Procyanidins are available in the diet from sources such as cocoa and grapes.
Procyanidins are unique in that they are comprised of repeating monomeric units and can exist in various degrees of polymerization. The degree of polymerization plays a role in determining the
biological activities of
procyanidins. However, generalizations cannot be made regarding the correlation between
procyanidin structure and bioactivity because the size-activity relationship appears to be system dependent. Our aim was to screen fractions of
procyanidins with differing degrees of polymerization in vitro for anti-inflammatory activities in models of colonic
inflammation. Monomeric, oligomeric and polymeric cocoa
procyanidin fractions were screened using cell models of disrupted membrane integrity and
inflammation in human colon cells. High-molecular-weight polymeric
procyanidins were the most effective at preserving membrane integrity and reducing secretion of
interleukin-8 in response to inflammatory stimuli. Conversely, oligomeric
procyanidins appeared to be the least effective. These results suggest that polymeric cocoa
procyanidins may be the most effective for preventing loss of gut barrier function and epithelial
inflammation, which are critical steps in the pathogenesis of metabolic
endotoxemia,
inflammatory bowel disease and
colon cancer. Therefore, further investigations of the potential health-protective benefits of cocoa
procyanidins with distinct degrees of polymerization, particularly high-molecular-weight
procyanidins, are warranted.