Determination of lutein from green tea and green tea by-products using accelerated solvent extraction and UPLC.

UNLABELLED: We aimed to identify the optimum conditions for the extraction of lutein from green tea using accelerated solvent extraction, and achieve improved analytical resolution and sensitivity between lutein and zeaxanthin using an ultra performance liquid chromatography (UPLC) system. The optimized method employed 80% ethanol as the extraction solvent, 160 °C as the temperature, 2 static cycles, and 5 min of static time. In the validation of the UPLC method, recovery was found to be in the range approximately 93.73 to 108.79%, with a correlation coefficient of 0.9974 and a relative standard deviation of <9.29% in inter- and intraday precision analyses. Finally, the lutein contents of green tea and green tea by-products were measured as 32.67 ± 0.70 and 18.18 ± 0.68 mg/100g dw, respectively. Furthermore, we verified that green tea by-products, which are discarded after producing green tea beverages, might be used as a great resource for massive lutein production. PRACTICAL APPLICATION: We have demonstrated that the common problem of inadequate resolution between lutein and zeaxanthin during carotenoid analyses can be overcome by optimizing the combined techniques of accelerated solvent extraction and ultra performance liquid chromatography (UPLC). UPLC was highly effective for saving time, solvent, and labor, as well as providing better resolution. The results in this study demonstrated that green tea by-products could be used as new sources for industrial lutein production owing to their massive production during the extraction of green tea beverages.

Emergence and spread of carbapenem-resistant Acinetobacter baumannii sequence type 191 in a Korean hospital.

Emergence and spread of specific carbapenem-resistant Acinetobacter baumannii (CRAB) clones cause a serious therapeutic problem. This study was aimed to investigate the clonal diversity and genetic basis of antimicrobial resistance among the 69 CRAB isolates from 2009 to 2010 in a Korean hospital. All CRAB isolates were found to be sequence type (ST) 2 using the Institute Pasteur's multilocus sequence typing (MLST) scheme, but classified into two sequence groups and nine pulsotypes. Fifty-six CRAB isolates belonging to two main pulsotypes were found to be ST191 using the Bartual's MLST scheme. All CRAB isolates showed an extensively drug-resistant phenotype. The blaOXA-51/blaOXA-23, blaAmpC/blaPER-1 and armA genes were largely responsible for resistance to carbapenems, extended-spectrum ß-lactams and aminoglycosides, respectively. The first CRAB strains identified in 2005 in this hospital were found to be ST2 using the Institute Pasteur's MLST scheme, but showed ST353 using the Bartual's MLST scheme and different pulsotypes from the CRAB isolates from 2009 to 2010. In conclusion, this is the first report of emergence and spread of A. baumannii ST191 in Korea, as well of the genetic basis of its antimicrobial resistance.

Embelin suppresses STAT3 signaling, proliferation, and survival of multiple myeloma via the protein tyrosine phosphatase PTEN.

Even though embelin, an inhibitor of the XIAP, is known to exhibit anti-inflammatory and anti-cancer activities, very little is known about its mechanism of action. Here, we investigated whether embelin mediates its effect through interference with the signal transducer and activator of transcription 3 (STAT3) pathway. We found that embelin inhibited constitutive STAT3 activation in a variety of human cancer cell lines such as U266, DU-145, and SCC4 cells. The suppression of STAT3 was mediated through inhibition of the activation of JAK2 and c-Src. Pervanadate treatment also reversed the embelin-induced down-regulation of STAT3, suggesting the involvement of a protein tyrosine phosphatase. Indeed, we found that embelin-induced the expression of the tyrosine phosphatase PTEN and deletion of the PTEN gene by small interfering RNA abolished the ability of embelin to inhibit STAT3 activation. Besides, embelin failed to suppress STAT3 activation in PTEN-null PC3 cells, thus indicating that the inhibitory effect of embelin on STAT3 is PTEN-dependent. Embelin down-regulated the expression of STAT3-regulated gene products; this correlated with the suppression of cell proliferation and invasion, and the induction of apoptosis through the activation of caspase-3. Overall, our results indicate that the anti-inflammatory and anti-cancer activities previously assigned to embelin may be mediated in part through the suppression of the STAT3 pathway.