We conducted a preliminary investigation of the effects of visible light irradiation on plant extracts, and we observed a strong suppressive effect on interleukin (IL) 2 expression with the inhibition of c-Jun amino-terminal kinase (JNK) phosphorylation in Jurkat cells by visible light irradiation to ethanol extract from green soybeans (LIEGS). This effect was produced only by extracts from green soybeans (Glycine max) and not other-color soybeans. LIEGS suppressed the lipopolysaccharide-induced IL-6, IL-12 and TNF-α expression levels in human monocyte THP-1 cells in a concentration-dependent manner. LIEGS was applied for 8 weeks to NC/Nga mice. LIEGS suppressed the development of atopic dermatitis (AD)-like skin lesions and reduced the dermatitis scores of the mice. The light irradiation changed the various types of small-molecule compounds in extracts. Visible light irradiation to daidzein with chlorophyll b induced a novel oxidative product of daidzein. This product suppressed IL-2 expression in Jurkat cells.

The importin/exportin transport system provides the machinery involved in nucleocytoplasmic transport. Alterations of the levels of importins and exportins may play crucial roles in development, differentiation and transformation. Employing human leukaemia HL-60 cells, we and others have revealed the differentiation-associated changes in the protein and gene expression of these factors. The recent finding that a switch to the importin-α subtype triggers neural differentiation of embryonic stem cells underscores the importance of nucleocytoplasmic transport factors in cellular events. This review focuses on current research into the roles of importins and exportins in cell differentiation.

Rat hepatoma H4IIE cells were stimulated with dexamethasone and dibutyryl cAMP to increase gene expressions of gluconeogenic enzymes, glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK). Inclusion of catechin-rich green tea beverage (GTB) in the culture medium reduced the up-regulation of these genes as well as that of hepatocyte nuclear factor 4 alpha (HNF4α) gene. GTB was fractionated into chloroform-soluble (Fraction I), ethyl acetatesoluble (Fraction II), methanol-soluble (Fraction III) and residual (Fraction IV) fractions. Fractions II and III containing catechins caused an attenuation of the up-regulated expression of these genes as well as the down-regulation of HNF4α gene expression. Fraction IV had a synergistic effect on the up-regulation by dexamethasone/dibutyryl cAMP of the PEPCK gene expression and upregulated HNF4α gene expression. These results suggest that GTB down-regulated the expression of the HNF4α gene to cause the down-regulated gene expression of gluconeogenic enzymes. One reason why GTB did not down-regulate hepatic PEPCK gene expression in previous animal experiments may be that the component(s) acting to up-regulate PEPCK gene expression was more effective in vivo than in cultured cells.Tea is one of the world's most popular beverages and has been regarded to possess anti-cancer, antiobesity, anti-atherosclerotic, anti-diabetic, anti-bacterial, and anti-viral effects (4,7,8,17). Recently, it has been demonstrated that (−)-epigallocatechin gallate (EGCG), a major component of green tea catechins, represses glucose production in rat hepatoma H4IIE cells through down-regulation of the gene expression of gluconeogenic enzymes, glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK), suggesting a beneficial effect of green tea on type 2 diabetes, since the disease is associated with enhanced glucose production in the post-absorptive state (16). Previously, we reported that the administration of catechin-rich green tea beverage (GTB) for 4 weeks caused a reduction in the gene expression of G6Pase, but not PEPCK, in the rat liver (1). The findings suggest that some component(s) of the green tea beverage other than catechins might affect the gene expression of PEPCK. We have also posed the possibility that forkhead box transcription factor 1a (Foxo1a) and hepatocyte nuclear factor 4α (HNF4α) may contribute to the down-regulated expression of G6Pase in the liver of GTB-treated rats (1).To answer these questions, we examined effects of GTB on the gene expression of gluconeogenic enzymes in rat hepatoma H4IIE cells using the quantitative real-time reverse transcription-polymerase chain reaction (Q-PCR). Our results suggest that the down-regulation of HNF4α by GTB is relat-

Normal rats were given catechin-rich green tea as drinking fluid and the effects on hepatic gene expression were examined. The results of DNA microarray analysis and quantitative real-time reverse transcription-polymerase chain reaction indicated the down-regulated expression of genes for glucose-6-phosphatase (G6Pase) and fatty acid synthase, and the up-regulated expression of peroxisome proliferator activated receptor α in the rats given green tea for 4 weeks as compared with the water-given animals. One may expect anti-diabetic activity by catechin-rich green tea through its chronic down-regulatory effect on G6Pase expression.

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