Boron nitride nanosheet-assisted matrix solid-phase dispersion microextraction of alkaloids from lotus plumule by high-performance liquid chromatography coupled with ultraviolet detection and ion mobility quadrupole time-of-flight mass spectrometry.

A boron nitride nanosheet (BNNS)-assisted matrix solid-phase dispersion method was established to microextract alkaloids from medicinal plants. The target compounds were identified by high-performance liquid chromatography coupled with ultraviolet detection and ion mobility quadrupole time-of-flight mass spectrometry. During the experimental process, several important parameters, including the type of dispersant, the amount of dispersant, the grinding time, and the type of elution solvent, were optimized. Finally, the BNNSs were chosen as the best dispersant, and their microcosmic morphologies were identified by scanning electron microscopy and transmission electron microscopy. Because of the special property of BNNSs, the cost of this experiment was greatly reduced, especially in elution volume, sample amount (50 mg), and extraction time (2 min). Under the best conditions, 50 mg of sample powder was dispersed with 50 mg of BNNSs, the grinding time was 120 s, the mixed powder was eluted with 200 µL of methanol, and good linearity (r2  > 0.9993) and satisfactory recoveries (80-100%) were obtained. The inter- and intraday precisions were acceptable, with RSDs lower than 2.01 and 4.84%, respectively. The limits of detection ranged from 2.54 to 15.00 ng/mL, and the limits of quantitation were 8.47 to 50.00 ng/mL. The proposed method was successfully applied for the determination of liensinine, isoliensinine, and neferine in lotus plumule.

[Preparation of hispidulin chitosan microsphere and its antiproliferation effect in vitro].

Hispidulin(HPDL) chitosan microspheres were prepared in this study to deliver HPDL to the lesion sitevia intravenous injection, and further evaluate their anticancer effects in vitro and the growth inhibition effect on A549 cells spheroids. HPDL chitosan microspheres were prepared by emulsion crosslinking method with chitosan as a drug carrier and the amount of HPDL was determined by high performance liquid chromatography (HPLC). The morphology of microspheres was observed under laser scanning confocal microscope. Additionally, the drug release amount of targeting microspheres was detected by dialysis method. Furthermore, the anti-proliferative effects against A549 lung cancer cells were tested by sulforhodamine B (SRB) method, and the effects of HPDL chitosan micrpsphereson early apoptosis of A549 cellswere determined by flow cytometry. A549 cells tumor spheroids were developed in vitro and then HPDL chitosan microspheres were added. On the 0, 1, 3, 7 d after adding the drugs, the inverted microscope was used to observe the mythologicaland volume changes of A549 cells spheroids. The encapsulation efficiency of HPDL chitosan microspheres was （75.32±0.52）%, and the drug loading amount was （7.76±0.67）%. Meanwhile, the microspheres were round shaped andhad smooth surface. The HPDL chitosan microspheres exhibited stronger inhibitory effects on A549 lung cancer cells. The results of flow cytometry indicated that, the early apoptosis rate of lung cancer A549 cells was （37.0±0.75）% at 24 h cells culture after drug administration. The volume of tumor spheroid was significantly inhibited, which had been shrunk by (50.09±11.06)% after the treatment by drug-loaded microsphere at day 7 as compared with blank group; meanwhile, the cells surface were obviously lysed. The preparation method in this research was simple and practicable, and the microspheres prepared with this method were round and smooth, with high encapsulation efficiency, which can significantly inhibit proliferation of lung adenocarcinoma A549 cells and induce cell apoptosis, and at the same time can cause lysisand death of A549 cell tumor spheroid.