Kiyoharu Takamatsu

Soy protein isolate and its hydrolysate reduce body fat of dietary obese rats and genetically obese mice (yellow KK).

This study examined in dietary obese and genetically obese rodents the effects of soy protein isolate (SPI) and its hydrolysate (SPI-H) on the rate of body-fat disappearance. Male Sprague-Dawley rats (4-16 wk old) and yellow KK mice (6-10 wk old) were made obese by feeding high-fat diets containing 30% fat. They were then fed energy-restricted, low-fat (5.0%), and high-protein (35% casein, SPI, or SPI-H) diets for 4 wk at 60% of the level of the energy intake of rodents on laboratory chow. The body-fat contents of rats and mice fed a high-fat diet were 27.3 and 33.6 g/100 g body weight, respectively, at the end of the obese period. For rats, the apparent absorbability of dietary energy and fat was significantly lower in the SPI and SPI-H groups than in the casein group, but vice-versa for nitrogen balance. Body-fat content in mice fed SPI and SPI-H diets was significantly lower than in those fed the casein diet. In rats, plasma total cholesterol level was lower with the SPI-H diet, and plasma glucose level was lower with the SPI and SPI-H diets than with the casein diet. These results indicate that SPI and SPI-H are suitable protein sources in energy-restricted diets for the treatment of obesity.

Effect of soy and milk whey protein isolates and their hydrolysates on weight reduction in genetically obese mice.

The effect on genetically obese mice of a milk whey protein isolate (WPI) and soy protein isolate (SPI) and their hydrolysates (WPI-H, SPI-H) on the rate of body fat disappearance was investigated. Male yellow KK mice were made obese by feeding with a high-fat diet containing 30% fat from 6 to 10 weeks of age. They were then fed with an energy-restricted low fat (5.0%) and high protein (35% WPI, WPI-H, SPI or SPI-H) diet for 2 weeks at the 60% level of energy intake by mice on laboratory feed. During the weight reduction period, the body weight of the WPI, WPI-H, SPI and SPI-H groups changed by -9.1, -9.1, -10.0 and -11.1 g/14 days, respectively, the reduction being significantly lower in the SPI-H group than in the WPI and WPI-H groups. The plasma total cholesterol level was significantly lower with the SPI diet, and the plasma glucose level was lower with the SPI and SPI-H diets than with the WPI and WPI-H diets. Although the body protein content was comparable in all the groups, the body fat content was significantly lower with the SPI diet than with the WPI diet, and was also significantly lower with the SPI-H diet than with the WPI and WPI-H diets. The weight of the perirenal fat pads was significantly lower with the SPI-H diet than with the WPI and WPI-H diets. These results indicate that SPI and SPI-H are suitable protein sources in an energy-restricted diet for treating obesity.

Effects of Soybean β-Conglycinin on Hepatic Lipid Metabolism and Fecal Lipid Excretion in Normal Adult Rats

β-Conglycinin decreased blood triacylglycerol (TAG) levels in male Wistar adult rats. Liver mitochondrial carnitine palmitoyltransferase activity in the β-conglycinin-fed group significantly increased as against the casein-fed group. Hepatic fatty acid synthase activity in the β-conglycinin group significantly decreased as against that of the casein-fed group. Fecal fatty acid excretion in the β-conglycinin group was significantly higher than in the casein group.

Structured triacylglycerol containing behenic and oleic acids suppresses triacylglycerol absorption and prevents obesity in rats

BackgroundDietary 1(3)-behenoyl-2,3(1)-dioleoyl-rac-glycerol (BOO) has been reported to inhibit pancreatic lipase activity in vitro and suppress postprandial hypertriacylglycerolemia in humans. In the present study, the anti-obesity activities of BOO and its inhibitory effects on lymphatic triacylglycerol (TAG) absorption were investigated in rats.MethodsIn Experiment 1, rats were fed either BOO or soybean oil (SO) diet for 6 weeks. In the BOO diet, 20% of SO was replaced with an experimental oil rich in BOO. In Experiments 2 and 3, rats cannulated in the thoracic duct were administered an emulsions containing trioleoylglycerol (OOO) or an oil mixture (OOO:BOO, 9:1). Tri[1-14C]oleoylglycerol (14C-OOO) was added to the emulsions administered in Experiment 3.ResultsNo observable differences were detected in food intake or body weight gain between the BOO and SO groups in Experiment 1. Plasma and liver TAG concentrations and visceral fat weights were significantly lower in the BOO group than in the SO group. The apparent absorption rate of fat was significantly lower in the BOO group than in the SO group. In Experiment 2, the lymphatic recovery of oleic and behenic acids was significantly lower at 5 and 6 h after BOO administration than after OOO administration. In Experiment 3, the lymphatic recovery of 14C-OOO was significantly lower at 5 and 6 h after BOO administration than after OOO administration.ConclusionsThese results suggest that BOO prevents deposition of visceral fat and hepatic TAG by lowering and delaying intestinal absorption of TAG.

Intracellular introduction of a fixed quantity of substances by pricking cells using a modified microscope.

Abstract We report here that pricking cells with a microneedle causes introduction into cells of a fixed quantity of material that is contained in the culture medium. Using fragment A of diphtheria toxin (21 500 D), the volume of injected external medium by a single prick was determined (1.4× 10 −15 l (μm 3 )). We also show that immunoglobulin G molecules of 1.6 × 10 5 D can be introduced into cells by this technique. The speed of the microinjection by this pricking method is fast (by using a modified microscope 2 000–7 000 cells/h).

Specific purification of elongation factor 2 and isolation of its antibody

Elongation factor 2 (EF-2) was purified from rat liver extracts by affinity chromatography using fragment A of diphtheria toxin as the ligand. Purified EF-2 has a molecular weight of 96,000 and isoelectric point of 6.6-6.8. The sequence of the nineteen N-terminal amino acid is Val-Asn-Phe-Thr-Val-Asp-Gln-Ile-Arg-Ala Ile-Met-Asp-Lys-Lys-Ala-Asn and the C-terminal amino acid is leucine. Purified rat EF-2 modified with ADP-ribose was injected into rabbits to prepare antibodies against EF-2. The anti-EF-2 antibodies can immunoprecipitate with EF-2 from various eukaryotic cells.

Malonyl isoflavone glucosides are chiefly hydrolyzed and absorbed in the colon.

Malonyl isoflavone glucosides are water-soluble derivatives of soybean hypocotyls. This study compared the hydrolysis and absorption of malonyl isoflavone glucosides and nonmalonyl isoflavone glucosides in rats. Plasma concentrations of isoflavones were measured after oral administration of malonyl isoflavone glucosides or isoflavone glucosides. After fasting, the duodenum, jejunum, ileum, and colon were excised, and homogenates were prepared. The extent of hydrolysis of each glucoside by each intestinal homogenate was measured. Plasma levels of isoflavone aglycones, such as daidzein and glycitein, were higher in rats administered malonyl isoflavone glucosides than in those administered isoflavone glucosides. The area under the curve of daidzein in plasma of rats administered malonyl isoflavone glucosides was also significantly greater than that in those administered isoflavone glucosides. A transport experiment using Caco-2 cells suggested that degradation of malonyl glucosides to aglycones is necessary for intestinal absorption. Malonyl isoflavone glucosides were hydrolyzed only in the colon, whereas hydrolysis of isoflavone glucosides occurred in the jejunum, ileum, and colon. These results indicated more effective absorption of malonyl isoflavone glucosides than of nonmalonyl isoflavone glucosides. Moreover, effective absorption of malonyl isoflavone aglycones in the colon contributed to the significant increase in plasma isoflavone levels.

Effects of Soybean Trypsin Inhibitor on Hemostasis

Soy bean trypsin inhibitor (SBTI) belongs to the family of serpins – serine protease inhibitors widely distributed in the nature [Silverman G.A. et al., 2004; 21]. Serpins participate in the regulation of proteopytic reactions underling very important physiological and pathological processes such as digestion [16], blood clotting [3, 14, 17], immunity [44] apoptosis [36, 42], inflammation [10], dystrophy [31], carcinogenesis [22, 11] and so on. Despite the apparent importance of the correction of imbalances of the proteolysis in pathology, in fact only the pancreatic trypsin inhibitor (aprotinin) is used more or less widely as a protease inhibitor drug (Trasisol, Contrical, Gordox etc) in the treatment of some diseases [24, 13, 40]. Being the animal protein aprotinin possesses substantial disadvantages [23, 12] and attempts to de‐ velop new drug on the base of plant or recombinant proteins or peptidomimetics are under‐ taken [35, 27]. SBTI is one of the candidates for such a role [34].

Antioxidant and Hypocholesterolemic Effects of Soy Foods and Cardiovascular Disease

Cardiovascular disease (CVD) is widespread in the modern world and represents one of the main causes of mortality (Levi et al., 2009). Increased blood cholesterol content (Hozawa, 2011) and oxidative modification of low density lipoproteins (Vogiatzi et al., 2009) represent risk factors for the development of CVD. The right nutrition is considered effective in the prevention and treatment of CVD (Rudkowska & Jones, 2007). The results of epidemiological, clinical and experimental studies show that soy foods decrease blood cholesterol in individuals with hyperlipidemia, as well as mortality rates from CVD both in Asians and Caucasians (Anderson et al., 1995; Borodin et al., 2009; Messina & Messina, 2003). Soy beans contain antioxidants that exert an antioxidant effect when people consume soy foods (Bertipaglia de Santana et al., 2008). This effect may be also beneficial for CVD patients. This review focuses on the discussion of modern data on antioxidant and hypocholesterolemic effects of soy foods, as well as on the potential role of soy foods in the prevention and treatment of CVD in Russia.