Immobilization of Amano lipase AK from Pseudomonas fluorescens on different types of chitosan-containing supports: use in the kinetic resolution of rac-indanol.

Amano lipase AK from P. fluorescens was immobilized on different types of chitosan-containing supports. Chitosan lower molecular weight (2.5%), chitosan lower molecular weight/sodium alginate (2.5%/2.5%) and chitosan lower molecular weight/carrageenan (2.5%/2.5%) allowed the highest values of immobilization yields (IY) of 81, 81 and 83%, respectively. Best activity results were achieved using chitosan average molecular weight (5%) and chitosan lower molecular weight/sodium alginate (2.5%/2.5%) as support, with values of 1.40 and 1.30 UpNPB/ggel and with recovery activities of 45.75 and 35.6%, respectively. These derivatives were evaluated in the kinetic resolution of rac-indanol to obtain a key intermediate in the synthesis of a drug used in the treatment of Parkinson's disease. The most efficient derivatives in the kinetic resolution were lipase immobilized on chitosan average molecular weight (5.0%) and chitosan low molecular weight/sodium alginate, the latter leading to obtaining both (S)-indanol and (R)-indanyl acetate with > 99% ee and 50% conversion.

Synthesis and in vitro antifungal activity of isoniazid-derived hydrazones against Coccidioides posadasii.

Coccidioidomycosis is a potentially severe infection caused by dimorphic fungi Coccidioides immitis and Coccidioides posadasii. Although guidelines are well established, refractory disease is a matter of concern in the clinical management of coccidioidomycosis. In the present study three isoniazid-derived hydrazones N'-[(E)-1-(4-methoxyphenyl)ethylidene]pyridine-4-carbohydrazide, N'-[(E)-1-(4-methylphenyl)ethylidene]pyridine-4-carbohydrazide, and N'-[(E)-1-(phenyl)ethylidene]pyridine-4-carbohydrazide were synthesized and evaluated for antifungal activity against C. posadasii. Susceptibility assays were performed by macrodilution testing. Interactions between the hydrazones and amphotericin B or itraconazole were evaluated by the checkerboard method. We also investigated the impairment of such compounds on cell ergosterol and membrane integrity. The synthesized molecules were able to inhibit C. posadasii in vitro with MIC values that ranged from 25 to 400 µg/mL. Drug interactions between synthesized molecules and amphotericin B proved synergistic for the majority of tested isolates; regarding itraconazole, synergism was observed only when strains were tested against N'-[(E)-1-(phenyl)ethylidene]pyridine-4-carbohydrazide. Reduction of cellular ergosterol was observed when strains were challenged with the hydrazones alone or combined with antifungals. Only N'-[(E)-1-(4-methylphenyl)ethylidene]pyridine-4-carbohydrazide altered membrane permeability of C. posadasii cells. Isoniazid-derived hydrazones were able to inhibit C. posadasii cells causing reduction of ergosterol content and alterations in the permeability of cell membrane. This study confirms the antifungal potential of hydrazones against pathogenic fungi.

Recent Advances in Lipase-Mediated Preparation of Pharmaceuticals and Their Intermediates.

Biocatalysis offers an alternative approach to conventional chemical processes for the production of single-isomer chiral drugs. Lipases are one of the most used enzymes in the synthesis of enantiomerically pure intermediates. The use of this type of enzyme is mainly due to the characteristics of their regio-, chemo- and enantioselectivity in the resolution process of racemates, without the use of cofactors. Moreover, this class of enzymes has generally excellent stability in the presence of organic solvents, facilitating the solubility of the organic substrate to be modified. Further improvements and new applications have been achieved in the syntheses of biologically active compounds catalyzed by lipases. This review critically reports and discusses examples from recent literature (2007 to mid-2015), concerning the synthesis of enantiomerically pure active pharmaceutical ingredients (APIs) and their intermediates in which the key step involves the action of a lipase.

Whole cells of recombinant CYP153A6-E. coli as biocatalyst for regioselective hydroxylation of monoterpenes.

Optimized recombinant whole cells of E. coli bearing CYP153A6 were employed for catalyzing the hydroxylation of different monoterpene derivatives. In most cases, high selectivity was observed with exclusive hydroxylation of the allylic methyl group bound to the aliphatic ring. In the case of (R)- and (S)-carvone, hydroxylation occurred also on the other allylic methyl group, although to a lesser extent. Biotransformations carried out in fed-batch mode on (S)-limonene and α-terpineol showed that recombinant whole cells retained activity for at least 24 h, allowing for the recovery of 3.25 mg mL-1 of (S)-perillyl alcohol and 5.45 mg mL-1 of 7-hydroxy-α-terpineol, respectively.

Quantification of Barbatusin and 3ß-Hydroxy-3-deoxybarbatusin in Plectranthus Species by HPLC-DAD.

The concentration of diterpenes barbatusin (1) and 3ß-hydroxy-3-deoxybarbatusin (2) in the extracts from leaves of Plectranthus grandis, P. barbatus, P. ornatus, and P. amboinicus was evaluated by HPLC-DAD analysis on a Luna C-18 column, using isocratic mixtures of water and acetonitrile as eluents. The regression equations were obtained with good linearity (r2 > 0.99) and limit of quantifications was higher than 0.1 µg/mL. The precision (lower than 3.5%, within day) and accuracy (higher than 81.7% and lower than 107.6%) of the methods were adequate. Barbatusin (1) was detected in P. grandis (15.432 ± 2.28 mg/g) and P. barbatus (5.198 ± 3.45 mg/g) extracts, while compound 2 was detected in P. grandis (4.068 ± 3.34 mg/g), P. barbatus (0.654 ± 5.86 mg/g), P. amboinicus (0.160 ± 7.25 mg/g), and P. ornatus (0.763 ± 5.10 mg/g). The evaluated validation parameters were satisfactorily achieved, and the developed methodology represents a suitable tool for application in the quantification of barbatusin (1) and 3ß-hydroxy-3-deoxybarbatusin (2) in Plectranthus species.

Esterases as stereoselective biocatalysts.

Non-lypolitic esterases are carboxylester hydrolases with preference for the hydrolysis of water-soluble esters bearing short-chain acyl residues. The potential of esterases as enantioselective biocatalysts has enlarged in the last few years due to the progresses achieved in different areas, such as screening methodologies, overproduction of recombinant esterases, structural information useful for understanding the rational behind enantioselectivity, and efficient methods in protein engineering. Contributions of these complementary know-hows to the development of new robust enantioselective esterases are critically discussed in this review.