Imidazole-modified C6 -chitosan derivatives used to extract ß-sitosterol from edible oil samples with a microwave-assisted solid phase extraction method.

ß-Sitosterol is a major bioactive constituent in plants with potent anticancer effects against many human cancer cells, but its bioavailability and therapeutic efficacy are limited by its poor solubility in water. In this study, C6 -imidazole chitosan, C6 -1-methylimidazole chitosan, C6 -1-ethylimidazole chitosan, C6 -1-vinylimidazole chitosan, C6 -1-allylimidazole chitosan, and C6 -1-butylimidazole chitosan were prepared to extract ß-sitosterol from edible oil samples via ultrasonic-assisted solid liquid extraction. The structures and properties of the newly synthesized products were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and elemental analysis. The extraction abilities of the derivatives were tested in the experiment with high-performance liquid chromatography (limit of detection 0.21 µg/g and limit of quantification 0.67 µg/g), and the % relative standard deviation (<3.25%) and recovery values of the prepared chitosan derivatives toward ß-sitosterol (average: 100.20%) were acceptable. The spiked interday and intraday recoveries of ß-sitosterol were 102.60 ± 2.78 and 103.90 ± 3.04%, respectively. The actual amounts of ß-sitosterol extracted from three real samples using C6 -imidazole chitosan according to the solid phase extraction method were 3302.40, 901.70, and 2045.60 mg/kg for corn oil, olive oil, and pea oil, respectively.

Application of amino-based chitosan cyclodextrin derivatives for the extraction of catechins in green tea with high-performance liquid chromatography.

Chitosan derivatives have been studied widely, but poor solubility in water restricts their applications. In this study, four types of amine-based chitosan derivatives were prepared and modified further with beta-cyclodextrin. The sequential microextraction of catechins ((+)-catechin and (-)-epigallocatechin gallate) from green tea powder by an optimized solid-phase extraction method using these four derivatives was investigated. The optimal conditions for the extraction of catechins were 60°C for a 40 min extraction period. The purity and amount of each catechin were determined by high-performance liquid chromatography. The different amines strengthened the extraction capacity of chitosan. Among the four types of amines, ethylene diamine grafted chitosan beta-cyclodextrin had the highest extraction capacity to catechins. Therefore, this material was used in the extraction assay, and the standard curves of (+)-catechin and (-)-epigallocatechin gallate were linear over the concentration range, 0.25-500 µg/mL, after assaying five data points in duplicate. Solid-phase extraction with the amino-based chitosan beta-cyclodextrin system is a new application of chitosan, which has potential applications in the extraction of bioactive compounds from plant materials or the removal of different impurities from specific extracts.

Application of Natural Deep Eutectic Solvents in the Extraction of Quercetin from Vegetables.

Quercetin is a phytochemical with disease prevention and health promotion activities that has attracted significant research attention. In this study, choline chloride and betaine-based natural deep eutectic solvents were prepared using a heating method. Their physical and chemical properties were also tested. Then, they were applied to extract quercetin from onion and broccoli with ultrasonic-assisted solid liquid method coupled with HPLC. Three factors (temperature, amount, and time) were considered for the optimization of the extraction assays. In the optimal conditions, the extraction recoveries were 88.91-98.99%, 88.45-99.01%, and 89.56-98.74% for quercetin, isorhamnetin, and kaempferol. Tailor-made natural deep eutectic solvents could be applied as sustainable and safe extraction media for biochemical applications.