## 2 Classes of Secondary Metabolites
### Diterpenes
Additionally, another nine cembranoids, sacrophytrols M-U **271-279**, were also reported. Their structures were interpreted with extensive spectral analysis and chemical conversion and the absolute configuration for sacrophytrols M-S **271-277** were investigated by the modified Mosher's assay. Sarcophytrols R and S **276** and **277** revealed a unique decaryiol skeleton with an uncommon C12/C15 cyclization [88]. Another cembranoid, trocheliolide B **280** from _S. trocheliorhorn_ was isolated [89]. Chemical determination of _S. trocheliorhorn_ organic extract, yielded pyrane-based dicterpene, 9-Hydroxy-10,11-dehydro-sarcotrocheliol **281**[90]. From _S. ethenbergi_ eight cembranoids, sarcophytonoxides A-E **282-286** were identified. Sarcophytonoxide A **282**, a cembrane dicterpene with epoxide, dihydrofuran, acetyl group and three olefin bonds were confirmed by spectral data analysis while sarcophytonoxide D **285** was the deacetylated form of sarcophytonoxide C **284** which has a structure similar to sarcophytonoxide A **282**. However, sarcophytonoxide C **283** differed in the chemical shift of C-19, C-6, C-7, and C-9 because of the 7,8-double bond configuration or chiral center of C-6. However, sarcophytonoxide E **286** differed in the position of acetyl group and the exocyclic double bond. [91]. From _S. trocheliorhorn_ a sarcolenane dicterpene, secodihydrosarsoleno **287** was identified [92]. The chemical investigation of both diethyl ether and dichloromethane extracts of _S. stellatum_ yielded the isolation of three cembranoid dicterpene and enantiomer, (+)-(1E,3E,11E)-7,8-epoxycembra-1,3,11,15-tetraene **288**, (+)-(7_R,8R_,14S_,1Z_,3E_,11E)-14-acetoxy-7,8-epoxycembra-1,3,11-triene **289**[93]. Five isopenroids from _S. glaucum_, 3,4,8,16-tetra-epi-lobocrasol, 1,15\(\beta\)-epoxy-deoxysarcophine, 3,4-dihydro-4\(\alpha\),7\(\beta\),8\(\alpha\)-trihydroxy-\(\Delta^{2}\)-sarcophine, ent-sarcophyolide E **290-293**, together with, 3,4-dihydro-4\(\alpha\)-hydroxy-\(\Delta^{2}\)-sarcophine, 3,4-dihydro-4\(\beta\)-hydroxy-\(\Delta^{2}\)-sarcophine **294** and **295** and klyflaccicembranol F **296** were reported and their structures were elucidated by spectral data. [70]. Moreover, five cembranoids, sarelengans C-G **297-301** from _S. elegans_ were also stated. Isolates structures were established by spectral data, and absolute configuration of sarelengans D-F **298-300** were investigated through single crystal X-ray diffraction [94]. Isolation of seven dicterpenes were reported from _S. ethenbergi_ and identified as sarcoehenbergilids A-C **302-304** together with sinuolides A and B **305** and **306**. The absolute configuration of sarcoehenbergilid A **301** was investigated by scattering of CaK\(\alpha\) radiation with the flack parameter [95]. Moreover, sarcoehenbergilid D-F **307-309**, dicterpenes isolated from _S. ethenbergi_ were isolated and their absolute configurations were investigated by experimental and TDDFT-simulated ECD spectra. Sarcoehenbergilid D **307** was found to differ from compound **301** only in stereochemistry [96]. Furthermore, five cembranes dicterpenes, Sarcoehenrolides A-E **310-314** were isolated from _S. ethenbergi_. Their chemical structures were determined through extensive spectral data. All isolates were related to ehrenbergol D **251** in structure, having an \(\alpha\),\(\beta\)-unsaturated-ylactone group at carbon-6 to carbon-19, however, they differ in migration of double bonds and/or oxidative configurations. Additionally, the absolute configuration of sarcoehenrolide A **310** was investigated by a single-crystal X-ray diffraction assay by Cu K\(\alpha\) radiation, and the absolute configurations of sarcoehenrolides B **311** and D **313** by TDDFT/ECD calculations [97]. From _S. infindibular_ two nitrogenous dicterpends with unusual tricycle [6.3.1.01,5] dodecane skeleton named, sarinfectamides A and B **315** and **316** and a known compound; nanolobatin B **317** were reported.