Gorgonian corals

PGAj derivatives can be obtained in relatively large amounts from gorgonian corals. Since PGAs are of little pharmaceutical interest, they are converted commercially to the highly active PGFj, and PGEj (G.L. Bundy, 1971, 1972). 

A guinea pig ileum bioassay was used to detect and aid in the isolation of a smooth-muscle-contracting substance from the Japanese gorgonian coral Euplexaura erecta [108]. This process led to the isolation of prostaglandin F2a (17) from the MeOH extract of the coral. Its identification was based on comparison with authentic PGF2a and its methyl ester by TLC, and comparison with authentic methyl PGF2a trimethylsilyl ether by mass spectrometry. Because of the nature of the techniques employed, some aspects of the stereochemistry in this isolate of PGF2a remain uncertain. 

Izac, R.R. Poet, S. Fenical, W. van Engen, D. Clardy, J. (1982) The structure of pacifigorgiol, an ichthyotoxic sesquiterpenoid from the Pacific gorgonian coral Pacifigorgia cf. adamsi. Tetrahedron Lett., 23, 3743-6. 

Kawaguti, S., Kamishima, Y. Electron microscopy on a gorgonian coral Anthoplexaura dimopha. Pubis. Seto mar. biol. Lab. 20, 785 (1973)... 

Gorgonians produce the largest complement of chlorine-containing marine metabolites - more than 50 were illustrated in the first survey (7) - and many more nonchlorinated gorgonian diterpenes are known (665-667). There is evidence to indicate that these gorgonian diterpenoids are feeding deterrents to reef fishes. Gorgonian corals can achieve densities of up to 20 colonies per square meter on the reef (668, 669). 

Sung P-J, Gwo H-H, Fan T-Y, Li J-J, Dong J, Han C-C, Wu S-L, Fang L-S (2004) Natural Product Chemistry of Gorgonian Corals of the Genus Junceella. Biochem Syst Ecol 32 185... 

Fenical W, Pawlik JR (1991) Defensive Properties of Secondary Metabolites from the Caribbean Gorgonian Coral Erythropodium caribaeorum. Mar Ecol Prog Ser 75 1... 

Harvell CD, Fenical W, Roussis V, Ruesink JL, Griggs CC, Greene CH (1993) Local and Geographic Variation in the Defensive Chemistry of a West Indian Gorgonian Coral (Briareum asbestinum). Mar Ecol Prog Ser 93 165... 

Sung P-J, Fan T-Y, Fang L-S, Sheu J-H, Wu S-L, Wang G-H, Lin M-R (2003) Juncin N, a New Briarane-Type Diterpenoid from the Gorgonian Coral Junceella juncea. Heterocycles 61 587... 

Kubota NK, Kobayashi Y, Iwamoto H, Fukazawa Y, Uchio Y (2006) Two New Haloge-nated Briarane Diterpenes from the Papuan Gorgonian Coral Junceella fragilis. Bull Chem Soc Jpn 79 634... 

Harvell, C. D., West, J. M., and Griggs, C., Chemical defense of embryos and larvae of a West Indian gorgonian coral, Invert. Reprod. Dev., 30, 239, 1996. 

Caribbean gorgonian coral Plexaura homomalla, Mar Ecol. Prog. Ser., 52, 95, 1989. 

Rodriguez, A. D. and Boulanger, A., New guaiane metabolites from the Caribbean gorgonian coral, Pseudopterogorgia americana, J. Nat. Prod., 60, 207, 1997. 

Pawlik, J.R., Burch, M.T., and Fenical, W., Patterns of chemical defenses among Caribbean gorgonian corals a preliminary survey, J. Exp. Mar. Biol. Ecol., 108, 55, 1987. 

Kim, K., Antimicrobial activity in gorgonian corals (Coelenterata, Octocorallia), Coral Reefs, 13, 75, 1994. 

West, J.M., Plasticity in the sclerites of a gorgonian coral tests of water motion, light level, and damage cues, Biol. Bull., 192, 279, 1997. 

Vrolijk, N.H., Targett, N.M., Baier, R.E., and Meyer, A.E., Surface characterization of two gorgonian coral species implications for a natural antifouling defence, Biofouling, 2, 39, 1990. 

The gorgonian coral Plexaura homomalla is a source of prostaglandin A2. This compound can be converted to medically useful prostaglandins that regulate mammalian reproduction, blood pressure, and digestion. 

Both antipatharian and gorgonian corals can also occur in golden varieties. Here there is even more difBculty in identifying the species with absolute accuracy as black coral can be bleached to a golden colour. The bleach can permeate quite deep into the coral, and it can be impossible to tell without complicated tests - srtiether the golden colour is natural or bleached (Figs 11.17 and 11.18),... 

Fignre 11.19 Slice of golden gorgonian coral, showing growth rii and absence of central canal. Natural colour (magnified). 

According to Greek mythology, there were three gorgons. They were sisters, and they all had wings, claws, enormous teeth, and snakes for hair. Medusa was the only sister who was mortal, and she was beheaded by Perseus in the course of one of his heroic feats. When he put the head down on a bed of leaves and seaweed, the snakes immediately turned to red coral. The gorgonian corals take their name from the myth. 

Iwata s synthesis of subergorgic acid (30), a silphiperfolane derivative isolated from a gorgonian coral, involved the reductive fragmentation of the cyclobutanone (28) to the alcohol (29) via an intermediate aldehyde (Scheme 13). 

Recently, Pseudopterosin C, a diterpene riboside isolated from the gorgonian corals Pseudopterogorgia bipinata and P. elisabethae [134] was launched by Estde Lauder as an additive to anti-aging cosmetics. It exhibits potent antiinflammatory and analgesic activities by reversibly affecting both, lipoxygenase and phospholipase A2 [135]. 

Heterocyclic natural products of gorgonian corals of genus Briareum exclusive of briarane-type diterpenoids 02H(57)1705. 

Ribes, M., Coma, R. and Gili, J.M. (1998) Heterotrophic feeding by gorgonian corals with symbiotic zooxanthella. limnology and Oceanography, 43, 1170-1179. 

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