Comparative Evaluation of Four Extraction Methods of Antioxidant Compounds from Decatropis bicolor in Aqueous Medium Applying Response Surface Design.

The objective of this paper is to compare conventional, ultrasound, microwave, and French press methods for the extraction of antioxidant compounds from Decatropis bicolor in an aqueous medium. This plant is widely used in Mexican traditional medicine for breast cancer treatment. Despite that, there are few studies on D. bicolor. Two response surface designs were applied to establish the best conditions of the liberation of antioxidants from D. bicolor, which were determined by DPPH• and Ferric Reducing Antioxidant Power (FRAP) techniques. The total phenolic content was evaluated by the Folin-Ciocalteu method. The results showed that D. bicolor is a source of antioxidants (669-2128 mg ET/100 g and 553-1920 mg EFe2+/100 g, respectively) and phenolic compounds (2232-9929 mg EGA/100 g). Among the physical factors that were analyzed, the temperature was the determinant factor to liberate the compounds of interest by using low concentrations of the sample and short times of extraction. The French press was the most efficient method, obtaining values of antioxidant activity and phenolic compounds even higher than those reported by using extraction methods with solvents such as methanol.

Lactobacillus pentosus ABHEAU-05: An in vitro digestion resistant lactic acid bacterium isolated from a traditional fermented Mexican beverage.

The health benefits attributed to probiotics generate interest in the search of competent strains adapted to several ecological niches, especially those related to traditional beverages and foods of each country. Pineapple tepache, a traditional Mexican fermented beverage, was used for the isolation of lactic acid bacteria with probiotic potential, one of which withstood the in vitro tests. The isolated strain AB-05, which exhibited the tested probiotic functional properties, was designated as Lactobacillus pentosus ABHEAU-05. The sequence was registered in GenBank under access code MK587617. This study is the first report of a lactic acid bacterium with in vitro digestion resistance isolated from pineapple tepache. The survival of L. pentosus ABHEAU-05 in a symbiotic medium was proven using fermented milk enriched with inulin. The in vitro digestion-resistant probiotic activity of lactobacilli was measured through analysis of pH and proteolysis. Results showed that L. pentosus grew properly in fermented milk; therefore, this microorganism could be used in the manufacture of this kind of products. The concentration of L. pentosus reached up to 8.5logCFU/ml after 40h of fermentation. In addition, the production of peptides and the decrease in pH indicated the vigorous and active metabolic state of the lactic acid bacterium tested. The activity and the concentration of this microorganism were maintained during refrigeration. The results of this research conclude that L. plantarum ABHEAU-05 is an in vitro digestion-resistant microorganism that can be used as a starter culture for the production of functional foods of dairy origin.

Bioactive compounds in aqueous extracts of lemon balm (Melissa officinalis) cultivated in Mexico

Lemon balm (Melissa officinalis) is a plant in the family of Lamiaceae. In Mexican traditional medicine it is used to alleviate gastrointestinal and hepatic problems. Studies carried out mainly in ethanolic and methanolic extracts, have revealed the presence of diverse compounds to which those medicinal properties are attributed. The objective of this research work was to extract in aqueous solution the antioxidants present in lemon balm and identify them through HPLC-MS. A Box-Behnken design was applied to determine the physical conditions of antioxidant extraction, where the analyzed variables were time, temperature and sample quantity. The antioxidant activity was determined through methodologies of DPPH*, FRAP and total phenolics. The aqueous solution with the highest antioxidant activity was analyzed through HPLC-MS. The results showed that the interaction temperature-time has a positive influence on the liberation of antioxidants. The best condition for a conventional extraction of antioxidants was 90°C, 15 min and 2 g of sample. Higher correlations were observed at r2>0.6 between determined antioxidant activity by DPPH* (or FRAP) vs Total phenolics; this would indicate that such activity could be attributed to phenolic compounds whose presence was confirmed through an analysis by HPLC-MS(AU)

El toronjil (Melissa officinalis) es una planta de la familia Lamiaceae. En la medicina tradicional mexicana es utilizado para aliviar problemas gastrointestinales y hepáticos. Algunos estudios realizados con extractos etanólicos y metanólicos de dicha planta, han revelado la presencia de diversos compuestos a los que se les atribuye sus propiedades medicinales. El objetivo de esta investigación fue extraer en solución acuosa los antioxidantes presentes en el toronjil e identificarlos a través de HPLC-MS. Para ello, se aplicó un diseño de experimentos Box-Behnken a fin de determinar las condiciones físicas de extracción de antioxidantes; las variables analizadas fueron tiempo, temperatura y cantidad de muestra. La actividad antioxidante fue determinada a través de las metodologías de DPPH*, FRAP y fenoles totales. El extracto acuoso con la mayor actividad antioxidante fue analizado mediante HPLCMS. Los resultados mostraron que la interacción tiempotemperatura tuvo una influencia positiva en la liberación de antioxidantes. La mejor condición para la extracción de antioxidantes presentes en el toronjil fue 90°C, 15 min y 2 g de muestra. Correlaciones superiores a r2>0.6 fueron determinadas entre la actividad antioxidante medida por DPPH* (o FRAP) vs Fenoles totales; esto podría indicar que la actividad antioxidante encontrada podría atribuirse a compuestos de tipo fenólico cuya presencia fue confirmada por el análisis en HPLC-MS(AU)

Optimization of Physical Conditions for the Aqueous Extraction of Antioxidant Compounds from Ginger (Zingiber officinale) Applying a Box-Behnken Design.

Since ancient times, ginger (Zingiber officinale) has been widely used for culinary and medicinal purposes. This rhizome possesses several chemical constituents; most of them present antioxidant capacity due mainly to the presence of phenolic compounds. Thus, the physical conditions for the optimal extraction of antioxidant components of ginger were investigated by applying a Box-Behnken experimental design. Extracts of ginger were prepared using water as solvent in a conventional solid-liquid extraction. The analyzed variables were time (5, 15 and 25 min), temperature (20, 55 and 90 °C) and sample concentration (2, 6 and 10 %). The antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl method and a modified ferric reducing antioxidant power assay while total phenolics were measured by Folin & Ciocalteu's method. The suggested experimental design allowed the acquisition of aqueous extracts of ginger with diverse antioxidant activity (100-555 mg Trolox/100 g, 147-1237 mg Fe2+/100 g and 50-332 mg gallic acid/100 g). Temperature was the determining factor in the extraction of components with antioxidant activity, regardless of time and sample quantity. The optimal physical conditions that allowed the highest antioxidant activity were: 90 °C, 15 min and 2 % of the sample. The correlation value between the antioxidant activity by ferric reducing antioxidant power assay and the content of total phenolics was R2 = 0.83. The experimental design applied allowed the determination of the physical conditions under which ginger aqueous extracts liberate compounds with antioxidant activity. Most of them are of the phenolic type as it was demonstrated through the correlation established between different methods used to measure antioxidant capacity.

Evaluation of natural materials as exogenous carbon sources for biological treatment of low carbon-to-nitrogen wastewater.

In the bacterial processes involved in the mitigation of nitrogen pollution, an adequately high carbon-to-nitrogen (C : N) ratio is key to sustain denitrification. We evaluated three natural materials (woodchips, barley grains, and peanut shells) as carbon sources for low C : N wastewater. The amount of organic matter released from these materials to aqueous media was evaluated, as well as their pollution swapping potential by measuring the release of total Kjeldahl nitrogen, N-NH4 (+), NO2 (-), and NO3 (-), and total phosphorous. Barley grains yielded the highest amount of organic matter, which also showed to be the most easily biodegradable. Woodchips and peanut shells released carbon rather steadily and so they would not require frequent replenishment from biological reactors. These materials produced eluates with lower concentrations of nutrients than the leachates from barley grains. However, as woodchips yielded lower amounts of suspended solids, they constitute an adequate exogenous source for the biological treatment of carbon-deficient effluents.