A synthetic mixture of fructo-oligosaccharides (mFOS), consisting largely of nystose (GF 3 ) and a lesser amount of 1-kestose (GF 2 ) has been reported to be selectively utilized by bifidobacteria. In the present study, we tried to identify which fructo-oligosaccharide molecule in mFOS is really involved in the stimulation of bifidobacteria in the gut, using both the gnotobiotic murine model and in vitro culture. 1-Kestose administration to gnotobiotic mice that were associated with human fecal microbiota significantly increased the number of bifidobacteria while mFOS administration was unable to sustain bifidobacteria in these hosts. Moreover a simultaneous decrease in the number of clostridia was found in host mice administered 1-kestose but not in those administered mFOS. The acetate/ propionate ratio in the feces was far higher in host mice administered 1-kestose than in those administered mFOS, suggesting the selective growth activation of bifidobacteria by 1-kestose. The culture study demonstrated that 1-kestose exerts a strong growth-stimulating activity on bifidobacteria but a negligible one on clostridia. On the other hand, nystose was able to stimulate clostridia if the clostridia were exposed to nystose for some time. These results suggest the superiority of 1-kestose to mFOS, which consists largely of nystose, in the selective stimulating activity on bifidobacteria.

Pf-gp6, a 6 kDa anti-degranulation glycoprotein purified from the extract of Perilla frutescens, was examined for its antiviral activity against HIV-1 and HIV-2 in vitro. HIV-1-induced cytopathic effect and proviral DNA synthesis were inhibited in the presence of Pf-gp6. The 50% inhibitory concentrations of Pf-gp6 for various HIV-1 strains, including clinical isolates and CCR5-using (R5) HIV-1, ranged between 1.3 and 71.0 microg/ml, depending on the combination of viral strain and host cell. Furthermore, Pf-gp6 did not directly inactivate infectious viral particles. A time-of-addition experiment revealed that Pf-gp6 lost its activity before zidovudine but after the CXCR-4 antagonist AMD3100 during the early stage of viral infection. Although the pinpoint target of Pf-gp6 remains to be elucidated, it may interfere with a step between viral entry and reverse transcription.

Glycoprotein showing inhibitory activity against mast cell degranulation and hyaluronidase activity was purified from the hot water extract of mint plant (Perilla frutescens Britton). The purified inhibitor gave a single band detected with Coomassie brilliant blue staining and periodic acid-Schiff staining on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The molecular mass was estimated to be 6.0 kDa on SDS-PAGE. The inhibitor did not become inactivated when boiled for 30 min or digested with trypsin, V8 protease, or proteinase K but was inactivated by NaIO(4) oxidation. The inhibitor prevented mast cell degranulation and hyaluronidase activity (IC(50) = 0.42 mg/mL) in a dose-dependent manner. The inhibitor also inhibited the protein kinase C activity. It is possible to purify and characterize a glycoprotein with putative pharmacological properties from mint plants.

Recently we found that some nucleosides such as inosine or adenosine inhibited alpha-glucosidase from rat intestine. The aim of this study was to determine whether these nucleosides are sucrase inhibitors in humans as well as rats. Blood glucose and insulin responses were examined in 23 healthy volunteers (18 males and 5 females) administered sucrose with inosine and 8 (males) administered sucrose with adenosine. The initial increase in plasma glucose and serum insulin concentrations at 30 min after loading sucrose (50 g) alone were significantly reduced by co-administration of inosine (2.5 and 1.0 g) or adenosine (2.5 g). The total increases in the areas under the plasma glucose and serum insulin concentration curves for 3 h after administration of the same amount of sucrose with inosine were also significantly less than those when the volunteers were administered sucrose alone. These results in humans agree with the findings obtained in our previous studies in rats. These nucleosides may be used as one of the components of artificial sweeteners when mixed with sucrose and may be useful as food additives to suppress increases in blood glucose and insulin.

Carrots, like most other vegetables, are classified into fresh or processing varieties in the food industry. To describe differences in volatile profiles and identify important volatiles among the carrot varieties of each type, gas chromatography-mass spectrometry (GC-MS) was used to determine the composition of individual volatiles in 12 carrot varieties, including 7 Kuroda (fresh) and 5 Flakee (processing) types. Fifty-four volatiles were identified and quantified. β-Myrcene, terpinolene, sabinene and 1,3,8-p-menthatriene were detected as odor-active volatiles by GC-olfactometry. PCA distinguished Kuroda from Flakee by PC1. β-Myrcene and sabinene also had high PCA loading values, and were shown to play an important role in the characteristics of Flakee. On the other hand, thymol methyl ether and caryophyllenes, especially caryophyllene oxide, were representative volatiles in Kuroda. Thus, these volatiles might be useful as novel molecular markers in the development of new, high-quality carrots.