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 with BGP. Artepillin C is 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.

Pharmacokinetics and metabolism of cinnamic acid derivatives and flavonoids after oral administration of Brazilian green propolis in humans.

Brazilian green propolis (BGP) has chemical compounds from botanical origin that are mainly cinnamic acid derivatives (artepillin C, baccharin, and drupanin) and flavonoids (kaempferide and 6-methoxykaempferide). These compounds are expected to play an important role in the pharmacological activities of BGP. However, there is little known about the pharmacokinetics and metabolism of these compounds after oral administration of BGP. The aim of this study is to investigate the pharmacokinetics and metabolism of BGP components in humans. Twelve volunteers received 3 capsules containing 360 mg of BGP ethanol extract powder. Plasma samples were collected before and up to 24 h after the intake of BGP capsules. The collected plasma samples with or without hydrolysis by the deconjugating enzyme were analyzed by LC/MS/MS. After enzymatic hydrolysis, the Cmax values of artepillin C and drupanin, which were detected mainly in plasma after ingestion of BGP capsules, were 1255 ± 517 and 2893 ± 711 nM, respectively, of which 89.3% and 88.2% were found to be the phenolic glucuronide conjugate. This is the first time that the pharmacokinetics of the BGP components of human metabolites have been reported. Our results could provide useful information for the design and interpretation of studies to investigate the mechanisms and pharmacological effects of BGP.