Enantioselective reduction of pentoxifylline to lisofylline using whole-cell Lactobacillus kefiri biotransformation

Chemoenzymatic deracemization of lisofylline catalyzed by a (laccase/TEMPO)-alcohol dehydrogenase system

This article reports on a novel biocatalytic method for the synthesis of both enantiomers of lisofylline based on Trametes versicolor laccase, TEMPO as a redox mediator and stereocomplementary recombinant alcohol dehydrogenases as biocatalysts.

Efficient asymmetric synthesis of chiral alcohols using high 2-propanol tolerance alcohol dehydrogenase SmADH2 via an environmentally friendly TBCR system

Based on substrate-coupled cofactor regeneration system, a high 2-propanol tolerance SmADH2 together with TBCR system can synthesise structurally diverse chiral alcohols at a high substrate loading with only 1.25 equivalents of 2-propanol.

Isolation of a Bacillus strain producing ketone reductase with high substrate tolerance

Target reaction-oriented screening from soil samples yielded a ketone reductase-producing Bacillus sp., strain ECU0013, which exhibits excellent stereoselectivity, high substrate tolerance and is capable of regenerating the required cofactor with glucose as a co-substrate. Whole-cells catalyzed the asymmetric reduction of 2-chloro-1-phenylethanone (50mM) to (R)-2-chloro-1-phenylethanol with a 93.3% conversion rate and 99% e.e. (enantiomeric excess). A variety of ketones were enantioselectively reduced by resting cells, giving corresponding chiral alcohols with good to excellent e.e. values. These results suggest the potential of this strain for the industrial production of chiral halogenated aromatic alcohols.

Pretreatment with R(+)-verapamil significantly reduces mortality and cytokine expression in murine model of septic shock

It is well known that cytokines play an important role in the pathogenesis of sepsis and septic shock. There is evidence indicating that the membrane transporter, P-glycoprotein (P-gp), may be involved in the release of cytokines, such as IL-2, IL-4 or IFN-gamma. The aim of this study was to assess the influence of P-gp inhibitor, R(+)-verapamil, on cytokine expression in serum and tissues as well as survival rate of mice with LPS-induced septic shock. These effects were compared with the response to treatment with pentoxifylline, lisofylline, and prednisolone administered alone or after pretreatment with R(+)-verapamil. When given as a single agent, R(+)-verapamil significantly decreased serum levels of TNF-alpha and IFN-gamma and protected mice from endotoxin lethality. Moreover, it decreased up-regulated by LPS TNF-alpha gene expression in the liver and lungs. Given concomitantly with immunomodulatory compounds, it enhanced their beneficial impact on the survival of mice with septic shock. The highest increase in survival rate was observed in combination with pentoxifylline (7% vs. 67%). The most striking differences observed between saline and R(+)-verapamil pretreated animals on combination therapy included down-regulation of TNF-alpha, higher levels of IL-6, and decreased IFN-gamma concentrations. These results suggest that P-gp may be involved in the release of IFN-gamma, and possibly also TNF-alpha, in mice with septic shock. R(+)verapamil improves survival of mice receiving a lethal dose of LPS and significantly potentiates the protective effect of pentoxifylline and prednisolone against LPS-induced lethality, probably as a result of both P-gp inhibition and a synergistic interaction at the gene level.

Microbial transformation of hydroxy metabolites of 1-oxohexyl derivatives of theobromine by Cunninghamella echinulata NRRL 1384

AIM

The biotransformation of pentoxifylline (PTX), propentofylline (PPT) and their racemic hydroxy metabolites ((+/-)-OHPTX and (+/-)-OHPPT) by using the fungus Cunninghamella echinulata NRRL 1384.

METHODS AND RESULTS

A fungus Cunninghamella echinulata NRRL 1384 was used to catalyse the (S)-selective oxidation of the racemic hydroxy metabolites: (+/-)-OHPTX and (+/-)-OHPPT and for reduction of PTX and PPT. The first oxidation step appears to be selective and relatively fast while the second reduction step is slower and more selective with PTX. Modifications involving supplementing the bioconversion with glucose give yields and enantiomeric excess (ee) values similar to those obtained without glucose.

CONCLUSIONS

The bioconversion of (+/-)-OHPTX gave an (R)-enantiomer (LSF-lisofylline) with a higher enantiopurity (maximum approximately 93% ee) compared to the bioconversion of (+/-)-OHPPT, when the maximum ee value for (R)-OHPPT was recorded at 83%.

SIGNIFICANCE AND IMPACT OF THE STUDY

The conversion of (+/-)-OHPTX and (+/-)-OHPPT using Cunninghamella echinulata can be recognized as a process, which may be recommended as an alternative to the methods used to obtain (R)-OHPTX and (R)-OHPPT.