## 2 Classes of Secondary Metabolites
### Diterpenes
Another seven polyoxygenated cembranoids with \(\alpha\)-methylene-\(\gamma\)-lactone group identified as crassocolides G-M **89-95**, were reported. The structures of all compounds were determined through a full spectral data analysis, and the absolute configuration of crassocolide G **89** was investigated by modified reaction of Mosher's assay [47]. Other crassocolides N-P **96-98** were isolated _from S. crassocoule_[48]. The CHCl\({}_{3}\)/MeOH extract of _S. flexuosum_ yielded three cembranes, identified through spectral data as flexusines A, B, and epimukulol **99-101**[49]. From ethyl acetate extract of _S. stolidum_, seven cembranes, sarcostolides A-G **102-108**, alongside isosacrophin **109**, were reported, and their structures were elucidated through spectral data. The authors also proposed a reasonable biogenic pathway for all isolates, in which cyclization of GPP with lactonization and oxidation may lead to the production of sarcostolide C **104**. Sarcostolides A and B **102** and **103** and D-G **105-108** were converted from saccostolide C **104** through migration and isomerization of double bonds [50]. _Sarcophyton millilatensis_ methanol extract yielded cembranoid diterpenes identified as (-)-7\(\beta\)-hydroxy-8\(\alpha\)-methoxy-deepoxy-sarcophytoxide **110**, (-)-7\(\beta\),8\(\beta\)-dihydroxy-deepoxy-sarcophytoxide **111**, (-)-17-hydroxy-sarcophytonin A **112**, sarcophytol V **113**, and sarcophytoxide **114**[51]. Two embrane diterpenes known as 17-hydroxysarcophytoxide **115** and 7\(\beta\)-acetoxy-8\(\alpha\)-hydroxydeepoxysacrophine **116**, along with 7\(\beta\),8\(\alpha\), dihydroxydeepoxysacrophine **117**, sacrophotonin A **118**, and (-)-\(\beta\)-elemene **119** reported from _Sarcophyton_ sp., were isolated from _S. glaucum_[52]. Investigation of _S. glaucum_ extract led to the isolation of two cembranoids, (7\(R\),8\(S\))-dihydroxydeepoxy-ent-sarcophine **120** and secosarcophinolide **121**, in addition to, ent-sarcophin **122**. Structural elucidation of the isolates was established by their spectral data and chemical correlation, as (7\(R\),8\(S\))-dihydroxydeepoxy-ent-sarcophine **120** was found to be the enantiomer of (7\(S\),8\(R\))-dihydroxydeepoxysacrophine **123** and compound **121** has a unique butyl ester group at C-16 [53]. Seven cembranoids were isolated from _Sarcophyton_ sp., 5-epi-sinuleptolide **124**, lobohedleolide **125**, (7\(Z\))-lobohedleolide **126**, and two uncommon cembranoids, sarcofuranochemenolide A **127**; with a unique carbon skeleton of 8,19-bisnorfuranacochemenolide, and sarcofuranacochemenolide B **128**; a furanochemenolide [54]. Sarcophytons F and G **129** and **130**, another two dihydrofuranacophenanoids, were reported from _Sarcophyton_ sp. [55]. Nineteen compounds from _Sarcophyton_ sp., of which five cembrane diterpends were isolated and identified as 7-acetyl-8-epi- sinumaximol G **131**, 8-epi-sinumaximol G **132**, 12-acetyl-7,12-epi- sinumaximol G **133**, 12-hydroxysarcoph-10-ene **134**, and 8-hydroxy-epi-sarcophinone **135**, together with sinumaximol G **136**, were reported [56]. Five isolated cembranoids, sarccrossacolides A-E **137-141**, together with sinularolide **142**, were isolated from _S. crassocaule_. Structural elucidation of the compounds was determined through spectral analysis, and the absolute configuration of sarccrossacolide A **137** was investigated by modified Mosher's method. It is worth mentioning that sarccrossacolides A-D **137-140** possessed a tetrahydrofuran group with a seldomly found 4,7-ether bond, which was discovered previously in _Eunicea mammosa_ soft coral [57; 58]. Another seven cembranoids with \(\alpha\)-methylene-\(\gamma\)-lactonic group and rare trans 6,7-disubstituted double bond, uncovered earlier only in soft coral _Eunicea pinta_, identified as sarccrossacolides F-L **143-149**, were isolated from _S. crassocaule_[59]. Besides the abovementioned sarccrossacolides, another three sarccrossacolides, M-O **150-152**, from _S. crassocaule_, were identified.