Chapter 158 - Effects of Oleanolic Acid and Maslinic Acid on Glucose and Lipid Metabolism: Implications for the Beneficial Effects of Olive Oil on Health

Abstract

There is firm evidence supporting the beneficial effects of olive oil consumption. The beneficial effects on atherosclerosis and plasma lipids are well recognized and are generally ascribed to monounsaturated fats or phenols. However, olives contain many other bioactive compounds including the pentacyclic triterpenes (PT) maslinic acid and oleanolic acid. Unfortunately, when olive oil is produced most of these substances are lost in the residual waste. Although only present in small amounts and less well understood, the role of these compounds in the beneficial effects of olive oil may be more significant than previously recognized. Plants containing pentacyclic triterpenes are widely distributed throughout the world. China and other Asian countries have a long history of using plants containing pentacyclic triterpenes (PT) as herbal remedies to cure diseases and treat symptoms. The antineoplastic effects of the higher doses may be more relevant to the medicinal use of PT in some Asian countries than the consumption of olive oil in the Mediterranean diet. This chapter reviews the available literature on the biological effects of maslinic acid and oleanolic acid but focuses on their roles in glucose and lipid metabolism. The mechanisms of action of PT and potential molecular targets for their hypoglycemic and lipid-lowering effects including glycogen phosphorylase (GP) and acyl-CoA cholesterol acyltransferase (ACAT) are also reviewed.