Search

Three extraction methods, involving maceration, reflux, and ultrasonic extractions, were used to evaluate the phytochemical content and antioxidant activity of leaf extracts from Capparis spinosa L. collected from five localities in South Tunisia. The results showed that the maceration extract contained the highest content of phenolic acids and flavonoid compounds. The maceration extraction method exhibited the highest antioxidant activities using the reducing power assay, the azinobis (3-ethylbenzothiazoline)-6-sulfonic acid (ABTS+), and the 2,2-diphényl-1-picrylhydrazyle (DPPH°) radical scavenging activity. The determination of the phytochemicals in the extracts was carried out using a quadrupole mass spectrometer equipped with an electrospray ionization source that was operated in the negative ionization mode (LC–ESI–MS). The results allowed the detection of seven phenolic acids in the maceration extract and ultrasonic assisted extraction, but only six phenolic acids in the reflux extract. The major identified phenolic acids were quinic acid, gallic acid, and protocatchuic acid. Ten flavonoids were detected, and their concentrations varied according to the extraction method. Catechin was the most abundant flavonoid in all of the extracts. This investigation provides additional support for the use of caper leaves in medicinal and food applications. [ABSTRACT FROM AUTHOR]

Sixty-four table grape samples from different regions of Tunisia were collected during three consecutive years (2015–2017). The presence of 96 pesticides, including dithiocarbamates, was assessed. Pesticides identification and quantification were performed by liquid or gas chromatography, coupled to tandem mass spectrometry. All samples contained multiple residues (4 to 24 residues), with an average of 11.6 residues per sample. Individual concentrations of pesticides in grapes ranged from 0.01 to 5.86 mg kg−1. For at least one chemical compound, exceedances of the European Maximum Residue Limits were found in 94% of the samples. To assess the potential risk of pesticides through consumption of grapes, the acute exposure was estimated by the determination of predicted short term intake which is expressed as a percentage of Acute Reference Dose (ARfD), for non-compliances of pesticides. The exceedance of ARfD was associated with carbofuran, carbendazim, chlorpyrifos, deltamethrin, dimethoate and omethoate. Consequently, these pesticides could present a risk for consumer's health. [ABSTRACT FROM AUTHOR]