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Li Y.,Shandong University | Yin H.,State Key Laboratory of Biological Fermentation Engineering of Beer | Qian Z.,State Key Laboratory of Biological Fermentation Engineering of Beer | Miao J.,First Institute of Oceanography | Huai Q.,Shandong University
Asian Journal of Chemistry

Four flavonoid glycosides i.e., isoquercitrin, astragalin, rutin and kaempferol 3-rutinoside, were isolated from the aqueous extract of the hop flowers. In the present study, we carried out the anti-allergic and antioxidant activity of each flavonoid glycosides separately. Isoquercitrin, rutin have the best anti-allergic and antioxidant activity. The structure-activity relationship of flavonoid glycosides for anti-allergic and antioxidant actions were studied. This study suggests that compounds from hop flowers are potential inhibitors against hyaluronidase and antioxidants, indicate a promising strategy for the development of natural anti-allergic, antioxidant medicines and functional foods. Source

Yin H.,State Key Laboratory of Biological Fermentation Engineering of Beer | Yin H.,Tsingtao Brewery Co. | Yin H.,Jiangnan University | Ma Y.,State Key Laboratory of Biological Fermentation Engineering of Beer | And 13 more authors.
Journal of Microbiological Methods

Genome shuffling is an efficient and promising approach for the rapid improvement of microbial phenotypes. In this study, genome shuffling was applied to enhance the yield of glutathione produced by Saccharomyces cerevisiae YS86. Six isolates with subtle improvements in glutathione yield were obtained from populations generated by ultraviolet (UV) irradiation and nitrosoguanidine (NTG) mutagenesis. These yeast strains were then subjected to recursive pool-wise protoplast fusion. A strain library that was likely to yield positive colonies was created by fusing the lethal protoplasts obtained from both UV irradiation and heat treatments. After two rounds of genome shuffling, a high-yield recombinant YSF2-19 strain that exhibited 3.2- and 3.3-fold increases in glutathione production in shake flask and fermenter respectively was obtained. Comparative analysis of synthetase gene expression was conducted between the initial and shuffled strains using FQ (fluorescent quantitation) RT-PCR (reverse transcription polymerase chain reaction). Delta CT (threshold cycle) relative quantitation analysis revealed that glutathione synthetase gene (GSH-I) expression at the transcriptional level in the YSF2-19 strain was 9.9-fold greater than in the initial YS86. The shuffled yeast strain has a potential application in brewing, other food, and pharmaceutical industries. Simultaneously, the analysis of improved phenotypes will provide more valuable data for inverse metabolic engineering. © 2016 Elsevier B.V. Source

Liu M.,Ocean University of China | Yin H.,State Key Laboratory of Biological Fermentation Engineering of Beer | Liu G.,CAS Qingdao Institute of Oceanology | Dong J.,State Key Laboratory of Biological Fermentation Engineering of Beer | And 3 more authors.
Journal of Agricultural and Food Chemistry

Xanthohumol (XN) is a unique prenylated flavonoid in hops (Humulus lupulus L.) and beer. XN alleviates hyperglycemia and has potential usage in the treatment of type 2 diabetes. In the present study, a series of in vitro experiments were performed to investigate whether XN was an effective inhibitor of α-glucosidase. The results showed that XN inhibited α-glucosidase in a reversible and noncompetitive manner, with an IC50 value of 8.8 μM and that XN inhibited the release of glucose from the maltose in the apical side of the Caco-2 cell monolayer. Fluorescence and circular dichroism spectra results indicated that XN directly bound to α-glucosidase and induced minor conformational changes of the enzyme. These results demonstrated that XN is a promising α-glucosidase inhibitor, which therefore could be used as functional food to alleviate postprandial hyperglycemia and as a potential candidate for the development of an antidiabetic agent. © 2014 American Chemical Society. Source

Huai Q.-Y.,State Oceanic Administration | Huai Q.-Y.,Shandong University | Gao C.-L.,State Key Laboratory of Biological Fermentation Engineering of Beer | Miao J.-L.,State Key Laboratory of Biological Fermentation Engineering of Beer | And 2 more authors.
Analytical Methods

Saxitoxin (STX) is a potent marine biotoxin which can cause paralytic shellfish poisoning when consumed. With the development of research, STX has become more and more important in red tide detection, medical research, food safety and warfare agent application. However, new methods for the fast analysis of STX are required. In this study, we used laser optical tweezers Raman spectroscopy (LTRS) combined with surface-enhanced Raman scattering (SERS) to detect STX. Sharp Raman peaks of very strong intensity were achieved. The spectra were obtained in 2 seconds without accumulations. Tentative vibrational mode assignments of the observed peaks in SERS spectra of STX are described. The detection limit and the minimum quantitative limit of this method were 2 nM and 16 nM, respectively. This study supports LTRS-SERS as a new fast, convenient analytical method for STX and other toxicants and pollutants in the environment. © 2013 The Royal Society of Chemistry. Source

Liu M.,Ocean University of China | Hansen P.E.,Roskilde University | Wang G.,Ocean University of China | Qiu L.,Chinese Academy of Sciences | And 6 more authors.

The female inflorescences of hops (Humulus lupulus L.), a well-known bittering agent used in the brewing industry, have long been used in traditional medicines. Xanthohumol (XN) is one of the bioactive substances contributing to its medical applications. Among foodstuffs XN is found primarily in beer and its natural occurrence is surveyed. In recent years, XN has received much attention for its biological effects. The present review describes the pharmacological aspects of XN and summarizes the most interesting findings obtained in the preclinical research related to this compound, including the pharmacological activity, the pharmacokinetics, and the safety of XN. Furthermore, the potential use of XN as a food additive considering its many positive biological effects is discussed. © 2015 by the authors licensee MDPI Basel Switzerland. Source

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