morphinans and paeonol

An accurate and reliable high-performance liquid chromatography-diode array detector (HPLC-DAD) method was developed and validated for determination of sinomenine (SI), paeoniflorin (PF) and paeonol (PA), which was further applied to assess the pharmacokinetics of SI, PF and PA in an anti-arthritic herbal product, Qingfu Guanjieshu (QFGJS) capsule, in rats. Successful separation was achieved with a C18 column and a mobile phase composed of acetonitrile and aqueous phase (containing 0.1% formic acid, adjusted with triethylamine to pH 3.5 ± 0.2). The method was validated with excellent precision, accuracy, recovery and stability in calibration ranges from 0.06 to 11.62 µg/mL for SI, from 0.09 to 35.70 µg/mL for PF, and from 0.15 to 4.53 µg/mL for PA (with r(2) > 0.999 for all three compounds). Our results showed that absorption of PF after administration of QFGJS was similar to that after oral administration of PF alone; the absorption of SI was decreased while the absorption of PA was increased after giving QFGJS orally compared with pure compounds. We may conclude that pharmacokinetic studies of complex herbal products are not only necessary but also feasible by using representative bioactive chemicals as indicators of establishing quality control standards and of determining pharmacokinetic behavior of herbal medicines.

Topics: Acetophenones; Administration, Oral; Animals; Chromatography, High Pressure Liquid; Drug Stability; Drugs, Chinese Herbal; Glucosides; Linear Models; Male; Monoterpenes; Morphinans; Rats; Rats, Sprague-Dawley; Reproducibility of Results; Sensitivity and Specificity

Currently, there is a considerable interest in discovering G-quadruplex ligands. Plant-derived agents, because of their diversity in structure and bioactivity and low toxicity, may be a very diverse source of G-quadruplex ligands. However, up to now, the screening of G-quadruplex ligands from natural plant extract has not been reported. Herein, in order to develop a simple method for fast identifying G-quadruplex ligands from plant extract, we intended to substitute the spectral shift in the imino region (delta 10-12) in (1)H NMR spectra of G-quadruplex for in vitro bioassay to judge the existence/nonexistence of G-quadruplex ligand(s) in plant extract, and then couple G-quadruplex recognition with NMR based structure elucidation to identify the structure of the ligand(s) without the need of prior separation. In this paper, we successfully screened a G-quadruplex ligand from a simulated plant extract using this approach. This research work provides a promising tactic to find new leading compounds from nature plant extract.

Topics: Acetophenones; Ascorbic Acid; Berberine; Buffers; Circular Dichroism; Computer Simulation; G-Quadruplexes; Hydrogen-Ion Concentration; Ligands; Molecular Structure; Morphinans; Nuclear Magnetic Resonance, Biomolecular; Plant Extracts; Protons