Caffeine [HSA]

In this study, the functionalization of nanofibers by incorporating different particles and additives into the polymeric matrix for developing ultraviolet protective materials was investigated. Titanium dioxide was selected because of its known characteristic of being a widely used material for obtaining ultraviolet protection. Besides, 1,3,7-Trimethyl xanthine, which was used previously in medical applications to decrease the harm of ultraviolet radiation on DNA, was used to see its potential in obtaining ultraviolet protective nanofibers. By using these two different additives in different concentrations, functionalized polyamide 6.6 nanofibers were produced, their ultraviolet protection property and ratings were recorded, and the results were evaluated comparatively. Addition of titanium dioxide in all concentrations significantly improved ultraviolet protection of polyamide 6.6 nanofibers for both UVA- and UVB-type radiations. Moreover, ultraviolet protection factor value of polyamide 6.6 nanofibers was considerably enhanced by incorporation of 1,3,7-Trimethyl xanthine in the concentrations of 15 and 20% w/w of the polymer; which of their protection ratings were defined as "excellent protection" for both.

Background: Camellia sinensis is a plant whose leaves and buds are used to produce tea. With many medicinal activities already found, green tea has been consumed widely in the world. Methods: The subcritical water extraction (SWE) of epigallocatechin gallate (EGCG) from green tea leaves and the effect of the different extraction conditions are investigated by response surface methodology (RSM). Furthermore, the model of the extraction processes is reviewed for application at the industrial scale. Results: Based on the RSM data, the maximum yield of extraction is determined via optimizing different parameters of the extraction processes. Optimal conditions are as follows: extraction time of 6 min, extraction temperature at 120 degrees C, and a sample/solvent ratio of 1:40 g/mL. Under such conditions, the best yield of EGCG is 4.665%. Moreover, the model of the extraction processes, which can be utilized for industry scale purpose, indicates a good correlation with the experimental data. Conclusions: Overall, SWE is competent and environmental-friendly, and it is also a highly selective and fast method. SWE is a promising method to take the place of organic solvents used in the extraction of weak polar and even non-polar natural compounds. Further studies on the scale-up of the extraction processes are ongoing.