Soft corals sarcodictyins

Scheme 6.3 illustrates a few of the main structural classes of soft coral compounds. Included in this list are the tubulin interactive agents, eleutherobin 41 and sarcodictyin A 42, which show nanomolar potency against cancer cell lines. Also of interest are the pseudopterosin A 44 terpenoids which reduce inflammation. Two other terpenoids, sarcophytol A 43 and sinulodurin A 45, have shown micromolar activity against BALB/3T3 and mammary epithelial cells respectively. 

The isolation of sarcodictyin A 42 (Scheme 6.3) began with a stolonifer coral Sarcodictyon roseum collected in 1986 off Cap Bear on the French Mediterranean coast.380 Soon afterwards, a series of sarcodictyins C, D, E and F414 were also found from the same species. Two other soft coral sources of sarcodictyins were later discovered—one from a South African Eleutherobia aurea3S1 and another from Bellonella albiflora378 collected in Southern Japan, which also yielded the (Z) diastereomer of sarcodictyin A. 

The anti-mitotic diterpene Eleutherobin (35) and Sarcodictyins A - D (36a-d) are structurally related, natural compounds isolated from the marine soft coral Eleutherobia spec, and Sarcodictyon roseum,... 

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]. 

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