Synthesis, antibacterial activities, and theoretical studies of dicoumarols.

Four dicoumarols (DC, 2-PyDC, 3-PyDC and 4-PyDC) were synthesized and characterized via IR, (1)H NMR, HRMS, and single crystal X-ray crystallography. Two classical intramolecular O-H···O hydrogen bonds (HBs) stabilized their structures. The total HB energies in DC, 2-PyDC, 3-PyDC and 4-PyDC were calculated with the density functional theory (DFT) [B3LYP/6-31G*] method.

Three-phase hollow fiber liquid-phase microextraction based on a magnetofluid for the analysis of aristolochic acids in plasma by high-performance liquid chromatography.

A new and fast sample preparation technique based on three-phase hollow fiber liquid-phase microextraction with a magnetofluid was developed and successfully used to quantify the aristolochic acid I (AA-I) and AA-II in plasma after oral administration of Caulis akebiae extract. Analysis was accomplished by reversed-phase high-performance liquid chromatography with fluorescence detection. Parameters that affect the hollow fiber liquid-phase microextraction processes, such as the solvent type, pH of donor and acceptor phases, content of magnetofluid, salt content, stirring speed, hollow fiber length, extraction temperature, and extraction time, were investigated and optimized.