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Fukui K.,Miyazaki JA Food Research and Development Inc. | Sugita K.,Miyazaki JA Food Research and Development Inc. | Terahara N.,Minami Kyushu University | Suda I.,Japan National Agriculture and Food Research Organization
Nippon Shokuhin Kagaku Kogaku Kaishi | Year: 2015

Purple sweet potato rich in acylated anthocyanin (YGM) pigments was used to develop a vinegar with a deep color and high functionality. The addition of purple sweet potato to the acetic acid fermentation process, together with seed vinegar and pure ethanol, was more effective than the use of a saccharification source, utilized previously. Furthermore, use of concentrated pigment extract instead of purple sweet potato provided a brewing method for 'red vinegar? exhibiting twofold higher YGM concentration. This red vinegar was expected to have high functionality since it contains acetic acid, purple sweet potato-derived components, and brewing ingredients. Isolation and structural determination of the brewing components resulted in the identification of new acylated polyphenols. A two-step purification method using an adsorption resin column was established for the large-scale preparation of the major component, 6-O-caffeoylsophorose (CS). A single oral administration of CS to maltose-loaded SD rats caused an effective anti-hyperglycemic effect via the acute inhibition of α-glucosidase in the small intestine. In addition, CS was found to be transported across Caco-2 monolayers by the monocarboxylate transporter. Absorbed CS may promote glucose uptake into skeletal muscle cells. Taken together, CS or the brewed vinegar developed in this study could serve as new functional foods and help prevent lifestyle-related diseases, for example by exhibiting an anti-diabetic effect. Copyright © 2015, Japanese Society for Food Science and Technology. Source

Nagahama K.,University of Miyazaki | Eto N.,University of Miyazaki | Shimojo T.,University of Miyazaki | Kondoh T.,University of Miyazaki | And 5 more authors.
Bioscience, Biotechnology and Biochemistry | Year: 2015

Natural killer (NK) cells play a key role in innate immune defense against infectious disease and cancer. A reduction of NK activity is likely to be associated with increased risk of these types of disease. In this study, we investigate the activation potential of kumquat pericarp acetone fraction (KPAF) on NK cells. It is shown to significantly increase IFN-γ production and NK cytotoxic activity in human KHYG-1 NK cells. Moreover, oral administration of KP-AF significantly improves both suppressed plasma IFN-γ levels and NK cytotoxic activity per splenocyte in restraint-stressed mice. These results indicate that raw kumquat pericarp activates NK cells in vitro and in vivo. To identify the active constituents, we also examined IFN-γ production on KHYG-1 cells by the predicted active components. Only β-cryptoxanthin increased IFN-γ production, suggesting that NK cell activation effects of KP-AF may be caused by carotenoids such as β-cryptoxanthin. © 2015 Japan Society for Bioscience, Biotechnology, and Agrochemistry. Source

Phuong H.L.,Kyushu University | Qiu J.,Kyushu University | Kuwahara T.,Kyushu University | Fukui K.,Miyazaki JA Food Research and Development Inc. | And 4 more authors.
Food Chemistry | Year: 2013

The aim of this study was to clarify the transport behaviour and mechanism of caffeic acid analogue bearing a sugar-moiety, 6-O-caffeoylsophorose (CS), in Caco-2 cells. The absorption of CS was investigated by its transport across Caco-2 cell monolayers using a high-performance liquid chromatography-time-of- flight-mass spectrometry (LC-TOF-MS). The permeation of CS was concentration-dependent and reached the plateau at >6 mM. The apparent permeability (Papp) of CS in the apical-to-basolateral direction was 5.4 × 10-7 cm/s, while in the reversed direction the P app value was significantly reduced (1.9 × 10-7 cm/s). CS transport was competitively inhibited by phloretin, an inhibitor of monocarboxylic acid transporter (MCT). Benzoic acid, an MCT substrate, also reduced CS transport. A less significant change of CS transport was observed across Caco-2 cell monolayers pretreated with quercetin, a suppressor of tight-junction. These findings strongly indicate that CS, a caffeic acid analogue bearing sophorose moiety, can be transported across Caco-2 cell monolayers via the MCT pathway. © 2012 Elsevier Ltd. All rights reserved. Source

Qiu J.,Kyushu University | Saito N.,Kyushu University | Noguchi M.,Kyushu University | Fukui K.,Miyazaki JA Food Research and Development Inc. | And 4 more authors.
Journal of Agricultural and Food Chemistry | Year: 2011

Absorption and metabolism of a natural compound, 6-O-caffeoylsophorose (CS) from acylated anthocyanins in a red vinegar fermented with purple sweetpotato, were clarified. The absorption of CS and conjugated CS in blood from orally administrated Sprague-Dawley rats at a dose of 400 mg/kg was investigated by electrochemical detection-high performance liquid chromatography. As a result, CS was successfully detected in rat plasma (AUC0-6h, 108.6 ± 8.1 nmol h/mL) and was found to be an intact absorbable polyphenol. In addition, half of the absorbed CS was detected as its conjugates (AUC0-6h, 50.7 ± 5.7 nmol h/mL) as well as caffeic and ferulic acids from CS. By a time-of-flight-mass spectrometric analysis of CS-administered plasma sample, glucuronide and methylated conjugates of CS were identified, in addition to glucuronide, methylated, or sulfate conjugates of caffeic and ferulic acids. Consequently, CS was absorbed in intact form into rat blood and partly degraded to caffeic and ferulic acids or metabolized by glucuronidation, methylation, or sulfatation. © 2011 American Chemical Society. Source

Kondo T.,Miyazaki JA Food Research and Development Inc. | Kondo T.,University of Miyazaki | Nakashima A.,Miyazaki JA Food Research and Development Inc. | Watanabe T.,Miyazaki JA Food Research and Development Inc. | And 6 more authors.
Nippon Shokuhin Kagaku Kogaku Kaishi | Year: 2016

Previous studies have demonstrated a number of physiological functions for shiitake mushroom (Lentinula edodes), among which the antioxidant activity has been evaluated primarily using conventional chemical techniques. To date, there have been no reports on the anti-oxidative stress effect or on the antioxidant enzyme induction activity of shiitake/shiitake artifact. Therefore, in this study, we evaluated the anti-oxidative stress effect of shiitake grown in Miyazaki Prefecture andshiitake artifact from luminescence values obtainedusing a HepG2-ARE luciferase reporter assay system. The results showedthat shiitake exhibitedan anti-oxidative stress effect and, based on western blot analysis, was able to induce the expression of the antioxidant enzyme HO-1. Moreover, the anti-oxidative stress effect was foundto be retainedin driedshiitake. It is possible that the anti-oxidative stress effect of shiitake might be increasedvia heat processing or lactic acidfermentation. Copyright © 2016, Japanese Society for Food Science and Technology. Source

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