Urtica dioica L. leaf chemical composition: A never-ending disclosure by means of HR-MS/MS techniques

The metabolite profiling of plant extracts always represents an exciting challenge, as the chemical diversity of natural products is still far beyond the researchers’ imagination, even focusing on a plant that is thought to have already been broadly investigated. Herein UHPLC-HRMS/MS techniques were applied to an alcoholic crude extract from nettle leaves and proved to be a precious tool for the disclosure of secondary metabolites never found before. Hydroxycinnamic acid derivatives were the most representative constituents, with a 2-caffeoilisocitric acid cyclodimer described for the first time, besides four C-glycosylated flavones, bearing a 3-hydroxy-3-methylglutaryl function. This deep investigation paves the way for the isolation and full characterization of these molecules by means of spectroscopic techniques. Moreover, based on preliminary cytotoxicity evaluation, further research on the use of this nettle extract as a valuable nutraceutical product is encouraged

A nutraceutical extract from Inula viscosa leaves: UHPLC-HR-MS/MS based polyphenol profile, and antioxidant and cytotoxic activities

Nowadays, advanced extraction techniques and highly sensitive metabolic profiling methods are effectively employed to get new information on plant chemical constituents. Among them wild medicinal plants or their parts, with large and ancient use in folk medicine, are investigated for their potential functional use and cultivation. In this context, Inula viscosa leaves engaged our attention. A simple experimental design, based on Soxhlet extraction and chromatographic fractionation, allowed us to obtain the investigated polyphenol fraction (IvE). UHPLC-HRMS analyses revealed shikimoyl depsides of caffeic acid and unusual dihydrobenzofuran lignans as main secondary metabolites. These compounds, together with cinchonain-type phenols, and hydroxycinnamoyl flavonol glycosides, are reported for the first time in inula. Overall, forty-three secondary metabolites were identified. The extract exerted a remarkable antiradical activity towards DPPH• and ABTS+•. Furthermore, it was able to inhibit cell viability and mitochondrial redox activity of neuroblastoma, hepatoblastoma and colon carcinoma cells, whereas it did not affect cell density of HaCaT cells immortalized human keratinocytes. As detected by the oxidant-sensing probe 2′,7′-dichlorodihydrofluorescein diacetate, the inhibitory responses seemed to be related to IvE-induced increase of intracellular reactive oxygen species (ROS). The obtained results highlighted that inula leaves, nowadays even undervalued and unexplored, could be considered a renewable source of nutraceutical compounds

J. food meas. charact

The recovery of food waste is a stimulating opportunity for and competitive development of agroindustries. In this context, the objective of this study was to report the antioxidant potential and phenolic compounds content of olive stones (OS) of six Algerian cultivars. Two extraction methods were used: microwave assisted extraction (MAE) and conventional solvent extraction (CSE) in order to improve the recovery of total phenolic content (TPC) and the maximization of the two extraction processes by the Box-Behnken design (BBD) from olive stone of Olea Europaea L. cv Ayemele. The optimal processing parameters obtained were (i) for MAE: 22% (v/v) ethanol, 40 s, 500 W, and ratio 65:1 (mL/g) and (ii) for CSE: 33% (v/v) ethanol, 24 min, 71°C, and ratio 60:1 (mL/g). Phenolic compounds were then extracted from olive stones of six Algerian cultivars with MAE best extraction conditions, as it was the best strategy in term of TPC recovery. The phenolic content was different according to the olive variety. The stones of Chemlale were the richest in TPC (7.23 mg GAE/g) followed by Azeboudj (6.33 mg GAE/g), Atefah (6.04 mg GAE/g), Agraraz (5.63 mg GAE/g), Azeradj (5.35 mg GAE/g) and Ayemel (5.14 mg GAE/g). A similar profile was observed with total flavonoids content and antioxidant activities. The anti-inflammatory effects of the optimized extracts by MAE were assessed regarding their ability to prevent lipopolysaccharide-induced of reactive oxygen species and nitric oxide production in a macrophage cell line (RAW 264.7). Olive stones that are issued from the production of olive oil, and table olives can therefore be considered as renewable by-products thanks to their compounds with high added value. These bioactive compounds can target the food natural additives markets, pharmaceutical and cosmetic industries, all of which are currently very receptive such natural products