Aslihan Kazan

Optimization of microwave assisted extraction of Morus nigra L. fruits maximizing tyrosinase inhibitory activity with isolation of bioactive constituents

Morus nigra L. is a beneficial food due to rich phenolic components. While aiming higher yields for bioactive constituents, reduction in terms of raw material, solvent, time and energy gained more importance to provide a sustainable life for human and nature. Microwave assisted extraction (MAE) of Morus nigra fruits was optimized in order to elicit process parameters maximizing bioactive metabolites and tyrosinase inhibitory activity. Spectrophotometry and UPLC-DAD-ESI-MS/MS systems were utilized for quantitative analysis of total phenol, flavonoid and anthocyanin contents. Optimum conditions for MAE were determined as 500 W, 35% ethanol, 10 min yielding 12.63 mg/g cya-3-glu equiv. anthocyanin and IC50 value of 1.60 mg/ml for tyrosinase inhibitory activity. Microwave extracts prevailed better outcomes compared to conventional extraction methods (10.93 mg/g content with IC50 of 2.81 mg/ml). MAE could be considered as an advanced technique to obtain extracts from Morus nigra fruits with higher bioactive content and activity.

Formulation of organic and inorganic hydrogel matrices for immobilization of β-glucosidase in microfluidic platform

The aim of this study was to formulate silica and alginate hydrogels for immobilization of β‐glucosidase. For this purpose, enzyme kinetics in hydrogels were determined, activity of immobilized enzymes was compared with that of free enzyme, and structures of silica and alginate hydrogels were characterized in terms of surface area and pore size. The addition of polyethylene oxide improved the mechanical strength of the silica gels and 68% of the initial activity of the enzyme was preserved after immobilizing into tetraethyl orthosilicate–polyethylene oxide matrix where the relative activity in alginate beads was 87%. The immobilized β‐glucosidase was loaded into glass–silicon–glass microreactors and catalysis of 4‐nitrophenyl β‐d‐glucopyranoside was carried out at various retention times (5, 10, and 15 min) to compare the performance of silica and alginate hydrogels as immobilization matrices. The results indicated that alginate hydrogels exhibited slightly better properties than silica, which can be utilized for biocatalysis in microfluidic platforms.

Investigating anthocyanin contents and in vitro tumor suppression properties of blueberry extracts prepared by various processes

Blueberries are best known for their high content of flavonoids and other phenolic compounds which provide health benefits. The objective of this study was to investigate the effect of microwave, pressurized solvent, and supercritical carbon dioxide (SC-CO2) extraction techniques on the anthocyanin content of the water extracts obtained from dry whole blueberries. Effect of the blueberry extracts on selected cancer cell lines was also investigated. Neat and ethanol entrained SC-CO2 extracts did not contain detectable amount of anthocyanin. Microwave power did not have a significant effect on anthocyanin recovery. The blueberry juice (BJ) prepared by homogenization of fresh berries followed by microfiltration had the highest anthocyanin content among the extracts examined in this study. However, the blueberry water extracts prepared using other extraction techniques had a higher total phenolic content than the BJ. The effect of the blueberry extracts on the cancer cell lines was dose-dependent and varied with the cell type and the composition of the extract. BJ had a similar IC50 to the commercial cancer treatment drug doxorubicin for the cancer cell line MCF7. Further research is needed to elucidate the mechanism underlying the effect of blueberry extract composition on the viability of different cancer lines.

Synthesis and characterization of cryogel structures for isolation of EPSs from Botryococcus braunii.

In this study, the objective was to separate exopolysaccharides (EPSs) released in the broth subsequent to outdoor cultivation of Botryococcus braunii. For this, poly(2-hydroxyethyl methacrylate) (PHEMA) cryogels were synthesized. After that, the surface was modified by coupling Concanavalin A. Box-Behnken statistical design was used to evaluate the effect of freezing temperature, Con A concentration and flow rate on Con A binding capacity. Optimum synthesis conditions were elicited as -14.48°C freezing temperature, 1.00mg/ml Con A concentration and 0.30ml/min flow rate yielding 3.18mg Con A/g cryogel, whereas -16°C, 1.00mg/ml and 0.30ml/min yielded the highest (3.38mg) binding capacity in experimental cryogel preparation. The EPS adsorption capacity of the optimum cryogel column was found as 3.26mg EPS/g cryogel corresponding to adsorption yield of 80%. Besides; swelling test, elemental analysis, Micro-CT, SEM and FTIR analysis were carried out for characterization of the synthesized cryogels.