T Tsujita

Ehime University, Matuyama, Ehime, Japan

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Publications (69)185.9 Total impact

  • Takahiro Tsujita, Tomoyoshi Shintani, Hiroaki Sato
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    ABSTRACT: Using α-amylase inhibition as a separation guide, polyphenolic compounds from peanut seed skin were prepared. During preparation, specific α-amylase inhibitory activities were increased about 4-fold. High-resolution MALDI-TOF mass spectra showed that the structure of this sample was a series of polyflavan-3-ols, up to 15-mer, composed of catechin/epicatechin units together with several afzelechin/epiafzelechin units and gallocatechin/epigallocatechin units. The observed precious mass values suggest that the polymers consist of both interflavanoid C–C linkages (A-type) and interflavanoid ether linkages (B-type). Oral administration of the polyphenol fraction to rats fed corn starch significantly suppressed an increase in blood glucose levels in a dose dependent manner. Administration of the polyphenol fraction to rats fed maltose or sucrose delayed the increase in blood glucose levels. These results suggest peanut seed skin contains polyphenols with strong α-amylase inhibitory activity, which retard absorption of carbohydrates and mainly function through inhibition of α-amylase.
    Food Chemistry 01/2014; 151:15–20. · 3.33 Impact Factor
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    ABSTRACT: Polyphenolic compounds from chestnut astringent skin (CAS) were purified by dialysis, using Diaion HP-20 and Sephadex LH-20 columns. During purification, specific α-amylase inhibitory activities were increased about 3.4-fold, and the 50% inhibition value was 5.71 μg/mL in the Sephadex LH-20 fraction (SE-fraction). The SE-fraction contained about 67% of the total polyphenols, 57.3% of the flavanol-type tannins, and 51.3% of the procyanidins. Strong antioxidant activity was observed in the SE-fraction. Oral administration of the SE-fraction in rats fed corn starch significantly suppressed an increase in blood glucose levels. The SE-fraction contained gallic acid and ellagic acid. The MALDI-TOF spectrum showed a peak series exhibiting a mass increment of 288 Da, reflecting the variation in the number of catechin/epicatechin units. Our results suggest CAS contains polyphenols with strong α-amylase inhibitory activity. The data also suggest CAS polyphenols might be oligomeric proanthocyanidins with gallic acid and ellagic acid.
    Journal of Agricultural and Food Chemistry 08/2011; 59(16):8646-54. · 3.11 Impact Factor
  • Takahiro Tsujita, Takeshi Takaku
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    ABSTRACT: In vitro, the inhibition by epsilon-polylysine depends on how the substrate is presented to the lipase. We therefore examined whether epsilon-polylysine can interact with the lipid emulsion and prevent lipase activity in digestive organs. To confirm lipase inhibition by epsilon-polylysine, a (14)C-trioleoylglycerol emulsion with or without epsilon-polylysine was orally administered to rats, and the radioactive lipid distribution determined at regular intervals. The radioactive plasma lipid was decreased, and radioactive fecal lipid was increased by the administration of epsilon-polylysine. The peak of radioactive lipids in the intestine was delayed by the administration of epsilon-polylysine. We used 20-week-old rats as a model for the middle-aged and elderly to test the effect of epsilon-polylysine on the body weight increase. epsilon-Polylysine significantly prevented any elevation in body weight and weight of the liver and epididymal adipose tissues. These data show that epsilon-polylysine inhibited the lipase activity in the digestive organ and had an anti-obesity function in the middle-aged rats.
    Bioscience Biotechnology and Biochemistry 04/2009; 73(3):536-42. · 1.27 Impact Factor
  • Takahiro TSUJITA, Takeshi TAKAKU
    Bioscience Biotechnology and Biochemistry - BIOSCI BIOTECHNOL BIOCHEM. 01/2009; 73(3):536-542.
  • Takahiro Tsujita, Takeshi Takaku
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    ABSTRACT: Chestnut astringent skin (CAS) extract inhibited pancreatic alpha-amylase and intestinal alpha-glucosidase in a concentration-dependent manner with the 50% inhibition concentration (IC50) for amylase, maltase and sucrase being 7.5, 650 and 390 microg/mL, respectively. We have investigated the effect of CAS extract on carbohydrate absorption in normal rats. Oral administration of CAS extract to rats fed cornstarch (2 g/kg body weight) significantly suppressed the increase of blood glucose levels and the area under the curve (AUC). Administration of CAS extract to rats fed maltose or sucrose delayed the increase of blood glucose level and slightly suppressed AUC, but not significantly. Administration of CAS extract to rats fed glucose did not affect the increase in blood glucose level or AUC. Similar results were observed with type-2 diabetic model rats (GK/jcl). To test the effect of CAS extract on diabetes, type 2 diabetic model mice (db/db mice) were fed a standard laboratory diet containing 1 or 2% CAS extract. CAS extract prevented increases in body weight and fasting blood glucose concentration. These data suggest that CAS extract has an anti-diabetic function in type 2 diabetic mice that mainly functions through inhibition of alpha-amylase.
    Journal of Nutritional Science and Vitaminology 11/2008; 54(5):416-21. · 0.99 Impact Factor
  • Yusuke Edashige, Naoko Murakami, Takahiro Tsujita
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    ABSTRACT: Segment membranes from 4 citrus species selected from 4 sections were treated with water to obtain polysaccharides containing pectin. The extracts, which inhibited pancreatic lipase activity in a concentration-dependent manner, were divided into high molecular weight fractions [molecular weight (M.W.) >300,000], which inhibited the activity strongly, and low molecular weight fractions (M.W. <300,000), which did not show such strong inhibition. The high molecular weight fractions were composed mainly of a characteristic sugar of pectin, namely, galacturonic acid. A galacturonic acid-rich fraction purified by anion exchange chromatography from a water extract also strongly inhibited the activity. The inhibitory activity of the high molecular weight fraction was much stronger than that of commercial citrus pectin. The results suggest that pectin from segment membranes of citrus fruits might be useful as a functional food, especially as a fat-reducing material.
    Journal of Nutritional Science and Vitaminology 10/2008; 54(5):409-15. · 0.99 Impact Factor
  • Takahiro Tsujita, Takeshi Takaku, Tsuneo Suzuki
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    ABSTRACT: Inhibitors of carbohydrate-hydrolyzing enzyme play an important role to control postprandial blood glucose levels. In this paper, we investigated the effect of an ethanol extract from chestnut astringent skin (CAS) on alpha-amylase. Chestnut astringent skin extract strongly inhibited human and porcine pancreatic alpha-amylase. We also investigated the effect of CAS extract on carbohydrate absorption in rats and humans. Oral administration of CAS extract to normal rats fed corn starch (2 g/kg body weight), significantly suppressed the increase of blood glucose levels after starch loading in a dose-dependent manner. The effective dose of CAS extract required to achieve 20 and 40% suppression of the rise in blood glucose level was estimated to be 40 and 155 mg/kg body weight, respectively. Chestnut astringent skin extract also suppressed the rise in plasma insulin level and the fall in plasma non-esterified fatty acid level. In the type 2 diabetic rat model, CAS extract significantly suppressed the rise in blood glucose level after starch loading in a dose-dependent manner. Chestnut astringent skin extract also suppressed the rise in plasma glucose level after boiled rice loading in a dose-dependent manner in humans. The amount of CAS extract required to achieve 11 and 23% suppression in the rise in plasma glucose level was 300 and 600 mg/person, respectively. These results suggest that CAS extract retards absorption of carbohydrate and reduces post-prandial hyperglycemia.
    Journal of Nutritional Science and Vitaminology 03/2008; 54(1):82-8. · 0.99 Impact Factor
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    Takahiro Tsujita, Takeshi Takaku
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    ABSTRACT: The lipolysis induced by Satsuma mandarin orange (Citrus unshu Mark) was investigated using rat fat cells. Peel or segment wall extract from Satsuma mandarin orange induced the lipolysis in a concentration-dependent manner, whereas juice sac extract did not induce the lipolysis. High concentration of synephrine, which is an adrenergic amine, was detected in the peel or segment wall extract, whereas it was not detected in the juice sac extract. The segment wall extracts from Iyokan and orange had high lipolytic activity, whereas the extracts from grapefruit and lemon did not have lipolytic activity. The beta-antagonist inhibited the lipolysis elicited by the segment wall extract from Satsuma mandarin orange, whereas alpha-antagonist did not inhibit the lipolysis induced by the segment wall. The lipolysis induced by the segment wall was considerably higher in the visceral fat cells when compared to the subcutaneous fat cells. These results suggest that the segment wall, an edible fraction, from Satsuma mandarin orange might be useful as a functional food, especially as a fat-reducing material.
    Journal of Nutritional Science and Vitaminology 01/2008; 53(6):547-51. · 0.99 Impact Factor
  • Takahiro TSUJITA, Takeshi TAKAKU, Tsuneo SUZUKI
    Journal of Nutritional Science and Vitaminology - J NUTR SCI VITAMINOL. 01/2008; 54(1):82-88.
  • Takahiro Tsujita, Takeshi Takaku
    Journal of The Japanese Society for Food Science and Technology-nippon Shokuhin Kagaku Kogaku Kaishi - J JPN SOC FOOD SCI TECHNOL. 01/2008; 55(3):102-108.
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    ABSTRACT: Basic polysaccharide strongly inhibited the hydrolysis of trioleoylglycerol (TO) emulsified with phosphatidylcholine and taurocholate by either pancreatic lipase or carboxylester lipase. DEAE-Sephadex dose-dependently inhibited the hydrolysis of TO by pancreatic lipase and carboxylester lipase; however, carboxymethyl-Sephadex and Sephadex G-50 did not inhibit the hydrolysis. Polydextrose (PD), a soluble polysaccharide, was a very weak inhibitor of pancreatic lipase. However, when a basic group, a DEAE group, was attached to PD, lipase inhibition by DEAE-PD was increased, and this was dependent on the substitution ratio of DEAE groups. The number of positive charges per PD molecule is important in lipase inhibition. Similar substitution effects were observed with other basic groups, such as piperidinoethyl and 3-triethylamino-2-hydroxypropyl. The natural basic polysaccharide, chitosan, also inhibited pancreatic lipase activity. Gel-filtration experiments suggested that DEAE-PD did not bind strongly to pancreatic lipase. The effect of DEAE-PD on TO hydrolysis by pancreatic lipase was studied using various emulsifiers: DEAE-PD (50 microg/ml) did not inhibit the hydrolysis of TO emulsified with arabic gum, phosphatidylserine, or phosphatidic acid. In vivo, oral administration of DEAE-PD to rats reduced the peak plasma triacylglycerol concentration and increased fecal lipid excretion. These results suggest that basic polysaccharide is able to suppress dietary fat absorption from the small intestine by inhibiting pancreatic lipase activity.
    The Journal of Lipid Research 03/2007; 48(2):358-65. · 4.39 Impact Factor
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    ABSTRACT: In vitro, -polylysine (EPL) strongly inhibited the hydrolysis of trioleoylglycerol emulsified with phosphatidylcholine (PC) and taurocholate by either pancreatic lipase or carboxylester lipase. The EPL concentration required for 50% inhibition of pancreatic lipase, 0.12 microM, was eight times lower than the concentration of orlistat required for the same effect. The 50% inhibition concentration by EPL was affected by emulsifier species: it was increased approximately 150 times, 70 times, and 230 times on gum arabic, phosphatidylserine, and phosphatidic acid emulsion, respectively, compared with PC emulsion. The 50% inhibition concentration by orlistat was little changed by emulsifier species. Gel-filtration experiments suggested that EPL did not bind strongly to pancreatic lipase, whereas orlistat did. To test the effect of EPL on obesity, mice were fed a high-fat diet containing 0.1, 0.2, or 0.4% EPL. EPL prevented the high-fat diet-induced increase in body weight and weight of the liver and visceral adipose tissues (epididymal and retroperitoneal). EPL also decreased plasma triacylglycerol and plasma cholesterol concentrations and liver triacylglycerol content after they had been increased by the high-fat diet. The fecal weights of mice were increased by the high-fat diet containing EPL compared with the high-fat diet alone. Fecal lipid was also increased by the diet containing EPL. These data clearly show that EPL has an antiobesity function in mice fed a high-fat diet that acts by inhibiting intestinal absorption of dietary fat.
    The Journal of Lipid Research 09/2006; 47(8):1852-8. · 4.39 Impact Factor
  • Takahiro Tsujita
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    ABSTRACT: The level of free fatty acid (FFA) in plasma is increased by diabetes. The increase in plasma FFA levels accompanied the stimulation of basal lipolysis (i.e. lipolysis in the absence of lipolytic agents) in fat cells. Injection of streptozotocin with rats resulted in a significant increase in basal FFA production (5.5 fold) in fat cells. However, basal glycerol production in fat cells was increased only 1.5 fold by streptozotocin-induced diabetes, implying that FFA re-esterification in fat cells was decreased by streptozotocin-induced diabetes. The FFA re-esterification in fat cells was also decreased by 1 d of fasting. Although basal lipolysis was increased by streptozotocin-induced diabetes or 1-d fasting, neutral triacylglycerol lipase activity and the immunoreactive HSL protein content in fat cells from streptozotocin-induced diabetic rats or 1-d fasting rats were not significantly changed. Although beta-blockers inhibited lipolysis induced by norepinephrine at a concentration of 10(-4) M, it failed to inhibit the basal lipolysis and FFA re-esterification in fat cells from streptozotocin-induced diabetic rats. Nor did insulin or H-89, another antilipolytic agent, affect basal lipolysis or FFA re-esterification in fat cells from streptozotocin-induced diabetic rats. These results indicate that basal FFA production may be induced by a decrease of re-esterification of FFA in diabetic rats and is not affected by antilipolytic agents such as insulin, beta-blockers or H-89.
    Journal of Nutritional Science and Vitaminology 03/2006; 52(1):47-53. · 0.99 Impact Factor
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    ABSTRACT: Raspberry ketone (4-(4-hydroxyphenyl) butan-2-one; RK) is a major aromatic compound of red raspberry (Rubus idaeus). The structure of RK is similar to the structures of capsaicin and synephrine, compounds known to exert anti-obese actions and alter the lipid metabolism. The present study was performed to clarify whether RK helps prevent obesity and activate lipid metabolism in rodents. To test the effect on obesity, our group designed the following in vivo experiments: 1) mice were fed a high-fat diet including 0.5, 1, or 2% of RK for 10 weeks; 2) mice were given a high-fat diet for 6 weeks and subsequently fed the same high-fat diet containing 1% RK for the next 5 weeks. RK prevented the high-fat-diet-induced elevations in body weight and the weights of the liver and visceral adipose tissues (epididymal, retroperitoneal, and mesenteric). RK also decreased these weights and hepatic triacylglycerol content after they had been increased by a high-fat diet. RK significantly increased norepinephrine-induced lipolysis associated with the translocation of hormone-sensitive lipase from the cytosol to lipid droplets in rat epididymal fat cells. In conclusion, RK prevents and improves obesity and fatty liver. These effects appear to stem from the action of RK in altering the lipid metabolism, or more specifically, in increasing norepinephrine-induced lipolysis in white adipocytes.
    Life Sciences 06/2005; 77(2):194-204. · 2.56 Impact Factor
  • Takahiro Tsujita
    Nippon rinsho. Japanese journal of clinical medicine 01/2005; 62 Suppl 12:86-8.
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    ABSTRACT: Oral administration of epsilon-polylysine to rats reduced the peak plasma triacylglycerol concentration. In vitro, epsilon-polylysine and polylysine strongly inhibited the hydrolysis, by either pancreatic lipase or carboxylester lipase, of trioleoylglycerol (TO) emulsified with phosphatidylcholine (PC) and taurocholate. The epsilon-polylysine concentration required for complete inhibition of pancreatic lipase, 10 microg/ml, is 1,000 times lower than that of BSA required for the same effect. Inhibition requires the presence of bile salt and, unlike inhibition of lipase by other proteins, is not reversed by supramicellar concentrations of bile salt. Inhibition increases with the degree of polylysine polymerization, is independent of lipase concentration, is independent of pH between 5.0 and 9.5, and is accompanied by an inhibition of lipase binding to TO-PC emulsion particles. However, epsilon-polylysine did not inhibit the hydrolysis by pancreatic lipase of TO emulsions prepared using anionic surfactants, TO hydrolysis catalyzed by lingual lipase, or the hydrolysis of a water-soluble substrate. In the presence of taurocholate, epsilon-polylysine becomes surface active and adsorbs to TO-PC monomolecular films. These results are consistent with epsilon-polylysine and taurocholate forming a surface-active complex that binds to emulsion particles, thereby retarding lipase adsorption and triacylglycerol hydrolysis both in vivo and in vitro.
    The Journal of Lipid Research 01/2004; 44(12):2278-86. · 4.39 Impact Factor
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    ABSTRACT: The oral administration of pectin to rats reduced and delayed the peak plasma triacylglycerol concentration. Pectin inhibited the hydrolysis of trioleoylglycerol emulsified with soybean phosphatidylcholine by pancreatic, carboxylester, and lingual lipases in a concentration-dependent manner. However, the effective concentration of pectin for lingual lipase was 100 times lower than that for pancreatic lipase. Pectin did not inhibit the tributyrin- and p-nitrophenylbutyrate-hydrolyzing activities by pancreatic and carboxylester lipase. When low molecular weight pectin was assayed, pectin at a molecular weight of 90,000 (MW 90) most strongly inhibited three lipase activities. When the effect of pH on pectin inhibition was analyzed using pancreatic lipase, strong inhibition was observed at an acidic pH (below pH 7.0). In the assay system, the pancreatic lipase protein levels in the supernatant and fat layer were estimated by Western blotting with an anti-pancreatic lipase antibody. Pectin reduced the amount of pancreatic lipase protein in the fat layer in a concentration-dependent manner and concomitantly increased that in the supernatant. These results suggest that pectin may interact with emulsified substrates and inhibit the adsorption of lipase to the surface of substrate emulsion.
    Journal of Nutritional Science and Vitaminology 11/2003; 49(5):340-5. · 0.99 Impact Factor
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    ABSTRACT: The aim of this experimental trial was to study the effect of ultrasound application on the lipolysis in adipose tissue. Rats were administered to pentobarbital (Nembutal) anesthesia and their abdomens were shaved. Rat abdomen was subjected to 24 kHz-1 MHz ultrasound for 10 min to investigate frequency and power-intensity dependency for fat mobilization. Blood was taken from the tail vein to estimate plasma free fatty acids (FFA). For frequency dependency two regions around 100 kHz and 300-500 kHz were effective for fat mobilization. For power-intensity dependency, effective regions were found to be from 24 to 1090 kHz. In the effective regions on frequency and power-intensity, application of ultrasound caused increases in plasma FFA and norepinephrine concentration of extra-cellular fluid of perirenal adipose tissue. These results suggest that ultrasound application stimulates fat mobilization through a local increase in norepinephrine secretion under the conditions of effective frequency and intensity.
    Pathophysiology 11/2002; 9(1):13.
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    ABSTRACT: Adipose tissue is a unique tissue because its mass is readily changed by altering nutritional conditions. Therefore the activity and content of enzyme in the adipose tissue is significantly differed according to the way of their presentation: per g tissue, per whole tissue, or per cell number. In the present study, the effects of the ways of expressing the hormone sensitive lipase (HSL) activity and content were studied in rat by decreasing or increasing adipose tissue. Fasting caused a progressive decline in body weight and in the weight of the epididymal fat pad. When the HSL content was expressed per g of adipose tissue, the lipase activity and immunoreactive HSL protein content in fasting rats were higher than those in fed rats. On the other hand, when they were expressed as per fat pad, the lipase activity and immunoreactive HSL protein in fasting rats were lower than those in fed rats. The opposite results were observed in obesity. When the HSL content was expressed per g of adipose tissue, the lipase activity and immunoreactive HSL protein in obese rats were lower than in control rats. However, when the HSL content was expressed per fat pad, the lipase activity and immunoreactive HSL protein in the obese rats were higher than in the control rats. Therefore we must pay careful attention to the way of presentation of adipose tissue enzyme contents.
    Journal of Nutritional Science and Vitaminology 05/2002; 48(2):120-7. · 0.99 Impact Factor
  • Takahiro Tsujita, Janice M. Smaby, Howard L. Brockman
    Biochemistry - BIOCHEMISTRY-USA. 04/2002; 26(25).

Publication Stats

724 Citations
185.90 Total Impact Points

Institutions

  • 1982–2014
    • Ehime University
      • • Integrated Center for Sciences
      • • Department of Medical Biochemistry
      • • School of Medicine
      Matuyama, Ehime, Japan
  • 2004
    • University of Pittsburgh
      Pittsburgh, Pennsylvania, United States
  • 1988–1989
    • University of Minnesota Duluth
      Duluth, Minnesota, United States