The antioxidant activities of natural d-α-tocopherol, mixed tocopherols and tocotrienols, and formulations comprising all forms of vitamin E, providing 400IU, were determined employing an improved oxygen radical absorbance capacity (ORAC) assay using fluorescein (FL) as the fluorescent probe, randomly methylated β-cyclodextrin (RMCD), 2, 2'-azobis(2-amidino-propane)dihydrochloride (AAPH) as the peroxyl radical generator, and Trolox as the standard in 75mM phosphate buffer. The antioxidant activities, expressed in μmol Trolox equivalent per gram, of d-α-tocopherol (87%), mixed tocopherols (70%), and tocotrienols (30%) were found to be 1, 293, 1, 948, and 1, 229, respectively. Some of the vitamin E formulations showed antioxidant activities superior to d-α-tocopherol.
Oxidative stress, produced as a consequence of normal metabolism or induced by extraneous stimuli, has been proved to be a mediator of cell death. The inherent antioxidant defense system and exogenous antioxidants can help the body to combat this oxidative stress-induced cell death. In this study, we explored the antiapoptotic potential of gallic acid, a dietary phenolic having antioxidative and anticarcinogenic properties, in normal human peripheral blood lymphocytes (PBLs). Incubation of PBLs with 100μM H2O2 for 1.5-2.0 h induced phosphatidyl serine externalisation, lipid peroxidation and high molecular weight DNA fragmentation. Pretreatment of lymphocytes with gallic acid for 18 h could effectively inhibit lipid peroxidation and apoptosis induced by oxidative stress. Treatment of PBLs with gallic acid failed to induce any change in the expression of Bcl-2, an antiapoptotic protein. It seems that the protection provided by gallic acid was due to its direct action in the scavenging of free radicals as it was found to be a stronger antiradical than trolox, a water- sol-uble analogue of vitamin E.
When dextrin, maltose, sucrose, glucose, and fructose were used as a source of carbohydrate in a diet, the food intake of rats fed either a Zn-adequate or Zn-deficient diet was evaluated daily over 28 d. The average food intake of all groups of rats fed the Zn-defi-cient diet was significantly lower than that of the corresponding groups of Zn-adequate control rats. The food intake of the dextrin group was the highest under both Zn-deficient and Zn-adequate diets, and that of the fructose group was the lowest. All rats of the dextrin, maltose, sucrose, glucose, and fructose groups with the Zn-deficient status showed a characteristic cyclic variation in food intake and fitted well to a Cosinor curve. The values of the mesor, amplitude, and period of the food intake cycles showed significant differences among the groups. The higher intake of the glucose diet than the fructose diet of rats fed a Zn-deficient diet may be related to the different metabolisms of the carbohydrates used, from the comparison of the quantities consumed in the corresponding carbohydrates of Zn-adequate diets.
Effects of the development of Fe deficiency on changes in Fe and Zn metabolism and its possible interactions with dietary Zn were determined. Adequate (25μg/g) and marginally deficient (5μg/g) Zn diets containing a sufficient (40μg/g) dietary Fe levels were fed for 2 wk. Thereafter, both dietary Zn groups were fed an Fe-deficient (2.2μg/g) diet for 4 wk. It was found that the effects of an Fe-deficient diet began to occur 7 and 14 d after feeding the Fe-deficient diet. At this time, tissue Fe concentrations were depleted and rats were unable to maintain hemoglobin levels. The Fe deficient diet also induced an immediate fall in plasma Fe concentration, transferrin saturation, and apparent Fe absorption, while the concentrations of liver cytochrome c increased as Fe deficiency developed. Decreases in liver and spleen Fe levels, as well as the activities of blood and bone marrow aminolevulinic acid dehydratase (ALA-D, EC 188.8.131.52) were observed 3, 7, and 14 d after feeding the Fe-deficient diet, and thereafter they were increased. On the other hand, the activity of plasma alkaline phosphatase (ALK-P, EC 184.108.40.206) decreased continuously as Fe deficiency progressed. With severe development of Fe deficiency, rats fed the Zn-adequate diet had increased levels of Zn concentration in the plasma, liver, spleen, kidney, and femur, whereas apparent Zn absorption was decreased. The decrease in apparent Zn absorption and the increase in tissue Zn concentration of rats might be related to the lowered Zn requirement, which is associated with the depressed Zn metabolism caused by feeding Fe-deficient diets.
The purpose of the present study was to investigate the relationship between intra-abdominal-obesity susceptibility and the adaptation of skeletal muscle metabolic and histochemical characteristics when fed a high-fat diet (HFD) for a short period of time. Twenty-four male Wistar rats were fed a HFD (39.7% calories of fat) for 5 wk. After the 5-wk dietary period, the rats were sacrificed and divided into intra-abdominal-obesity-prone (OP) or obesity-resistant (OR) groups according to the total intra-abdominal fat pads (epididymal, mesenteric, and perirenal) weights. A superficial portion of the Muscle (M.) gastrocnemius tissue obtained from 2 groups before and after feeding the HFD were analyzed to determine their hexokinase (HK), β-hydroxyacyl CoA dehydrogenase (β-HAD), and citrate synthase (CS) activities. Muscle fiber composition and capillary density were examined in the deep portion of the M. gastrocnemius, soleus, and extensor digitorum longus (EDL) gained after the HFD. While the OP group had more intra-abdominal fat pads and a heavier final body weight than the OR group, there was no significant difference in the energy intake between the two. Due to the HFD, the OP group showed significant increases in β-HAD and CS activities, while the OR group did not. Change of β-HAD activity by HFD in the OP group was significantly greater than that in the OR group. The ratio of fat oxidation, expressed as β-HAD/CS, significantly increased in the OP group, but not in the OR group. No differences were found in either the muscle fiber composition or capillarization. These results suggest that intra-abdominal-obesity-susceptive rats may have a higher adaptation degree in muscle oxidative enzyme activities as characteristic in the early stage of intraabdominal adipose accumulation.
The activity of hepatic serine dehydratase (SDH) increases in tandem with its gene expression when the intake of protein greatly exceeds protein requirements. The actual conditions of plasma free amino acids and pancreatic hormones in weanling and mature rats when fed SDH-inducible and non-inducible diets were examined in relation to incentive factors to secure high SDH activity from a physiological standpoint. Both weanling and mature groups differing in protein requirements were allowed free access to respective diets diverse in protein content (i.e. 25% or 50% casein diet for the former and 6% or 25% casein diet for the latter) during the dark cycle (lights-out) over a period of 1 wk. Despite the difference in protein intake among these groups, there were no conspicuous changes in the plasma concentration of the urea or total or essential amino acids. Therefore, it appears that the individual amino acids did not up regulate the gene and function expressions of SDH merely by their superabundance and subsequent disposal. Portal venous insulin concentration was far higher in mature groups than in weanling groups, although there was little difference between the two groups of the same age in terms of insulin or glucagon concentration and their ratio in abdominal vena cava blood. Accordingly, it follows that the SDH gene undergoes transcriptional regulation through a combined signaling pathway triggered by perceiving surplus protein nutrition as a whole rather than directly through already-known plasma constituents such as free amino acids or pancreatic hormones in the circulatory system.
Vitamin K2 (menaquinone) acts on the bone metabolism. Menatetrenon (MK-4) is a vitamin K2 homologue that has been used as a therapeutic agent for osteoporosis in Japan. Rat models of immobilization induced by sciatic neurectomy are characterized by transiently increased bone resorption and sustained reduction in bone formation. Using such a rat model, we investigated the efficacy of MK-4 on bone loss. Male Sprague-Dawley rats were subjected to unilateral sciatic neurectomy and administered MK-4 for 28 d beginning day 21 after operation. The effect of MK-4 on the immobilized bone was assessed by measuring the bone mineral density of the femur, breaking force of the femoral diaphysis, and bone histomorphometry in tibial diaphysis. The BMD on both the femoral distal metaphysis and diaphysis was reduced by sciatic neurectomy. The administration of MK-4 ameliorated this reduction in a dose-dependent manner. The administration of 30mg/kg MK-4 ameliorated the reduction in bone strength. An improvement in bone formation was observed following the administration of MK-4. These results suggest that MK-4 has a therapeutic potential for immobilization-induced osteopenia.
In comparison with the energy expenditure determined by a whole-body indirect human calorimeter, which provides 24-h energy expenditure (TEE) With high precision and accuracy, the accuracy of predicting energy expenditure (EE) using an activity diary (AD) method was evaluated. Observed and predicted basal metabolic rate (BMR) as well as literature values for typical physical activities were used for TEE prediction. The effect of the number of recorded items in the activity diary on the accuracy of TEE was also examined. Additionally, predicted EE was divided into sleeping, exercise, and sedentary EE to evaluate the estimation errors in the AD method. Subjects were 20- to 69-y-old Japanese women (n=20) and men (n=21). Predicted TEE based on the AD was derived by applying the observed or predicted BMR to literature values for physical activities; i.e., relative metabolic rate (R.M.R.), physical activity ratio (PAR), and metabolic equivalent (MET). The BMR value observed for each subject was obtained by indirect calorimetey using a Douglas bag. The BMR for the subject was also estimated from the predictive equations in the 6th revision of the Recommended Dietary Allowances for the Japanese (1999). The correlations between observed and predicted TEE appeared stronger when using observed BMR than those using predicted BMR. Although the difference of mean values between the predicted and observed TEE was small, the limits of agreement between the predicted and observed TEE were around ±400 kcal. Predicted EE, excluding the time periods for exercise and rest laying down when determining BMR, showed similar results to those of TEE. Furthermore, the number of recorded items in the AD was not significantly correlated to the accuracy of the predicted TEE (r=-0.03). These findings indicate that the predicted TEE of the AD using observed or predicted BMR and literature values is favorably comparable to observed TEE using a wholebody human calorimeter on a group basis; however, its use as a proxy measure of TEE or EE on an individual basis may be limited.
We have previously reported that dietary sesamin and sesaminol, major lignans of sesame seed, elevate the α-tocopherol concentration and decrease the thiobarbituric acid reactive substance (TBARS) concentration in the plasma and liver of rats. In this study, the effects of dietary sesamin and sesaminol on the lipid peroxidation in the plasma and tissues of rats fed docosahexaenoic acid (DHA, 22:6 n-3) were examined. Male Wistar rats (4-wk-old) were divided into the following six experimental groups: control group, fed a basal diet; sesamin group, fed a diet with sesamin (2g/kg); sesaminol group, fed a diet with sesaminol (2g/kg); DHA group, fed a diet containing DHA (5g/kg); DHA+sesamin group, fed a diet containing DHA with sesamin; and DHA+sesaminol group, fed a diet containing DHA with sesaminol. Each diet contained either 0.01 or 0.05g D-α-tocopherol/kg, and the rats were fed the respective experimental diet for 5wk. The dietary DHA elevated the TBARS concentration and also increased the red blood-cell hemolysis induced by the dialuric acid. The dietary sesamin and sesaminol lowered the TBARS concentrations and decreased the red blood hemolysis. The dietary sesamin and sesaminol elevated the a-tocopherol concentrations in the plasma, liver, and brain of the rats fed a diet with or without DHA. These results suggest that dietary sesame lignans decrease lipid peroxidation as a result of elevating the α-tocopherol concentration in rats fed DHA.
Phytosterol contained in vegetable oils is known to exert a hypocholesterolemic function. In the present study, the antioxidant effects of phytosterol and its components, β-sitosterol, stigmasterol, and campesterol, against lipid peroxidation were examined by making a comparison with 2, 2, 5, 7, 8-pentamethyl-6-chromanol (PMC). It was found that these compounds exerted antioxidant effects on the oxidation of methyl linoleate in solution and its effect decreased in the order of: PMC>>phytosterolcampesterolβ-sitosterol>stigmasterol. Phytosterol also suppressed the oxidation and consumption of α-tocopherol in β-linoleoyl-γ-palmitoyl phosphatidylcholine (PLPC) liposomal membranes, the effects being more significant than dimyristoyl PC of the same concentration. Stigmasterol accelerated the oxidation of both methyl linoleate in solution and PLPC liposomal membranes in aqueous dispersions, which was ascribed to the oxidation of allylic hydrogens at the 21- and 24-positions. Taken together, the present study shows that phytosterol chemically acts as an antioxidant, a modest radical scavenger, and physically as a stabilizer in the membranes.
We examined the effects of the resistant starches of adzuki (Vigna angularis), kintoki (Phaseolns vulgaris, variety), and tebou (P. vulgaris, variety) beans on the lipid metabolism in rats. Rats were fed a cholesterol-free diet with 25g of cornstarch (CS)/100g diet, 25g of adzuki starch (AS)/ 100g diet, 25g of kintoki starch (KS)/100g diet, or 25g of tebou starch (TS)/100g diet for 4 wk. The cecal contents in the TS group were significantly higher than those in the CS and KS groups. There were no significant differences in body weight or food intake among the groups. The relative liver weight in the CS group was sig-nificantly greater than that of the AS, KS, and TS groups. The serum total cholesterol, VLDL+IDL+LDL-cholesterol, and triglyceride concentrations in the AS, KS, and TS groups were significantly lower than those in the CS group throughout the feeding period. Though the total hepatic cholesterol concentration in the TS group was significantly higher than that in the KS group, there were no significant differences between the CS and other starch groups. The cecal pH value in the CS group was significantly higher than that of the bean starch groups. The cecal butyric acid concentrations in the AS, KS, and TS groups were significantly higher than that in the CS group, and the cecal total short-chain fatty acid (SCFA) concentrations in the AS and TS groups were significantly higher than those of the CS group. The fecal cholesterol excretion of the AS, KS, and TS groups were significantly higher than that in the CS group. The fecal coprostanol excretion in the AS group was significantly higher than that in the CS group. There was a negative correlation between the serum VLDL+IDL+LDL-cholesterol concentration and fecal neutral steroid excretion (r=-0.664, p<0.001) in the present experiment. Furthermore, the cecal total SCFA concentration was negatively correlated with the serum VLDL+IDL+LDL-cholesterol concentration (r=-0.665, p<0.001) and positively correlated with fecal neutral steroid excretion (r=0.481, p<0.05). The cecal butyric acid level was also negatively correlated with the serum VLDL+IDL+LDL-cholesterol concentration (r=-0.609, p<0.01) and positively correlated with fecal neutral steroid excretion (r=0.658, p<0.001). The results suggest that AS, KS, and TS elevate cecal SCFA concentration, in particular butyric acid concentration, and fecal neutral sterol excretion, and lower the serum total cholesterol level.
Recent evidence indicates that longevity may be achieved when efficient defence mechanisms against oxidative stress, infections, neoplasia, and cardiovascular events are preserved. Centenarians represent an example of “successful aging, ” and the aim of this study was to evaluate serum levels of vitamins A and E, which represent two important nonenzymatic antioxidant defence systems, and their correlation in 16 healthy centenarians and two groups of control subjects. Centenarians showed normal values of retinol (450.9±240.3ng/mL) and α-tocopherol (9220.2±3410.9ng/mL). Moreover, a significant direct correlation between the two vitamins was observed in centenarians (Rho=0.715, p=0.0056), such as in younger control subjects (Rho=0.618, p=0.0168), but not in older control subjects. We assume that the preservation of normal values and the correlation between vitamin A and E concentrations protects centenarians against oxidative stress and contributes to their extreme longevity.
Transferrin and hemoglobin have been reported to oxidize L-ascorbic acid (AA) in vitro. The aim of this study was to determine whether or not physiological concentrations of serum transferrin (reference range 22-45μmol/L) and hemoglobin (reference range 0-3.0μmol/L) interfer with the measurement of AA in the serum. Transferrin (33 to 41μmol/L) and hemoglobin (1.9μmollL) added to freshly pooled serum significantly decreased measured AA in the serum (p<0.05). However, we found that the magnitude of the decrease in AA due to transferrin at concentrations within the reference range or up to 80μmol/L was inconsequential, and had no clinical importance in diagnosing a low AA concentration. Hemoglobin at concentrations within the reference range had little affect on the serum AA measurement. However, when serum specimens were stored at 4°C for more than 1.5h, the magnitude of the decrease in AA due to hemoglobin at physiological concentrations may cause a misleading clinical diagnostic evaluation of low AA concentration.
In the current study, we show the anti-oxidative and hypocholesterol effects of aloe vera in the liver. Male specific pathogen-free (SPF) Fischer 344 rats were randomly assigned to one of four groups: Group A (control) was fed test chow without aloe supplementation; Group B was fed a diet containing a 1% (per weight basis) freeze-dried aloe filet; Group C was fed a diet containing a 1% (per weight basis) charcoal-processed, freeze-dried aloe filet; and Group D was fed a diet containing a-charcoal-processed freeze-dried, whole leaf aloe (0.02% per weight basis) in the drinking water. Our results show that a life-long intake of aloe had superior anti-oxidative action against lipid peroxidation in vivo, as indicated by reduced levels of hepatic phosphatidylcholine hydroperoxide. Additional anti-oxidative action was evidenced by enhanced superoxide dismutase (SOD) and catalase activity in groups B and C. Furthermore, our study revealed that hepatic cholesterol significantly increased in the control group during aging in contrast to the aloe-supplemented groups, which showed approximately 30% lower cholesterol levels, thereby an effective hypocholesteremic efficacy. In this report, we suggest that life-long dietary aloe supplementation suppresses free radical-induced oxidative damage and age-related increases in hepatic cholesterol.
The antibacterial activity of garlic powder was examined against Bacillus anthracis using agar plate cultivation and test tube methods. On the agar plate test, 1-5% garlic powder inhibited the growth of B. anthracis and Escherichia coli O 157 used as references. A 1% water solution of garlic powder in the test tube method killed B. anthracis at 107 cfu/mL within 3h of treatment at room temperature. A number of intestinal bacteria in a BALB/c mouse decreased after the oral administration of 1 mL of 1% garlic powder solution once a day for 3 d. These results suggest that the oral administration of garlic powder is effective against pathogenic bacteria invasion into the intestine as an infection.