 2D NMR methods and chemical conversion.

Four Novel Diterpenes, Cyanthiwigin A-D (1–4) Have Been Isolated From The Marine Sponge E. Reiswigi And Their Structure Elucidated By Mass And Mainly Nmr Spectra. The Tricarbocyclic Structure Of 1 Was Confirmed By An X-Ray Analysis And Its Absolute Configuration Was Established To Be 4s, 5r, 6s, 9s By The Modified Mosher's Method. The Four Compounds Have The Same Planar Skeleton As Cyanthin But Differ In Their Stereochemistry.

Two novel steroids, polasterol A (1) and polasterol B sulfate (2), along with two known compounds, 22(E),24-isopropylcholesta-5, 22-dien-3 beta-ol (3) and halistanol sulfate (4), have been isolated from the Japanese marine sponge Epipolasis sp. The structures of 1 and 2 were determined as 3 beta-hydroxy-24-isopropylcholesta-5, 22(E)-dien-7-one and 24xi-isopropenylcholesta-22(Z), 28(29)-diene-2 beta,3 alpha,6 alpha-triyl trisodium sulfate on the basis of spectroscopic investigations and a chemical conversion.

Three new diterpenes, polasols A-C (1-3), have been isolated from the Japanese marine sponge Epipolasis sp. The structures of 1-3 were assigned primarily by 2D NMR methods.

Two new sterols, epipolasterol and 22(23)-dihydroepipolasterol, have been isolated from the marine sponge Epipolasis sp. These are unusual metabolites as they both contain a t -butyl group in the sterol side chain. In addition, the presence of two degrees of unsaturation in the side chain of epipolasterol is rare. The known sterol, 22-dehydro-24-isopropylcholesterol was also found in this sponge.

Two diterpenes, epipolone (1) and epipolol (3), produced by terpenoid pathways leading to a tricarbocyclic structure with an irregular "head to tail" isoprene configuration, have been isolated from the Caribbean marine sponge Epipolasis reiswigi collected in Puerto Rico. The structures of 1 and 3 were elucidated largely by 1D and 2D NMR methods and chemical conversion.

A new diterpene, umabanol, has been isolated from the sponge Epipolasis kushimotoensis and its structure determined by spectroscopic analysis. Umabanol possesses a new tetracyclic ring system related to verrucosane class diterpenes.

Two isothiocyanates, epipolasin-A 1 and-B 2, and two corresponding thiourea derivatives, epipolasinthiourea-A 14 and-B 15, were isolated from the marine sponge E. kushimotoensis. Their structures were elucidated on the basis of chemical and spectral evidence. The thioureas 14 and 15 showed cell growth inhibition activity.

Three new species of Demospongiae from coral reefs of the Archipiélago de Los Roques National Park (Venezuelan Caribbean) and Curaçao (Netherlands Antilles) are described, viz. Eurypon laughlini n. sp., Topsentia roquensis n. sp., and Epipolasis reiswigi n. sp. The new species and the genera to which they have been assigned are discussed, as a result of which the genus Fasubera De Laubenfels, 1936, is synonymized with Eurypon Gray, 1867, and the genus Epipolasis is redefined based on characters of its typespecies. Extensive ecological data are provided for each species.

Two H,K-ATPase inhibitors and an inactive related compound have been isolated from a marine sponge Epipolasis sp. They are aromatic sesquiterpene alpha-curcumenes.