Background/Objective: An animal study was carried out to examine the beneficial influence of known hypolipidemic spice principles – curcumin and capsaicin – and the spice garlic on the antioxidant status of red blood cells and liver tissue in hyperlipidemic rats. Methods: Rats were rendered hyperlipidemic by maintaining them on a high-fat (30%) diet for 8 weeks. Spice principles – curcumin (0.2%) or capsaicin (0.015%) – or garlic (2.0%) were included in the diets of separate animal groups. Erythrocytes isolated at the end of the study were analyzed for intracellular antioxidant molecules and antioxidant enzymes. Results: Intracellular total thiols in the erythrocytes of high-fat-fed rats were depleted significantly (16%). Similarly, the intracellular glutathione content in erythrocytes was depleted in high-fat-fed rats (28%). The concentration of lipid peroxides in the erythrocytes (intracellular as well as membrane) induced by H2O2 was significantly higher in the high-fat-fed group. Curcumin (0.2%) or capsaicin (0.015%) or garlic (2.0%) in the diet which produced the hypotriglyceridemic effect were also effective in reducing oxidant stress, which was indicated by a significant countering of the depleted intracellular antioxidants – total thiols and glutathione – and elevated lipid peroxides in erythrocytes. The elevated lipid peroxide in blood plasma due to the high-fat diet was also significantly countered by the spice treatments. The severely depleted hepatic glutathione in high-fat treatment was also effectively reversed by dietary curcumin, capsaicin and garlic. Conclusions: Thus, dietary hypolipidemic spices were effective in reducing the oxidant stress, which was indicated by countering the depleted antioxidant molecules and antioxidant enzymes in erythrocytes and liver, and decreasing the elevated lipid peroxide content.
An animal study was carried out to examine the beneficial influence of the known hypocholesterolemic spice principle-capsaicin on the susceptibility of low-density lipoprotein to oxidation in normal and hypercholesterolemic condition. In rats rendered hypercholeterolemic by maintaining them on a cholesterol-enriched diet for eight weeks, inclusion of capsaicin (0.015%) in the diet, produced significant hypocholesterolemic effect. Oxidation of low-density lipoprotein was induced either by copper ion in vitro after its isolation, or by ferrous ion in vivo in experimental rats under either normal or hypercholesterolemic situation and the beneficial effect of dietary capsaicin on the same was evaluated. LDL oxidation was measured by the thiobarbituric acid reactive substances (TBARS) formed and relative electrophoretic mobility of oxidized LDL. Dietary capsaicin was found to be protective to the LDL oxidation in vitro in the case of normal rats as indicated by reduction in TBARS by more than 40%. In the case of LDL isolated from hypercholesterolemic rats the extent of copper induced LDL oxidation was significantly lower than that of LDL isolated from normal rats. Dietary capsaicin did not make any difference in the extent of LDL oxidation in vitro in hypercholesterolemic rats. Ferrous ion induced in vivo oxidation of LDL was 71% lower in capsaicin fed normal rats. In high cholesterol feeding, Fe-induced in vivo oxidation of LDL was 73% lower, while the same was still marginally lower in capsaicin fed hypercholesterolemic rats. Hepatic lipid peroxidation was significantly decreased by dietary capsaicin in normal rats. While a significantly decreased level of lipid peroxidation was observed in hypercholesterolemic rats compared to normal rats, the same was not significantly altered by dietary capsaicin. Results suggest that dietary spice principle capsaicin is protective to LDL oxidation both in vivo and in vitro under normal situation, while in hypercholesterolemic situation where the extent of LDL oxidation is already lowered, capsaicin does not offer any further reduction.
In rats rendered hypercholesterolaemic by maintaining them on a cholesterol-enriched diet (0·5 %) for 8 weeks, as a result of alteration in membrane structural lipids, erythrocytes were observed to be deformed and become more fragile. This deformity and fragility was partially reversed by the two dietary spice principles, curcumin and capsaicin, and the spice, garlic, by virtue of their ability to lower the extent of hypercholesterolaemia. A further insight into the factors that might have reduced the fluidity of erythrocytes in hypercholesterolaemic rats revealed changes in fatty acid profile of the membranes, phospholipid composition of the membrane bilayer, reduced Ca 2þ ,Mg 2þ -ATPase, and reduction in the sensitivity of erythrocytes to concanavaline A. Dietary capsaicin appeared to counter these changes partially in hypercholesterolaemic rats. Electron spin resonance (ESR) spectra and fluorescence anisotropy parameters also revealed altered fluidity of erythrocytes in hypercholesterolaemic rats. Dietary capsaicin and curcumin significantly reversed this alteration. Scanning electron microscopic examination revealed that the echinocyte population was increased in the erythrocytes of hypercholesterolaemic rats, and this was significantly countered by dietary capsaicin. The membrane protein profile and the active cation efflux appeared to be unaffected in the hypercholesterolaemic situation.
Animal studies were carried out to examine the beneficial influence of known hypolipidemic spice principles--curcumin, capsaicin, and garlic--on the antioxidant status of red blood cells and liver under induced hypercholesterolemic conditions. Groups of experimental rats rendered hypercholesterolemic were maintained on curcumin (0.2%)/capsaicin (0.015%)/garlic (2.0% dry powder)-containing diets for eight weeks. Erythrocytes isolated at the end of the study were analyzed for intracellular antioxidant molecules and antioxidant enzymes. Intracellular thiols and glutathione content in red blood cells were significantly depleted (by about 35%) in hypercholesterolemic rats. This depletion in intracellular thiols and glutathione was effectively countered by dietary spice principles - curcumin, capsaicin, and garlic. Glutathione reductase activity that was lowered in hypercholesterolemic conditions (by 25%) was completely countered by dietary spice principles and garlic. Activities of glutathione transferase, glutathione peroxidase, and catalase in erythrocytes remained unchanged under hypercholesterolemic conditions. Although hemoglobin levels of erythrocytes were not affected, methemoglobin concentration was significantly increased in hypercholesterolemic rats. This alteration was partially countered by dietary spice principles. Significant fall in hepatic total thiols in the hypercholesterolemic situation was partially corrected by dietary spice treatment. Similarly, the lowered activities of hepatic antioxidant enzymes--glutathione reductase, glutathione-S-transferase, catalase, and superoxide dismutase--in hypercholesterolemic rats were effectively countered by the dietary spices treatment.
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