We found that dehydrated legume seeds (6 genera, 19 species and cultivated varieties) contained considerable amounts of vitamin C (VC). The average value of total VC content per 100 g of dry weight in dehydrated seeds varied from 0.24 mg (kidney beans) to 4.14 mg (green peas). Yard beans showed highest values among all legumes examined here in the both dehydrated and rehydrated forms (3.19 and 10.8 mg, respectively). By soaking for 16 h in the dark at 20oC, total VC contents of black grams and mung beans increased to 3.1- and 4.5-fold, respectively. However, three varieties of green peas (Hakuryu, Kurumeyutaka, and Nankaimidori) significantly lost their VC during the same soaking treatment. Total VC content of a rehydrated and cooked mung beans was higher than that of a dehydrated form. Appreciable amounts of total VC were detected in the immature seeds of six different genera such as yard beans, kidney beans, broad beans, green peas, soybeans and peanuts. Except for mung beans, 70-100% of VC in dehydrated seeds of adzuki beans, broad beans, green peas, black soybeans, and soybeans was lost by boiling. Total VC and L-ascorbic acid in mung beans, green peas, broad beans, black soybeans, and adzuki beans remained even after boiling, suggesting that it is possible to obtain VC from the cooked forms of these legume seeds.
The biosynthetic route of the pyrimidine moiety of thiamin is different in prokaryotes and eukaryotes. In prokaryotes, the pyrimidine moiety is synthesized from aminoimidazole ribonucleotide, an intermediate of purine biosynthesis, while in eukaryotes, we have reported that the N-1, C-2, and N-3 atoms of the imidazole ring of histidine are incorporated into N-3, C-4, and the amino group attached to the C-4 atoms of the pyrimidine moiety, respectively, as a unit; the rest of the atoms of the pyrimidine moiety originate from pyridoxine as a unit. It has been reported that urocanic acid, the deaminated compound of histidine, is the direct precursor of the pyrimidine moiety. In the present report, we have investigated whether histidine or urocanic acid is the direct precursor of the pyrimidine moiety in Saccharomyces cerevisiae, using tracer experiments with 1) 13C-formate and urocanic acid, 2) 15N-NH4Cl and urocanic acid, 3) 15N-NH4Cl and histidine, and 4) 13C-histidine and urocanic acid. The GC-MS analysis revealed that the incorporation of the 15N atom of 15NH4Cl was not affected by the presence of urocanic acid, although it was affected by histidine, and the incorporation of 13C-histidine was not affected by the presence of urocanic acid. These results confirm that histidine is the direct precursor of the pyrimidine moiety of thiamin in S. cerevisiae.
The purpose of the present study was to examine the effects of combined administration of alendronate (ALN) and alfacalcidol (ALF) on the cancellous and cortical bone mass of the tibia in orchidectomized rats. Fifty male Sprague-Dawley rats, 3 mo of age, were randomized by the stratified weight method into five groups: age-matched control, orchidectomy, and orchidectomy with administration of ALN (2.5 μg/kg, s.c., 5 times a week), ALF (0.05 μg/kg, p.o., 5 times a week), or ALN+ALF. The total experimental period was 12 wk. Orchidectomy reduced the cancellous bone mass of the proximal tibial metaphysis and maturation-related cortical bone gain of the tibial diaphysis as a result of increased trabecular bone resorption and decreased periosteal bone formation and also increased endocortical bone erosion and formation. ALN suppressed trabecular bone resorption and endocortical bone erosion and formation and increased periosteal bone formation, while ALF increased the number of osteoblasts and suppressed trabecular bone resorption and markedly increased periosteal and endocortical bone formation. Thus, both ALN and ALF prevented the orchidectomy-induced reduction in the cancellous bone mass and maturation-related cortical bone gain. Combined administration of ALN and ALF increased the cancellous bone mass as compared with the values observed in age-matched controls by causing more marked suppression of trabecular bone resorption. The present study showed the beneficial effects of combined administration of ALN and ALF on the cancellous bone mass of the tibia in orchidectomized rats.
A determination method for individual natural vitamin B6 compounds was developed. The vitamin B6 compounds were specifically converted into 4-pyridoxolactone (PAL), a highly fluorescent compound, through a combination of enzymatic reactions and HCl-hydrolysis. PAL was then determined by HPLC. Pyridoxal was completely oxidized to PAL with pyridoxal 4-dehydrogenase (PLDH). Pyridoxine and pyridoxamine were totally converted into PAL through a coupling reaction involving pyridoxine 4-oxidase and PLDH, and one involving pyridoxamine-pyruvate aminotransferase and PLDH, respectively. The 5'-phosphate forms and pyridoxine-β-glucoside were hydrolyzed with HCl, and then determined as their free forms. Pyridoxine 5'-phosphate and pyridoxine-β-glucoside were not separately determined here. Three food samples were analyzed by this method.
There have been no simple methods to estimate dietary nutrient intakes for the prevention and management of osteoporosis. The aim of this study was to develop and validate a new, simple food frequency questionnaire (FFQ) for dietary intake of calcium and other nutrients relevant to the bone health of adult Japanese women. We developed a 28-item FFQ. To validate this, 208 and 72 adult women aged between 18 and 69 y were recruited for testing reliability and reproducibility, respectively. In the 208 women, moderate-to-high Spearman's correlation coefficients between our FFQ and the conventional diet record method were found in intakes of calcium (r=0.668), sodium chloride (NaCl) (r=0.475), vitamin A (r=0.501), vitamin D (r=0.413), vitamin K (r=0.649), and energy (r=0.471). In the 72 women, coefficients of variance of the four repeated measurements of intakes throughout a year were 14.1% for calcium, 7.3% for NaCl, 21.2% for vitamin A, 13.6% for vitamin D, 36.8% for vitamin K, and 9.6% for energy. In conclusion, the FFQ we developed is a useful tool to evaluate the intake of dietary calcium of adult Japanese women. Although it can also measure intakes of dietary vitamin A, vitamin D, vitamin K, NaCl, and energy, further improvement is needed to measure intakes of these nutrients and energy.
Epithelial cells and their intercellular junctions play a primary role in the intestinal mucosal diffusion barrier to the invasion of noxious agents. Our previous study has shown that the mouse jejunum, when incubated in Ussing chambers for 4 h, exhibited morphological deterioration of the villi with denudation of the epithelia while it retained cAMP-induced potential difference (PD), suggesting that some subepithelial tissues had taken part in the barrier functions when the primary epithelial barrier on the villous surface was broken. To further characterize the barrier function of the jejunum in Ussing chambers, we measured the unidirectional lucifer yellow flux (JLY), which represents the permeation of a medium-sized anion, the transmural electrical conductance (Gt), which reflects the permeation of electrolytes, mainly NaCl, and forskolin-induced PD. The values of JLY, Gt and forskolin-induced PD were not affected by removing the muscularis propria, suggesting that this tissue did not substantially contribute to the barrier. In addition, the values of JLY, Gt and forskolin-induced PD were not correlated with the degree of denudation of epithelial cells on the mucosal surface, supporting the notion that the main barrier function is constituted by the subepithelial tissues rather than the epithelium. Loosening the tissue (thereby approximating the free diffusion condition) by removing Ca2+ from the bathing solution increased both JLY and Gt, with the former being larger than the latter. In conclusion, the mucosa propria and/or the submucosa constitute a diffusion barrier that restricted the permeation of lucifer yellow more tightly than NaCl in the injured jejunum incubated in Ussing chambers.
Previous studies have suggested that if exercise intensity is established by perceived effort, the metabolic demand varies among exercise machines and the treadmill optimizes energy expenditure (EE). However, these studies have been completed utilizing young people with normal body fat percentages. Therefore, the purpose of this study was to assess whether there was a difference in acute EE when obese people used different exercise modes at a self-selected intensity (ratings of perceived exertion 11-12) commonly recommended for overweight individuals. Twelve obese subjects (7 male; 5 female; BMI>29 kg/m2), aged 37-71 y completed two familiarization trials on four machines: treadmill (TM), stationary cycle (C), body trec elliptical arm/leg (BT), and airdyne (AD). On separate days, subjects then completed a 15 min trial on each machine at a self-selected intensity corresponding to a target RPE of 11-12 on the Borg 15-point scale. Machine order was randomly assigned, and subjects were blinded to the workload throughout each trial. Workload was self-adjusted during the first 5 min and then remained stable for the rest of the trial. Physiological data were obtained during the last 5 min of each trial. The BT produced the highest rate of EE among exercise machines and C the lowest. These results suggest that perceptually-based exercise prescriptions are not reliable across modes typically found in a fitness center environment, and that weight-bearing arm/leg exercise optimizes EE during self-selected exercise of moderate intensity in obese subjects.
To investigate the influence of parental fat intake on preferential fat intake by pups after weaning, two groups of dams in study 1 were fed either a low-fat diet (LFD) or a lard high-fat diet (HFD) and those in study 2 were fed either a LFD or a fish-oil HFD after day 5 of pregnancy and during lactation. In study 1, when pups were placed on a self-selection regimen of the LFD and the lard HFD within the first week after weaning, the ratio of the lard HFD intake [lard HFD intake (g)/total intake (g)] by pups of both groups was about 70%. Although pups nursed by dams fed the lard HFD continued to eat the same ratio of the lard HFD, the ratio for pups nursed by dams fed the LFD gradually decreased to 20% in week 3 after weaning. In study 2, when pups were placed on a self-selection regimen of the LFD and the fish-oil HFD after weaning, the ratio of the fish-oil HFD intake in both groups of pups nursed by dams fed the LFD and the fish-oil HFD was about 20% for 3 wk after weaning. In studies 1 and 2, although no significant difference in dietary intake or body weight of dams and pups was observed among all groups through the experimental period, perirenal fat tissue weight of dams fed the lard HFD was higher than that of dams fed the LFD. These findings indicate that (1) fat preference of weaning pups nursed by dams fed the lard HFD is higher than that of weaning pups nursed by dams fed the LFD, and (2) intake of dam's fish-oil HFD diet guards against pups' intake of excessive fat.
Zinc fortification of milk or soft drinks is usually used to combat zinc deficiencies in developing countries. Water-soluble zinc compounds, such as zinc sulfate or zinc citrate, are better absorbed but have an unacceptable taste. A micronised, dispersible zinc oxide (MDZnO), which does not have such a problem concerning taste, had higher solubility compared to ZnO (zinc oxide) in an artificial gastric solution. MDZnO was tested for its bioavailability using zinc-deficient Wistar rats. Prior to the experiment, rats were fed zinc-deficient diet for 3 wk and were orally administered control (distilled water) or zinc solutions (ZnO, ZnO+L-histidine (His), MDZnO, MDZnO+His, 1 mg zinc/kg or 3.2 mg His/kg body weight). Compared to ZnO, MDZnO showed a lag in peak time and a lengthy period of continued high plasma zinc concentration after the single oral administration of zinc compounds. Addition of His to MDZnO elevated serum zinc concentration. Serum zinc concentration (area under the curve) in rats administered MDZnO with His was significantly higher than in rats administered distilled water (p<0.05). Liver zinc level was significantly higher in rats administered MDZnO with His compared with control rats (p<0.05), although the level was not affected by the administration with ZnO alone, ZnO+His, or MDZnO alone. In conclusion, the solubility of ZnO was elevated by the micronised dispersion tecnique and an in vivo study using zinc-deficient rats confirmed that its bioavailability was significantly improved compared to ZnO and the coadministration of His additively enhanced the bioavailability of MDZnO.
The aim of this study was to investigate the effect of the changes of taurine levels in the hearts of old rats on endogenous malondialdehyde (MDA) and diene conjugate (DC) levels and ascorbic acid (AA)- and NADPH-induced lipid peroxidation as well as non-enzymatic (glutathione, vitamin E and vitamin C) and enzymatic antioxidants (superoxide dismutase, glutathione peroxidase and glutathione transferase). Two groups of old (22 mo) rats were treated with β-alanine (3%, w/v; in drinking water), a taurine depleting agent, or taurine (2% w/v; in drinking water) for 6 wk. Significant decreases were observed in taurine contents of hearts in old rats as compared to young (5 mo) rats. We found that MDA and DC levels and AA- and NADPH-induced lipid peroxidation increased, but non-enzymatic and enzymatic antioxidants did not alter in heart homogenates of aged rats. β-Alanine administration resulted in significant decreases in heart taurine levels of old rats. This treatment did not cause further increases in MDA or DC levels or changes in antioxidants. However, AA- and NADPH-induced lipid peroxidation was higher than that of old rats. Taurine treatment caused significant increases in heart taurine levels of old rats. This treatment was found to decrease endogenous MDA and DC levels without affecting the antioxidant system in the heart homogenates of aged rats. AA- and NADPH-induced lipid peroxidation was also reduced in old rats when given taurine, although not statistically significantly. Our results indicate that the changes in heart taurine levels may influence the susceptibility of heart tissue to lipid peroxidation in aged rats and that taurine supplementation has protective effects on age-dependent oxidative stress in heart tissue.
The purpose of this study was to determine whether the growth hormone (GH) affects the rate of brain protein synthesis in hypophysectomized aged rats. Experiments were conducted on three groups of 24-wk-old male rats: group 1 were hypophysectomized to reduce the level of plasma GH, group 2 were hypophysectomized and treated with GH and group 3 were sham-operated controls. The fractional rates of protein synthesis in the brains of hypophysectomized rats with GH were significantly greater than those in hypophysectomized rats without GH. In the cerebral cortex and cerebellum, the RNA activity [g protein synthesized/(g RNA·d)] significantly correlated with the fractional rate of protein synthesis (r>0.88, p<0.001). The RNA concentration (mg RNA/ g protein) was also related to the fractional rate of protein synthesis in these organs (r>0.56, p<0.05). The results suggest that the treatment of GH to hypophysectomized aged rats is likely to increase the rate of protein synthesis in the brain, and that RNA activity is at least partly related to the fractional rate of brain protein synthesis.
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.
Many food products are claimed to be effective in controlling halitosis. Halitosis is caused mainly by volatile sulfur compounds (VSCs) such as H2S and CH3SH produced in the oral cavity. Oral microorganisms degrade proteinaceous substrates to cysteine and methionine, which are then converted to VSCs. Most treatments for halitosis focus on controlling the number of microorganisms in the oral cavity. Since tea polyphenols have been shown to have antimicrobial and deodorant effects, we have investigated whether green tea powder reduces VSCs in mouth air, and compared its effectiveness with that of other foods which are claimed to control halitosis. Immediately after administrating the products, green tea showed the largest reduction in concentration of both H2S and CH3SH gases, especially CH3SH which also demonstrated a better correlation with odor strength than H2S; however, no reduction was observed at 1, 2 and 3 h after administration. Chewing gum, mints and parsley-seed oil product did not reduce the concentration of VSCs in mouth air at any time. Toothpaste, mints and green tea strongly inhibited VSCs production in a saliva-putrefaction system, but chewing gum and parsley-seed oil product could not inhibit saliva putrefaction. Toothpaste and green tea also demonstrated strong deodorant activities in vitro, but no significant deodorant activity of mints, chewing gum or parsley-seed oil product were observed. We concluded that green tea was very effective in reducing oral malodor temporarily because of its disinfectant and deodorant activities, whereas other foods were not effective.
Glucosyl hesperidin (G-hesperidin) is a water-soluble derivative of hesperidin. In the present study, the short-term effects of G-hesperidin and hesperetin, a putative metabolite of G-hesperidin, in spontaneously hypertensive rats (SHR) and in normotensive Wistar-Kyoto rats (WKY) were investigated. Single oral administration of G-hesperidin (10 to 50 mg/kg) induced a dose-dependent reduction in systolic blood pressure (SBP) in SHR, but had no effects in WKY. Intraperitoneal injection of hesperetin (50 mg/kg) into SHR also caused a significant reduction in SBP. The depressor effect was significantly inhibited by a nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester. Moreover, hesperetin (10−5 M) enhanced endothelium-dependent relaxation induced by acetylcholine, but had no effect on endothelium-independent relaxation induced by sodium nitroprusside in isolated aortas from SHR. These data suggest that the hypotensive effect of hesperetin in SHR is associated with nitric oxide-mediated vasodilation. Therefore, this effect may be involved in the mechanisms by which G-hesperidin lowers blood pressure in hypertension.
Methylglyoxal (MG), a reactive dicarbonyl compound, is a metabolic byproduct of glycolysis often found at high levels in blood from diabetic patients. The effect of lipoic acid on MG-induced oxidative stress was investigated using LLC-PK1 renal tubular epithelial cells, which are susceptible to oxidative stress. MG (500 μM) treatment induced LLC-PK1 cell death to nearly 50% compared with non-treated control cells, but lipoic acid significantly inhibited the MG-induced cytotoxicity in a concentration-dependent manner. In addition, lipoic acid treatment dose-dependently reduced the intracellular reactive oxygen species level increased by 500 μM MG. The nitric oxide level was also increased by 500 μM MG treatment, but it was significantly inhibited by lipoic acid. Furthermore, lipoic acid treatment at 50 μM inhibited the nuclear translocation of nuclear factor-kappa B induced by MG treatment in LLC-PK1 cells. These findings indicate that lipoic acid has potential as a therapeutic agent against the development of diabetic complications related to MG-induced oxidative stress in diabetes.