The present study investigated pharmacokinetic and electroencephalographic responses to caffeine (140 mg) in two groups of healthy volunteers reporting, or not, caffeine-related sleep disturbances. Significant differences in caffeine consumption and smoking habits were observed between the two groups. Plasma samples were taken from each subject before (T 0 ) and after caffeine intake at 0.5, 1, 2, 4, 6 and 24 h. Three pharmacokinetic parameters: half-life (t 1/2 ), maximum time (T max ) and maximum plasma concentration (C max ) were calculated from caffeine plasma concentration measurements determined by reversed phase HPLC analysis. Caffeine-sensitive subjects showed significantly greater half-life values when calculated on 24 h after the administration than tolerant subjects (p < 0.05). Since the elimination kinetics were similar on the first 6 h after caffeine administration, the increased caffeine clearance observed overnight, when smoking was resumed in the control group, may indicate a short delay for the induction of hepatic cytochrome, reported here for the first time. Electrophysiological responses to caffeine, including vigilance and cortical activity, were assessed by ambulatory electroencephalographic (EEG) recorded during a period of 6 h before and after caffeine consumption. Following caffeine intake, the caffeine-intolerant subjects presented an increase in vigilance levels with faster peak alpha, beta frequency and lower delta and theta power when compared to tolerant subjects. Pharmacokinetic parameters and EEG data showed significant differences between sleep-sensitive and control subjects. These variations may be, in part, explained by cigarette smoking and the higher caffeine intake observed in the subjects of the control groups while caffeine sleep-sensitive subjects have a significantly lower caffeine intake, as already reported in previous studies on patients with sleep disturbances.
We report an analysis of chemical components of essential oils from barks of Ceylon cinnamon and cloves of Syzygium aromaticum and an investigation of their antibacterial activity. The components of oils were determined by using Gas Chromatography/Mass Spectrometry (GC-MS) analysis, and the antimicrobial activity was assessed by the disk diffusion test. The synergic effect of essential oils mixture (cinnamon oil and clove oil) was evaluated. Antimicrobial properties were conferred to cellulosic fibers through microencapsulation using citric acid as a green binding agent. Essential oil mixture was encapsulated by coacervation using chitosan as a wall material and sodium hydroxide as a hardening agent. The diameter of the produced microcapsules varies between 12 and 48 μm. Attachment of the produced microcapsules onto cotton fabrics surface was confirmed by Attenuated Total Reflectance-Fourier Transformed Infrared (ATR-FTIR) spectroscopy, optical microscopy and Scanning Electron Microscopy (SEM) analysis. The results show that microcapsules were successfully attached on cotton fabric surfaces, imparting antibacterial activity without significantly affecting their properties. The finished cotton fabrics exhibited good mechanical properties and wettability.
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