Catechins and Caffeine Inhibit Fat Accumulation in Mice through the Improvement of Hepatic Lipid Metabolism.

To elucidate the inhibiting mechanisms of fat accumulation by catechins, caffeine, and epigallocatechin gallate (EGCG), ICR mice were fed diets containing either 0.3% catechins or 0.1% EGCG and/or 0.05% caffeine for 4 weeks. After the feeding, intraperitoneal adipose tissues weights were significantly lower in the caffeine, catechins + caffeine, and EGCG + caffeine groups compared to controls. Hepatic fatty acid synthase (FAS) activity in the catechins + caffeine group was significantly lower, and the activities of acyl-CoA oxidase (ACO) and carnitine palmitoyltransferase-II (CPT-II) were significantly higher, compared to the control group. However, these activities were not observed in the other groups. FAS mRNA expression levels in the catechins + caffeine group were significantly lower than in the control group. ACO and CPT-II mRNA levels were not different among all of the treatment groups. These findings indicate that the inhibitory effects of fat accumulation via a combination of catechins, EGCG, or caffeine were stronger collectively than by either catechins, EGCG, or caffeine alone. Moreover, it was demonstrated that the combination of catechins and caffeine induced inhibition of fat accumulation by suppression of fatty acid synthesis and upregulation of the enzymatic activities involved in ß-oxidation of fatty acid in the liver, but this result was not observed by combination of EGCG and caffeine.

Reduction of allergenic proteins by the effect of the ripening inhibitor (rin) mutant gene in an F1 hybrid of the rin mutant tomato.

The ripening inhibitor (rin) mutant tomato yields non-ripening fruit, and the rin hybrid fruit (RIN/rin) shows an intermediate phenotype between the wild and mutant fruit, that is, red-ripe and extended shelf life. We found by a microarray analysis that the genes encoding possible allergenic proteins were expressed at a significantly lower level in the rin hybrid fruit than in the wild-type fruit. These allergenic proteins, which were beta-fructofuranosidase and polygalacturonase 2A (PG-2A), were confirmed to accumulate at a lower level in the rin hybrid fruit than in the wild-type fruit. The immunoglobulin E (IgE) in serum from a tomato-allergic patient showed lower reactivity to the extract of the rin hybrid fruit than to that of the wild fruit. These results suggest that the rin gene has the potential to regulate allergen accumulation in tomato fruit.

Influence of royal jelly on mouse hepatic gene expression and safety assessment with a DNA microarray.

We used a DNA microarray to compare the gene expression profiles in liver among three groups of mice fed a diet containing 5% royal jelly (RJ), a diet containing 5% RJ stored at 40 degrees C for 7 d (40-7d RJ) or a control diet which provides the same total energy as RJ. Expression of 267 genes was increased or decreased by 1.8-fold or more in animals given the RJ diet for 14 d as compared with control diet, though serum total cholesterol, triglyceride, phospholipid, glucose, insulin and leptin levels were unaffected. Many genes involved in cell growth, signal transduction, energy metabolism and transcription regulation were responsive to the RJ diet. Among the 267 genes whose expression was altered by RJ, 60% showed no change or a reduced change in response to 40-7d RJ diet. The 40-7d RJ diet contained little 57-kDa protein, identified as a possible freshness marker of RJ. Furthermore, the RJ diet did not influence the gene expression of cytochrome P450 enzymes and detoxifying enzymes, whereas the 40-7d RJ diet increased the gene expression of glutathione S-transferase and glutathione peroxidase. Indeed, the RJ diet decreased the gene expression of cytochrome P450 4A14 (CYP4A14), which catalyzes peroxidation of endogenous lipids that is associated with nonalcoholic steatohepatitis and alcoholic liver disease, while the 40-7d RJ diet was not effective to decrease the gene expression of CYP4A14. The results indicate that the efficacy of RJ decreased and the toxicity of RJ increased during storage at high temperature. We suggest that application of DNA microarray technology to the biochemical evaluation of food safety may be effective for rapid and precise quality control.

A novel enzyme-linked immunosorbent assay for quantification of soybean beta-conglycinin, a major soybean storage protein, in soybean and soybean food products.

Soybean (Glycine max L.) storage proteins are composed of two major components, beta-conglycinin and glycinin, corresponding to 7S and 11S globulins, respectively. Recently, soybean beta-conglycinin (7S globulin) has been reported to show beneficial functions in animals and human. To date, there is no method for the precise quantification of soybean beta-conglycinin in processed food products or soybean seeds. We report here a novel method for this purpose. At first, antibodies specifically reactive to the subunits of beta-conglycinin were prepared. And then, a direct enzyme-linked immunosorbent assay (ELISA) for the quantification of soybean beta-conglycinin in processed foods and seeds was developed. In this assay, the sample was treated with sodium dodecyl sulfate sample buffer followed by dilution with phosphate-buffered saline. The diluted samples were poured and coated onto an ELISA plate and reacted with rabbit anti-beta-conglycinin antibody and peroxidase-labeled anti-rabbit IgG. Finally, the bound peroxidase-labeled antibody was detected by colorimetric reaction. By using this system, it has been possible to measure soybean beta-conglycinin concentrations in several processed food products. In addition, this simple quantification ELISA system was demonstrated to be adaptable for the quantification of beta-conglycinin contents of various soybean cultivars.