Clathria

Unusual pteridine alkaloids including 224-226 have been identified from sponges Clathria spp.) collected off Argentina <2002T4481>. The pteridines, which are 6(2 -hydroxypropyl) and 6-propyl derivatives of 1,3-dimethyl-lumazine, are linked to a core tryptophan through an ester and 1-, 2-, or 4-alkylation, respectively. 

An Acanthodendrilla sp. from Japan contained ten steroidal sulfates, acanthosterol sulfates A-J (561-570). Acanthosterol sulfates I (569) and J (570) showed antifungal activity against Saccharomyces cervisiae and its mutants [463]. Clathsterol (571), was isolated from the Red Sea sponge Clathria sp. The structure was established mainly by interpretation of spectral data and a chemical transformation. Clathsterol (571) was active against HIV-1 reverse transcriptase (RT) at a concentration of 10 iM [464]. Toxadocia zumi contains three sterol sulfates (572-574) that are antimicrobial, cytotoxic, ichthyotoxic and larvicidal [465]. 

Thio-D-mannose (638), the first example of a naturally occurring 5-thio-sugar has been isolated from Clathria pyramida [504] and was later synthesised in 12 steps from D-mannose [505]. 

Capon, R. J. and MacLeod, J. K., 5-Thio-D-mannose from sponge Clathria pyramida (Lendenfeld). First example of a naturally occurring 5-thiosugar., J. Chem. Soc., Chem. Commun., 1200, 1987. 

Leucetta leptorhapsis, the Antarctic rubber sponge, so called due to its stretched appearance, produces the acetogenin rhapsamine (Structure 7.22), which bears the unusual bis(l,3-diaminoglyc-erol) group.39 Rhapsamine has antipredatory and cytotoxic activity and is structurally related to the coriacenins, which are produced by the Mediterranean sponge Clathria coriacea.104... 

Three novel pteridine alkaloids bearing two pteridine units and a tryptophan core have been isolated from the sponge Clathria sp <02T4481>. Structural requirements for inhibition of neural nitric oxide synthase (NOS-I) and 3D-QSAR analysis of 4-oxo-pteridine-based and 4-amino-pteridine-based inhibitors have been reported <02JMC2923>. 

Thio-D-mannose 7, discovered as a metabolite of the marine sponge Clathria pyramida (Lendenfeld), is still unique as the only example of a 5-thioaldopyranose occurring in nature [45]. Shortly after its discovery, a synthesis from methyl 2,3 5,6-di-0-isopropylidene-a-D-mannofurano-side was reported [46], which essentially followed the principle of the approach depicted in Scheme 9.1. Earlier, 5-thio-D-mannose had been available by molybdate catalyzed epimerization [47,48] of 5-thio-D-glucose 10 [37]. 

The only arylquinolizidine alkaloid to have been isolated from a marine source is clathyrimine A (907), a unique tetrahydroquinolizinium alkaloid isolated from the Indonesian sponge Clathria basilana (594). This compound was imstable in solution, and imderwent partial decarboxylation to clathyrimine B (908) during NMR spectroscopic studies. The reaction could be driven to completion merely by heating at 40 C in deuteriated chloroform. 

Tanaka Y, Fujita Y, Katayama T (1977) Biochemical studies on the carotenoids in Porifera. Identification of the aromatic ketocarotenoid in Clathria frondifera and Tedania digitata. Bull Jpn Soc Sci Fish 43 767-772... 

Microcionidae° Antho, Artemisina, Clathria, Echinochalina, Echinoclathria, Holopsamma, Ophlitaspongia, Pandaros... 

Microcionidae Echinochalina, Eurypon Microciona (= Clathria), Sesquiterpenes, aromatic carotenes, cyclic peptides, a polyarsenic compound Echinochalina)... 

Northcote, and Webb, 2002). Echinoclathria subhispida contains echinoclasterol sulfate, a polyhydroxylated sterol monosulfated at 2p, whose counterion is P-phenylethy-lammonium (see above) (Li et al, 1993). Clathsterol is a new 2p,3a- disulfated sterol which has anti-HIV-1 properties it was isolated from an undetermined species of the genus Clathria harvested in the Red Sea, in the Dahlak Archipelago (Rudi et al, 2001). This type of polyhydroxylated and sulfated sterol is common among halichondrid sponges (see above). 

More recently, three meroterpenes, or related compounds, have been isolated from one Australian species of the genus Clathria and two of them, clathrins B and C, can be considered to be aromatic meromonoterpenes. Clathrin A is a merosesquiterpene (Capon, Miller, and... 

Microcionamides [Clathria abietina) and Other Cyclic Peptides... 

Microdonamides A and B, on the contrary, are cytotoxic to human cancer lines MCF-7 and SKBR-3 (breast cancer), with IC50 values of 100-180 nM, and inhibit the tuberculosis badllus Mycobacterium tuberculosis with MIC 5.7 pM. These two peptides were isolated from Clathria (= Tha-lysias) abietina harvested in the Philippines, and are the only other examples of such derivatives from the Micro-cionidae. Microdonamides have an atypical structure and are considered as . . . the first examples of sponge-derived linear peptides that are cyclized via a cysteine residue" (Davis et al, 2004). 

---