The effects of yucca saponin and konjak flour on lipid metabolism were investigated using male Wistar rats weighing about 290g. The rats were divided into 5 groups; control, yucca saponin, soybean saponin, konjak flour, and yucca saponin plus konjak flour groups. All the rats were fed a high-fat diet containing cholesterol for 4 weeks, followed by the experimental diets for a further 2 weeks. The diets were preparedby adding 1.5% yucca saponin, 1% soybean saponin, 3% konjak flour, or 1.5% yucca saponin plus 3% konjak flour, respectively. There was no significant difference in food intake in any of the experimental diet groups when compared to the control group. The ratio of abdominal adipose tissue weight to body weight decreased in both the konjak flour and the yucca saponin plus konjak flour groups. The excretion rate of cholesterol in feces increased, and the serum and liver cholesterol concentrations were reduced in both the yucca saponin and the yucca saponin plus konjak flour groups. Although there was no significant difference in the excretion rate of cholesterol between the soybean saponin and the konjak flour groups, the serum total cholesterol concentration decreased in the soybean saponin group. Total lipid, cholesterol and triglyceride in the liver decreased in the yucca saponin group and were more reduced in the yucca saponin and konjak flour groups. These results suggest that a diet containing yucca saponin and konjak flour improves lipid metabolism in rats fed a high-fat and high-cholesterol diet.
We investigated the effects of calcium on absorption of fat from chocolate in human males. For three days nine human male adults (Ca-group) were administered 23 pieces of chocolate, each piese (8.0g) containing 3.1g of total fat and 150mg of calcium (derived from eggshell), and a control group was administered the same chocolate without the calcium. All subjects were fed a diet containing a small quantity of fat. All feces were collected and analysed for the levels of total lipid and fatty acids during the study period. The results were as follows. 1) The fecal levels of total lipid were significantly higher in the Ca-group than in the control group. 2) The fecal levels of palmitic and stearic acids were also higher in the Ca-group. 3) There was a marked correlation between the concentration of fecal calcium and fecal total lipid. 4) No marked change was observed in serum lipid or calcium. These results suggest that the calcium in the chocolate combined particularly with saturated fatty acids in the digestive canal and inhibited their absorption, although no change in serum lipids was observed in the short term.
We examined the relationship between soybean hull-derived water-soluble hemicellulose (SSH) and the role of the cecum in order to clarify the function of SSH in the regulation of serum cholesterol level. When rats were fed a semi-purified diet containing SSH, we observed a reduced serum cholesterol level (p<0.05) and a notable increase (p<0.05) of cecum weight in comparison with those in other groups, where no increase in the fecal sterol concentration was observed. Although the serum cholesterol level of cecectomized rats fed SSH was roughly comparable with that of rats given a sham operation, the cecum, when present, showed a different pattern of fecal steroid excretion. Lower excretion (p<0.05) of fecal bile acids and neutral sterols was observed in the rats given a sham operation and fed SSH. These results indicate that the cecum plays an important role in the regulation of fecal steroid excretion, rather than having a hypocholesterolemic effect.
We have confirmed that the determination of DF (dietary fiber) in foods by the AOAC enzymaticgravimetric method yields very low recovery of pectin which is stable in weak acidic solution at pH 3 to 5, but degrades on heating of the solution at near neutral pH 5 to 7. This degradation might be due to splitting of high-molecular-weight pectin into low-molecular-weight fragments. Therefore, enzymatic digestion for determination of DF should be done in weakly acidic conditions. Heat-stable α-amylase has considerable activity under weakly acidic conditions at low temperature. Foods were dissolved in hot dimethyl sulfoxide, and digested by heat-stable α-amylase at pH 4.7 and 70°C for 2h in dialysis tubes. The tubes were then dialyzed against running deionized water for 7h at room temperature, and the inner fluids were evaporated to dryness in a rotary evaporator flask. The residues in the flasks gave almost no iodine coloration of starch, except for residues from heated food homogenates. For the separation of lipids, residues were refluxed twice with ethanol and once with acetone, and weighed. Then the ash and protein contents were estimated. This procedure consisted of only α-amylase treatment in a dialysis tube and successive separation of the digestion products by dialysis. The estimation of DF in foods by this new simplified method yields somewhat less variable results.
The effects of orally administered glutathione-enriched yeast extract were studied in a model of acute hepatotoxicity induced by a high intraperitoneal dose of acetaminophen in rats. The reduced glutathione (GSH)-enriched extract showed dose-dependent hepatoprotective effects which were associated with recovery of the liver GSH level. Because no hepatoprotective effects were obtained using bread yeast extract that contained only low levels of GSH, the GSH-enriched yeast extract was shown to be effective by serving as a useful precursor for GSH biosynthesis in the liver. Because the hepatoprotective effect of GSH-enriched yeast extract tended to be stronger than that calculated from its GSH contents, substances other than GSH might also have contributed. Oxidized glutathione (GSSG) -enriched yeast extract given orally also showed a hepatoprotective effect together with recovery of the liver GSH level.
Crude extracts of black matpe showed ACE inhibitory activity. The Sephadex G-100 gel filtration patterns of these extracts indicated that the ACE inhibitory activity was present in the low-molecular-weight fraction. The Sephadex G-15 gel filtration patterns of the active fraction obtained from the Sephadex G-100 column indicated that the molecular weight of the inhibitors was about 400-800. The active fractions obtained from the Sephadex G-15 column were purified by HPLC using an ODS column. The active fractions were not absorbed, and were eluted with 0.05% trifluoroacetic acid. The ACE inhibitory activity of seeds germinated for 6 days was 40% of that of the black matpe extracts. Oral and intraperitoneal administration of a pepsin hydrolysate of the black matpe extract decreased the blood pressure of SHR rats significantly.
A study was conducted to investigate changes in the hepatic phosphatidylcholine hydroperoxide (PCOOH) level, and activities of related metalloenzymes such as xanthine oxidase (XOD), superoxide dismutase (SOD), glutathione peroxidase (GPX) and phospholipid hydroperoxide gluthathione peroxidase (PHGPX) in male rats fed an iron-deficient diet from 1 to 4 weeks. Four-week-old male Wistar rats, each weighing about 45g, were divided into 2 groups (a control diet (C) group and an iron deficient diet group (D)). Each group was fed its respective diet ad libitum. The PCOOH level in the liver was increased at 4 weeks in group D, compared with group C, and showed an increase of about 500%. This is the period when there is no mobilization of iron from ferritin at 4 weeks, compared to the early stage of iron deficiency at 1 week. The activity of hepatic XOD increased between 2 and 3 weeks and remained at an elevated level from 3 weeks until 4 weeks in group D. The activity of hepatic Cu, Zn-SOD at 1 and 4 weeks was lower in group D than in group C. The activity of hepatic PHGPX was lower in group D than in group C at 4 weeks. The copper concentration in the cytosol increased linearly from 1 to 4 weeks in group D, while the cytosolic iron concentration decreased. There was an increase in the hepatic PCOOH level from 1 to 4 weeks in the iron-deficient rats. These results suggest that the increase in the hepatic PCOOH level is caused by a simultaneous increase in the copper concentration and the cytosolic XOD activity when there is no mobilization of iron from ferritin.
The effects of antioxidant (tert-butylhydroquinone, TBHQ) and a peroxide decomposer (thiodipropionic acid, TDPA and thiourea, TU) on the rancid point (induction time, I.T.) and organic acid content of volatile degradation products during oxidation of oil were investigated by the Rancimat method. Organic acids in volatile degradation products collected in distilled water were analyzed by HPLC. The I.T. of the tested oils was prolonged, and the suppression of formation of organic acids (formic, propionic and isovaleric acids etc.) was also noted upon addition of TBHQ, TDPA and TU. In particular, TBHQ showed a greater preventive effect on both oxidation of oil and formation of organic acids than those of TDPA and TU. The amounts of organic acids produced from rancid oil (POV 98 and 224meq/kg) were markedly higher than in peroxide-free rancid oils.
In the present study, we prepared chondroitin sulfate and its oligosaccharide mixture from the nasal cartilage of the salmon, and investigated the effects of these samples on intestinal absorption of glucose. The samples were found to inhibit glucose uptake in brush border membrane vesicles prepared from rat jejurum. These results suggest that chondroitin sulfate from salmon nasal cartilage may improve pathological states of obesity by inhibiting the intestinal absorption of glucose derived from dietary carbohydrate.