Absorption and Metabolism of Components in Brazilian Green Propolis

Abstract

Propolis, a bee product, has antibacterial and antioxidant properties and has been used in folk medicine since ancient times. Brazilian green propolis (BGP), produced in southeastern Brazil, has been reported to demonstrate numerous biological activities in clinical studies. BGP characteristically contains cinnamic acid derivatives such as artepillin C and drupanin. Although these compounds are expected to be active components of BGP, there have been few reports on their pharmacokinetics and metabolism in vivo. We have investigated the blood absorption and metabolism of BGP components after BGP administration in humans and rats, and found that the plasma concentration of total artepillin C, the major component of BGP, was lower than that of total drupanin, which was present at a lower level. Furthermore, it was shown that both the native forms and their hydroxylated metabolites were detected in plasma as their conjugated and unconjugated forms, indicating that their metabolic conversion affected their apparent absorption efficiency. Based on our studies, this review focuses on the pharmacokinetics and metabolism of BGP components, particularly cinnamic acid derivatives, and outlines the prospects for bioavailability studies that will contribute to a better understanding of the functional mechanisms of BGP.