Four new N-phenethylbenzamide derivatives from the stems of piper betle and their antimicrobial activity.

Four new N-phenethylbenzamide derivatives, named piperbetamides A-D (1-4), and six allylbenzene derivatives (5-10) were isolated from the stems of Piper betle L. Their structures were determined by HR-ESI-MS and NMR spectroscopic methods. Compounds 1-10 were evaluated for their inhibitory effects on the growth of nine microorganisms including five Gram-negative (Escherichia coli, Salmonella enterica serovar Typhimurium, Shigella flexneri, Pseudomonas aeruginosa, and Extended-spectrum beta-lactam resistant Klebsiella pneumoniae), three Gram-positive (Listeria monocytogenes, Methicilin-resistant Staphylococcus aureus, Vancomycin-resistant Enterococcus faecalis), and one yeast (Candida albicans) strains. Compounds 1, 3, 4, 6 and 10 exhibited potential antimicrobial activity against S. flexneri, L. monocytogenes, methicillin-resistant S. aureus and vancomycin-resistant E. faecalis with minimum inhibitory concentration (MIC) values in the range of 16-32 µg/mL.

Metal Doped Manganese Oxide Thin Films for Supercapacitor Application.

Co and Fe doped manganese oxide thin films were prepared by anodic deposition at current density of 50 mA cm(-2) using the electrolyte containing manganese sulfate and either cobalt sulfate or ferrous sulfate. Surface morphology and crystal structure of oxides were studied by scanning electron microscope (SEM) and X-ray diffraction (XRD). Chemical composition of materials was analyzed by X-ray energy dispersive spectroscope (EDS), iodometric titration method and complexometric titration method, respectively. Supercapacitive behavior of Co and Fe doped manganese oxide films were characterized by cyclic voltammetry (CV) and impedance spectroscopy (EIS). The results show that the doped manganese oxides are composed of nano fiber-like structure with radius of 5-20 nm and remain amorphous structure after heat treatment at 100 degrees C for 2 hours. The average valence of manganese increases from +3.808 to +3.867 after doping Co and from +3.808 to +3.846 after doping Fe. The doped manganese oxide film electrodes exhibited preferably ideal pseudo-capacitive behavior. The specific capacitance value of deposited manganese oxide reaches a maximum of 175.3 F/g for doping Co and 244.6 F/g for doping Fe. The thin films retained about 84% of the initial capacity even after 500 cycles of charge-discharge test. Doping Co and Fe decreases diffusion and charge transfer resistance of the films. The electric double layer capacitance and capacitor response frequency are increased after doping.