RESUMEN
Caffeine is a metabolite derived from purine nucleotides, typically accounting for 2-5% of the dry weight of tea and 1-2% of the dry weight of coffee. In the tea and coffee plants, the main synthesis pathway of caffeine is a four-step sequence consisting of three methylation reactions and one nucleosidase reaction using xanthine as a precursor. In bacteria, caffeine degradation occurs mainly through the pathways of N-demethylation and C-8 oxidation. However, a study fully and systematically summarizing the metabolism and application of caffeine in microorganisms has not been established elsewhere. In the present study, we provide a review of the biosynthesis, microbial degradation, gene expression, and application of caffeine microbial degradation. The present review aims to further elaborate the mechanism of caffeine metabolism by microorganisms and explore the development prospects in this field.
RESUMEN
In this work, a novel triphenylamine-benzofuran derived fluorescent probe, TBF-SS, was developed for detecting hydrogen polysulfide in tea samples and intracellular imaging. TBF-SS showed the practical advantages including high sensitivity (LOD = 0.01 µM), high selectivity, rapid response (within 15 min), and steadiness in various environmental conditions. The detecting system was steady within pH range of 6.0-11.0 and temperature range of 20-55 °C. The probe TBF-SS could guarantee the stable detection of H2Sn for 7 d in storage of either solid or solution. In particular, in the application of various tea samples with different brewing times and testing temperatures, the recovery percentages varied in the range of 95.22 % to 105.0 %. Therefore accurate monitoring of H2Sn could be achieved by using the probe TBF-SS. In addition, TBF-SS could monitor the exogenous level, the ß-lapachone-induced generation and the tea-sample-treated introduction of H2Sn in living MCF-7 cells. This work might inspire the improvement of the serviceability of fluorescent implements.
