Hypolipidemic effect of the edible mushroom Agaricus blazei in rats subjected to a hypercholesterolemic diet

The effects of Agaricus blazei intake on the lipid profile of animals fed a hypercholesterolemic diet were evaluated. Thirty-two female Fisher rats were divided into four groups and given the standard AIN-93 M diet (C), this diet?+?1 % A. blazei (CAb), a hypercholesterolemic diet with 25 % soybean oil and 1 % cholesterol (H) or this diet?+?1 % A. blazei (HAb) for 6 weeks. Food intake, weight gain, liver and serum lipid profiles, activity of aminotransferases [alanine aminotransferase (ALT) and aspartate aminotransferase (AST)], and creatinine and urea levels as well as abdominal fat weight were measured. Histological analysis of kidney and liver tissue was also performed. The HAb group had a higher food intake, but a lower weight gain as compared to group H. This resulted in a significant decrease in abdominal fat weight, to values close to those of groups C and CAb. Supplementing the hypercholesterolemic diet with A. blazei promoted a significant reduction in total and non-HDL cholesterol, as well as in the atherogenic index, as compared to group H, and this effect was more pronounced in the serum. There was no hepatotoxic effect caused by the supplementation of the diets with the mushroom. We conclude that in our experimental model and in the concentration used, A. blazei was effective in improving the lipid profile of the animals.     

Cardioprotective effect of coconut kernel protein in isoproterenol administered rats

Male albino rats were given subcutaneous injection of isoproterenol (10 mg/100 g body wt) twice at an interval of 24 hr to induce myocardial infarction. The rats showed massive myocardial necrosis and increased activities of creatinine phosphokinase (CPK), glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT), in serum, while a decrease in nitric oxide synthase activity and lower levels of palmitate oxidation into CO2 and ATP were observed in the heart. Rats pre-treated with coconut protein or L-arginine showed significantly decreased CPK, GOT and GPT activities in the serum. There was significantly higher nitric oxide synthase activity and higher rate of palmitate oxidation into CO2 and increased levels of ATP in the heart in these groups. These observations indicate the cardioprotective effect of coconut protein, which may be attributed to the high content of L-arginine present in it.     

Hypolipidemic effect of diet supplementation with bacterial levan in cholesterol-fed rats

Levan polysaccharide, a type of fructan, has been shown to have industrial applications as a new industrial gum in the fields of cosmetics, foods like dietary fiber and pharmaceutical goods. The objective of this current study was to investigate the possible hypolipidemic and antioxidative effects of levan in rats fed with a high-cholesterol diet. Animals were allocated into four groups of six rats each: a normal diet group (Control), normal rats received levan (L), a high-cholesterol diet group (Chol) and a high-cholesterol diet with a daily dose of levan equivalent to 5%. Treated hypercholesterolemic rats were administrated with levan in drinking water through oral gavage for 60 days. After the treatment period, the plasma antioxidant enzymes and lipid profiles were determined. Our results show that treatment with levan polysaccharide positively changed plasma antioxidant enzyme activities and lipid profiles (total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides) in cholesterol-rats, and thus may have potential hypolipidemic and antioxidant effects. Levan could protect against oxidative stress linked atherosclerosis and decrease the atherogenic index.     

The hypercholesterolemic effect of cafestol in coffee oil in gerbils and rats

Coffee beans contain the diterpene cafestol, which raises plasma cholesterol concentrations in humans. Daily consumption of 2 g coffee oil, which provides approximately 60 mg cafestol (equivalent to 5.7 mg cafestol/MJ), increases plasma cholesterol concentrations by 28%. We studied the effect of cafestol in coffee oil on gerbils and rats to determine whether the pathways that lead to cafestol-induced hypercholesterolemia in humans are also present in other species. We fed coffee oil from the same batch used in humans to female gerbils and rats. Gerbils were fed a semipurified diet containing 0.5% or 5% (w/w) coffee oil (equivalent to 8.7 and 86.8 mg cafestol/MJ, respectively) in the presence or absence of 0.05% (w/w) cholesterol for a period of 10 weeks. When compared with the gerbils fed no coffee oil, the addition of 0.5% coffee oil to the diets did not affect plasma cholesterol. Plasma cholesterol was significantly higher only when 5% coffee oil was fed, both in the absence (1.01 mmol/L, 33% higher) and presence (1.87 mmol/L, 70% higher) of dietary cholesterol. Liver weight was also significantly higher when 5% coffee oil was fed. Rats were also fed diets containing 0.5% or 5% coffee oil (equivalent to 8.7 and 86.8 mg cafestol/MJ) with and without 0.05% cholesterol for 8 weeks. Feeding 0.5% coffee oil compared with no coffee oil resulted in significantly higher plasma cholesterol levels throughout the study both in the absence (0.46 mmol/L, 27% higher) and presence (0.28 mmol/L, 15% higher) of dietary cholesterol. Diets containing 5% coffee oil appeared to be toxic. Thus, coffee oil diterpenes can result in higher plasma cholesterol in gerbils and rats. The failure to observe these effects in previous studies may be due to doses that were too low.     

Mechanism of potent antiperoxidative effect of capsaicin

The effect of a pungent ingredient of red pepper, capsaicin, on lipid peroxidation of rat liver mitochondria (RLM) induced by ADP/Fe(2+) was studied. Capsaicin inhibited the lipid peroxidation significantly, being more effective than the well-known antioxidant alpha-tocopherol. Capsaicin was also found to scavenge 1,1'-diphenyl-2-picrylhydrazyl (DPPH) radicals both in solution and in membranes, especially the latter. Capsaicin was found to scavenge radicals both at/near the membrane surface and in the interior of the membrane. The phenolic OH-group of capsaicin remained intact after reaction with DPPH radicals, indicating that the hydroxyl group is not associated with the radical scavenging reaction. From the results of quantum chemical calculations of various radical intermediates derived from the model compound N-vanillylacetamide, and the findings that vanillin and 8-methyl-6-noneamide were major reaction products of capsaicin with DPPH radicals, it was concluded that the radical scavenging site of capsaicin is the C7-benzyl carbon.     

Hypolipidemic effect of Coriandrum sativum L. in triton-induced hyperlipidemic rats

In the biphasic model of triton-induced hyperlipidemia, C. sativum at a dose of 1g/kg body weight reduced cholesterol and triglycerides levels in both synthesis and excretory phases in rats, and the results were comparable with that of Liponil, a commercially available herbal hypolipidemic drug. The results suggest that coriander decreases the uptake and enhances the breakdown of lipids. From the study it can be assumed that coriander has the potential to be popularized as a household herbal remedy with preventive and curative effect against hyperlipidemia.     

Antioxidant effect of red mould rice in hypercholesterolemic Wistar male rats

The effect of Monascus purpureus red mould rice (RMR) on modulation of lipid metabolism and oxidative stress was studied in hypercholesterolemic rats. Cholesterol feeding for 14 weeks caused a significant increase in the lipid peroxides and total thiols and antioxidant enzymes, viz. glutathione peroxidase (GPx), glutathione reductase (GRd), superoxide dismutase (SOD) and catalase (CAT) in serum and liver in comparison to the control group. However, supplementation of RMR to hypercholesterolemic rats at 8, 12 and 16% significantly increased the GRd, GPx, SOD and CAT activities in serum and liver tissues. Furthermore, RMR feeding significantly decreased total thiols and lipid peroxides and also increased other antioxidant molecules such as glutathione and ascorbic acid in high-cholesterol fed rats. The efficiency of RMR (16%) in modulating the antioxidant molecules and antioxidant enzymes is comparable to standard drug-lovastatin. Thus, this study suggests that the long-term administration of RMR may play an important role in suppressing oxidative stress and, thus, may be useful for the prevention and/or early treatment of hypercholesterolemia.     

Arginine rich coconut kernel protein modulates diabetes in alloxan treated rats

Diabetes mellitus is a syndrome characterized by the loss of glucose homeostasis due to several reasons. In spite of the presence of known anti-diabetic medicines in the pharmaceutical market, remedies from natural resources are used with success to treat this disease. The present study was undertaken to investigate the effect of coconut kernel protein (CKP) on alloxan induced diabetes in Sprague-Dawley rats. Diabetes was induced by injecting a single dose of alloxan (150mg/kg body weight) intraperitoneally. After inducing diabetes, purified CKP isolated from dried coconut kernel was administered to rats along with a semi synthetic diet for 45 days. After the experimental period, serum glucose, insulin, activities of different key enzymes involved in glucose metabolism, liver glycogen levels and the histopathology of the pancreas were evaluated. The amount of individual amino acids of CKP was also determined using HPLC. Results showed that CKP has significant amount of arginine. CKP feeding attenuated the increase in the glucose and insulin levels in diabetic rats. Glycogen levels in the liver and the activities of carbohydrate metabolizing enzymes in the serum of treated diabetic rats were reverted back to the normal levels compared to that of control. Histopathology revealed that CKP feeding reduced the diabetes related pancreatic damage in treated rats compared to the control. These results clearly demonstrated the potent anti-diabetic activity of CKP which may be probably due to its effect on pancreatic β cell regeneration through arginine.     

Influence of coconut kernel protein on lipid metabolism in alcohol fed rats

Male albino rats were given ethanol (3.76 g/kg body weight/day) to induce hyperlipidemia. The rats showed increased concentration of cholesterol and triglycerides in the serum and tissues. Inclusion of coconut protein and L-arginine into ethanol fed rats produced lower levels of total cholesterol, LDL+ VLDL cholesterol, triglycerides and atherogenic index in the serum. Concentration of tissue cholesterol and triglycerides was also lower in these groups. Administration of coconut protein and L-arginine in the ethanol fed rats caused decreased activity of HMG-CoA reductase in the liver and increased activity of lipoprotein lipase in the heart. The activities of malic enzyme and glucose-6-phosphate dehydrogenase were also lower in these groups. Feeding coconut protein and L-arginine in ethanol treated rats showed increased concentration of hepatic bile acids and fecal excretion of neutral sterols and bile acids. All these effects were comparable in rats fed coconut protein and those fed L-arginine. These observations indicate that the major factor responsible for the hypolipidemic effect of coconut protein is due to the high content of L-arginine.     

Availability and antiperoxidative effects of beta-carotene from Dunaliella bardawil in alcohol-drinking rats

The present study demonstrated the high bioavailability and antiperoxidative capacity of the natural beta-carotene isomer mixture of Dunaliella bardawil compared with synthetic beta-carotene under alcohol-induced oxidative stress. Weanling rats were adapted to ethanol by increasing ethanol levels in their drinking water to 30% at 5% intervals per week; other rats received water with no added ethanol. One water-drinking group and one alcohol-drinking group with no dietary carotene were used as controls. Two water-drinking groups were supplemented with 1 g/kg diet beta-carotene either from Dunaliella or a synthetic source, and due to reduced food intake, two ethanol-fed groups received 2 g beta-carotene per kilogram of diet from each source. Following 3 months of ethanol consumption, both carotene sources were found to prevent ethanol-induced lipid peroxidation as expressed by the hepatic conjugated oxidized dienes level. However, in the algal-fed rats, hepatic carotene and vitamin A levels were higher. In addition to a lower performance of the group fed ethanol and synthetic beta-carotene, there were three deaths in this group.     

Hypolipidemic action of taurine in rats.

The effect of taurine on the serum and liver cholesterol and triglyceride levels was studied in rats fed cholesterol plus cholic acid. Four groups of 4 weeks old rats were fed control diet, hypercholesterolemic diet (HCD), HCD + 1% taurine or HCD + 2% taurine for 8 weeks. Addition of taurine in HCD diet showed a significant reduction not only in serum total cholesterol and triglyceride levels but also in liver total cholesterol, lipid and triglyceride contents compared to the animals fed HCD alone. Histological examination of organs of these animals showed severe fatty vacuolation in livers and signet ring type vacuolation in kidneys of rats fed HCD. Taurine showed ameliorating effect on these abnormalities. The animals fed taurine in HCD also showed increased bile and sterol excretion in faeces compared to rats fed HCD alone. Taurine showed significant hypocholesterolemia in rats probably by enhancing the catabolism of cholesterol and reducing the absorption of dietary cholesterol.     

Effect of antiperoxidative drugs on gastric damage induced by ethanol in rats

Lesion formation due to oral administration of absolute ethanol could be prevented by parenteral pretreatment with antiperoxidative drugs such as butylated hydroxytoluene (BHT), quercetin and quinacrine. Also effective were allopurinol and oxypurinol, inhibitors of xanthine oxidase, but not superoxide dismutase (SOD) and hydroxyl radical scavengers, such as sodium benzoate and dimethyl sulfoxide (DMSO). BHT, quercetin, quinacrine and sulfhydryl compounds such as reduced glutathione and cysteamine which offer gastroprotection in vivo against ethanol inhibited lipid peroxidation induced in vitro by ferrous ion in porcine gastric mucosal homogenate, but SOD, sodium benzoate, DMSO, allopurinol and oxypurinol did not. These results suggest the possibility that an active species, probably derived from free iron mobilized by the xanthine oxidase system, other than oxygen radicals such as hydroxyl radicals, contributes to lipid peroxidation and lesion formation in the gastric mucosa after absolute ethanol administration.     

Dietary effect of Pleurotus eryngii on biochemical function and histology in hypercholesterolemic rats

This work was conducted to investigate diet supplement of king oyster mushroom fruiting bodies on biochemical and histological changes in hypercholesterolemic rats. Six-week old female Sprague–Dawley albino rats were divided into three groups of 10 rats each. The feeding of 5% powder of the fruiting bodies of Pleurotus eryngii to hypercholesterolemic rats reduced their plasma total cholesterol, triglyceride, low-density lipoprotein, total lipid, phospholipids, and LDL/HDL ratio by 24.05%, 46.33%, 62.50%, 24.63%, 19.22%, and 57.14%, respectively. Mushroom also significantly reduced body weight in hypercholesterolemic rats. However, it had no adverse effects on plasma albumin, total bilirubin, direct bilirubin, creatinine, blood urea nitrogen, uric acid, glucose, total protein, calcium, sodium, potassium, chloride, inorganic phosphate, magnesium, and enzyme profiles. Feeding mushroom increased total lipid and cholesterol excretion in feces. The plasma lipoprotein fraction, separated by agarose gel electrophoresis, indicated that P. eryngii significantly reduced plasma β and pre-β-lipoprotein, while increased α-lipoprotein. A histological study of hepatic cells by conventional hematoxylin–eosin and oil red O staining showed normal findings for mushroom-fed hypercholesterolemic rat. The present study suggests that 5% P. eryngii diet supplement provided health benefits by acting on the atherogenic lipid profile in hypercholesterolaemic rats. Therefore, king oyster mushroom could be recommended as a natural cholesterol lowering substance within the human diet.     

Hypolipidemic effect of pregnancy in the rabbit

New Zealand white rabbits showed large decreases in plasma cholesterol and phospholipid concentrations during the second half of pregnancy. All lipoproteins (very low density, low density, and high density) participated in the decrease. Very large decreases in plasma cholesterol concentrations were observed even when the animals were maintained on high cholesterol diets. Increases in plasma cholesterol concentrations, after the intravenous administration of Triton WR 1339, were at least as great in pregnant as in nonpregnant animals. It is concluded that the decrease in plasma cholesterol concentrations is not the result of impaired plasma lipoprotein production.     

Hypolipidemic effect of an exo-biopolymer produced from submerged mycelial culture of Auricularia polytricha in rats

The hypolipidemic effect of an exo-biopolymer (EBP) produced from a submerged mycelial culture of the mushroom fungus, Auricularia polytricha, was investigated in the dietary-induced hyperlipidemic rats. In a dose-dependent study, the EBP was fed at 50–100 mg kg^–1 body weight and significantly decreased the concentrations of the plasma triacylglycerols, total cholesterol, and low-density lipoprotein (LDL) cholesterol. The plasma LDL cholesterol concentration was decreased up to 70%. Production of A. polytricha biomass and EBP were optimal at pH 4 with maximum growth at 20 °C and EBP production at 30 °C. Gel chromatography of the EBP revealed a single peak of a glycoprotein with a molecular size of 32 kDa. It contained 77.5% carbohydrate and 22.5% protein. The sugar and amino acid compositions of the EBP were analyzed.     

Intestinal lipoprotein synthesis in control and hypercholesterolemic rats

Previous studies in our laboratory have shown that very-low-density lipoproteins (VLDL) synthesized by the intestine of the diet-induced hypercholesterolemic rat are enriched in cholesteryl esters and unesterified cholesterol compared with intestinal VLDL from control rats. In these studies, we isolated and characterized nascent intestinal Golgi intermediate-density lipoproteins (IDL, d 1.006-1.040 g/ml) and studied isotope incorporation into apoliproteins of Golgi VLDL from control and hypercholesterolemic rats. IDL were triacylglycerol-rich lipoproteins but contained more cholesteryl ester and protein than the corresponding Golgi VLDL fractions. IDL from hypercholesterolemic rats were enriched in cholesteryl esters to a greater extent than IDL from control rats. The apolipoprotein patterns of IDL fractions were the same as those of intestinal Golgi VLDL, consisting of apolipoproteins (apo) B-48, A-I and A-IV. Time-course isotope incorporation curves for apo A-I and A-IV in Golgi VLDL were similar, but they differed from curves for apo B-48. None of these curves was markedly altered in the hypercholesterolemic rat. We conclude that the major effect of increased dietary cholesterol on intestinal lipoprotein biosynthesis is to increase the percentage of cholesteryl esters in Golgi lipoproteins. Dietary cholesterol does not alter the apolipoprotein composition of Golgi lipoproteins, nor does it have a significant effect on the pattern of isotope incorporation into apolipoproteins of Golgi VLDL. The effect of cholesteryl ester enrichment on the subsequent metabolism of these particles in the circulation and the effect of these particles on hepatic lipoprotein production remain to be determined.     

Hypolipidemic effect of beta, beta'-methyl-substituted hexadecanedioic acid (MEDICA 16) in normal and nephrotic rats

Treatment of normal or puromycin aminonucleoside-nephrotic rats, kept on a balanced Purina chow diet, with beta, beta'-tetramethyl-substituted hexadecanedioic acid (MEDICA 16) (Bar-Tana, J., G. Rose-Kahn, and M. Srebnik. 1985. J. Biol. Chem. 260: 8404-8410) resulted in an acute reversible inhibition of liver lipogenesis and cholesterogenesis with a concomitant hypolipidemic effect which was sustained as long as the drug was administered. The hypolipidemic effect in normal and nephrotic rats consisted of 70-80% and 40-60% reduction in plasma VLDL-triacylglycerols and cholesterol, respectively, with a respective increase in the HDL-cholesterol/(VLDL + LDL)-cholesterol ratio. The observed hypolipidemic effect was accompanied by a 10-fold decrease in VLDL-apoC-III content with a concomitant enrichment of the VLDL fraction by VLDL remnants having an increased apoB-100/apoB-48 ratio. The pharmacological reduction of VLDL by MEDICA 16 may offer a treatment mode of choice for selected hyperlipidemic states.     

Hypolipidemic and antioxidant effects of curcumin and capsaicin in high-fat-fed rats

The beneficial hypolipidemic and antioxidant influences of the dietary spice compounds curcumin and capsaicin were evaluated. Curcumin, capsaicin, or their combination were included in the diet of high-(30%)-fat-fed rats for 8 weeks. Dietary high-fat-induced hypertriglyceridemia was countered by dietary curcumin, capsaicin, or their combination by 12%-20%. Curcumin, capsaicin, and their combination also produced a slight decrease in serum total cholesterol in these animals. Serum alpha-tocopherol content was increased by dietary curcumin, capsaicin, and their combination in high-fat-fed rats. Serum total thiol content in high-fat-fed animals and serum ascorbic acid in normal animals was elevated by the combination of curcumin and capsaicin. Hepatic glutathione was increased by curcumin, capsaicin, or their combination in normal animals. Hepatic glutathione and alpha-tocopherol were increased, whereas lipid peroxide level was reduced by dietary curcumin and combination of curcumin and capsaicin in high-fat-fed animals. Serum glutathione peroxidase and glutathione transferase in high-fat-fed rats were generally higher as a result of dietary curcumin, capsaicin, and the combination of curcumin and capsaicin. Hepatic glutathione reductase and glutathione peroxidase were significantly elevated by dietary spice principles in high-fat-fed animals. The additive effect of the 2 bioactive compounds was generally not evident with respect to hypolipidemic or antioxidant potential. However, the effectiveness of the combination was higher in a few instances.     

Hepatoprotective and antioxidant effect of tender coconut water on carbon tetrachloride induced liver injury in rats

Hepatoprotective and antioxidant effects of tender coconut water (TCW) were investigated in carbon tetrachloride (CCl4)-intoxicated female rats. Liver damage was evidenced by the increased levels of serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) and decreased levels of serum proteins and by histopathological studies in CCl4-intoxicated rats. Increased lipid peroxidation was evidenced by elevated levels of thiobarbituric acid reactive substance (TBARS) viz, malondialdehyde (MDA), hydroperoxides (HP) and conjugated dienes (CD), and also by significant decrease in antioxidant enzymes activities, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (Gpx) and glutathione reductase (GR) and also reduced glutathione (GSH) content in liver. On the other hand, CCl4-intoxicated rats treated with TCW retained almost normal levels of these constituents. Decreased activities of antioxidant enzymes in CCl4-intoxicated rats and their reversal of antioxidant enzyme activities in TCW treated rats, shows the effectiveness of TCW in combating CCl4-induced oxidative stress. Hepatoprotective effect of TCW is also evidenced from the histopathological studies of liver, which did not show any fatty infiltration or necrosis, as observed in CCl4-intoxicated rats.