Corals Xenia

Xeniolides A (152) and B (153) are a pair of lactones, related to the prenylated caryophyllene xeniaphyllenol and xenicin, which have been isolated from the soft coral Xenia macrospiculata. Hydroxydilophol (154) is a germacrene-like diterpenoid which has been obtained from the brown alga Dictyota masonii. The full paper, including an X-ray analysis, has appeared on dictyodial and dictyolactone which were obtained from various Dictyota and Aplysia species. A... 

Again, soft corals and gorgonians are a rich source of diterpenoids of 19 structural classes, some of which are specific to them (35, 36). Besides tobacco plants, cembranoid diterpenes are limited to soft corals. Lophotoxin (126) isolated from sea whips of the genus Lophogorgia is a sodium channel inhibitor (3). Xenicin (127) from the soft coral Xenia elongata and briarein A (128) from the gorgonian Briareum asbestinum represent non-cembranolide diterpenes. Diterpenoids of these classes show antimicrobial, cytotoxic, and insecticidal activities. 

There have been no natural products investigations of soft corals from the cool temperate west coast of southern Africa. Soft corals are common along the south-east coast of South Africa and as part of our ongoing search for bioactive metabolites from the marine invertebrate fauna of the Tsitsikamma Marine Reserve we isolated four bioactive xenicane diterpenes, the tsitsixenicins A - D (93 - 96) from the endemic soft coral Capnella thyrsoidea (Family Nephtheidae) [91]. The structures of 93 -96 were delineated from standard analysis of their NMR data and comparison of these data with those published for related compounds e.g. 9-deacetoxy-14,15-deepoxyxeniculin (diastereomic with 93) isolated from the Red Sea soft coral Xenia macrospiculata [92]. 

An unusual intraspecific variation in the structures of the diterpene metabolites produced by the soft coral Eleutherobia aurea (formerly Alcyonium aurea) has been observed from several collections of this species made from the Aliwal Shoal and Sodwana Bay regions [95]. The Sodwana Bay specimens yielded antheliatin (106), zahavins A and B (107,108) [96], sarcodictyin A (109) and eleuthosides A and B (110, 111) [95], In addition to 107, other xenicane diterpenes including 9-deacetoxy-14,15-deepoxyxeniculin (112), 7,8-epoxyzahavin A (113) and xeniolide C (114) were isolated from the Aliwal Shoal specimens of E. aurea [97]. Sarcodictyon A and 9-deacetoxy-14,15-deepoxyxeniculin were isolated previously from the stoloniferous octocoral Sarcodictyon roseum [98] and the soft coral Xenia obscuronata [99]. 

Kashman, Y., and A. Groweiss New Diterpenoids from the Soft Corals Xenia macrospiculata and Xenia obscuronata. J. Org. Chem. 45, 3814 (1980). 

Anta, C., Gonzalez, N., Rodriguez, J., and Jimenez, C. (2002b) New Xenia diterpenoids from the Indonesian soft coral Xenia sp. /. Nat. Prod., 65, 766-768. 

Bishara, A., Rudi, A., Goldberg, I., Benayahu, Y., and Kashman, Y. (2006) Novaxenicins A-D and xeniolides I-K, seven new diterpenes from the soft coral Xenia novaebrittania. Tetrahedron, 62, 12092-12097. 

El-Gamal, AA.H., Chiang, C.-Y, Huang, S.-H., Wang, S.-K., and Duh, C.-Y. (2005b) Xenia diterpenoids from the Formosan soft coral Xenia blumi.J. Nat. Prod., 68,1336-1340. 

Fattorusso, E., Romano, A., Taglialatela-Scafati, O., Achmad, M.J., Bavestrdlo, G., and Cerrano, C. (2008a) Xenimanadins A—D, a family of xenicane diterpenoids from the Indonesian soft coral Xenia sp. Tetrahedron, 64, 3141—3146. 

Groweiss, A. and Kashman, Y. (1978b) Xeniculin, xeniaphyllenol and xeniaphyllenol oxide new diterpenoids from the soft coral Xenia macrospiculata. Tetrahedron Lett., 19, 2205-2208. 

Iwagawa, T., Amano, Y, Nakatani, M., and Hase, T. (1996b) New xenia diterpenoids from a soft coral, Xenia species containing fatty add acyl side chains. Bull. Chem. Soc. Japan, 69, 1309—1312. 

Iwagawa, T, Nakamura, K., Hirose, T., Okamura, H., and Nakatani, M. (2000b) New xenicane diterpenes isolated from the acetone extract of the soft coral Xenia Jlorida. J. Nat. Prod., 63, 468 72. 

Miyaoka, H., Mitome, H., Nakano, M., and Yamada, Y. (2000) Xeniaoxolane a new xenicane-type diterpenoid from the Okinawan soft coral, Xenia sp. absolute configuration of xeniaoxolane, xeniolide-A and xenialactol. Tetrahedron, 56, 7737-7740. 

Vanderah, D.J., Steudler, P.A., Ciereszko, L.S., Schmitz, F.J., Ekstrand, J.D., and Van der Helm, D. (1977) Marine natural products. Xenidn a diterpenoid possessing a nine-membered ring from the soft coral Xenia elongata.J. Am. Chem. Soc., 99, 5780-5784. 

Discovered in 1977 in xenicin, isolated from the soft coral Xenia ebngata, the carbon skeleton of xenicane is the... 

Iwagawa, X, Kawasaki, J., and Hase, X (1998) New Xenia diterpenes isolated from the soft coral Xenia Jlorida.J. Nat. Prod., 61, 1513-1515. 

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