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BACKGROUND Steam explosion is increasingly being used in the food processing industry as an efficient pretreatment technology. It is currently being used to pretreat adzuki beans at a pressure of 0.25-1.0 Mpa for 30 s and 90 s. In this study, the total polyphenol (TP) content in adzuki beans, including free polyphenols (FP) and bound polyphenols (BP), and their antioxidant activity, were determined after steam explosion treatment. RESULTS The results showed that steam explosion can form large cavities and intercellular spaces, which aid the release of polyphenols. After steam explosion, the FP, BP, and TP content increased. The antioxidant capacity of FP and BP also increased, which demonstrated that there was a positive correlation between the polyphenol content and antioxidant capacity. Compounds of FP and BP were further identified by high-performance liquid chromatography (HPLC). Protocatechin was the main ingredient in FP and BP, and protocatechin was higher in FP. Isoquercetin only exists in FP, and caffeic acid only in BP. After steam explosion, an increase in the protocatechin, catechin, and epicatechin content was detected in FP and BP. The phenolic compound and antioxidant capacity yield was increased at a pressure of 0.25-0.75 Mpa, however it decreased at 1.0 Mpa. A pressure of 0.75 Mpa for 90 s is the optimal condition for polyphenol separation in adzuki beans. CONCLUSION A proper and reasonable steam explosion can effectively increase the release of phenolics and enhance the antioxidant capacity in adzuki beans. © 2020 Society of Chemical Industry.

Herein, we first reported a facile synthesis method for fabrication of highly photoluminescent carbon quantum dots (CQDs) using sodium alginate as the carbon source and histidine as both the nitrogen source and functional monomer by one-pot hydrothermal synthesis. The as-prepared CQDs gave a high quantum yield of 32%. By employing the new CQDs and rhodamine B (RhB), we demonstrated a simple, facile, sensitive, and accurate ratiometric sensor for detection of Hg2+ and biological thiols. The photoluminescence of CQDs in the ratiometric sensor can be selectively and intensively suppressed by Hg2+ due to strong electrostatic interaction between the surface functional groups of the CQDs and Hg2+. When glutathione (GSH) was introduced into the “Turn Off” CQDs-RhB-Hg2+ sensing system, the fluorescence of the CQDs can be recovered rapidly due to the stronger affinity between thiol and Hg2+, while the fluorescence of the RhB remained constant in this sensing process. Based on the above principle, the ratiometric strategy for detecting Hg2+ and GSH can be achieved readily, and gives satisfactory limit of detections (LODs) of 30 and 20 nM for Hg2+ and GSH, respectively. The dual-emission fluorescent CQDs-RhB sensor does not need the complicated molecular design and the synthesis of dual-emission fluorophores. Meanwhile, the feasibility of the proposed method for analysis of water samples, food samples, and biological samples (plasma from mice oxidative stress study) was investigated. The developed ratiometric nanosensor is proven to be facile, with less sample consumption, rapid, lost cost, highly sensitive, and very selective for Hg2+ and biological thiol detection, which offers a new approach for environmental, food, and biological analysis.

BACKGROUND Plant polyphenols are rich in blueberries that have a wide range of properties beneficial to human health. There are two types, according to the solubility of polyphenols, which were defined as extractable polyphenols (EPP) and non-extractable polyphenols (NEPP), respectively. At present, in most of reports, ‘total polyphenol’ refers only to EPP excluding NEPP. In this paper, the effects of EPP and NEPP on lipopolysaccharides (LPS) induced production of nitric oxide (NO) and gene expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) in RAW264.7 cells via nuclear factor-κB (NF-κB) signalling pathway were compared. RESULTS The results showed that EPP and NEPP from blueberries significantly inhibited the LPS-induced production of NO and gene expression of iNOS and COX-2 in cells. The constitutive level of p65 sub-unit of NF-κB was obviously detected after the treatments with EPP or NEPP. By contrast, the level of phosphorylated p65 (P-p65) was strongly inhibited by EPP or NEPP. EPP had a stronger inhibition on the gene expression of iNOS and COX-2 than that of NEPP. CONCLUSION These findings of inhibition of iNOS and COX-2 mRNA expression through the suppression of NF-κB suggest that EPP and ENPP from blueberries have significant anti-inflammatory effect and may be a potential medicine. © 2015 Society of Chemical Industry

β-Cyclodextrin–phenylethanoid glycosides inclusion complex was prepared and its releasing characteristic was investigated in this study. The results, obtained from Fourier-transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction, indicated that phenylethanoid glycosides (PG) were able to form an inclusion complex with β-cyclodextrin (β-CD). This complex exhibited different spectroscopic features, thermal stability and crystalline structure from PG. Molecular simulation results showed the benzene rings of PG incorporating into the hydrophobic cavity of β-CD during the complex formation. Furthermore, the releasing rate of the included PG in the inclusion complex was positively correlated with temperature and it was slightly higher in 0.5 % HCl solution than in water. These results suggested that the complexation technique using β-CD was a promising strategy for increasing the applications of PG in food and healthcare industries.

The effects of γ-irradiation with different doses (0, 2, 4, 6, 8 and 10 kGy) and storage time (0–30 days) on the lipid oxidation of chilled pork and the combined effect of irradiation and antioxidant on the lipid oxidative stability during storage at 4 °C were investigated. The results indicated that irradiation treatment increased lipid oxidation, measured as peroxide (PV) and thiobarbituric acid reactive substance (TBARS) values. Lipid oxidation was increased with the increase in storage time. The addition of tea polyphenol (TP) was effective in controlling the lipid oxidation of chilled pork after irradiation during cold storage.

A purified fraction of water-soluble polysaccharides was isolated from Glycyrrhiza uralensis Fisch using ion exchange and size exclusion chromatography. The present study was undertaken to discuss the preliminary immunoregulation mechanism of glycyrrhiza polysaccharide (GP) by cytochemistry and quantitative analyses, and intracellular enzyme measurement of macrophages. Acid phosphatase (ACPase), adenosine triphosphatase (ATPase), acid α-naphthyl acetate esterase (ANAE) and succinate dehydrogenase (SDH) in macrophages were stained with different methods. The results indicate that GP increased the production of ACPase, ATPase, ANAE and SDH; the activities of lysozyme (LSZ) and superoxide dismutase (SOD) of macrophages were also induced by GP. Our data suggest that the beneficial therapeutic effects of GP may be attributed partly to its ability to modulate macrophage immune functions.

Water-soluble polysaccharide(Glycyrrhiza polysaccharide, GP) was isolated from Glycyrrhiza uralensis Fisch, with glycosidic units were composed of alpha (1-4) linked D-glucana. We demonstrated that GP significantly induces nitric oxides (NO) production and inducible NO synthase (iNOS) transcription in peritoneal macrophages. Moreover, iNOS mRNA expression was strongly induced by GP. NO in the culture supernatant was measured by Griess reaction, the production of iNOS was determined by commercially available iNOS kit. GP (10-400 microg/ml) alone increased significantly NO and iNOS production in macrophages. Macrophages simultaneously treated with GP plus lipopolysaccharide (LPS)/interferon-gamma (IFN-gamma) increased NO and iNOS production as compared to that of GP treatments alone. The production of NO and iNOS in macrophages pretreated with LPS followed by GP was higher than that of treatment with GP and LPS simultaneously. Using RT-PCR reveals that GP may provide a second triggering signal for the expression of iNOS mRNA. Thus, the iNOS-mediated NO synthesis in response to GP may be one of the mechanisms whereby this herbal medicine elicits its therapeutic effects.

The objective of this study was to evaluate the immunomodulatory effects of the purified glycyrrhiza polysaccharides (GP) on the activity of macrophages. A purified fraction of water-soluble polysaccharides, with estimated molecular weight of 10 kDa, was isolated from Glycyrrhiza uralensis Fish using ion exchange and size exclusion chromatography. The results indicate that GP increased the pinocytic activity, the production of nitric oxide (NO), interleukin-1 (IL-1), IL-6 and IL-12 in a dose-dependent manner. The production of IL-1 was induced by GP at a dose of 10 microg/mL; but, NO, IL-6 and IL-12 was significantly induced at 100 microg/mL. A time-dependent enhancement showed that the production of IL-1, NO and IL-12 were significantly increased within 6 h. Superoxide anion (O(2)(-)) production by macrophages from GP-treated mice was higher than that of cells from untreated mice. Moreover, cells from both untreated and treated mice responded to phorbol 12-myristate 13-acetate (PMA) treatment; however, the O(2)(-) production was higher in the cells from treated mice than that of cells from untreated mice. Our data suggest that the beneficial therapeutic effects of GP may be attributed partly to its ability to modulate macrophage immune functions.