Héctor Luna

Synthesis and evaluation of the cardiovascular effects of two, membrane impermeant, macromolecular complexes of dextran-testosterone

The incidence of cardiovascular disease is greater in men than in premenopausal women. Testosterone has been considered a significant risk factor for cardiovascular disease, but testosterones mechanism of action and its cellular site of action are still not clear. However, it is likely that non-genomic extracellular effects of the hormone are involved. With the aim of providing further information about this phenomenon, two membrane impermeant, macromolecular complexes of testosterone were synthesized and their cardiovascular effects were evaluated. We covalently bound testosterone (through carbon 3 or C-17 functional groups) to dextran (2 MDa) and evaluated its effects on isolated and perfused rat hearts (Langerdorff model). Our results showed that the macromolecular complexes increased vascular resistance similarly to free testosterone and blocked adenosine-induced vasodilatation. These effects were exerted rapidly and possibly through a non-genomic mechanism. Blockade of C-3 or C-17 functional groups by binding to macromolecular dextran induced no qualitative and/or quantitative changes in testosterone-induced effects.

Evaluation of guanabana (Annona muricata) seed meal as a source of (S)-oxynitrilase

Guanabana seed meal is a source of (S)-oxynitrilase which biocatalyzes the enantioselective addition of HCN to aromatic, heteroaromatic and α,β-unsaturated aldehydes to produce cyanohydrins.

New sources of (R)-oxynitrilase: capulin (Prunnus capuli) and mamey (Mammea americana)

Abstract(R)-Cyanohydrins were prepared from aldehydes and HCN in diisopropyl ether with high enantiomeric purity (89–98 %ee) by using the defatted meal from capulin (Prunnus capuli) or mamey (Mammea americana) as sources of (R)-oxynitrilase.

Resolution of methylarylmethanols via oxidation with Nocardia corallina

Abstract Ten different racemates of methylarylmethanols were subjected to whole cells of Nocardia corallina B-276 to give, via enantioselective oxidations, the corresponding ketone and the enantiomerically enriched secondary alcohol in moderate yields and excellent e.e.s. The configuration of the resulting alcohol is ( R ). This procedure permits a very good separation of the racemates of meta - and para -monosubstituted methylarylmethanols.

Nitrile hydratase activity of Nocardia corallina B-276

The nitrile hydratase activity of Nocardia corallina B-276 is described, and the only detected product during the biocatalyzed hydrolysis of selected nitriles was the corresponding amide. The best results were obtained using a suspension of cells in a phosphate buffer (pH= 7.0), with conversion percentages ranging from 31% to > 99%.

Enantioselective oxidation of diaryl carbinols by Nocardia corallina B-276

Abstract Whole cells of Nocardia corallina B-276 oxidized diaryl carbinols enantioselectively to give ketones in moderate yields, and some of the unreacted alcohols showed high ees. This asymmetric oxidation is a simple and efficient method for preparing meta- and para- monosubstituted optically active diaryl carbinols from the racemates. The para- substituted chiral alcohols have an R configuration.

Growth Inhibition of Streptococcus from the Oral Cavity by α-Amyrin Esters

Five terpenoids were tested by the macrodilution broth method to determine their inhibition activity on cariogenic bacterial growth. In general, α-, β-amyrin and α-amyrin phenylacetate proved to be active, reducing the bacterial viability to less than 20%.

Comparative esterification of phenylpropanoids versus hydrophenylpropanoids acids catalyzed by lipase in organic solvent media

The esterification of phenylpropanoid and hydrophenylpropanoid acids, catalyzed by candida antarctica lipase B (CAL-B), with several alcohols has demonstrated that the substitution pattern on the aromatic ring has a very significant influence on the reactivity of the carboxyl group due, mainly, to electronic effects, when compared to the unsaturated acids with the hydrogenated acids. It is also clear that in the saturated acids there still remain some unclear effects related to the aromatic substituents.

Oxidation of substituted benzyl alcohols to carboxylic acids by Nocardia corallina B-276

Whole cells of Nocardia corallina B-276, oxidized 21 substituted benzyl alcohols, at 1 mM scale, to carboxylic acids at 28-30°C, giving yields of products from 5 to 77%.

A Facile One-Pot Synthesis of 4-Hydroxy-3-methoxycarbonyl-2-methyl-2h-1,2-benzothiazine 1,1-Dioxide, a Key Intermediate in the Synthesis of Oxicam Anti-Inflammatory Agents

Abstract 4-Hydroxy-3-methoxycarbonyl-2-methyl-2H-1,2-benzothiazine 1,1-dioxide (8) was synthesized by a one-pot procedure, starting from the readily available saccharine. The synthesis involves 4 transformations with an overall yield equivalent to that from the stepwise process.