Clavukoelloids A—M, Thirteen Rare N‐Containing Nardosinane Type Sesquiterpenoids from the Soft Coral Clavularia koellikeri

Abstract

Comprehensive SummaryThirteen new nitrogen‐containing nardosinane‐type sesquiterpenoids, clavukoelloids A—M (1—13) with unique acrylamide fragments vs. the reported general nardosinane‐type sesquiterpenoids containing lactone, were isolated from the soft coral Clavularia koellikeri collected from the South China Sea. The structures and absolute configurations of new compounds were unambiguously determined by analysis of spectroscopic data, CP3, DP4+, ECD spectra, and X‐ray diffraction. Compound 6 showed anti‐inflammatory activities and hepatoprotective activities in transgenic fluorescent zebrafish.

Terpenoids from the Soft Coral Stereonephthya bellissima

“…Therefore, to further assign the relative configuration of 8 , calculations based on the gauge-independent atomic orbital (GIAO) method at the NMR chemical shifts were carried out, and four possible configurations, 8A (3 S *, 4 S *, 5 S *, 8 R *, 9 R *, 10 R *), 8B (3 S *, 4 S *, 5 S *, 8 R *, 9 S *, 10 R *), 8C (3 S *, 4 R *, 5 S *, 8 S *, 9 R *, 10 R *), and 8D (3 S *, 4 R *, 5 S *, 8 S *, 9 S *, 10 R *), were calculated. The DP4+ probability analysis for compound 8 turned out to give the best match for isomer 8A (3 S *, 4 S *, 5 S *, 8 R *, 9 R *, 10 R *) with 100% probability (Figure S5). ECD calculations performed on 8A showed that the calculated ECD curve of the enantiomer 3 R , 4 R , 5 R , 8 S , 9 S , 10 S matched well to the experimental ECD data (Figure b).…”

Heterolactone and Heterolactams A–M, Verticillane Diterpenoids with Anti-Inflammatory and Hepatoprotective Activities from the Soft Coral Heteroxenia ghardaqensis

“…Up to now, about 50 verticillane- and norverticillane-type diterpenoids have been reported from soft corals. − The first verticillane diterpenes from marine organisms were isolated from the Formosan soft coral Cespitularia hypotentaculata in 2002 . Only 11 alkylnitrogen-substituted verticillane diterpenoids have been reported. , In our ongoing research aimed at discovering new metabolites from soft coral, , we encountered the soft coral Heteroxenia ghardaqensis , and a systematic chemical study resulted in the isolation of 14 new verticillane diterpenoids, heterolactone ( 1 ) and heterolactams A–M ( 2 – 14 ). Here, we report the isolation, structure identification, and biological activities of these new compounds.…”