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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.

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.