Optimizing the Vanillin-Acid Sulfuric Method to Total Saponin Content in Leaves of Yerba Mate Clones.

Yerba mate (Ilex paraguariensis) is a forest species consumed in the form of non-alcoholic beverages in South America, with applications in foods, cosmetics, and pharmaceutical industries. The species leaves are globally recognized for their important bioactive compounds, including, saponins. We adjusted the vanillin-acid sulfuric method for determining spectrophotometrically the total saponin in yerba mate leaves. Seeking to maximize the extraction of saponins from leaves, a Doehlert design combined with Response Surface Methodology (RSM) was used, considering ethanol:water ratios and ultrasound times. In addition, the same methodology was used for the analysis of times and temperatures in the vanillin-sulfuric acid reaction heating. The contents of total saponin in mature leaves were compared in four yerba mate clones. The extraction was maximized using 40 % ethanol:60 % water and 60 minutes of ultrasound assisted extraction (UAE) without heating. For the reaction conditions, 70 °C for 10 minutes heating is recommended, and UV/Vis reading from 460 to 680 nm. Using the optimized methodology, total saponin contents ranged from 28.43 to 53.09 mg g-1 in the four yerba mate clones. The significant difference in saponin contents between clones indicate great genetic diversity and potential for clones' selection and extraction of these compounds from yerba mate leaves.

Ecotoxicological evaluation of fruit extracts from yerba mate progenies (Ilex paraguariensis a St-Hil.): a natural biopesticide.

This study evaluated the biocidal activity of aqueous fruit extracts from Ilex paraguariensis progenies at different ripening stages in two ecotoxicity assays using Pomacea canaliculata juveniles and Danio rerio larvae. Mutagenicity was verified by the Salmonella/microsome assay (TA 98 and TA 100) in the presence and absence of hepatic metabolism in vitro. The results showed that the snails were more sensitive than the larvae to the P.1 progeny extracts in all three evaluated ripening stages. P.3 progeny extracts were the most toxic to Danio rerio larvae after 96 hours of exposure. The toxicity results indicate that the progenies' selection influenced the metabolic contents present in the fruits in all ripening stages over time, indicating high molluscicidal activity for the P.1 progeny. In the Salmonella/microsome assays, the semi-ripe and ripe extracts from progenies P.1 and P.3 showed mainly base pair substitution mutation in assays with metabolism, but at higher doses than the toxic concentrations detected for Danio rerio or Pomacea canaliculata. Therefore, the toxicological investigation of the progenies' extracts can be interesting, given the selection of plant materials influenced the response of the bioassays.

Influence of stingless bee genus (Scaptotrigona and Melipona) on the mineral content, physicochemical and microbiological properties of honey.

Stingless bees, important pollinating insects in the tropics, produce honey whose unique quality features differentiate their origin. The feasibility of multivariate data analysis for quality discrimination of stingless bee honey from different genera (Melipona bicolor, quadrifasciata, marginata and Scaptotrigona bipunctata) by mineral content, physicochemical and microbiological properties were investigated. The principal component analysis explained 72.12% of the total variance of the data, and the separation into two main groups in a scatter plot was observed. Group 2 was formed by Scaptotrigona genus, that showed the highest values of pH, ash, and soluble solids. Potassium was the most abundant mineral followed by calcium and sodium for both groups quantified by inductively coupled plasma optical emission spectrometry. This honey has higher acidity and moisture than Apis mellifera honey. Microbiological analyses showed that total aerobic mesophiles ranged between 2.00 and 4.77 log CFU/g. Salmonella spp. was not detected, while the mould and yeast content was above the maximum allowed under the Apis mellifera honey legislation. The evaluated honey samples presented the lactic acid bacteria, which are considered a benefit. The multivariate statistical analysis was efficient in discriminate stingless bee honey, contributing to approaches that can be used for standardization and regulation.

Main differences between volatiles of sparkling and base wines accessed through comprehensive two dimensional gas chromatography with time-of-flight mass spectrometric detection and chemometric tools.

The main changes in the volatile profile of base wines and their corresponding sparkling wines produced by traditional method were evaluated and investigated for the first time using headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC×GC/TOFMS) and chemometric tools. Fisher ratios helped to find the 119 analytes that were responsible for the main differences between base and sparkling wines and principal component analysis explained 93.1% of the total variance related to the selected 78 compounds. It was also possible to observe five subclusters in base wines and four subclusters in sparkling wines samples through hierarchical cluster analysis, which seemed to have an organised distribution according to the regions where the wines came from. Twenty of the most important volatile compounds co-eluted with other components and separation of some of them was possible due to GC×GC/TOFMS performance.

Differentiation of wines according to grape variety using multivariate analysis of comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection data.

Headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC×GC/TOFMS) was used to analyse the volatiles in five types of wines elaborated with grapes of Cabernet Sauvignon, Merlot, Chardonnay, Sauvignon Blanc and Pinot Noir varieties. Fisher ratio, principal component analysis (PCA) and stepwise linear discriminant analysis (SLDA) were used to develop a discriminant model and, as a result, 12 volatile compounds enabled differentiation and classification of wines according to grape cultivars. A detailed examination of GC×GC/TOFMS data showed that the use of one-dimensional gas chromatography with a mass spectrometric detector (1D-GC/MS) would probably result in misidentification of some of these 12 compounds, as they showed partial coelution with other components in the first chromatographic dimension.

Optimized modified topliss method: a tool for quantitative structure-activity relationship studies.

The structural variation of lead compounds often includes the variation of substituents at a particular site. A common difficulty, in quantitative structure-activity relationship (QSAR) studies, is to select the best substituents to obtain, with a minimum number of experiments, a major change in some impor. tant properties of the molecule. To improve a proposed modified Topliss method, 187 different substituted compounds belonging to 70 series were studied. A single linear regression was carried out between the experimental activity of each series of compounds and the molecular structure parameters pi, sigma, Es and MR, along with some combinations of them, in order to select the best substituents for constructing the "reduced" correlation. This selection considered the scaled smallest residue average of the substituent, the number of times that the substituent is inserted in the 70 series and its quadrant in the Craig graph. The results obtained in this study with this simple method showed a good predictive capacity when compared with the multiple regression analysis, using the Hansch method.

From the manual method of Topliss to a modified quantitative method.

The optimization of the properties of a lead compound is the first goal of most pre-clinical research projects. Optimization strategies may be applied to the synthesis of analogous compounds in order to minimize cost and time. One strategy of synthesis is the change of the substituents in the molecule. The manual method of Topliss was introduced for the prediction of the substituted compounds that will have the most potent activity in a series of aromatic substituted analogues. A modified Topliss method is proposed that consist of the quantitative correlation by a single regression equation of the activity of a series of 4 or 5 substituted aromatic compounds with the descriptor parameters: hydrophobic (pi), electronic (sigma) and sterics (Es and MR) and some combinations of them in order to predict future synthesis, or to obtain a training set of compounds to be used in the application of more advanced experimental design methods. These results when compared with those of multiple regression analysis applying the Hansch equation are very satisfactory.