Biological and pharmacological effects of hexahydrocurcumin, a metabolite of curcumin

Curcumin, one of the most precious pharmacologically relevant natural products, has gained considerable attention among scientists for decades because of its multi-pharmacological activities in the clinical. However, critical studies on its pharmacological and toxicological activities are needed to understand how this compound can have these biological functions considering its poor oral bioavailability and the low plasma concentration. Moreover, curcumin undergoes extensive and rapid metabolism in vivo, indicating that the pharmacological activity of consuming curcumin might be mediated partly by its metabolites. And as one of the major curcumin metabolites, hexahydrocurcumin (HHC), exhibits similar or more potent bioactivity than curcumin by in vitro and in vivo studies, such as antioxidant, anti-inflammatory, antitumor and cardiovascular protective properties, which may provide important information for us to have a profound comprehension of the effectiveness of curcumin. This review mainly summarizes the current knowledge and underlying molecular mechanisms of the biological activities of HHC and its potential effects on the development of various human diseases.