The effect of dried tomato, grape and apple pomace on the cholesterol metabolism and antioxidative enzymatic system in rats with hypercholesterolemia.

The effect of dried tomato, grape and apple pomace (5% in diet) on the cholesterol levels in serum and selected organs was studied in male Wistar rats fed a cholesterol diet (0.3%) shortly after weaning. Pomace of individual fruits contained 47.2, 67.0 and 46.2 g of total dietary fiber per 100 g of dry matter for tomato, grape and apple pomace, respectively. Corresponding values for the soluble components of the fiber were 10.3, 14.7 and 26.0%. None of the tested products affected the serum cholesterol levels. Tomato and apple pomace significantly reduced cholesterol level in liver by 15% and 11%, respectively, and all tested pomace species reduced cholesterol content in heart (by 18-21%). Triacylglycerol content was affected only by tomato pomace and solely in the heart. Cholesterol absorption measured by dual-isotope ratio method, was not significantly affected by the pomace, however, all products strongly reduced (up to the half of the original value) the activity of HMG-CoA reductase in liver and increased the fractional catabolic rate of plasma cholesterol (by 60-120%). All tested pomace reduced plasma levels of conjugated dienes and tomato and grape pomace exhibited this effect also in the liver. All tested pomace reduced the activities of antioxidant enzymes superoxid dismutase, catalase and glutathione peroxidase in erythrocytes (by 34-56%).

Effect of oyster mushroom (Pleurotus ostreatus) on pathological changes in dimethylhydrazine-induced rat colon cancer.

The effect of 5% of dried oyster mushroom (Pleurotus ostreatus) in the diet on the dimethylhydrazine (DMH)-induced colon carcinogenesis was studied in male Wistar rats. DMH in a dose of 20 mg/kg of body weight was applied to animals once a week during a period of 12 weeks. Mushroom diet was applied either after treatment with DMH for another 21 weeks or during the whole experiment. Mushroom diet reduced significantly the incidence of lymphoid hyperplasia foci when mushroom was supplemented during the whole experiment. Tumour lesions could be characterized either as carcinoma in situ, or as infiltrating adenocarcinoma. Mushroom diet did not affect significantly the incidence of tumours. Nevertheless, a reduction in total number of tumours was observed in both groups of animals fed mushroom diet. A significant reduction of the number of tumour foci of the type carcinoma in situ was observed in animals fed the oyster mushroom during the whole experiment. Also these animals had the significantly lower number of aberrant crypt foci. Mushroom diet reduced the ornithine decarboxylase activity in the colon and in the liver when oyster mushroom diet was administered during the whole experiment.

Dose- and time-dependent hypocholesterolemic effect of oyster mushroom (Pleurotus ostreatus) in rats.

The effect of the dose of oyster mushroom in the diet (1.0, 2.5, and 5.0%) and of the period of application (8, 16, 28, and 52 wk) on cholesterol accumulation in blood and body organs was studied in weanling male Wistar rats fed a diet containing 0.3% cholesterol. Reduction of cholesterol in serum and body organs was found to be dependent on the amount of dietary oyster mushroom administered. A negative correlation between the mushroom dose and cholesterol level was found after 8 and 28 wk of feeding (r=-0.9821 and -0.9803, respectively; P < 0.02 for both cases). The dose of 1% oyster mushroom did not affect cholesterol levels in serum or body organs. A significant reduction of cholesterol levels was observed in serum (31-46%) and liver (25-30%) at a dose of 5% of oyster mushroom for all periods. Reduced cholesterol content in very low-density lipoproteins (VLDL) was also observed at this level. The highest dose of oyster mushroom induced a decrease in conjugated diene levels in erythrocytes and an increase in the levels of reduced glutathione in the liver and stimulated the activities of catalase and glutathione peroxidase in the liver in the final period of the experiment.

[The effect of n-3 fatty acid administration on selected indicators of cardiovascular disease risk in patients with type 2 diabetes mellitus]. / Vplyv podávania n-3 mastných kyselín na vybrané ukazovatele kardiovaskulárnych rizík u pacientov s diabetom mellitus II. typu.

BACKGROUND: Serum triacylglycerols (TG), VLDL, HDL, fatty acid and eicosanoid spectrum are among the factors determining the risk of cardiovascular complications in NIDDM. N-3 polyunsaturated fatty acids (PUFA) are expected to have beneficial effects on these factors. In NIDDM patients there have however been previously reported (late 1980s) some adverse effects. OBJECTIVES: Our aim was to verify the effects of n-3 PUFA in NIDDM patients using relatively low dosage. METHODS: The investigated group included 21 NIDDM patients with dyslipoproteinemia type IV. The patients were treated for 28 days with 1.7 g EPA (eicosapentaenoic acid) + 1.15 g DHA (docosahexaenoic acid)/day (10 capsules/day of MAXEPA, Seven Seas U.K.). The lipoproteins were measured using the BIO-LACHEMA kits, the fatty acid spectrum in phospholipids was determined by gas chromatography and prostanoids (after their separation) were measured by RIA methods. MAIN RESULTS AND CONCLUSIONS: After the MAXEPA treatment there has been a strong decrease in TG (p < 0.005) and VLDL (p < 0.002) serum levels, accompanied by a significant increase in HDL (p < 0.02). The final-to-baseline TG ratio in individual patients negatively correlated with the relative percentage of EPA in phospholipids after the treatment (p < 0.03; r = -0.474). There was no significant change in serum total cholesterol, fasting glycaemia and glycosylated hemoglobin. There was a slight, but statistically already significant (p < 0.05), rise in LDL. The relative percentage of EPA, docosapentaenoic acid and DHA in serum phospholipids increased sharply (p < 0.001, p < 0.001, p < 0.001). The increase of n-3 PUFA in individual patients was linked with the decrease in n-6 PUFA (p < 0.001; r = -0.686). The spectrum of the latter has changed also very markedly. The prostacyclin PGI2-to-thromboxane TxA2 ratio increased significantly (p < 0.001). Beneficial effects of n-3 fatty acids have prevailed and this kind of treatment seems very encouraging also in NIDDM patients. The results are logically compatible with other authors' results pattern formed in 1990s. A slight rise in serum LDL needs a more detailed discussion since only its phenotype B ("small dense LDL particles") has been recently found to be atherogenic. (Tab. 2, Fig. 5, Ref. 15.)

[Regulation of cholesterol metabolism with dietary addition of oyster mushrooms (Pleurotus ostreatus) in rats with hypercholesterolemia]. / Regulácia metabolizmu cholesterolu hlivou ústricovitou (Pleurotus ostreatus) v diéte u potkana s hypercholesterolémiou.

BACKGROUND: It is generally accepted that lowering of serum cholesterol levels reduces the risk of atherosclerosis. Identification and characterization of natural substances with hypocholesterolemic activity useful in dietetic prevention or treatment of hypercholesterolemia is still relevant in countries with persistent progression of hypercholesterolemia. Addition of oyster mushroom (Pleurotus ostreatus), an industrially produced wood-rotting fungus, to the diet effectively reduced cholesterol accumulation in serum and liver of rats fed a cholesterol diet. The aim of a series of experiments was to explain the biochemical mechanism of this effect. METHODS AND RESULTS: Male Wistar rats fed a cholesterol (0.3%) diet shortly after weaning for a period of 8-10 weeks were used in the experiments. The addition of 5% of dried oyster mushroom to the diet had following effects: reduction of cholesterol level both in serum (5.12 +/- 0.55 vs. 3.44 +/- 0.16 mmol/l, p < 0.02) and liver (241 +/- 12 vs. 113 +/- 11 mmol/kg, p < 0.001); redistribution of cholesterol in favour of high-density lipoproteins; reduced production of very-low-density lipoproteins (135 +/- 7 vs. 96.5 +/- 5 mumol/h/kg, p < 0.001); reduced cholesterol absorption (61.2 +/- 2 vs. 53 +/- 2%, p < 0.02) and reduced HMG-CoA activity in liver (137 +/- 16 vs. 86 +/- 9 pmol/min/mg proteins, p < 0.02). Simultaneously, an increase in 7 alfa-hydroxylase activity in liver (17 +/- 1 vs. 22 +/- 1 pmol/min/mg proteins. p < 0.02) and bile acid excretion (7 +/- 0.9 vs. 11 +/- 0.5 mg/day/rat, p < 0.02) was observed. (Values shown are means +/- SEM.) CONCLUSIONS: Biochemical mechanism of hypocholesterolemic effect of oyster mushroom on cholesterol-fed rats includes reduced production of cholesterol-rich very-low-density and low-density lipoproteins which principally determine cholesterol levels in serum. This effect is related to decreased absorption and biosynthesis of cholesterol together with increase in cholesterol catabolism and excretion of degradation products-bile acids.

Dose-dependent hypocholesterolaemic effect of oyster mushroom (Pleurotus ostreatus) in rats.

A highly significant negative correlation (r=-0.981, p < 0.001) between the amount of oyster mushroom (Pleurotus ostreatus) in the diet and cholesterol levels in the serum has been found in male Wistar rats fed shortly after weaning by a a diet with 0.3% cholesterol. The addition of 1.0, 2.5 and 5.0% of oyster mushroom to the diet reduced the levels of serum cholesterol by 11, 31 and 46%, respectively. The diet containing 5% of oyster mushroom suppressed cholesterol accumulation in the liver and increased the fraction of cholesterol carried by high-density lipoproteins.

Oyster mushroom (Pleurotus ostreatus) reduces the production and secretion of very low density lipoproteins in hypercholesterolemic rats.

Oyster mushroom (Pleurotus ostreatus) reduced the production and secretion of nascent very low density lipoproteins in hypercholesterolemic rats. In male Wistar rats (initial body weight about 70 g) fed a semisynthetic diet with 0.3% of cholesterol, the addition of 5% of powdered oyster mushroom (Pleurotus ostreatus) to the diet reduced after 8 weeks the level of serum cholesterol (by 36%) and accumulation of cholesterol and triglycerides in liver (by 51 and 32%, respectively). The decreased levels of serum cholesterol were caused to the same extent by reduction of cholesterol content in very low density lipoproteins (VLDL) and in low density lipoproteins (LDL) (by 53 and 47%, respectively). Biosynthesis of all structural lipids of VLDL (phospholipids, cholesterol, triglycerides) in liver and incorporation of de novo synthesized lipids into secreted nascent VLDL (measured by simultaneous application of Na-acetate-1-14 C and Triton WR 1339 which inhibits peripheral lipolysis) was reduced by application of diet with oyster mushroom.

Effect of oyster mushroom (Pleurotus Ostreatus) and its ethanolic extract in diet on absorption and turnover of cholesterol in hypercholesterolemic rat.

The effect of the diet containing 5% of powdered oyster mushroom (Pleurotus ostreatus) or an equivalent amount of mushroom ethanolic extract on cholesterol content in serum and liver, on its distribution in lipoproteins, absorption and turnover was studied in male Wistar rats (initial body weight about 70 g) fed a diet with 0.3% cholesterol. 12 weeks of feeding with whole oyster mushroom or mushroom extract reduced cholesterol level in serum by 52 and 33%, respectively. However, cholesterol content in liver was reduced only by whole oyster mushroom (by 20%). Diminished serum cholesterol level was mediated in 60% by reduction of cholesterol in very-low-density lipoproteins. Both whole oyster mushroom and mushroom extract increased the concentration of cholesterol in high-density lipoproteins. Consuming whole oyster mushroom decreased cholesterol absorption (estimated by dual-isotope plasma ratio method) by nearly 16% while no significant effect of mushroom extract could be demonstrated. Feeding the diet containing whole oyster mushroom or its extract reduced the half-times of decay curve of cholesterol-4-14C by 29 and 35%, respectively and reciprocally increased the fractional catabolic rate of plasma cholesterol.

Effect of fatty acid composition, cadmium and vitamin E intake on prooxidative-antioxidative state of rat liver.

The effect of cadmium intake (100 micrograms/kg body weight/day as cadmium chloride over a period of three months) on the prooxidative-antioxidative state of liver was studied in 30 days old weaned male rats. Animals were fed a nutritionally balanced lacto-vegetable diet containing high-quality amino acid mixture (casein + gluten 1:1), lipids in form of either pork fat PF (% of polyunsaturated fatty acids PUFA = 11.9; unsaturation index UI = 72), margarine MA (% PUFA = 21.9; UI = 98), or soybean oil SO (% PUFA = 61.2; UI = 156) and vitamin E at amount of 60 mg/kg of food (groups PF, PF + Cd, MA, MA + Cd, SO, SO + Cd) or 600 mg (groups PF + Cd + E, MA + Cd + E, SO + Cd + E) in form of alpha-tocopheryl acetate. The following parameters were measured: conjugated dienes of fatty acids (CD), activities of superoxide dismutase (SOD), catalase (CAT) (as relative generation of H2O2) and glutathione peroxidase (GSH-Px). A direct relation between lipoperoxidation values and unsaturation index of lipids was found both in spontaneous (PF, MA, SO-control) and cadmium-induced generation of free oxygen radicals. Cadmium intake resulted in a disbalance in prooxidative-antioxidative processes which was manifested in a significant increase of CD in all fat sources (the degree of increase was directly proportional to UI and PUFA), in similar values of relative H2O2 generation and in a nonsignificant increase of GSH-Px in animals with most developed lipoperoxidation (SO). A tenfold increase in the administered dose of vitamin E restored a prooxidative-antioxidative equilibrium disturbed by cadmium intake in the liver of rats fed the diet with animal fat (PF + Cd + E) and margarine (MA + Cd + E) (reduction of CD to the level of control groups, decrease of relative generation of H2O2-significant in MA). In animals fed with soybean oil, a vitamin E-induced reduction of CD was significantly over the control level simultaneously with significant stimulation of GSH-Px activity. No changes in H2O2 generation together with CD levels and GSH-Px activity indicated that a synergic effect of several antioxidants is essential in the case of high lipoperoxidation. Presented results are important with respect to possible control or regulation of the equilibrium between prooxidative and antioxidative processes by nutrition.