LC-MS- and 1H NMR-Based Metabolomics to Highlight the Impact of Extraction Solvents on Chemical Profile and Antioxidant Activity of Daikon Sprouts (Raphanus sativus L.)

Abstract

Currently, the interest of consumers towards functional foods as source of bioactive compounds is increasing. The sprouts of Raphanus sativus var longipinnatus (Brassicaceae) are “microgreens” popular, especially in gourmet cuisine, for their appealing aspect and piquant flavour. They represent a functional food due to their high nutritional value and health-promoting effects. Herein, the sprouts of daikon were extracted by different solvent mixtures to highlight how this process can affect the chemical profile and the antioxidant activity. An in-depth investigation based on a preliminary LC-ESI/LTQOrbitrap/MS profiling was carried out, leading to the identification of nineteen compounds, including glucosinolates and hydroxycinnamic acid derivatives. An undescribed compound, 1-O-feruloyl-2-O-sinapoyl-β-D-glucopyranoside, was isolated, and its structure was elucidated by NMR spectroscopy. The phenolic content and radical scavenging activity (DPPH and TEAC assays), along with the ability to activate Nrf2 (Nrf2-mediated luciferase reporter gene assay) of polar extracts, were evaluated. The results showed the highest antioxidant activity for the 70% EtOH/H2O extract with a TEAC value of 1.95 mM and IC50 = 93.97 µg/mL in the DPPH assay. Some 50% and 70% EtOH/H2O extracts showed a pronounced concentration-dependent induction of Nrf2 activity. The extracts of daikon sprouts were submitted to 1H NMR experiments and then analyzed by untargeted and targeted approaches of multivariate data analysis to highlight differences related to extraction solvents.

Comparison of Anti-Inflammatory and Antibacterial Properties of Raphanus sativus L. Leaf and Root Kombucha-Fermented Extracts

“…It has been proven that the antioxidant properties of active substances contained in plant extracts can contribute The results obtained when assessing the antioxidant properties using the ABTS and DPPH methods correspond to the results obtained in the chromatographic analysis (Tables 1 and 2). As indicated by the literature data and chromatographic analyses, radish extracts and ferments are characterized by the presence of compounds such as gallic acid, catechin, gallocatechin, rutoside, quercetin glucoside, and caffeoylmalic acid, which have proven antioxidant properties [30][31][32]. Kombucha ferments showed higher antioxidant activity compared with non-fermented extracts due to the decomposition of polyphenolic compounds into smaller phenolic substances by microbial enzymes present in the biofilm formed by bacteria and yeast during fermentation.…”

Non-Destructive Characterization of Italian Local Brassicaceae Cultivars Using ATR-FT-IR and Chemometrics

“…The latter technique is particularly attractive for large-scale analysis and industry conditions, especially when combined with chemometrics, since it is relatively fast, inexpensive, non-destructive, and does not require complex sample preparation [13]. Several studies have focused on optimizing extraction processes on this remarkable matrix, which can be actually considered a functional food [14]; Baky et al [15] characterized, using headspace solid-phase microextraction (HS-SPME) technique and gas chromatographymass spectrometry (GC-MS), volatile and nonvolatile profiles of six Brassicaceae cultivar leaves (Brassica oleracea (cabbage), Brassica oleracea var. italica (broccoli), Brassica oleracea var.…”