In order to search for novel bioactive compounds, we have investigated the secondary metabolites of the soft corals Nephthea erecta, Lobophytum durum, and Sarcophyton ehrenbergi. Chemical examinations on the organic extracts of N. erecta, have resulted in the isolation of six new sesquiterpenoids (1-6), a new calamenene-type sesquiterpene with a mercaptan group, erectathiol (7), a new tri-nor-eudesmadienone (8), two known sesquiterpenoids (9 and 10), one novel seco-germacrane sesquiterpene (11), three unexpected artificial 19-oxygenated steroids (12-14), as well as twelve new polyhydroxylated steroids (15-26). Furthermore, twelve new cembranolids, durumolides A-L (27-38), three unprecedented hemiketal cembranoids, durumhemiketalolides A-C (39-41), six previously described cembranolids (42-47), together with one known metabolite, peridinin (48), were isolated from the acetone extracts of L. durum. Chemical investigation of S. ehrenbergi, has led to the isolation of a known ceramide (49), two new cerebrosides, sarcoehrenosides A (50) and B (51), along with three previously characterized cerebrosides (52-54). The structures of the isolated metabolites were elucidated through extensive spectroscopic analyses, while the relative stereochemistry of 10 and 44 were further confirmed by X-ray diffraction analyses. Moreover, the absolute configurations of 24, 25, 29, 34, 38, and 43-45 were established by application of modified Mosher¡¦s method. The cytotoxicities, antibacterial activities, anti-inflammatory effects, and inhibition assay of HCMV (human cytomegalovirus) endonuclease activities of these isolated metabolites were evaluated in vitro.

Corals are the dominant species of the coral reefs. The diversity of species is classified by traditional morphological traits, especially relied on the calcious deposits-sclerites. The formation of sclerites may be affected by the environmental conditions; therefore, some controversies may exist. The ambiguities may be clarified with molecular approaches. Five soft coral species, Lobophytum pauciflorum, Sinularia leptoclado, Sinularia flexibilis, Sarcophyton sp., Nephthea erecta were chosen for this study. The total mitochondrial DNA sequences were determined by PCR and primer walking. The genome contains 18562 bp, 18732 bp, 18752 bp, 18806 bp, 18716 bp separately, which harbors 14 protein-coding genes (ATP6¡BATP8¡BCOI¡BCOII¡BCOIIII¡BCYTB¡BND1¡BND2¡BND3¡BND4¡BND4L¡BND5¡BND6¡BMSH), 2 rRNA and only 1 tRNA genes. The phylogenetic relationship of alcyonacea corals were analyzed and compared with published sequences. The possibility of using a short ¡§DNA bar-code sequence¡¨ of the mitochondria as an alternative for species identification may be feasible. We found the short DNA signature sequences for these five corals. They may speed up the identification of corals in the long run.