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BACKGROUND: The fruit of Cucurbita ficifolia Bouché is known in Mexico as 'chilacayote'. The scientific interest that C. ficifolia Bouché has acquired is due to its important hypoglycemic effect. The present research aimed (i) to discover whether this hypoglycemic property is present at different stages of development of this fruit, and (ii) to characterize some bioactive compounds with antioxidant or anti-inflammatory properties. Ethylene production, respiration rate, and maturity indices were determined during fruit development. The chemical characterization of the aqueous extracts of each stage of maturity studied was determined and their hypoglycemic effects were bioassayed using groups of normal mice with diabetes induced by streptozotocin at a dose of 500 mg −1 kg −1 body weight. RESULTS: Respiration rate and ethylene production showed a typical pattern for non-climacteric fruit and the quality parameters did not show significant changes. Phenolic compounds such as gallic acid and chlorogenic acid were found to have the highest concentration at 15 days of development. Extracts at 15 days showed a hypoglycemic effect that was 11% greater than that of glibenclamide in diabetized mice. CONCLUSION: All stages of development of C. ficifolia fruit had a hypoglycemic effect; however, the aqueous extract from the fruit at 15 days of development showed a better effect than glibenclamide. This finding highlights the potential of this maturity stage, and shows that it is appropriate for inclusion in treatments of type 2 diabetes mellitus. The results also indicate that phenolic compounds are mainly responsible for this effect and not D-chiro-inositol as previously thought.

BACKGROUND: Low permeability of substrates across the cell membrane, cofactor regeneration and product inhibition are some drawbacks of (+)-nootkatone bioconversion. The aim of this work was to evaluate and enhance the bioconversion of (+)-valencene to (+)-nootkatone with Yarrowia lipolytica in a partitioning bioreactor using orange essential oil as the dispersed phase.

Catharanthus roseus (L.) G. (C. roseus) is a medicinal plant used traditionally for diabetes mellitus control. Several compounds of an alkaloidal nature have been proposed as hypoglycemic principles. However, little attention has been paid to other compounds in this plant that could also participate in this hypoglycemic activity. This study aimed to analyze the hypoglycemic effect of a polyphenolic fraction from C. roseus, as well as its action on insulin secretion and expression in RINm5F cells. Methods. An alkaloid-free aqueous extract was obtained from C. roseus stems. The hypoglycemic effect of different doses of this extract was evaluated in normal and streptozotocin-induced diabetic mice. This extract was fractionated by bipartition, and the resultant fractions were assessed by their hypoglycemic effects. Subsequently, the fraction with the greater hypoglycemic activity was added to the RINm5F cells, and the expression and secretion of insulin were analyzed. The antioxidant activity was determined by the DPPH method and through chromatographic analysis of the most active fraction by HPLC, using an Econosphere C18 column. Results. The aqueous alkaloid-free extract of C. roseus stems significantly reduced blood glucose in normal and diabetic mice. The fractionation of this extract provided three fractions, one of which (a precipitate) showed significant reductions in glycemia at 6 h (48.1 and 64.5% in normal and diabetic mice, respectively). This precipitate contained phenolic compounds and saponins. Its chromatographic analysis showed that it is formed by several phenolic compounds; gallic acid (0.053%) and chlorogenic acid (0.216%) were identified and quantified. Conclusion. The phenolic fraction of C. roseus containing gallic acid and chlorogenic acid had a hypoglycemic effect that may be explained by an increase in insulin secretion.

Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo intemperizados en suelos y sedimentos (Biodegradation modeling of sludge bioreactors of total petroleum hydrocarbons weathering in soil and sediments)

Sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) share common niches in coastal sediments during the terminal phases of the anaerobic mineralization of organic matter. The purpose of this study was to analyse the spatial-temporal variation of SRB and MA in the sediments of a tropical coastal lagoon with ephemeral inlet and its relationship with environmental changes. Sediment samples were collected during the dry, rainy and northers seasons. Microbiological analyses included the quantification of the viable SRB and MA with different substrates, as well as mineralization experiments to determine the effect of sulfate on acetate oxidation. The analyzed environmental variables included temperature, pH, Eh, salinity, sulfates, H2S, volatile solids, carbohydrates, and granulometric characteristics. Major changes occurred between the dry and rainy seasons. During the dry season, sulfate-reducing abundance was significantly greater with lactate (8.3x105-1.2x107 cells/g) and propionate (1.8x105-6.6x106 cells/g) as substrates, while the MA that use methanol were dominant (4.2x105-9.1x106 cells/g). In contrast, during the rainy season, hydrogenophylic (2.6x105-8.3x106 cells/g) and acetoclastic (5.4x105-6.4x106 cells/g) MA increased significantly and SRB decreased in the analyzed substrates. An apparent competition for acetate was observed, with a greater oxidation in the media with sulfates in the dry (0.06 mM acetate/g sediment/day) season, and a greater oxidation in the media without sulfates in the rainy season (0.02 mM acetate/g sediment/day). SRB and MA were present throughout the sediment column, however SRB dominated in the first centimeters of the sediment while MA were abundant in deeper layers. Salinity, sulfate, the organic fractions, and silt were the environmental variables that explained the SRB and MA dynamics.

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The whey is a byproduct of the dairy industry that, if not treated properly, can cause serious environmental pollution problems. Anaerobic treatment is an alternative for its recovery, since, in addition to reducing the organic load. it allows the generation of value-added products such as volatile fatty acids (VFA) and biogas. However, the process is very complex and requires specific operating conditions that guarantee its stability and favor the production of value-added compounds. In this work, an unstructured mathematical model is proposed to evaluate the dynamic behavior of the stages of the anaerobic degradation process of the whey (i.e., hydrolysis, acidogenesis, acetogenesis and methanogenesis). The proposed model considers the dynamic variation in pH during the experiment. To validate the model, an experimental set was carried out at pH and temperature conditions that favor the production of VFAs. Experimental results show that the anaerobic treatment of the raw cheese whey favors pH = 5.5; for T = 40 °C, the maximum VFA production is obtained (30.71 gCOD L−1), and for T = 35 °C, a 45.81% COD degradation is reached. The proposed model considers the effect of pH and temperature and it is validated in the region where the experimental tests were carried out. The model parameters were estimated using the Levenberg–Marquardt method, obtaining coefficients of determination R2 > 0.94. The proposed model can describe the dynamic behavior of the key variables in the anaerobic treatment of raw cheese whey at different pH and temperature conditions, finding that VFA production is favored at pH ≥ 7, while the highest COD removal results in acidic conditions