The genus Salix includes about 500 different, mainly woody species with potentially significant medicinal values. The aim of this study was to evaluate the chemical composition and antioxidant activity of little-studied bark and leaves extracts of seven different species of the genus Salix, and to examine the acetylcholinesterase (AChE) inhibitory potential of selected compounds. The extracts were characterized by High Pressure Liquid Chromatography (HPLC). Total phenolics and flavonoids content was determined spectrophotometrically and the antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and hydroxyl radical (•OH) scavenging assays. Molecular docking studies were conducted in order to elucidate the interaction and binding affinity between selected compounds of willow bark and leaves against AChE. The major components in bark and leaves of most of the species were rutin (1.26–22.09 mg/g), salicin (1.62–17.33 mg/g), chlorogenic acid (0.74–7.53 mg/g) and epicatechin (0.71–4.83 mg/g). The latter three compounds demonstrated significant inhibitory potential against AChE in docking studies. All extracts exhibited notable antioxidant activity as scavengers of both DPPH• and •OH. The obtained results indicate that willow species other than those in commercial use, and not only bark, but willow leaves as well, could be utilized as sources of valuable phytocompounds with antioxidant and neuroprotective properties.

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Seasonal variations of bisphenol A (BPA, IUPAC: 4,4′-(propane-2,2--diyl)diphenol) were investigated in the Danube River along the Novi Sad bank, Serbia using solid-phase extraction followed by the gas chromatographic mass spectrometric method. The obtained results confirmed the presence of BPA above the limit of quantification (6 ng L -1 ) in 22 out of 32 the water samples at all eight sampling sites. The BPA concentration varied from <6 to 693 ng L -1 . The mean BPA concentration for summer (220 ng L -1 ) significantly differed from those obtained for autumn (39 ng L -1 ), winter (6 ng L -1 ) and spring (41 ng L -1 ). The risk quotients, expressed as the ratio of the 95 th percentile of the measured environmental concentrations for each season and the predicted no-effect concentration were higher than one (>1) for autumn, spring and summer. The high potential risk that is attributed to the elevated summer concentrations is probably the result of increased human activities and weather conditions.

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Article Highlights • The supercritical extraction of purine alkaloids from Ilex paraguariensis was performed • Caffeine and theobromine contents were analyzed • The evaluation of the extraction conditions was carried out by chemometric analysis