Effects of cacao lignin on blood pressure and lipid metabolism in spontaneously hypertensive rats

Lignin is a kind of insoluble dietary fiber. Cacao contains about 10% lignin, but effect of cacao lignin is not studied. We prepared cacao lignins from defatted cocoa powder by two methods Klason lignin (KL) was prepared by the Klason method with concentrated H2SO4 Alkali soluble lignin (ASL) was extracted with 1% NaOH solution. Their effects on blood pressure and lipid metabolism were studied in spontaneously hypertensive rats (SHR). Adult male SHR were kept on a diet of semipurified feed containing 1% NaCl and 2% KL, ASL, or cholestyramine (CL) for 19 days. The mean blood pressure of the control increased. The mean blood pressure of groups fed KL, ASL, or CL was significantly lower than that of the controls on days 10 and 15 of the diet. The plasma Na/K ratio of groups fed KL, ASL, or CL was lower than in the control group at day 15. There were no significant differences in the mineral balance of cations. Fecal excretion of Na was increased in groups fed KL, ASL, or CL compared with the control group, and fecal excretion of K was increased in the KL group compared with the control group. Fecal excretion of Ca and Mg did not increase in the KL, ASL, or CL groups compared with the control group. The plasma level of total cholesterol in the KL group was significantly lower than that of the control groups at days 7 and 15. The ability of lignins to adsorb bile acids depended on the pH in vitro, on the other hand the ability of CL to adsorb bile acids did not depend on the pH. These results suggest that cacao lignins may suppress lncreases in blood pressure and plasma levels of total cholesterol.