Cyanidins: metabolism and biological properties.

Cyanidin and its glycosides belong to the anthocyanins, a widespread class of water-soluble plant compounds that are responsible for the brilliant color (red, orange, blue) of fruits and flowers. They are widely ingested by humans as it has been estimated a daily intake around 180 mg, mainly deriving from fruits and red wines. This paper reviews the literature on the biological activities, absorption and metabolism of cyanidins, with emphasis to the antioxidant, antimutagenic and other protective activities ascribed to these compounds. Their role in contrasting development of cancer and other pathologies is also reviewed. It is concluded that a great deal of work is still necessary to i) definitively clarify the metabolism of cyanidins in human beings; ii) assess the dietary burden and variations within and between populations; iii) evaluate the relationship between cyanidin glycosides-rich food consumption and incidence of given pathologies. The amount of work to be performed is even more significant when considering a possible therapeutic use of cyanidin glycosides-based drugs. With this aim, information on absorption, distribution, metabolism and excretion of cyanidin-glycosides administered by main possible routes are largely insufficient. However, consisting findings allow looking at cyanidins as dietary compounds with a potential beneficial role for human health.