Investigation on the Anticonvulsant Potential of Luteolin and Micronized Luteolin in Adult Zebrafish (Danio rerio).

Epilepsy affects around 50 million people worldwide, and an important number of patients (30%) fail to respond to any available antiepileptic drug. Previous studies have shown that luteolin presents a promising potential as an anticonvulsant. On the other hand, different studies showed that luteolin does not promote anticonvulsant effects. Therefore, there is a lack of consensus about the use of luteolin for seizure control. Luteolin low bioavailability could be a limiting factor to obtain better results. Attractively, micronization technology has been applied to improve flavonoids bioavailability. Thus, the present study aimed to investigate the effects of luteolin on its raw form and micronized luteolin in a PTZ-induced seizure model in adult zebrafish (Danio rerio). Our results demonstrate that luteolin and micronized luteolin did not block PTZ-induced seizures in adult zebrafish. Also, luteolin and micronized luteolin did not provoke behavioral changes. Finally, our results show that 24 h after seizure occurrence, no changes were detected for p70S6Kb, interleukin 1ß, and caspase-3 transcript levels. Altogether, we failed to observe an anticonvulsant potential of luteolin in adult zebrafish, even in its micronized form. However, we recommend new studies to investigate luteolin benefits in epilepsy.

Effect of supercritical carbon dioxide processing on Vibrio parahaemolyticus in nutrient broth and in oysters (Crassostrea gigas).

This study aimed to evaluate the technical feasibility of supercritical carbon dioxide (sc-CO2) treatment for Vibrio parahaemolyticus inactivation in oysters (Crassostrea gigas) and in nutrient broth. For this purpose, a variable-volume reactor was used as experimental system and a 23 factorial design was adopted considering the mass ratio between carbon dioxide and the product, pressurization and depressurization rate and pressurization cycles. Through statistical analysis of the experimental data, the mass ratio of 1:0.8 (product:carbon dioxide), depressurization rate of 10.0 MPa/min and one cycle of pressurization was determined as the best process condition to eliminate V. parahaemolyticus, and this was the condition used for the inactivation kinetic analysis. Comparison between the inactivation kinetics of V. parahaemolyticus showed that the behavior of this microorganism inactivation depends on the environment in which it operates and its initial count. The results confirm that the supercritical carbon dioxide is effective in inactivating microorganisms in oysters, including pathogenic V. parahaemolyticus, demonstrating the potential of this technology in the food industry.

Optimal Production of a Rhodococcus erythropolis ATCC 4277 Biocatalyst for Biodesulfurization and Biodenitrogenation Applications.

Rhodococcus sp. has a broad catabolic diversity and unique enzymatic capabilities, and it is able to adapt under extreme conditions. Thereby, the production of this remarkable bacterium has a great biotechnological and industrial importance. In this sense, we sought to improve the R. erythropolis ATCC 4277 growth through a central composite design, by varying the components of nutrient medium (glucose, malt extract, yeast extract, CaCO3), temperature, and agitation. It was found that the concentrations of glucose and malt extract are not statistically significant, being reduced of 4.0 and 10.0 g L-1 to 2.0 and 5.0 g L-1, respectively. The CaCO3 concentration and temperature were also diminished of 2.0 to 1.16 g L-1and 28 to 23.7 °C, respectively. Optimal growth conditions provided a 240% increase in final biomass concentration, an increment in specific growth rate, and a growth yield coefficient about five times greater. Application of the optimal conditions in biodesulfurization and biodenitrogenation processes showed that desulfurization capability is not associated with optimal growth conditions; however, it was achieved a 47% of nitrogen removal in the assay containing 10% (w/w) of heavy gas oil. Graphical Abstract ᅟ.

Effect of compressed fluids treatment on ß-galactosidase activity and stability.

This study aimed at assessing the influence of different pressurized fluids treatment on the enzymatic activity and stability of a lyophilized ß-galactosidase. The effects of system pressure, exposure time and depressurization rate, using propane, n-butane, carbon dioxide and liquefied petroleum gas on the enzymatic activity were evaluated. The ß-galactosidase activity changed significantly depending on the experimental conditions investigated, allowing the selection of the proper compressed fluid for advantageous application of this biocatalyst in enzymatic reactions. The residual activity ranged from 32.1 to 93.8 % after treatment. The storage stability of the enzyme after high-pressure pre-treatment was also monitored, and results showed that the biocatalyst activity presents strong dependence of the fluid used in the pretreatment. The activity gradually decreases over the time for the enzyme treated with LGP and propane, while the enzyme treated with n-butane maintained 96 % of its initial activity until 120 days. For CO(2), there was a reduction of around 40 % in the initial activity 90 days of storage. The enzyme treated with n-butane also showed a better thermostability in terms of enzymatic half-life.

Kinetics of ultrasound-assisted lipase-catalyzed glycerolysis of olive oil in solvent-free system.

This work reports experimental kinetic data of solvent-free glycerolysis of olive oil using a commercial immobilized lipase (Novozym 435) under the influence of ultrasound irradiation. The experiments were performed in a mechanically stirred reactor under ultrasound irradiation, evaluating the effects of temperature (50-70 °C), enzyme concentration (2.5-10 wt%) and glycerol to oil molar ratio (0.8:1-3:1). Results show that ultrasound-assisted lipase-catalyzed glycerolysis might be a potential alternative route to conventional methods, as high contents of reaction products, especially monoglycerides, were achieved at mild irradiation power supply (~130 W) and temperature, in a relatively short reaction time (2h) and low enzyme content (7.5 wt%). To completeness, two simplified kinetic modeling approaches, based on the ordered-sequential bi bi mechanism and reaction stoichiometry, were employed to represent the experimental data, thus allowing a better understanding of the reaction kinetics.

Ultrasound-assisted synthesis of aliphatic acid esters at room temperature.

This work describes the ultrasound-assisted synthesis of saturated aliphatic esters from synthetic aliphatic acids and either methanol or ethanol. The products were isolated in good yields after short reaction times under mild conditions.

Immobilization of inulinase from Kluyveromyces marxianus NRRL Y-7571 using modified sodium alginate beads.

An experimental design was carried out to evaluate the effect of the concentrations of sodium alginate, glutaraldehyde and activated coal on the immobilization of inulinase from Kluyveromyces marxianus NRRL Y-7571. The experimental condition of 20 g/L of sodium alginate, 50 mL/L of glutaraldehyde and 30 g/L of activated coal led to the highest specific activity (2,063.5 U/mg of protein), corresponding to an enhancement of about 26 times compared to the activity of the free enzyme (79.1 U/mg of protein). The effect of pH and temperature on the immobilized enzyme activity was also evaluated, showing optimal activities at pH of 5.5 and 55 °C. The study of storage of immobilized inulinase in different temperatures showed that the extract kept its initial activity after 43 days of storage at 40 and 50 °C and after 138 days of storage either at 4 or 25 °C.

Assessment of process variables on 2-ethylhexyl palmitate production using Novozym 435 as catalyst in a solvent-free system.

This work reports the optimization of 2-ethylhexyl palmitate production by esterification reaction in a solvent-free system using a commercial lipase as catalyst. For this, a sequential strategy was performed applying three experimental designs. An empirical model was built so as to assess the effects of process variables on the reaction conversion. Afterward, the operating conditions that optimized 2-ethylhexyl palmitate production were determined to be acid to alcohol molar ratio of 1:5.5, 70 degrees C, 150 rpm and 10.5 wt% of enzyme, leading to a reaction conversion as high as 93%. From this point, a kinetic study was carried out evaluating the influence of acid to alcohol molar ratio, enzyme concentration and temperature on product yield. Results obtained in this step allow to conclude that an excess of alcohol (acid to alcohol molar ratio of 1:6), relatively low enzyme concentration (10 wt%) and temperature of 70 degrees C led to nearly complete reaction conversion.

Oxidases from mate tea leaves (Ilex paraguariensis): extraction optimization and stability at low and high temperatures.

Mate (Ilex paraguariensis) is an important natural product in the economic and cultural context of Brazil. Peroxidase and polyphenol oxidase have been responsible for quality deterioration and browning in mate. The objective of this work was to investigate a methodology of extraction and enzymatic activity determination of oxidases present in mate tea leaves and to evaluate the oxidases stability. The effects of raw-material mass, buffer molar concentration, Triton X-100 addition, extraction pH, pH activity measurement, polyvinylpyrrolidone K90 addition, and centrifugation time were evaluated by the experimental planning methodology. The storage of the oxidases along 150 days at low temperatures showed that no significant difference was found at -4 and -80 degrees C but significant difference was observed when compared to 4 degrees C. The results showed that higher activities of oxidases are obtained at similar conditions. The exposition to high-temperatures and the variation of the time of exposition affected the enzymatic activity significantly.

Application of Origanum majorana L. essential oil as an antimicrobial agent in sausage.

This work reports on the antimicrobial activity in fresh sausage of marjoram (Origanum majorana L.) essential oil against several species of bacteria. The in vitro minimum inhibitory concentration (MIC) was determined for 10 selected aerobic heterotrophic bacterial species. The antimicrobial activity of distinct concentrations of the essential oil based on the highest MIC value was tested in a food system comprising fresh sausage. Batch food samples were also inoculated with a fixed concentration of Escherichia coli and the time course of the product was evaluated with respect to the action of the different concentrations of essential oil. Results showed that addition of marjoram essential oil to fresh sausage exerted a bacteriostatic effect at oil concentrations lower than the MIC, while a bactericidal effect was observed at higher oil concentrations which also caused alterations in the taste of the product.