Anhydrotetracycline hydrochloride

Terahertz (THz) spectroscopy has emerged as an attractive technique for qualitative and quantitative detection. Analysis of these chemicals in the THz range under various temperatures can yield detailed information on molecular vibrational modes, which is of utmost importance for effective detection. Here we report the use of THz time-domain spectroscopy (THz-TDS) to measure tetracyclines hydrochloride (TCH) and its degradation products including epitetracycline hydrochloride (ETCH), anhydrotetracycline hydrochloride (ATCH), and epianhydrotetracycline hydrochloride (EATCH) over the temperature range of 4.5-300 K for the first time. The results showed that these four tetracyclines exhibited numerous distinct spectral features in frequency-dependent absorption spectra, which demonstrated the qualitative capacity of THz-TDS. Through density functional theory (DFT) calculations and analysis of temperature-dependent absorption spectra, the origin of the observed terahertz absorption peaks of these four tetracyclines were well interpreted. This study could lay the foundation for high-performance analysis of biological and chemical molecules by THz spectroscopy, which is essential for sensing application.

Fluorescence enhancement of anhydrotetracycline hydrochloride and iso-tetracycline has been described. The fluorescence intensities of anhydrotetracycline hydrochloride and iso-tetracycline with cetyltrimethylammonium bromide (CTMAB) enhanced by micellar solution have been examined. It is found that fluorescence enhancement of anhydrotetracycline hydrochloride and iso-tetracycline depends on the concentration of CTMAB and pH of the solution. It can be used to develop sensitive methods for the determination of tetracycline hydrochloride and its decomposition product.

Tetracycline antibiotics are the most widely used antibiotics in the world and the most common veterinary drugs and feed additives used in livestock, poultry and aquaculture operations. Because antibiotics cannot be completely removed by currently existing sewage treatment facilities, these materials enter the environment directly via sewage treatment plant discharge, where they degrade. Accordingly, the metabolism and the ecological toxicity of tetracycline degradation products are worthy of attention. Herein, we investigated the effects of tetracycline and its degradation products (anhydrotetracycline and epitetracycline hydrochloride) on the growth, cell structure and algal cell oxidative stress of common Chlorella vulgaris. The results showed that the 96h-EC50values of tetracycline (TC), anhydrotetracycline (ATC) and epitetracycline (ETC) on algal cells were 7.73, 5.96 and 8.42 mg/L, respectively. Moreover, the permeability of algal cells exposed to high concentrations of these three drugs was significantly enhanced. In addition, there were structural changes in the cells such as plasmolysis and starch granule deposition appeared, the thylakoid lamellae in the chloroplasts became blurred and deformed, and the vacuoles became larger. Exposure to higher concentrations (>5 mg/L) of TC and its degradation products ATC and ETC significantly upregulated the activity of ROS, as well as the antioxidants SOD and CAT. The levels of the lipid peroxidation product MDA also showed the same trend. Finally, ATC had the strongest toxicity toward algal cells, followed by TC and then ETC.