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A novel diterpenoid, sinunanolobatone A ( 1 ), featuring an unprecedented bicyclo[13.1.0]pentadecane carbon framework, along with two new casbane diterpenoids ( 2 and 3 ), and five known related ones ( 4 - 8 ) were isolated from the Sanya soft coral Sinularia nanolobata . The structures of the new compounds were established by detailed spectroscopic analysis, X-ray diffraction analysis, chemical reactions, or a quantum chemical computation method. A plausible biosynthetic pathway of 1 was proposed. In bioassay, the novel compound 1 showed significant inhibitory activity against lipopolysaccharide (LPS) induced inflammation in BV-2 microglial cells.

A novel diterpenoid, sinueretone A ( 1 ), featuring an unprecedented tricyclo[12.1.0.0 5,9 ]pentadecane carbon framework, along with two new ( 2 and 3 ) and one known ( 4 ) casbane diterpenoids were isolated from the South China Sea soft coral Sinularia erecta . The structures of the new compounds, especially their absolute stereochemistry, were established by extensive spectroscopic analysis, various quantum chemical calculations, and/or X-ray diffraction analyses. A plausible biogenetic relationship of 1 - 4 was proposed, which gave an insight for future biomimetic synthesis of the novel compounds. In a bioassay, compounds 1 and 2 displayed interesting anti-inflammatory activity by the inhibition of lipopolysaccharide-induced tumor necrosis factor-α protein release.

A novel norditerpenoid, sinusiaetone A ( 1 ), featuring an uncommon bicyclo[11.3.0]hexadecane carbon skeleton, and four polyoxygenated cembranoids ( 2-5 ) were isolated from the Hainan soft coral Sinularia siaesensis . Their structures were established by spectroscopic analysis, X-ray diffraction, quantum chemical computational approaches, and/or a modified Mosher's method. A plausible biosynthetic pathway of 1 and its biogenetic relationship with 2-5 were proposed. New compounds 1-3 displayed an interesting inhibitory activity against lipopolysaccharide-induced inflammation in BV-2 microglial cells.

The chemical investigation of the South China Sea soft coral Sinularia humilis has resulted in the isolation of a library of diverse diterpenoids, including four new cembranoids, namely, humilisins A-D ( 1 - 4 ), two new uncommon diterpenoids possessing a tetradecahydrocyclopenta[3',4']cyclobuta[1',2':4,5]cyclonona[1,2- b ]oxirene ring system, namely, humilisins E and F ( 5 and 6 ), and eight known related compounds ( 7 - 14 ). Humilisin A ( 1 ) is the first cembranoid with an ether linkage between C-3 and C-7. The structures and absolute configurations of 1 - 8 were determined by extensive spectroscopic data analyses, chemical reactions, and a series of quantum chemical calculations including quantum mechanical-nuclear magnetic resonance (QM-NMR), time-dependent density functional theory-electronic circular dichroism (TDDFT-ECD), and optical rotatory dispersion (ORD) methods. In bioassay, compound 6 displayed anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated BV-2 microglia cells.

Two novel polyoxygenated diterpenoids, klyflaccilides A ( 1 ) and B ( 2 ), featuring an uncommon 6/5/8/3 tetracyclic ring system, were isolated from the Hainan soft coral Klyxum flaccidum . Their structures were established by extensive spectroscopic analysis, X-ray diffraction analysis, and/or a quantum chemical computation method. A plausible biosynthetic relationship of 1 and 2 with their potential precursor 3 was further proposed. Compounds 1 and 3 exhibited moderate anti-inflammatory activity by the inhibition of LPS-induced TNF-α protein release.

A novel diterpenoid, sarcomililate A (1), possessing a previously undescribed tricyclo[11.3.0.0 2,16 ]hexadecane scaffold, along with two new cembranoids, sarcomililatols A and B (2 and 3), and two known related diterpenoids (4 and 5), was isolated from the Hainan soft coral Sarcophyton mililatensis. The complete chemical structure including absolute configuration (AC) of 1 was unambiguously determined by a combination of residual dipolar coupling (RDC)-based NMR analysis, TDDFT-ECD (ECD = electronic circular dichroism) calculation, and Snatzke's method. The AC of 1 was further confirmed by a comparison with 2, whose AC was determined by anomalous X-ray diffraction. A plausible biogenetic relationship of 1-3 was further proposed. All the reported compounds exhibited interesting inhibitory effects on the ConA-induced T lymphocytes and/or lipopolysaccharide (LPS)-induced B lymphocytes proliferation.

Two novel nitrogenous diterpenoids, sarinfacetamides A (1) and B (2), featuring an uncommon tricyclo[6.3.1.0 1,5 ]dodecane scaffold, and a known related diterpene (3) were isolated from the South China Sea soft coral Sarcophyton infundibuliforme. Their structures, including the absolute configuration of 1, were established by extensive spectroscopic analysis and TDDFT-ECD calculation. Compounds 1 and 3 exhibited interesting promotion effects on the ConA-induced T lymphocyte proliferation. A plausible biosynthetic pathway for 1 and 2 was also proposed.

Three new diterpenes, xishacorenes A-C, featuring an undescribed bicyclo[3.3.1]nonane nucleus bearing 1-vinyl and 13-[(E)-4-methylpenta-1,3-dien-1-yl] alkyl chains, and a related monocyclic known compound, were isolated from the Xisha soft coral Sinularia polydactyla. The structures of xishacorenes A-C, including their absolute configurations, were elucidated by extensive spectroscopic analysis and TDDFT ECD calculations. The new compounds exhibit an interesting dose-dependent promotion effect on the ConA-induced T lymphocyte proliferation. A plausible biosynthetic pathway of xishacorenes A-C is proposed.

The first total synthesis of a marine derived polyacetylene, distaminolyne A, and its enantiomer were achieved from the commercially available undec-10-en-1-ol. A key proline-catalyzed asymmetric α-aminooxylation of an aldehyde intermediate was used to introduce the chiral center en route to the enantiomerically pure 1,2-amino alcohols. The absolute configuration of both synthesized enantiomers of distaminolyne A was confirmed by using chiral derivatizing agents, leading to revision of the natural product absolute configuration from 2S to 2R. Antibacterial, pancreatic lipase (PL) inhibitory, and protein-tyrosine phosphatase 1B (PTP1B) inhibitory activities were evaluated.