Soft corals toxins

Ne eman I, Fishelson L, Kashman Y, Sarcophine. New toxin from the soft coral Sarcophyton glaucum PAcyonsena) Toxicon 12 593—598, 1974. 

Additional biological properties have been reported from toxins of marine origin, such as actin-inhibitory activity [527,528], and inactivation of a serotonin-gated ion channel [529], More recently, marine toxins have also been identified from sea cucumbers [530], and coral reef animals [531], These toxins, which have been detected in zoanthid species of the genus Palythoa, also occur in various marine organisms living in dose association with zoanthid colonies, e g., sponges, soft corals, mussels and crustaceans. 

Enantioselective reduction of an a, -enone. One of the final steps in a synthesis of palytoxin, a toxin of marine soft corals containing 115 carbon atoms and 60 chiral centers, involves, in addition to the usual deprotections, enantioselective reduction of an enone to an allylic alcohol. A mixture (1 1) is obtained with borohydrides, but lithium borohydride combined with EuC13 provides an 8 1 mixture, with the desired isomer being favored. 

Sarcophyton species contain diterpenes up to 10% of their dry weight, and this large quantity of secondary metabolites plays an important role in the survival of Octo-corals with defensive, competitive, reproductive, and possibly pheromonal functions. Soft corals lacking physical defense thus seem to be protected from predation by the presence of diterpene toxins in their tissue. Nearly 25 species of this genus occurring in different seawaters have been examined chemically so far, and more than 80 cembranoid diterpenes have been isolated from the Sarcophyton genus since the 1970s. 

Biotic stress factors due to predation are usually severe in coral reefs whose biota is characterized by rich and diverse fauna and flora. Many of sessile organisms such as sponges, ascidians, soft corals, etc. have had toxins and noxious compounds to protect themselves fi om the predators. These compounds may be important sources for natural products based drugs and medicines [1-3]-... 

Neurotoxin found in soft coral and believed to be produced by a flagellate and concentrated by the coral (Palythoa toxica). Most deadly non-protein toxin known LD50 (mice) 0.15 pg/kg. 20-50 times as toxic as tetrodotoxin. Intense vasoconstrictor 0.06 pg/kg IV in dogs produced a transient rise in blood pressure followed by rapid hypotension and death within 5 min. 

Paly toxin Marine soft coral Biotoxin ... 

Marine toxins may be developed from marine organisms. Examples include saxitoxin, tetrodotoxin, palytoxin, brevetoxins, and microcystin. Saxitoxin is a sodium-channel blocker and is most toxic by inhalation compared to the other routes of exposure. Saxitoxin and tetrodotoxin are similar in mechanical action, toxicity, and physical attributes. They can be lethal within a few minutes when inhaled. It has not yet been chemically synthesized efficiently, or easily created in large quantities from natural sources. Palytoxin is produced from soft coral and is highly toxic. It is, however, difficult to produce or harvest from nature. 

Tetrodotoxin, from the puffer fish and other members of the order Tetraodontiformes, is a neurotoxin much like saxitoxin in its mechanism of action, toxicity, and physical characteristics. Palytoxin, from the soft coral Palythoa tuberculosa, is extremely toxic and quite stable in impure form, but difficulty of production or harvest from nature reduces the likelihood that an aggressor would use it as an MCBW. The brevetoxins, commonly associated with red tide dinoflagellate blooms, and the blue-green algal toxins like microcystin, a hepatotoxin, have limited toxicity. 

An association has also been described between young of the fish Abudefduf leucogaster and the alcyonarian Lithophyton viridis. The latter secretes a toxic chemical substance rendering it unpalatable to large predators. The toxin affects A. leucogaster more slowly than other fishes they can thus remain near the soft coral and benefit indirectly from its chemical protection 405). 

Three new sesquiterpenes named valerenenol (517), isovalerenenol (518), and anhydrovalerenenol (519) from an unidentified Okinawan soft coral are based on the bicarbocyclic carbon skeleton of e /-valeren-ane 413) and pacifigorgiol (520) is a related sesquiterpene from Pacifigorgia adamsii 414). The structure of 520 which showed modest activity as a fish toxin was established by a combination of spectral and X-ray crystallographic techniques and was confirmed by an eleven step synthesis 415). 

Coll, J.C., and P.W. Sammarco Terpenoid Toxins of Soft Corals (Cnidaria, Octo-corallia) Their Nature, Toxicity, and Ecological Significance. Toxicon Suppl. 3, 69 (1983). 

Bowden, B.F., Alino, P.M., and Coll, J. (1992) Soft corals and their toxins, in Toxins and Targets (eds D. Watters, M. Lavin, D. Maguire, and J. Pearn), Harwood Academic Publishers, Newark, Nf, pp. 55-64. 

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