Rapid Screening of Active Components with Topoisomerase I Inhibitory Activity in Sophora alopecuroides L. Based on Ultrafiltration Coupled with UPLC-QTOF-MS.

BACKGROUND: Topoisomerase I (Topo I) is a key target of many antitumor drugs in vivo. Alkaloids in Sophora alopecuroides L. can reportedly inhibit Topo I activity, but the pharmacodynamic material basis has not yet been determined. OBJECTIVE: This study aimed to rapidly identify active components which inhibit Topo I in S. alopecuroides L. METHODS: Affinity ultrafiltration coupled with ultra-performance liquid chromatography-quadrupole time of flight-mass spectrometry (UF-UPLC-QTOF-MS) screening system based on Topo I protein was established to screen and isolate a total alkaloid fraction in S. alopecuroides L. Topo I inhibitory activity and anti-tumor proliferation activity of the screened components were evaluated, and their molecular mechanisms were studied. RESULTS: Six compounds that bound specifically to Topo I were obtained. Further screening showed that matrine, cytisine, and sophoridine presented higher inhibitory activity on Topo I and were able to inhibit the proliferation of breast cancer MDA-MB-468 cells with IC50 values of 9.40 ± 1.12 mM, 17.4 ± 2.20 mM, and 10.4 ± 1.37 mM, respectively. To the best of our knowledge, their dual molecular mechanisms against Topo I have not discussed to date. In this study, the following dual mechanisms are reviewed for the first time: (1) stabilization of the Topo I-DNA complex and (2) inhibition or blocking of Topo I binding to DNA. CONCLUSION: Matrine, cytisine, and sophoridine from S. alopecuroides L. were defined as the active components possessing Topo I inhibitory activity, and their pharmacological mechanism was confirmed, which provided an important base for further research and development of antitumor components from S. alopecuroides L.

Preparation and evaluation of photo-responsive hollow SnO2 molecularly imprinted polymers for the selective recognition of kaempferol.

Novel photo-responsive hollow structured molecularly imprinted polymers (PHMIPs) were developed as a selective sorbent to recognize and separate analytes in complex samples. The PHMIPs were prepared using kaempferol (KAE) as the template, 4-[(4-methacryloyloxy) phenylazo] benzenesulfonic acid as a photo-responsive functional monomer, and hollow SnO2 (Ho-SnO2) as the support via free radical polymerization. The structure and physical properties of the developed polymers were characterized using different nano structural techniques and spectroscopy. Under alternating irradiation at 365 and 440 nm, the PHMIPs could release and uptake KAE, indicating that the template molecules can be easily bound to recognition sites and released back into solution. From adsorption experiments, the binding properties were evaluated, and the maximal adsorption capacity of the PHMIPs was 11.04 mg g-1. Furthermore, the developed PHMIPs showed high selectivity towards KAE compared to other compounds. Subsequently, the materials were successfully applied to the photo-controlled extraction of KAE from sea buckthorn leaves. The recoveries for KAE were higher than 90% and relative standard deviation values were between 1.81% and 2.53%, indicating the potential of the developed materials for use in extracting KAE from complex samples.

Preparation and Characterization of PVA-Co-PE Drug-Loaded Nanofiber Membrane by Electrospinning Technology.

A new transdermal drug delivery system of nanofiber membrane with good biocompatibility and high drug loading was developed by electrospinning technology in this study. Using vinyl alcohol-co-ethylene (PVA-co-PE) polymer as a spinning matrix and non-steroidal anti-inflammatory drug (NSAID) sulindac (SUL) as a model drug, the SUL@PVA-co-PE nanofiber membrane was prepared and characterized systematically. The morphology, molecular vibrational transitions, thermogravimetric attributes, and in vitro drug release and transdermal characteristics of drug-loaded nanofiber membranes were analyzed. The results indicated that the surface of PVA-co-PE nanofibers was uniform and smooth with the diameter ranged from 461 to 696 nm. Notably in vitro simulation experiments demonstrated that SUL@PVA-co-PE nanofiber membrane could provide a continuous drug release to reach the effective concentration of the drug, and exhibited significantly higher cumulative drug permeability compared to commercially available patches, Taken together, PVA-co-PE nanofiber membranes exhibited the characteristics of high drug loading and stability, and represented the potential to be utilized as a new transdermal drug delivery carrier with pronounced development prospect.

Tunable Bubble Assembling on a Hybrid Superhydrophobic-Superhydrophilic Surface Fabricated by Selective Laser Texturing.

Inspired by water striders walking on water, aluminum alloy plates with patterned superhydrophobic (SH) surfaces made by picosecond laser texturing and stearic acid treatment were enabled floating with load on water. Self-assembling of shape tunable air bubbles was achieved on the designated surface with hybrid SH/superhydrophilic (SHL) patterns that fabricated by the second selective laser texturing of the prepared SH plate. Different load-bearing capacities were obtained by changing the position and area of SH surfaces, and an outstanding weight loading capacity of 7.5 g on a 20 cm2 aluminum alloy plate (3750 g/m2, 1.34 times the self-weight) was gained with strip-shaped air bubbles adhered to the sample bottom surface. The drag reduction characteristics of SH/SHL surfaces with different shaped air bubbles were tested by a self-built single pendulum impact device; the results indicated that the sample with the whole exterior SH surface achieved the longest sailing distance, which is 26.7% increase than that of the untreated bare sample. The research implies a promising strategy to increase the load-bearing capacity and voyage of marine vehicles by manipulating the underwater solid/air/liquid interaction on biomimic functional surfaces.