Metabolic pathways of cinnamic acid derivatives in Brazilian green propolis in rats

Cinnamic acid derivatives, which are dietary phenolic compounds, are attracting attention for their health benefits. Artepillin C, drupanin, baccharin, and p-coumaric acid are major cinnamic acid derivatives in Brazilian green propolis (BGP) used as functional food materials. To investigate the metabolism of these cinnamic acid derivatives, each compound was administered to rats, and their metabolic profiles were compared with those administered BGP. Artepillin C metabolized to hydroxylated metabolites (capillartemisin A), as well as glucuronide. Drupanin sulfate, glucuronide, and hydroxylated form were detected in plasma both after ingestion of drupanin and its 3-phenylpropionic acid ester (baccharin). p-Coumaric acid underwent sulfation, but not glucuronidation. These results reveal that the metabolic pathways of cinnamic acid derivatives in rats comprise ester hydrolysis and hydroxylation, as well as phase-II conjugation. Our findings may provide significant information for estimating the potential activity of various cinnamic acid derivatives derived from functional food materials.