Current knowledge of anthocyanin metabolism in the digestive tract: absorption, distribution, degradation, and interconversion

Abstract

Potential roles for anthocyanins in preventing various chronic diseases have been reported. These compounds are highly sensitive to external conditions and are susceptible to degradation, which increases the complexity of their metabolism in vivo. This review discusses anthocyanin metabolism in the digestive tract, phase I and II metabolism, and enterohepatic circulation (EHC), as well as their distribution of anthocyanins in blood, urine, and several organs. In the oral cavity, anthocyanins are partly hydrolyzed by microbiota into aglycones which are then conjugated by glucuronidase. In stomach, anthocyanins are absorbed without deglycosylation via specific transporters, such as sodium-dependent glucose co-transporter 1 and facilitative glucose transporters 1, while in small intestine, they are mainly absorbed as aglycones. High polymeric anthocyanins are easily degraded into low-polymeric forms or smaller phenolic acids by colonic microbiota, which improves their absorption. Anthocyanins and their derivatives are modified by phase I and II metabolic enzymes in cells and are released into the blood via the gastrovascular cavity into EHC. Notably, interconversion can be occurred under the action of enzymes such as catechol-O-methyltransferase. Taking together, differences in anthocyanin absorption, distribution, metabolism, and excretion largely depend on their glycoside and aglycone structures.

Keywords:

• Anthocyanins
• metabolism
• absorption
• distribution
• interconversion

Acknowledgments

We are grateful to Dr. Jian Dai for her valuable comments and careful examination on this manuscript.

Author’s contributions

Hailong Gui contributed to writing – original draft, Lijun Sun contributed to writing – original draft, Ruihai Liu contributed to conceptualization, Xu Si contributed to editing, Qiao Jiang contributed to editing and supervision, Yanyan Qiao contributed to grammar, Bin Li contributed to conceptualization, funding acquisition, and writing – review and editing, and Jinlong Tian contributed to writing – review and editing.

Disclosure statement

The authors declare no conflicts of interest.

Funding

This work was supported by the National Natural Science Foundation of China (U21A20273), China Agriculture Research System of MOF and MARA (CARS-29), and the First Batch of Liaoning “Unveiling Leader” Scientific and Technological Projects (2021JH1/10400036).