Chabrolols A, B and C, three new norditerpenes from the soft coral Nephthea chabroli

Litoamentenes A-K, eleven undescribed cembranoids with cytotoxicity from the South China Sea soft coral Litophyton amentaceum

Eleven undescribed cembrane-type diterpenoids, named litoamentenes A-K (1-11), were isolated from the soft coral Litophyton amentaceum collected from the South China Sea. Their structures were elucidated by extensive analysis of spectroscopic data, comparison with the literature data, single crystal X-ray diffraction, quantum chemical calculations and TDDFT-ECD calculations. This is the first systematic investigation of L. amentaceum. In particular, compounds 1-3 are cembrane-type norditerpenoids that lack isopropyl side chains. Compound 6 is a cembrane-type norditerpenoid without a methyl group at C-4, the first natural product identified with this carbon skeleton. Compounds 6, 9 and 10 showed modest cytotoxicity against several human cancer cell lines with IC50 values ranging from 3.99 to 14.56 μM.

A catalytic process enables efficient and programmable access to precisely altered indole alkaloid scaffolds

A compound's overall contour impacts its ability to elicit biological response, rendering access to distinctly shaped molecules desirable. A natural product's framework can be modified, but only if it is abundant and contains suitably modifiable functional groups. Here we introduce a programmable strategy for concise synthesis of precisely altered scaffolds of scarce bridged polycyclic alkaloids. Central to our approach is a scalable catalytic multi-component process that delivers diastereo- and enantiomerically enriched tertiary homoallylic alcohols bearing differentiable alkenyl moieties. We used one product to launch progressively divergent syntheses of a naturally occurring alkaloid and its precisely expanded, contracted and/or distorted framework analogues (average number of steps/scaffold of seven). In vitro testing showed that a skeleton expanded by one methylene in two regions is cytotoxic against four types of cancer cell line. Mechanistic and computational studies offer an account for several unanticipated selectivity trends.

Phellilane L, Sesquiterpene Metabolite of Phellinus linteus: Isolation, Structure Elucidation, and Asymmetric Total Synthesis

A new cyclopropane-containing sesquiterpenoid, phellilane L (1), was isolated from the medicinal mushroom Phellinus linteus ("Meshimakobu" in Japanese), a member of the Hymenochaetaceae family and a well-known fungus that is widely used in East Asia. The planar structure of 1 was determined on the basis of spectroscopic analysis. The authors achieved the first total synthesis of 1. Our protecting group-free synthesis features a highly stereoselective one-pot synthesis involving an intermolecular alkylation/cyclization/lactonization strategy for construction of the key cyclopropane-γ-lactone intermediate. Additionally, our synthesis determined the absolute configuration of phellilane L (1).

New steroids from the soft coral Nephthea chabrolii

A new cytotoxic 19-oxygenated steroid, nebrosteroid Q (1) and two new cytotoxic 19-norergosterols, nebrosteroids R and S (2 and 3) were isolated from the soft coral Nephthea chabrolii collected at San-Hsian-Tai. The structures of nebrosteroids Q–S (1–3) were elucidated by spectral analysis, and their cytotoxicity against selected cancer cells as well as antiviral activity against human cytomegalovirus (HCMV) were measured in vitro.

New 19-oxygenated steroids from the soft coral Nephthea chabrolii

In order to search for novel bioactive substances from marine organisms, we investigated the acetone extract of the soft coral Nephthea chabrolii collected at San-Hsian-Tai, Taitong County, Taiwan. From this extract three new 19-oxygenated steroids, nebrosteroids N–P (1–3) were isolated. The structures of these compounds were elucidated by extensive spectroscopic analyses.

New 19-oxygenated and 4-methylated steroids from the Formosan soft coral Nephthea chabroli

Chemical investigation of the Formosan soft coral Nephthea chabroli resulted in the isolation of four new 19-oxygenated steroids, nebrosteroids I-L (1-4), together with a new 4alpha-methylated steroid, nebrosteroid M (5). The molecular structures of these isolated metabolites were elucidated on the basis of extensive spectroscopic analysis and by comparison of the data with those of related metabolites. Compounds 1-5 were evaluated for anti-inflammatory activity using RAW 264.7 macrophages.

Revision of the absolute configuration at C(23) of lanostanoids and isolation of secondary metabolites from formosan soft coral Nephthea erecta

Three new oxygenated ergostanoids, 1-3, one known ergostanoid, 4, one new trinoreudesmadienone, 5, one new calamenene type sesquiterpene, 6, and one known aristolane-type sesquiterpene, (-)-aristolone (7), have been isolated from the AcOEt extract of the soft coral Nephthea erecta. The structures of these compounds were determined by extensive spectroscopic and X-ray crystallographic analysis, as well as Mosher's method. We revised the absolute configuration at C(23) in the side chain of some lanostanoids as a result of the Mosher's products of 1 (i.e., 1a and 1b). The cytotoxicities against selected cancer cells and the anti-inflammatory effects of these tested metabolites 1-7 were determined in vitro.

New anti-inflammatory 4-methylated steroids from the Formosan soft coral Nephthea chabroli

Eight new 4-methylated steroids, nebrosteroids A-H (1-8) were isolated from the acetone solubles of the Formosan soft coral Nephthea chabroli. The structures were elucidated by extensive NMR spectroscopic analysis and their anti-inflammatory activity was measured in vitro.

New 4-methylated and 19-oxygenated steroids from the Formosan soft coral Nephthea erecta

Two new 4-methylated steroids, erectasteroids A and B (1 and 2), six new 19-oxygenated steroids, erectasteroids C-H (3-8) and two known 19-oxygenated steroids (9 and 10) were isolated from the acetone solubles of the Formosan soft coral Nephthea erecta. The structures were elucidated by extensive NMR spectroscopic analysis and their cytotoxicity against selected cancer cells was measured in vitro.

Nardosinane Sesquiterpenoids from the Formosan Soft Coral Nephthea elongata

Seven new nardosinane sesquiterpenoids, elongatols A-G (1-7) were isolated from the methylene chloride solubles of the Formosan soft coral Nephthea elongata. Their structures were elucidated by extensive spectroscopic analysis and their cytotoxicity against selected cancer cells was measured in vitro.

Prenylbicyclogermacrane Diterpenoids from the Formosan Soft Coral Nephthea elongata

Seven new prenylbicyclogermacrane diterpenoids, pacificins K--Q (1--7), were isolated from the methylene chloride solubles of the Formosan soft coral Nephthea elongata. Their structures were elucidated by extensive spectroscopic analysis and their cytotoxicity against selected cancer cells was measured in vitro.

Cycloartanes from the red alga Galaxaura sp

Six cycloartane triterpenes have been isolated from the red alga Galaxaura sp. The new structures (galaxaurols A-E) were determined to be methyl 3beta-hydroxy-23-oxocycloart-24-en-29-oate (2), methyl 23(E)-3beta-hydroxy-25-methoxycycloart-23-en-29-oate (3), methyl 23(E)-3beta-hydroxycycloarta-23,25-dien-29-oate (4), 23(E)-25-methoxycycloart-23-en-3beta,29-diol (5), and cycloart-24-en-3beta,23alpha,29-triol (6), respectively.

Polyhydroxylated steroids and other constituents of the soft coral Nephthea chabroli

Polyhydroxylated steroids and other metabolites were isolated from the soft coral Nephthea chabroli collected in South China Sea. The structures of two new compounds were determined to be 24-methylcholesta-9(11), 24(28)-diene-3beta,12alpha,19-triol and 4alpha-methyl-3beta,14beta-dihydroxy-5alpha-ergost-24(28)-en-23-one on the basis of spectroscopic analysis. Cytotoxic activities of the polyhydroxylated sterols were evaluated on prostate carcinoma LNCaP cell line.