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.

Anaerobic treatment is a viable alternative for the treatment of agro-industrial waste. Anaerobic digestion reduces organic load and produces volatile fatty acids (VFA), which are precursors of value-added products such as methane-rich biogas, biohydrogen, and biopolymers. Nowadays, there are no low-cost diagnosis and monitoring systems that analyze the dynamic behavior of key variables in real time, representing a significant limitation for its practical implementation. In this work, the feasibility of using the multiscale analysis to diagnose and monitor the key variables in VFA production by anaerobic treatment of raw cheese whey is presented. First, experiments were carried out to evaluate the performance of the proposed methodology under different operating conditions. Then, experimental pH time series were analyzed using rescaled range (R/S) techniques. Time-series analysis shows that the anaerobic VFA production exhibits a multiscale behavior, identifying three characteristic regions (i.e., three values of Hurst exponent). In addition, the dynamic Hurst exponents show satisfactory correlations with the chemical oxygen demand (COD) consumption and VFA production. The multiscale analysis of pH time series is easy to implement and inexpensive. Hence, it could be used as a diagnosis and indirect monitoring system of key variables in the anaerobic treatment of raw cheese whey.

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 g_COD 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

The fate of polycyclic aromatic hydrocarbons is a major environmental concern that has attracted much attention in current literature. The physicochemical properties of contaminants, along with soil characteristics and ageing, translate into an unusual sorption that leads to high sequestration and low bioavailability. In the present study, fresh (non-sterile) and aged (sterile) synthetic soils (sand-perlite 1:1 v/v) were characterized and spiked (hexadecane, phenanthrene and pyrene 2:1:0.5) to evaluate sequestration extents. Hydrocarbons extraction differed for sand and perlite in fresh samples, on the contrary, the artificial ageing process affected equally the extraction in the synthetic soil components. In the synthetic soil, the extractability of hexadecane and phenanthrene were 80% and 60%, respectively, in fresh samples, but for both hydrocarbons it was only 20% in aged samples. Pyrene extractability was not affected by the components of the synthetic soil or by ageing, and this may be related to an in-situ crystallisation process. The characteristics of the soil and its contaminants, coupled with long-term interactions, significantly modified the PAHs environmental fate, leading to the formation of non-extractable residues, also known as sequestered contaminants. This study expands current knowledge about the fate of these contaminants and should serve as motivation for further experimental and theoretical research on this subject.