Identification and determination of bioactive phenylpropanoid glycosides of Aloysia polystachya (Griseb. et Moldenke) by HPLC-MS.

Aloysia polystachya (Griseb. et Moldenke) has not been deeply investigated in past years and currently data about its chemical composition are limited. Phenolic compounds characterization can be very difficult in vegetable matrices, owing to bonds to sugar moieties or conjugation, giving rise to complex structures. In this work, methanolic extracts of Aloysia polystachya leaves were analyzed by HPLC-ESI-MS, the favourite technique for the separation and quantification of their polyphenols. To assess the complete characterization and quantification of the phenylpropanoid fraction, three different MS techniques have been coupled to HPLC: ion trap mass spectrometry (Ion Trap LC/MS), quadrupole-time of flight high resolution mass spectrometry (Q-TOF HRMS) and triple-quadrupole (TQ LC/MS) for the quantification. Eleven phenylpropanoid glycosides were identified and quantified and, among them, the compounds forsythoside A, plantainoside C, purpureaside D, martynoside and its two isomers were detected for the first time to the best of our knowledge. The results presented here could be helpful to assess the quality of this plant and could further contribute to the chemotaxonomy of the genus.

Novel 2D-NMR Approach for the Classification of Balsamic Vinegars of Modena.

The aim of this work is to evaluate the possibility of using 2D-NMR for the construction of classification models for balsamic vinegars of Modena. The goal was to obtain an indirect indicator of authenticity and a quality control tool. The spectral data were analyzed by chemometric methods, aiming to discriminate the samples in relation to their origin. Application of general discriminant analysis (GDA) revealed a good discrimination; the two obtained models explained 83.9% and 97.3% of the total variance with a predictive capacity of 98.6% and 98.4%, respectively. The signals of 5-HMF, ß-glucose, 2,3-butanediol, 6-acetyl glucose, and different aliphatic signals of sugars were the most significant variables. These results are very promising for giving an important contribution in quality control and characterization of such very valuable foods.

Application of one- and two-dimensional NMR spectroscopy for the characterization of Protected Designation of Origin Lambrusco wines of Modena.

Lambrusco is a Protected Designation of Origin (PDO) red wine of Modena (Italy) produced according to the production regulation (Decreto Ministeriale (DM) July 27, 2009; GU no. 184-187-188, 13/08/2009). Here the use of (1)H NMR spectroscopy as molecular fingerprints of several PDO Lambrusco wines was proposed to serve as indicators of authenticity and quality control. Application of partial least squares discriminant analysis (PLS-DA) revealed a good varietal discrimination by analyzing the low-frequency spectral region. This model explains 68.8% of the variance for the Y vector (classification factor: varietal source). In particular, the signals of 2,3-butanediol, lactic, succinic and malic acids, and threonine were found to be the most statistically significant variables in the model. These findings seem to be very promising in the attempt to extend the study to geographical discrimination.