Dietary Phenolic Compounds and Their Effects on Cholesterol and Tocopherol Levels in Our Body

摘要

Phenolic compounds are abundant in our diets and are involved in the antioxidant defense mechanisms in our body. Dietary phenolic compounds have different biological functions related to their effects as free radical scavengers and their variable effects on metabolic enzymes. This lecture will review literature evidence for interaction between dietary phenolic compounds and presents some of our results on their effects on two lipid parameters on significant relevance to coronary heart disease, i.e. cholesterol and alpha- and gamma-tocopherols. Research have shown that many phenolic compounds (e.g. sesamin, curcumin, tocotrienols) reduce cholesterol levels in experimental animals and in humans. Our results showed that while sesamin and curcumin (added at 2 or 4 g/kg diet) significantly lowered plasma total cholesterol in rats, other phenolic compounds (namely BHT, caffeic acid and chlorogenic acid) tended to increase plasma total and LDL-cholesterol. In rats, sesamin increased plasma gamma-tocopherol ca 9-fold without effects on alpha-tocopherol while BHT and beta-catechin increased alpha-tocopherol levels 2-3 fold without effects on gamma-tocopherol levels. These variable effects on tocopherol and cholesterol levels in rats may be due to interference of phenolic compounds with transport and/or metabolism of lipid components of importance to coronary heart disease.