In this study, an effective ultra-high performance liquid chromatography (UHPLC) method for simultaneous determination of 15 constituents of catechins, caffeine, gallic acid and theaflavins was developed. Employing the developed UHPLC method, the contents of the 15 constituents were analyzed in 245 samples of 6 types of Chinese teas collected from different places. The catechin contents in these samples ranged from 16.50 to 94.35 mg/g. Theaflavins were not detected in green tea and white tea, and caffeine did not strongly relate to germplasm resource or fermentation degree. Principal component analysis (PCA) of UHPLC data revealed that white, oolong and green tea samples could be clustered closely, demonstrating notable difference of functional components between the three types of teas resulting from preparation process and varieties. The constituent profile could be primarily attributed to the structural transformation of catechins and pigments during tea processing. This study would advance our understanding of chemical profile of Chinese teas afforded by different processing technologies.
Fifteen propolis samples collected from different regions of China were investigated and compared for their phytochemical composition and anti-inflammatory and radical scavenging properties. Eleven compounds including caffeic, p-coumaric, ferulic, isoferulic, and 3,4-dimethylcaffeic acids, pinobanksin, chrysin, pinocembrin, galangin, pinobanksin 3-acetate, and caffeic acid phenylethyl ester were quantified for the 15 propolis samples using a UHPLC method, whereas 38 compounds were identified by UPLC/Q-TOF-MS. The 15 propolis samples significantly differed in their total phenolic and total flavonoid contents, as well as their phytochemical profiles. The methanol extracts of propolis also showed significant anti-inflammatory effects in LPS-stimulated RAW 264.7 mouse macrophage cells at 10 μg propolis extract/mL concentration. Additionally, the propolis samples differed in their DPPH, ABTS cation, hydroxyl, and peroxide radical scavenging capacities and ferric reducing abilities. The results from this study may be used to improve the commercial production and consumption of Chinese propolis products.
Introduction In this paper, the authors presented a case of acrylamide poisoning in a middle-aged woman who had underwent unsuccessful cosmetic surgery six years earlier. The victim was told that the product that had been injected into her face was Restylane®, which mainly contained sodium hyaluronate and was the first and only Food and Drug Administration (FDA)-approved dermal filler for lip enhancement in the USA for more than 20 years. Widespread facial infections occurred several years post-injection; finally, the victim had to undergo removal surgery. Acrylamide poisoning was strongly suspected based on the victim's clinical manifestation. The product that had been injected into the victim's face was probably polyacrylamide hydrogel-based product, which had been prohibited by the State Food and Drug Administration (SFDA) in China in 2006. To confirm this suspicion, a systematical method was established to differentiate varieties of cosmetic surgery products and identify residential acrylamide. Methods The removed objects, original products and a certified reference sample of Restylane® were collected for examination. A direct microscopic examination was applied as a rapid screening method. Fourier transform infrared (FTIR) microspectroscopy analysis was subsequently performed to distinguish the main components from each sample. Automated solid phase extraction , ultra high performance liquid chromatography (SPE UHPLC) analysis was ultimately utilised and optimised to detect the residual acrylamide. Chromatographic separation was achieved on an ACQUITY UHPLC HSS T3 column. The mobile phase consisted of 0.01% aqueous formic acid solution and acetonitrile . The tunable UV (TUV) detection wavelength was at 202 nm. Results The microscopic examination indicated that different samples had different morphological characteristics , depending on their main components. The FTIR spectrum showed that different polymers could be distinguished according to the C O stretching vibration (1655 cm − 1 ), N H bending vibration (1540 cm − 1 ) and C O stretching vibration (1078 and 1045 cm − 1 ). The UHPLC results demonstrated that the calibration curve was linear in the range of 0.5–20.0 μg/mL, with a correlation coefficient of 0.999. The average recoveries of the method were 99–107% with an RSD of 1.6–6.3%. The detection limit was 0.1 μg/mL (S/N = 3). The analytical time was 6 min per sample. Acrylamide was detected in the allegedly Restylane® injection. Conclusions This systematical method provides a rapid, accurate and sensitive determination of polyacrylamide and residual acrylamide. The microscopic and FTIR spectroscopic examinations help to verify the existence of polyacrylamide quickly and easily. The optimised SPE UHPLC-TUV method offers a simpler and more sensitive approach to confirm the amount of acrylamide, comparing to the methods in the literature.
危险品化学品经营许可证（带存储）