著者

Kensuke Yasui Noriko Paeng Noriyuki Miyoshi Takuji Suzuki Kyoko Taguchi Yoko Ishigami Ryuuta Fukutomi Shinjiro Imai Mamoru Isemura Tsutomu Nakayama

出版者

Biomedical Research Press

雑誌

Biomedical Research (ISSN:03886107)

巻号頁・発行日

vol.33, no.1, pp.9-13, 2012 (Released:2012-02-24)

参考文献数

18

被引用文献数

14 18

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Many biological activities of green tea have been attributed to a major constituent, (minus;)-epigallocatechin gallate (EGCG). We previously reported that EGCG and an EGCG-free fraction derived from green tea modulated the gene expression of gluconeogenic enzymes, glucose-6-phosphatase and phosphoenolpyruvate carboxykinase, in the mouse liver. EGCG is also known to affect the gene expression of enzymes related to lipid metabolism. However, it remains to be examined whether or not a constituent other than EGCG contributes to the change in gene expression of these enzymes. In this study, we prepared an EGCG-free water-soluble fraction (GT-W), and examined its effects on the hepatic gene expression of lipogenic enzymes in mice. The results of quantitative real-time PCR assays indicated that the dietary administration of GT-W for 4 weeks reduced the hepatic gene expression of lipogenic enzymes: fatty acid synthase, hydroxymethylglutaryl coenzyme A reductase, and acetyl-coenzyme A carboxylase alpha. Also, the gene expression of sterol regulatory element-binding transcription factor (Srebf)1 and/or Srebf2 was reduced, suggesting that the reduction of Srebfs contributed to the down-regulation of the lipogenic enzymes, since these transcription factors bind the promoter region to enhance their expression. The plasma levels of triglycerides and cholesterol were reduced with statistical significance in the group given a diet containing GT-W. These results suggest that in addition to EGCG, green tea contains some component(s) which may help to prevent arteriosclerosis and obesity.

著者

Kota Kera Shohei Makino Risako Takeda Aoi Shimeno Masaya Hojo Sadahiro Hamasaki Akihito Endo Masumi Iijima Tsutomu Nakayama

出版者

Japanese Society for Food Science and Technology

雑誌

Food Science and Technology Research (ISSN:13446606)

巻号頁・発行日

pp.FSTR-D-23-00189, (Released:2023-12-27)

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The astringency of persimmon fruits is a significant factor for consumers and the nutritional industry. To date, astringents, such as polyphenols, specifically persimmon condensed tannins, have been assessed using polyphenol quantification assays, such as the Folin–Ciocalteu method, based on their reducing power. However, these methods are influenced by the presence of other reducing substances. In this study, we developed a cost-effective liposome turbidity analysis using a portable visible spectrophotometer based on the interaction between liposomes and astringents. Authentic astringents, such as catechins and theaflavin-3-O-gallate, were analyzed, and their half-maximal effective concentrations (EC50) were calculated. These results indicated that the affinity to the membrane was similar to that of astringency, as determined by sensory analysis. Additionally, the EC50 values of partially purified tannins from non-astringent and astringent persimmons were calculated. In conclusion, we determined the application methods to assess astringent persimmon fruits with and without the removal of astringency.

著者

Tsutomu Nakayama Hideharu Huriya Asuka Kamo Kenzi Kosako Takeyuki Kozima Maki Sugawara Taiki Suzuki Mie Nishizima Ai Yamashita Megumi Yano Shouhei Makino Kota Kera Masumi Iijima

出版者

Japanese Society for Food Science and Technology

雑誌

Food Science and Technology Research (ISSN:13446606)

巻号頁・発行日

pp.FSTR-D-22-00202, (Released:2023-01-20)

被引用文献数

2

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The molecular interaction of black tea components with phospholipid vesicles has been investigated to elucidate the various functions of black tea infusions, such as astringency, inhibition of cholesterol absorption, and inactivation of viruses. We have developed a simple method to analyze the turbidity of phospholipid vesicle solutions reacted with black tea infusions or components as an indicator of the molecular interaction. Using a portable visible spectrophotometer, the dose-dependency of catechins, theaflavins, thearubigins, and black tea infusions on turbidity was analyzed. The results indicate that authentic catechins and theaflavins independently caused aggregation of the phospholipid vesicles; however, their concentrations in the tea infusions were insufficient. Meanwhile, thearubigins prepared from black tea leaves caused aggregation at the concentration found in the tea infusions. It is concluded that thearubigins, instead of theaflavins, mainly contribute to the interaction with phospholipid vesicles.

著者

Ai YOTO Tsuyoshi MORIYAMA Hidehiko YOKOGOSHI Yoriyuki NAKAMURA Tsuyoshi KATSUNO Tsutomu NAKAYAMA

出版者

日本感性工学会

雑誌

International Journal of Affective Engineering (ISSN:21875413)

巻号頁・発行日

vol.13, no.4, pp.227-233, 2014 (Released:2014-12-25)

参考文献数

23

被引用文献数

7

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We investigated the memory task performance and the central nervous activity after smelling two kinds of pan-fired Japanese green tea to examine their physical and psychological effects. Twenty eight subjects participated in this study. We used Koushun and Kouju for test samples, which were made by different manufacturing processes. After smelling each odor sample, a memory task and an arithmetic task were used to test mental stress. Electroencephalogram (EEG) was recorded before and after smelling the test samples, and EEG activity was estimated for 4 frequency bands (alpha 1, alpha 2, beta 1 and beta 2). The profiles of mood states (POMS) and the visual analog scale (VAS) after mental stress task were completed for subjective assessments. The results showed that the odor of Kouju may induce a positive emotion. It may also affect the EEG band power of beta 1 at right frontal region and improve memory task performance.