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Cultivation of goji berries (GB), fruits of Lycium barbarum L. (Solanaceae), is expanding worldwide, including in Europe. In this study, a comparative analysis of the nutritional value, chemical composition and in vitro biological activities of GB from different locations in Serbia was performed. Proximate compositions were evaluated according to standard methods. Minerals were assessed by inductively coupled plasma techniques, while fatty acids, sterols, and phenolic profiles were analyzed by gas- and liquid chromatography-based techniques coupled with flame-ionization, mass spectrometry, or diode array detection. The total content of phenolics, flavonoids, carotenoids, and polysaccharides was assessed using spectrophotometric methods. Methanol extracts from GB were examined for their antioxidant, enzyme inhibitory (α-amylase, α-glucosidase, acetylcholinesterase and tyrosinase) and antibacterial activities. Despite significant variations among samples from different locations, the results confirmed that GB are a valuable source of dietary fiber and protein and are characterized by favorable fatty acid profiles. Phytochemical analysis revealed that β-sitosterol, Δ5-avenasterol, and 24-methyldesmosterol are the predominant sterols and caffeic acid, gallic acid, quercetin and rutin are the main phenols. All GB samples showed both antioxidant and mild antimicrobial activity. A dose-dependent anti-enzymatic activity (IC50 ranging 1.68–6.88 mg/mL) was demonstrated. The results support further promotion of GB cultivation in Serbia and further investigations on their potential applications in various industries. [ABSTRACT FROM AUTHOR]

We calculate the dielectric function within the framework of the random-phase approximation (RPA) based on DFT ground-state calculations, starting from eigenvectors and eigenvalues. The final goal of our theoretical work is a comparison to corresponding experimental data. We compare our computational results with optical measurements on MoS2 and WS2 nanoflakes. MoS2 and WS2 were exfoliated by ultrasonic treatment in high-boiling point organic solvent and characterized using UV-VIS spectrophotometry. We find that DFT-RPA yields a good, computationally inexpensive first approximation of the imaginary part of the dielectric function, although excitonic effects require more complex code and extra computing power. [ABSTRACT FROM AUTHOR]