Browsing by Author "Politi, Matteo"
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- Antioxidant principles and volatile constituents from the north-western Iberian mint “erva-peixeira”, mentha cervinaPublication . Politi, Matteo; Rodrigues, César L.; Gião, Maria S.; Pintado, Manuela E.; Castro, Paula M. L.Total phenol content determined by the Folin–Ciocalteu assay and total antioxidant capacity measured by the ABTS•+ method were applied for the first time to analyze the aqueous extract prepared from the dried aerial parts of Mentha cervina, a Portuguese mint species traditionally used as a culinary herb in river fish-based dishes and currently commercialized to prepare digestive infusions. LC-MS/MS analysis was performed directly on the crude aqueous extract allowing the identification of seven phenolic compounds. The overall plant aroma was analyzed by the SPME/GC-MS method; this approach allowed the characterization of various constituents, as well as the comparison between the fresh and dried plant material. Such a comparison highlighted several metabolic changes that occur during the drying process of the aerial parts of this plant.
- Different approaches to study the traditional remedy of 'hierba del canto', Sisymbrium officinale (L.) Scop.Publication . Politi, Matteo; Braca, Alessandra; Altinier, Gianmario; Sosa, Silvio; Ndjoko, Karine; Wolfender, Jean-Luc; Hostettmann, Kurt; Jimenez-Barbero, JesusThe infusion of the semi-fresh flowering aerial parts of Sisymbrium officinale (L.) Scop. (Brassicaceae), commonly known as hierba del canto in Spanish, is a popular remedy for the treatment of sore throats, coughs, and hoarseness, but little is known about its chemistry and pharmacology. HPLC-UV/PDA analyses of the dichloromethane and methanol extracts of both the fresh and the dried plant material showed the occurrence of some biochemical reactions during the drying process. The freeze-dried residue of the infusion (SOw) prepared according to the traditional recipe, was re-dissolved in methanol obtaining a soluble fraction (SOw_s) and a precipitate (SOw_p). Further fractionation of SOw_s allowed the identification of adenine, adenosine, and guanosine that were present in significant quantities only in the traditionally prepared aqueous extract. Polysaccharides were detected in the SOw_p fraction and their molecular weight evaluated by DOSY experiments. When they all were tested for the topical anti-inflammatory activity in the murine Croton oil-induced ear oedema model, only a modest effect was observed at high concentrations. Saturation Transfer Difference-NMR experiments for the study of the binding activity between the plant metabolites and the Lens culinaris lectin gave partial data on the active principles. This work affords new data on the phytochemistry of the plant but the question about the identity of the active principles responsible for the traditional use of S. officinale remains open.
- Direct metabolic fingerprinting of commercial herbal tinctures by nuclear magnetic resonance spectroscopy and mass spectrometryPublication . Politi, Matteo; Zloh, Mire; Pintado, Manuela E.; Castro, Paula M. L.; Heinrich, Michael; Prieto, Jose M.Introduction – Tinctures are widely used liquid pharmaceutical preparations traditionally obtained by maceration of one or more medicinal plants in ethanol–water solutions. Such a process results in the extraction of virtually hundreds of structurally diverse compounds with different polarities. Owing to the large chemical diversity of the constituents present in the herbal tinctures, the analytical tools used for the quality control of tinctures are usually optimised only for the detection of single chemical entities or specific class of compounds. Objective – In order to overcome the major limitations of the current methods used for analysis of tinctures, a new methodological approach based on NMR spectroscopy and MS spectrometry has been tested with different commercial tinctures. Methodology – Diffusion-edited 1H-NMR (1D DOSY) and 1H-NMR with suppression of the ethanol and water signals have been applied here for the first time to the direct analysis of commercial herbal tinctures derived from Echinacea purpurea, Hypericum perforatum, Ginkgo biloba and Valeriana officinalis. The direct injection of the tinctures in the MS detector in order to obtain the corresponding metabolic profiles was also performed. Results – Using both NMR and MS methods it was possible, without evaporation or separation steps, to obtain a metabolic fingerprint able to distinguish between tinctures prepared with different plants. Batch-to-batch homogeneity, as well as degradation after the expiry date of a batch, was also investigated. Conclusion – The techniques proposed here represent fast and convenient direct analyses of medicinal herbal tinctures.