Japanese sponge

The dicytodendrins A-E (Fig. 9) are one of the most recent 3,4-diarylpyrrole natural products to be reported [64], Their isolation by Fusetani and coworkers from a Japanese marine sponge was reported in 2003. These substances (144-148) have been shown to inhibit telomerase at a concentration of 50 pg/mL thereby making such compounds potentially useful as antitumor agents given that telomerase activity is found in 90% of cancer cells but... 

Cyclotheonamide A (CtA), a macrocyclic marine natural product derived from the Japanese sponge, Theonella sp., inhibits thrombin with an IC50 value of... 

A species of Halichondria from the Marshall Islands contained an isothiocyanate (249) [255] and an isothiocyanate based on the guai-6-ene skeleton (250) was isolated from an unidentified sponge from Japanese waters [256]. Acanthella pulcherrima from Australia contained two isothiocyanates (251-252), in addition to known sesquiterpenes [257]. 

A Japanese sponge of the Adociidae family contained 10-isothiocyanatobiflora-4,15-diene (290), which was identified by spectral analysis [283], A. cavernosa from Fiji yielded a diterpene isothiocyanate (291) [284]. 

An unusual 6a-sterol sulfate (557) was isolated from Dysidea fragilis, from the Venetian lagoon and displayed cytotoxicity against two different tumour cell lines in vitro [460]. Tamosterone sulfates (558-559) are a C14 epimeric pair of polyhydroxylated sterols isolated from a new species of Oceanapia [461]. The Japanese marine sponge Epipolasis sp. contained the steroid polasterol B sulfate (560) along with the known compound halistanol sulfate (532). The structure of compound 560 was determined on the basis of spectroscopic evidence and a chemical conversion [462]. 

Discorhabdins A (8), B (9) and C (10) have been isolated from several sponge species of the genus Latrunculia from New Zealand. They are powerful cytotoxins with IC50 values against the murine leukemia P-388 cell line in the range 0.03 - 0.01 pg/ml. Discorhabdin A has also been isolated from a Japanese sponge of the genus Prianos [29]. 

A new bromopyrrole alkaloid 15 along with racemic 16 was isolated from the Japanese marine sponge Homaxinellct sp. They exhibit weak cytotoxic activity against P-388 lymphocytic leukemia cells with ED50 values of 21.5 pg/ml and 30 pg/ml, respectively [34]. 

Perthamide B (1099) is a novel cyclic octapeptide found in a Theonella sp. sponge near Perth, Australia (1122). A collection of the Japanese sponge Halichon-dria cylindrata has afforded halicylindramides A-E (1100-1103), and the absolute configurations are shown (1123,1124). Each compound features a 4-bromophenyl-alanine residue. 

Theonellamides A-E (1104-1108), which are analogs of the previously isolated theonellamide F (7), were characterized from the Japanese sponge Theonella sp. (7725). The related theopalauamide (= P951) (1109) was isolated from Theonella swinhoei found in both Palau and Mozambique (1126,1127). It should be noted that a minor structural correction (misplaced methyl group) has been reported for the previously known theonegramide (1128). 

The antifouling sponge metabolite pseudoceratidine (1245) was characterized from the Japanese Pseudoceratina purpurea (1253). This spermidine derivative has excellent larval settlement and metamorphosis inhibitory activity against the barnacle Balanus amphitrite (ED50 = 8.0 pig cm-3), and is the first example of an antifouling spermidine derivative. The four tauroacidins A (1246/1247) and B (1248/1249), with tyrosine kinase inhibitory activity, were isolated from the... 

An Australian sponge Axinella sp. has afforded the novel axinellamines A-D (1310-1313), which exhibit activity against Helicobacter pylori (1301). The similar massadine (1314) from the Japanese sponge Stylissa aff. massa inhibits geranylger-anyltransferase type I and the fungus Candida albicans (1302). Like many of these 2-aminoimidazole alkaloids, 1310-1314 were isolated as acid salts trifluoroacetic acid salts in these cases. 

The Japanese sponge Discodermia calyx has yielded the new calyculin, calyculin J (1669) (1631). The highly toxic (ichthyotoxicity, hemolytic activity) prymnesin-1 (1670) and -2 (1671), possessing unprecedented structural complexity, were characterized from the red tide alga Prymnesium parvum (1632-1634). 

From a Japanese sponge of the genus Haliclona two cytotoxic alkaloids, haliclamines A and B (252 and 253), were isolated (213). They are proposed to be biogenetic precursors of the petrosins or sarains. 

The compounds isolated from the nudibranch Hexabranchus sanguineus varied with collecting location but usually included dihydrohalichondra-mide (261) and tetrahydrohalichondramide (268). Compounds 261, 263, 265, and 268 show antifungal activity and inhibit cell division in the fertilized sea urchin egg assay (218). Three cytotoxic macrolides, mycalolides A-C (269-271), were isolated from a Japanese sponge of the genus My-cale, and their structures were elucidated to be hybrids of ulapualides and halichondramide (219). 

Three hemolytic constituents were isolated from the Japanese hy-droid Solanderia secunda and identified as l-hexadecyl-sn-glycerol-3-phosphorylcholine (311), 1 -tetradecyl-sw-glycerol-3-phosphorylcholine (312), and l-(l-hexadecenyl)-s/i-glycerol-3-phosphorylethanolamine (313) (254) Eighteen long-chain aliphatic a,w-bisisothiocyanates (314-331) and three a-isothiocyano-w-formyl compounds (332-334) were isolated from a Fijian sponge (Pseudaxinyssa sp.) (255). 

Four antimicrobial peptides, discodermins A-D (383-386), isolated from the Japanese sponge Discodermia kiiensis also show inhibitory activity on the development of starfish embryos (317,318). Three ichthyo-toxic peptides, pardaxins P-1 through P-3 (387-389), were isolated from... 

As an illustration of two sorts of diaslereoselectivity, our next example is a natural product called penaresidin A. It was isolated from a Japanese sponge in 1991, and has the structure shown below OH... 

---