Effect of Feeding of Leaf Proteins on Serum Cholesterol Concentration in Rats

Abstract

Leaf proteins (LPs) were prepared by heating the green juice from Italian ryegrass and alfalfa at 80-85°C and were compared with casein and soybean protein isolate for their hypocholesterolemic action in Wistar male rats. Each protein source was incorporated into a cholesterol-free, low-fat diet to provide a protein level of 20%. The values of serum total and LDL-cholesterol in rats fed Italian ryegrass and alfalfa LPs were significantly lower than those of rats fed casein and were comparable to those of rats fed soybean protein. p-Coumaric, ferulic and caffeic acids and coumestrol, which were presumed to be contaminants in LPs, had no lowering effect on serum total and LDL-cholesterol. In addition, it was shown that the ratios of Arg/Lys and Met+Cys/Gly of both the LPs were very close to those of soybean protein. These data suggest that both of the LPs tested appear to function in a similar way to soybean protein in their hypocholesterolemic action.