ABSTRACT:Cinobufagin (CB), a major bioactive component of the traditional Chinese medicine Chansu, has been reported to have potent antitumor activity. In this study, in vitro metabolism of CB among species was compared with respect to metabolic profiles, enzymes involved, and catalytic efficiency by using liver microsomes from human (HLM), mouse (MLM), rat (RLM), dog (DLM), minipig (PLM), and monkey (CyLM). Significant species differences in CB metabolism were revealed. In particular, species-specific deacetylation and epimerization combined with hydroxylation existed in RLM, whereas hydroxylation was a major pathway in HLM, MLM, DLM, PLM, and CyLM. Two monohydroxylated metabolites of CB in human and animal species were identified as 1␣-hydroxylcinobufagin and 5␤-hydroxylcinobufagin by using liquid chromatography-mass spectrometry and two-dimensional NMR techniques. CYP3A4 was identified as the main isoform involved in CB hydroxylation in HLM on the basis of the chemical inhibition studies and screen assays with recombinant human cytochrome P450s. Furthermore, ketoconazole, a specific inhibitor of CYP3A, strongly inhibited CB hydroxylation in MLM, DLM, PLM, and CyLM, indicating that CYP3A was responsible for CB hydroxylation in these animal species. The apparent substrate affinity and catalytic efficiency for 1␣-and 5␤-hydroxylation of CB in liver microsomes from various species were also determined. PLM appears to have K m and total intrinsic clearance value (V max /K m ) similar to those for HLM, and the total microsomal intrinsic clearance values for CB obeyed the following order: mouse > dog > monkey > human > minipig. These findings provide vital information to better understand the metabolic behaviors of CB among various species.

A preparative high-speed counter-current chromatography method for isolation and purification of bufadienolides from ChanSu was developed by using a stepwise elution with two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water at the ratios of 4:6:2:4 v/v, 4:6:2.5:4 v/v and 4:6:3.2:4 v/v. A total of 3.8 mg of gamabufotalin (1), 7.2 mg of arenobufagin (2), 3.4 mg of telocinobufagin (3), 5.3 mg of bufotalin (4), 8.5 mg of cinobufotalin (5) and 8 mg of bufalin (6) were obtained in one-step separation from 80 mg of the crude extract with purity of 92.7, 96.7, 87.2, 97.3, 94.9 and 99.4%, respectively. Their chemical structures were identified on the basis of (1)H-NMR and (13)C-NMR technology.

This paper introduces a topology optimization design method for flexible mechanism of composite wing leading edge based on discrete material optimization (DMO) with composite material. The DMO method is combined with the topology optimization to select the deviation of the actual displacement and the target displacement of the 10 coordinate points on the initial curve of the leading edge as the objective function, and the volume fraction of each phase material is used as the constraint to establish the composite material optimization model, which is solved by the OC optimization criterion method. The MATLAB codes are compiled to calculate the optimization problem and a distinct result image is obtained. The CATIA software is used to model the topology image in three dimensions, and the model is imported into Hyperworks software for simulation analysis. The results show that this complaint mechanism can achieve a maximum deflection of 9.1 degrees, which verifies the feasibility of the method.

The combination of nano-metal and wood to prepare copper-coated wood-based composite materials has important research value and practical significance for improving the function of wood, expanding the application field of wood, and adding added value. In this paper, 31-year-old wood (Pinus sylvestris L. var. mongholica Litv) veneer was taken as the research object. The wood veneer was pretreated by ultrasonic wave, and copper film was deposited on the surface of the wood veneer by magnetron sputtering to prepare “environmentally friendly” copper-plated wood-based composite materials. The microstructure and hydrophobic properties of Cu-coated wood-based composites were characterized and studied. With the increase in coating time, the diffraction peak intensity of wood cellulose gradually decreased, and the diffraction peaks of Cu (111), Cu (200), and Cu (220) of metallic copper appeared. Under the sputtering condition of a substrate temperature of 200 °C, the copper film deposit on the surface of the wood was uniform and densely arranged. The surface water contact angle reached 149.9°. Ultrasonic treatment increases the porous structure of wood, and the rough metal copper film interface was constructed on the surface of wood by magnetron sputtering to transform the surface wettability of the wood from hydrophilic to super-hydrophobic. The lotus leaf effect was realized on the wood surface.