Toxicity of CuS/CdS semiconductor nanocomposites to liver cells and mice liver.

Semiconductor nanomaterials not only bring great convenience to peoples lives but also become a potential hazard to human health. The purpose of this study was to evaluate the toxicity of CuS/CdS nanocomposites in hepatocytes and mice liver. The CuS/CdS semiconductor nanocomposites were synthesized by a biomimetic synthesis - ion exchange strategy. Nanosize was confirmed by high-resolution transmission electron microscopy and dynamic light scattering. The composition and physical properties were measured by powder X-ray diffraction, Fourier transform infrared spectra, atomic absorption spectroscopy, thermogravimetry-differential scanning calorimetry and zeta potential analysis. The results revealed that CuS/CdS nanocomposites had 8.7 nm diameter and negative potential. Ion exchange time could adjust the ratio of CuS and CdS in nanocomposites. The toxicological study revealed that CuS/CdS nanocomposites could be internalized into liver cells, inhibited endogenous defense system (e.g. GSH and SOD), induced the accumulation of oxidation products (e.g. ROS, GSSG and MDA), and caused hepatocyte apoptosis. The in vivo experiments in Balb/c mice showed that the experimental dose (4 mg/kg) didn't cause observable changes in mice behavior, physical activity and pathological characteristics, but the continuous accumulation of Cd2+ in the liver and kidney might be responsible for its long-term toxicity.

[Simultaneous determination of four flavone C-glycosides in Phyllostachys edulis leaves by high-performance liquid chromatography with ultraviolet spectrometry].

High-performance liquid chromatography with ultraviolet spectrometer (HPLC-UV) was used to simultaneously detect the four flavone C-glycosides, i. e. orientin, isoorientin, vitexin and isovitexin. Analytes were separated with Waters XTerra MS C18 column (250 mm x 4.6 mm, 5 µm) using acetonitrile and 0.5% (φ) formic acid as mobile phase. The flow rate was set at 1.0 mL · min(-1) with the column temperature at 30 °C, and the detection wavelength was 360 nm. The calibration curve was linear over the concentration range of 0.1-10.0 mg · L(-1) for the mixed standard solution. Analytes were separated in 22 minutes, and the relative standard deviation values were all above 0.999. LOD values of standards were found to be between 0.03 and 0.07 mg · L(-1), and LOQ values were in the range of 0.04-0.08 mg · L(-1). After comparing the spectra (240-400 nm) of four flavone C-glycosides in mixed standards and the final product purified by macroporous resin, respectively, the curve shape and characteristic ultraviolet absorption wavelength of each flavone C-glycoside including orientin, isoorientin, vitexin and isovitexin were fitted well. The bamboo leaves sample was extracted by ethanol under reflux, and then partitioned with water and petroleum ether. The aqueous phase was added onto macroporous resin (AB-8), and the fraction of ethanol-water (40%, φ) was concentrated. It was found that the contents of orientin, isoorientin, vitexin and isovitexin relative to the fraction of ethanol- water were 13.73, 49.68, 7.85 and 30.70 mg · g(-1), respectively. In addition, the average recovery of the four flavone C-glycosides ranged from 34.90% to 87.64% with RSD values from 0.41% to 10.83%. The results showed that bamboo leaves sample had good stability and repeatability. The new method was used to analyze the four flavone C-glycosides quickly and provide quality control for commercial products.

[Detection of antioxidative capacity of bamboo leaf extract by scavenging hydroxyl free radical].

By studying on absorption spectrum of red compound coming from the reaction system of Fe2+ and 1, 10-phenanthroline and the capacity of antioxidant TBHQ and bamboo leaf extract for scavenging hydroxyl free radical, some results were drawn as follows: the determining wavelength of bamboo leaf extract for scavenging hydroxyl free radical by spectrophotometric method is 509.1 nm, and IC50 (the value of antioxidant concentration at scavenging half of hydroxyl free radical)was used as the index to evaluate scavenging capacity. The determined IC50 values were TBHQ (0.040), M20 (0.378), M40 (0.323), M60 (0.334), and bamboo leaf extract could be used as natural antioxidant.