Solving the delivery of Lactococcus lactis: Improved survival and storage stability through the bioencapsulation with different carriers.

Probiotics are live microorganisms that confer beneficial effects on the health of the host if administered in adequate amounts (106  CFU viable microorganisms/g of food). As the most frequent route of administration of these microorganisms is oral, the number of them that remains viable through the gastrointestinal tract decreases substantially. Thus, in this research work, we developed a series of alginate-based microparticles using different adjuvants such as methylcellulose, carboxymethylcellulose, chitosan, carbopol, ß-cyclodextrin, starch, carrageenan, and Eudragit® RS 100 as carriers for improving the survival of Lactococcus lactis. The alginate-based formulations exhibited very good drug encapsulation efficiency, up to 90%. Release studies from selected microparticles revealed that almost 100% of bacteria were in solution at 30 min. By scanning electron microscopy, irregular nonporous particles with a size between 200 and 500 µm were seen. In particular, microparticles formulated with alginate-carboxymethylcellulose and alginate-methylcellulose exhibited the best protection for the bacterial cells against both simulated gastric juice and simulated intestinal juice. In addition, those microparticulate systems were able to maintain the viability of the encapsulated bacteria in large numbers for at least 24 weeks. Thus, the present study confirmed that these alginate-based microparticles are a valuable approach for keeping the viability and storage stability of L. lactis.

Experimental, Spectroscopic, and Computational Insights into the Reactivity of "Methanal" with 2-Naphthylamines.

The reactions of 2-naphthylamine and methyl 6-amino-2-naphthoate with formalin and paraformaldehyde were studied experimentally, spectrally, and by quantum chemical calculations. It was found that neither the corresponding aminals nor imines were formed under the described conditions but could be prepared and spectrally characterized at least in situ under modified conditions. Several of the previously undescribed intermediates and by-products were isolated or at least spectrally characterized. First principle density functional theory (DFT) calculations were performed to shed light on the key aspects of the thermochemistry of decomposition and further condensation of the corresponding aminals and imines. The calculations also revealed that the electrophilicity of methanal was significantly greater than that of ordinary oxo-compounds, except for perfluorinated ones. In summary, methanal was not behaving as the simplest aldehyde but as a very electron-deficient oxo-compound.

Synthesis of new cyano-substituted analogues of Tröger's bases from bromo-derivatives. A stereochemical dependence of long-range (n JHH , n = 4, 5, and 6) proton-proton and proton-carbon (n JCH , n = 1, 2, 3, 4, and 5) coupling constants of these compounds.

A free-catalyst microwave-assisted cyanation of brominated Tröger's base derivatives (2a-f) is reported. The procedure is simple, efficient, and clean affording the nitrile compounds (3a-e, I) in very good yields. Complete assignment of 1 H and 13 C chemical shifts of 2a-f, I and 3a-d, I was achieved using gradient selected 1D nuclear magnetic resonance (NMR) techniques (1D zTOCSY, PSYCHE, DPFGSE NOE, and DEPT), homonuclear 2D NMR techniques (gCOSY and zTOCSY), and heteronuclear 2D NMR techniques (gHSQCAD/or pure-shift gHSQCAD, gHMBCAD, bsHSQCNOESY, and gHSQCAD-TOCSY) with adiabatic pulses. Determination of the long-range proton-proton coupling constants n JHH (n = 4, 5, 6) was accomplished by simultaneous irradiation of two protons at appropriate power levels. In turn, determined coupling constants were tested by an iterative simulation program by calculating the 1 H NMR spectrum and comparing it to the experimental spectrum. The excitation-sculptured indirect-detection experiment (EXSIDE) and 1 H-15 N CIGARAD-HMBC (constant time inverse-detection gradient accordion rescaled heteronuclear multiple bond correlation) were applied for determination of long-range carbon-proton coupling constants n JCH (n = 2, 3, and 4) and for assignment of 15 N chemical shift at natural abundance, respectively. DFT/B3LYP optimization studies were performed in order to determine the geometry of 2c using 6-31G(d,p), 6-311G(d,p), and 6-311 + G(d,p) basis sets. For calculation of 1 H and 13 C chemical shifts, n JHH (n = 2, 3, 4, 5, and 6), and n JCH (n = 1, 2, 3, and 4) coupling constants, the GIAO method was employed at the B3LYP/6-31G(d,p), B3LYP/6-31+G(d,p), B3LYP/6-311+G(d,p), B3LYP/6-311++G(2d,2p), B3LYP/cc-pVTZ), and B3LYP/aug-cc-pVTZ) levels of theory. For the first time, a stereochemical dependence magnitude of the long-range n JHH (n = 4, 5, and 6) and n JCH (n = 1, 2, 3, 4, and 5) have been found in bromo-substituted analogues of Tröger's bases.