UHPLC-HRMS Analysis of Fagus sylvatica (Fagaceae) Leaves: A Renewable Source of Antioxidant Polyphenols

Abstract

European beech (Fagus sylvatica L.) is a deciduous tree, widely distributed in Europe and largely appreciated for its wood and nutritive nuts. Beech leaf also enjoys food use as salad, but an understanding of its nutraceutical value is still far from being achieved. Indeed, and also taking into account beech leaf as a consistent biomass residue available beechwood production and use, it needs to be explored as a valuable renewable specialized source of bioactive molecules. In this context, an untargeted ultra-high-performance liquid chromatography hyphenated with high resolution mass spectrometry (UHPLC-HRMS) approach was favorably applied to a beech leaf alcoholic extract, which also was evaluated for its antiradical capability (by means of assays based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and [2,2’-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid)] (ABTS) radical cation) and its ferric ion reducing power. Redox mitochondrial activity towards Caco-2 cells paved the way to explore the extract’s capability to inhibit intracellular Reactive Oxygen Species (ROS) using 2’,7’dichlorofluorescin diacetate (DCFH-DA) assay. Hydroxycinnamoyl derivatives, mainly belonging to the chlorogenic acid class, and flavonoids were the main constituents. Uncommon flavanone C-glycosides were also found, together with a plentiful flavonol diversity. Cell-free and cell-based assays highlight its dose-dependent antioxidant efficacy, providing a foundation for further investigation of beech leaf constituents and its valorization and use as a reservoir of bioactive natural products with potential nutraceutical applications.

UHPLC-ESI-QqTOF Analysis and In Vitro Rumen Fermentation for Exploiting Fagus sylvatica Leaf in Ruminant Diet

“…The alcoholic extract of F. sylvatica leaf (Fs/1/1), whose chemical profiling was previously reported [ 25 ], consisted of an abundant polyphenol part and fatty acids. Polyphenols were mainly flavonols, beyond hydroxycinnamoyl compounds, while mono- or polyhydroxylated fatty acids were identified, also according to the literature [ 26 ], at the highest retention time in the total ion chromatogram [ 25 ].…”

“…The alcoholic extract of F. sylvatica leaf (Fs/1/1), whose chemical profiling was previously reported [ 25 ], consisted of an abundant polyphenol part and fatty acids. Polyphenols were mainly flavonols, beyond hydroxycinnamoyl compounds, while mono- or polyhydroxylated fatty acids were identified, also according to the literature [ 26 ], at the highest retention time in the total ion chromatogram [ 25 ]. The Fs/1/1 extract exhibited a good antioxidant efficacy, which was supposed to be enhanced following fractionation and with the obtainment of fractions differently composed in terms of polarity and identity of their specialized metabolites.…”

“…The ability to reduce the Fe(III) of beach leaf Fs/1/1 extract and its fractions (at the 200,100, 50, 25, 12.5, 6.25, and 3.125-µg/mL final concentration levels) was evaluated using the ferricyanide FRAP assay, according to PFRAP procedure [ 25 ]. The absorbance was measured at 700 nm.…”

“…In this context, based on a previous phytochemical investigation on F. sylvatica leaves [ 25 ] as a renewable source for feed and food, herein, a two-steps fractionation process has been proposed, achieving two main fractions. The latter, together with their parental extract, were preliminarily screened for their total phenolic (TPC), flavonoidic (TFC), and lipidic contents (TLC), as well as for their antiradical and reducing activity.…”

Calendula arvensis (Vaill.) L.: A Systematic Plant Analysis of the Polar Extracts from Its Organs by UHPLC-HRMS

“…The potassium ferricyanide reducing power (PFRAP) assay was also performed to estimate the reducing power of the investigated alcoholic extracts (at 100, 50, 25, 10, and 2.5 µg/mL final concentration levels). The absorbance was measured at 700 nm [46,47]. A blank was considered, preparing a solution with PFRAP reagent without samples, as well as Trolox as a positive standard.…”