Micellar Solution as Green Extractive Solvent for Determination of Content of Quercetin as Natural Antioxidant in Oil Samples

An environmentally friendly and novel amine-based liquid phase microextraction of quercetin in food samples prior to its determination by UV-vis spectrophotometry

A novel and environmentally-friendly method, which includes determination of trace amounts of quercetin in samples by using UV-vis spectrophotometry after enrichment with amine-based liquid phase microextraction (LPME), has been developed. As extraction solvent, N,N-dimethyl-n-octylamine has been used and the quercetin concentration in extraction phase was determined by UV-vis spectrophotometry at 382.5 nm. Important analytical parameters such as pH, extraction solvent type and volume, sample volume, extraction time were optimized by the method. Quercetin in the sample solution was extracted to 200 μL of N,N-dimethyl-n-octylamine phase at pH 4.0. The detection limit (LOD) and the quantitation limit (LOQ) values for quercetin were calculated as 0.07 μg·mL^-1 and 0.24 μg·mL^-1, respectively. Accuracy studies for the food samples was carried out by addition and recovery experiments. The developed method has been successfully applied to different food samples including spinach, green pepper, red onion and dill weed.

Polyphenols Content, Antioxidant Activity, and Cytotoxicity Assessment of Taraxacum officinale Extracts Prepared through the Micelle-Mediated Extraction Method

This experiment was conducted with extracts prepared from dandelion (Taraxacum officinale F. H. Wigg) leaves and flowers, using the micelle-mediated extraction method, with the surface active compound Triton X-100 and water–acetone as the extraction solvents. Extracts were, first, examined for the content of total phenols and the antioxidant capacity. All extracts showed good anti-radical properties, especially for leaves, in comparison to the flower samples. Flavonoids (mainly luteolin derivatives) and phenolic acids, predominated among the determined polyphenols. Quantitative analyses indicated acetone extract to be the richest in phenols (up to 0.535 mg/mL), in the case of dandelion leaves, and Triton X-100 extract in the case of flowers (0.385 mg/mL). Extracts were also evaluated for cytotoxicity to the model cell line (epithelial rabbit kidney cells RK13), using the colorimetric 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test and the real-time cell analysis method ((RTCA); xCELLigence system). The obtained results indicated that surfactants, especially non-ionic ones, can be effectively used as modifiers in the aqueous extraction of phenolic compounds from plant materials. An advantage over the traditional organic solvents is their non-flammability. Furthermore, surfactants might also be used at low concentrations. Studies on cell lines, however, indicated the cytotoxic effect of this type of compound, even in the trace amounts present in the extracts.

Preparation of two-dimensional magnetic molecularly imprinted polymers based on boron nitride and a deep eutectic solvent for the selective recognition of flavonoids

Two-dimensional (2D) boron nitride (BN) were developed as a 2D scaffold material in preparation of magnetic molecularly imprinted polymers (MMIPs).