A highly hyphenated preparative method with emulsion liquid membrane extraction-in situ magnetization-magnetic separation for bioactive constituents from typical medicinal plant

Effect of magnetization on antibacterial, lipid-lowering and antioxidant activities of isoquinoline alkaloids

The magnetization strategy of isoquinoline alkaloids has been successfully used in the extraction and isolation, but the effect of the magnetization on biological activities of those alkaloids still deserves further investigation. Therefore, the antibacterial, lipid-lowering and antioxidant activities of five isoquinoline alkaloids (berberine, tetrahydroberberine, palmatine, tetrahydropalmatine and tetrahydropapavine) before and after magnetization were compared in this study, and the results showed that the relevant activities were enhanced after magnetization. Additionally, among the five magnetic derivatives studied, berberine magnetic derivative ([Ber·H]+[FeCl4]-) had the best antibacterial effect on S. aureus and E. coli with MIC of 200 and 800 µM, respectively; palmatine magnetic derivative ([Pal·H]+[FeCl4]-) showed the strongest lipid-lowering activity with IC50 of 429 mM, and the inhibitory effect and type on lipase was reversible and mixed inhibition of competition and non-competition type; tetrahydroberberine magnetic derivative ([THBer·H]+[FeCl4]-) had the strongest antioxidant activity. This study provides new ideas and references for the further application of magnetization strategy.

A new approach of magnetic field application in miniaturized pipette-tip extraction for trace analysis of four synthetic hormones in breast milk samples

Herein, a novel homemade electrical device was designed, including two pieces of external neodymium magnets, providing a reciprocating magnetic field to introduce a magnetic-assisted dispersive pipette-tip micro solid-phase extraction. To evaluate the performance efficiency of the proposed method, a novel magnetic calcined GO/SiO₂@Co-Fe nanocube sorbent was synthesized, filled into the pipette-tip, exposed to the reciprocating magnetic field, and applied for the preconcentration of some hormone therapy drugs in human biological matrices. The effective adsorption and desorption parameters were optimized using a rotatable central composite design and one-variable-at-a-time approaches. Under the optimized conditions, the target analytes' detection limits were found to be below 0.02 ng mL^-1. Moreover, the calibration curves were linear in the range of 0.03-500.00 ng mL^-1 (R² > 0.9966), with RSDs% less than 7.8 %. Eventually, the established method was applied to extract the analytes from breast milk samples, followed by LC-ESI-MS/MS analysis.