Influence of dietary spices on the fluidity of erythrocytes in hypercholesterolaemic rats

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 Ca2+,Mg2+-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.