Takehito Miura

Isoflavone aglycon produced by culture of soybean extracts with basidiomycetes and its anti-angiogenic activity

Soybean extracts (SBE) containing isoflavone glycosides were cultured with Ganoderma lucidum mycelia producing β-glucosidase. The anti-angiogenic effects of the cultivated product, containing rich in genistein, named GCP (genistein combined polysaccharide), were assessed with chick chorioallantoic membranes (CAM) and a mouse dorsal air-sac model. β-Glucosidase produced by the mycelia converted the isoflavone glycosides into aglycons. A test of volunteers showed that serum concentrations of genistein in the subjects treated with GCP (n=4) at 3 h after administration were significantly higher than those in the subjects treated with SBE (n=4). GCP inhibited angiogenesis in CAM, and the activity of GCP was greater than that of SBE. GCP inhibited the formation of new vessels induced by colon carcinoma cells in vivo.

Inhibition of human breast cancer growth by GCP™ (genistein combined polysaccharide) in xenogeneic athymic mice: involvement of genistein biotransformation by β-glucuronidase from tumor tissues

The role of beta-glucuronidase in genistein biotransformation was investigated in a human breast cancer MDA-MB-231 xenogeneic athymic mouse model. Genistein combined polysaccharide (GCP), a genistein aglycone rich functional food supplement was used in these experiments. Tumor-bearing mice were subjected to oral administration of GCP for 28 days. GCP treatment significantly inhibited tumor growth. Induction of apoptosis by GCP treatment was related to activation of cleavage of poly(ADP-ribose)polymerase, induction of the p21 protein expression and reduction of cyclin B1 expression in the tumor tissues. Genistein exists as a glucuronide conjugate in normal organ tissues, and the conjugated genistein lacks the physiological activity of the aglycone. Tumor tissues contain large amounts of beta-glucuronidase, the enzyme that converts the genistein beta-glucuronide conjugate into genistein aglycone. The resulting genistein aglycone exerts its chemopreventive activities, including the induction of apoptosis in tumor tissues, and, finally, leads to tumor growth inhibition.

Supplementation with a flavanol-rich lychee fruit extract influences the inflammatory status of young athletes.

Flavanol‐rich lychee fruit extract (FRLFE) is a processed lychee fruit extract that is higher in flavanols (monomers, dimers and trimers) than its unprocessed counterpart. FRLFE exerts antioxidant activities in vitro and is expected to protect against inflammation and tissue damage. However, the physiological effects of FRLFE intake have not been explored in vivo. The aim of this study was to examine the effects of FRLFE supplementation on inflammation and tissue damage in young athletes during intense physical training. Twenty healthy male long‐distance runners at a university were randomly assigned to receive FRLFE or placebo in a double‐blind manner. Blood and serum parameters associated with inflammation, tissue damage and oxidative stress were evaluated before (pre‐training), during (mid‐training) and after (post‐training) a 2‐month training period. Some parameters, including the white blood cell count, were significantly modified by FRLFE supplementation. Compared with the placebo group, the change in the serum interleukin‐6 level between pre‐ and mid‐training were significantly lower in the FRLFE group, while the change in the transforming growth factor‐β level between pre‐ and post‐training was significantly greater in the FRLFE group. These findings suggest that FRLFE supplementation may suppress inflammation or tissue damage caused by high‐intensity exercise training. Copyright

Toxicological assessment of enzyme-treated asparagus extract in rat acute and subchronic oral toxicity studies and genotoxicity tests.

The safety of enzyme-treated asparagus extract (ETAS) developed as a novel anti-stress functional material was assessed in acute and subchronic studies and genotoxicity assays. In the acute oral dose toxicity study, all rats survived during the test period and ETAS did not influence clinical appearance, body weight gain and necropsy findings at a dosage of 2000mg/kg body weight. Thus, the 50% lethal dose (LD50) of ETAS was determined to be greater than 2000mg/kg. The 90-day subchronic study (500, 1000 and 2000mg/kg body weight, delivered by gavage) in rats reported no significant adverse effects in food consumption, body weight, mortality, urinalysis, hematology, biochemistry, necropsy, organ weight and histopathology. In the micronucleus test of mice, the incidence of micronuclei in ETAS-administered groups (500, 1000 and 2000mg/kg/day, injected twice) was equivalent to that of the negative control group, while the positive control group receiving mitomycin C showed a high incidence. The potential of ETAS to induce gene mutation was tested using four Salmonella typhimurium strains and Escherichia coli WP2uvrA. The test sample was not mutagenic to the test strains. These results support the safety of ETAS as food and dietary supplement.

Perilla frutescens Extracts Protects against Dextran Sulfate Sodium-Induced Murine Colitis: NF-κB, STAT3, and Nrf2 as Putative Targets

Perilla frutescens is a culinary and medicinal herb which has a strong anti-inflammatory and antioxidative effects. In the present study, we investigated the effects of Perilla frutescens extract (PE) against dextran sulfate sodium (DSS)-induced mouse colitis, an animal model that mimics human inflammatory bowel disease (IBD). Five-week-old male ICR mice were treated with a daily dose of PE (20 or 100 mg/kg, p.o.) for 1 week, followed by administration of 3% DSS in double distilled drinking water and PE by gavage for another week. DSS-induced colitis was characterized by body weight loss, colon length shortening, diarrhea and bloody stool, and these symptoms were significantly ameliorated by PE treatment. PE administration suppressed DSS-induced expression of proinflammatory enzymes, including cyclooxygenase-2 and inducible nitric oxide synthase as well as cyclin D1, in a dose-dependent fashion. Nuclear factor-kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3) are major transcriptional regulators of inflammatory signaling. PE administration significantly inhibited the activation of both NF-κB and STAT3 induced by DSS, while it elevated the accumulation of Nrf2 and heme oxygenase-1 in the colon. In another experiment, treatment of CCD841CoN human normal colon epithelial cells with PE (10 mg/ml) resulted in the attenuation of the tumor necrosis factor-α-induced expression/activation of mediators of proinflammatory signaling. The above results indicate that PE has a preventive potential for use in the management of IBD.

Effects of Active Hexose Correlated Compound on the Seasonal Variations of Immune Competence in Healthy Subjects

The aim of this study was to evaluate the effects of active hexose correlated compound intake on the immune competence in healthy volunteers. Thirty-four subjects were randomized to receive placebo or active hexose correlated compound at 1.0 g/d for 4 weeks in early winter. Natural killer cell activity was significantly increased in both groups during the study period, the natural killer cell number, however, was not altered in the active hexose correlated compound group while placebo group showed remarkable decline. In addition, the score of immunological vigor, an index of total immune competence, was maintained in the active hexose correlated compound group although that of placebo group lowered during the test period. These results suggested that the continuous active hexose correlated compound intake maintained the immune competence against the seasonal change.

Enzyme-treated asparagus extract promotes expression of heat shock protein and exerts antistress effects.

A novel enzyme-treated asparagus extract (ETAS) has been developed as a functional material produced from asparagus stem. Studies were conducted to determine the effect of ETAS on heat shock protein 70 (HSP70) expression and alleviation of stress. HeLa cells were treated with ETAS, and HSP70 mRNA and protein levels were measured using a reverse transcription-polymerase chain reaction (RT-PCR) assay and an enzyme-linked immunosorbent assay (ELISA), respectively. ETAS showed significant increases in HSP70 mRNA at more than 0.125 mg/mL and the protein at more than 1.0 mg/mL. The antistress effect was evaluated in a murine sleep-deprivation model. A sleep-deprivation stress load resulted in elevation of blood corticosterone and lipid peroxide concentrations, while supplementation with ETAS at 200 and 1000 mg/kg body weight was associated with significantly reduced levels of both stress markers, which were in the normal range. The HSP70 protein expression level in mice subjected to sleep-deprivation stress and supplemented with ETAS was significantly enhanced in stomach, liver, and kidney, compared to ETAS-untreated mice. A preliminary and small-sized human study was conducted among healthy volunteers consuming up to 150 mg/d of ETAS daily for 7 d. The mRNA expression of HSP70 in peripheral leukocytes was significantly elevated at intakes of 100 or 150 mg/d, compared to their baseline levels. Since HSP70 is known to be a stress-related protein and its induction leads to cytoprotection, the present results suggest that ETAS might exert antistress effects under stressful conditions, resulting from enhancement of HSP70 expression.

DNA microarray analysis of gene expression changes in ICR mouse liver following treatment with active hexose correlated compound

Active hexose correlated compound (AHCC) is a mixture of glucan-rich polysaccharides isolated from the culture extract of shiitake mushroom mycelium. Multiple bioactivities, including immune regulation, have been reported in both basic and clinical studies. This compound has also been used as an adjunct treatment for cancer, but no study has examined whether AHCC can alter the metabolism of therapeutic agents, such as anticancer drugs, in the liver by altering the expression of drug-metabolizing enzymes. Here, we assessed AHCC-induced changes in the expression of genes encoding drug-metabolizing enzymes using a DNA microarray. A 3% AHCC solution was provided ad libitum for 5 days to ICR mice, followed by liver excision, total RNA extraction, and DNA microarray analyses using the Genopal® Metabolic chip (195 genes) and Oxidative stress chip (219 genes). The Metabolic chip identified eight differentially expressed genes (DEGs), defined by a minimum 2.0-fold change in expression from that in control mice. Of these DEGs, two involved in drug metabolism exhibited modest upregulation (CYP3A11, signal intensity ratio [SIR] = 1.15 and CYP7A1, SIR = 1.02). In addition, the Oxidative stress chip identified 23 DEGs, of which five (BCL10, BCL6, ICAM1, MAP3K5, and CASP9) showed very strong suppression (SIR < -10). Oral administration of AHCC to healthy mice altered the expression of multiple genes in the liver, including slight upregulation of drug-metabolizing enzymes and marked suppression of genes involved in tumor necrosis factor signaling and apoptosis. Thus, AHCC may protect liver function against the adverse effects of anticancer agents, such as inflammation, while having little effect on drug metabolism.