Varying the Directionality of Protein Catalysts for Aldol and Retro-Aldol Reactions.

Natural aldolase enzymes and created retro-aldolase protein catalysts often catalyze both aldol and retro-aldol reactions depending on the concentrations of the reactants and the products. Here, we report that the directionality of protein catalysts can be altered by replacing one amino acid. The protein catalyst derived from a scaffold of a previously reported retro-aldolase catalyst, catalyzed aldol reactions more efficiently than the previously reported retro-aldolase catalyst. The retro-aldolase catalyst efficiently catalyzed the retro-aldol reaction but was less efficient in catalyzing the aldol reaction. The results indicate that protein catalysts with varying levels of directionality in usually reversibly catalyzed aldol and retro-aldol reactions can be generated from the same protein scaffold.

New cytotoxic cembranolides from an Okinawan soft coral, Lobophytum sp.

Three new cembranolides (1-3) were isolated from an Okinawan soft coral, Lobophytum sp., together with the known cembranolide diterpenoids (4-9). Their structures were determined by extensive analysis of spectroscopic data (1D and 2D NMR, IR, and MS), molecular modeling, and comparison with data reported elsewhere. All compounds contain an α-methylene-γ-lactone ring adjacent to a cembrane, and some of them (1, 6-8) have an epoxide ring as well. The new metabolites were evaluated for cytotoxicity against HeLa, A459, B16-F10, and RAW 264.7 cells and anti-inflammatory effect in LPS-stimulated inflammatory RAW 264.7 macrophage cells.

New Casbane and Cembrane Diterpenoids from an Okinawan Soft Coral, Lobophytum sp.

A new rare casbane-type diterpenoid 1 and two new cembrane diterpenoids 2, 3 were isolated from an Okinawan soft coral, Lobophytum sp., together with four known cembrane diterpenoids 4-7. Their structures were elucidated by extensive analysis of spectroscopic data (1D and 2D NMR, IR, and MS) and a molecular modeling study. The new isolates showed weak anti-bacterial activity, mild cytotoxicity against HCT116 cells, and anti-inflammatory effect in LPS/IFN-γ-stimulated RAW 264.7 macrophage cells.

Endoperoxy and hydroperoxy cadinane-type sesquiterpenoids from an Okinawan soft coral, Sinularia sp.

Three cadinane-type sesquiterpenoids, endoperoxide (1) and hydroperoxides (2, 3) together with three known sesquiterpenoids (4-6) were isolated from an Okinawan soft coral, Sinularia species. Structures of these isolates were elucidated by spectroscopic analyses (NMR, IR and MS) and molecular modeling. In addition, the isolates 1-3 as new compounds were examined for biological activities, resulting that they have antibacterial activity and weak cytotoxicity against HCT116 cells as well as anti-inflammatory effect on LPS/IFN-γ-stimulated RAW 264.7 macrophage cells.

Dual biological functions of the apoptotic activity and anti-inflammatory effect by alcyonolide congeners from the Okinawan soft coral, Cespitularia sp.

In our current study, alcyonolide and its congeners isolated from the Okinawan soft coral, Cespitularia sp., have shown an antitumor activity in HCT116 colon cancer cells. This study investigated the biological activities of these compounds (1-12) for the apoptotic activity in the HCT116 cells and the anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. As a result, the apoptotic cells with a nuclear condensation were detected by treatment with these compounds. The apoptotic cells dependent on the caspase 3/7 activation was also induced in the low concentration range of 2.5-10 µM. While a similar concentration of the compounds inhibited the NO production in the LPS-stimulated inflammatory RAW264.7 cells, the pro-inflammatory gene expressions of the iNOS and COX-2 mRNA were also suppressed. The structurally unique alcyonolides (5, 12) having the dual biological activity of apoptotic activity and anti-inflammatory effect could be a potential development as pharmaceutical agents.

Five new diterpenoids from an Okinawan soft coral, Cespitularia sp.

Five new diterpenoids 1-5 were isolated from an Okinawan soft coral, Cespitularia sp., together with the known diterpenoid, alcyonolide (6). New diterpenoid structures were elucidated by spectroscopic methods and by comparison of their NMR data with those of related compounds. Alcyonolide (6) was cytotoxic against HCT 116 cells (IC50 5.85 µM), while these new diterpenoids 1-5 were much less active (IC50 28.2-91.4 µM).