Cinnamon for Metabolic Diseases and Their Cardiovascular and Hepatic Complications: A Mechanistic Review

Cinnamon is one of the world's oldest and most popular spices, and is derived from the inner bark of several tree species from the genus Cinnamomum. During the last two decades, cinnamon has demonstrated beneficial metabolic effects not only in animal experiments but also in clinical trials. Even recent meta-analyses have shown the protective effects of cinnamon on different components of metabolic syndrome and their complications. In the last 5 years, several experimental studies have unraveled the intricate molecular mechanisms underlying the antihypertensive, antihyperglycemic, lipid-lowering, weight-lowering, and cardioprotective properties of cinnamon. This review paper will discuss how cinnamon and its active components, particularly cinnamaldehyde, suppress inflammation and oxidative stress, modulate mitochondrial dysfunction, and regulate glucose uptake, insulin resistance, lipogenesis, beta-oxidation, Ca2+ signaling, and other cellar events at the molecular level. Specifically, we will delve into the molecular mechanisms involved in the metabolic effects of cinnamon to provide a deeper insight into how cinnamon can bring such beneficial effects. This review hopes to encourage the use of cinnamon in clinical settings, guide the combination of cinnamon with other drugs used to treat different components of metabolic syndrome based on their mechanism of action, and support the concept of complementary medicine for metabolic diseases.