Tedarenes A and B: structural and stereochemical analysis of two new strained cyclic diarylheptanoids from the marine sponge Tedania ignis.

Ring strain causes planar chirality in tedarenes A and B, two cyclic diarylheptanoids isolated from the marine sponge Tedania ignis. In both molecules, the chiral plane is an olefinic system, which is very rare among natural products. In tedarene A (1), interconversion is too fast to allow isolation of the enantiomeric atropisomers but still slow enough to cause coalescence of some (1)H and (13)C NMR signals at room temperature. In tedarene B (2), which also shows stable central and axial chirality, the two planar diastereomers are in slow equilibrium. Tedarene B is the smallest natural product with central, axial, and planar chirality in the same simple molecule. The identification of planar chirality as the difference between its conformational isomers allowed the use of theoretical prediction of the CD spectrum to determine the absolute configuration of the stereogenic carbon C-9 as well as of the biphenyl chiral axis.

Evaluation of the antiproliferative activity of diterpene isonitriles from the sponge Pseudoaxinella flava in apoptosis-sensitive and apoptosis-resistant cancer cell lines.

One new (1) and three known (2-4) isonitrile diterpenes, isolated from the Caribbean sponge Pseudoaxinella flava, were assayed in human cancer cell lines in vitro using an MTT colorimetric assay and quantitative videomicroscopy. Compounds 1-4 displayed activity for human PC3 prostate apoptosis-sensitive cancer cell lines. Compounds 3 and 4 demonstrated similar growth inhibitory effects for three apoptosis-sensitive and three apoptosis-resistant cancer cell lines. Quantitative videomicroscopy analysis revealed that compounds 1 and 2 exerted their activity through cytotoxic effects, and compounds 3 and 4 through cytostatic effects. These results identify marine diterpene isonitriles as potential lead compounds for anticancer drug discovery.

Tedanol: a potent anti-inflammatory ent-pimarane diterpene from the Caribbean Sponge Tedania ignis.

Tedanol, a new brominated and sulfated pimarane diterpene was isolated from the Caribbean sponge Tedania ignis. Structure of tedanol was elucidated by mass spectroscopy and extensive NMR studies (including spectral simulation), and its absolute configuration was determined using the Mosher method. Tedanol showed a potent anti-inflammatory activity at 1mg/kg evaluated in vivo in a mouse model of inflammation. After a single intraperitoneal administration, tedanol significantly reduced both the acute and the subchronic phases of carrageenan-induced inflammation. The anti-inflammatory activity was coupled with a strong inhibition of COX-2 expression, inhibition of cellular infiltration measured as mieloperoxidase (MPO) levels, and inhibition of iNOS expression. These features make tedanol a promising template for the development of new anti-inflammatory molecules with low gastrointestinal toxicity.

(13)C and (15)N NMR characterization of amine reactivity and solvent effects in CO2 capture.

Factors influencing the reactivity of selected amine absorbents for carbon dioxide (CO2) capture, in terms of the tendency to form amine carbamate, have been studied. Four linear primary alkanolamines at varying chain lengths (MEA, 3A1P, 4A1B , and 5A1P ), two primary amines with different substituents in the ß-position to the nitrogen (1A2P and ISOB), a secondary alkanolamine (DEA), and a sterically hindered primary amine (AMP) were investigated. The relationship between the (15)N NMR data of aqueous amines and their ability to form carbamate, as determined at equilibrium by quantitative (13)C NMR experiments, was analyzed, taking into account structural-chemical properties. For all the amines, the (15)N chemical shifts fairly reflected the observed reactivity for carbamate formation. In addition to being a useful tool for the investigation of amine reactivity, (15)N NMR data clearly provided evidence of the importance of solvent effects for the understanding of chemical dynamics in CO2 capture by aqueous amine absorbents.