Anthocyanins and anthocyanin-rich extracts: role in diabetes and eye function.

Anthocyanins are the largest group of water-soluble pigments in the plant kingdom, known collectively as flavonoids. More than 8000 flavonoids, and 500 anthocyanin structures had been reported by the year 2000 and more are continually being isolated. Anthocyanins are believed to display an array of beneficial actions on human health and well-being. Due to our increasing understanding and awareness of the potential beneficial human health effects, research on anthocyanins has recently intensified. During the past two decades an increasing number of studies have investigated the diverse protective effects elicited by polyphenolics present in various fruits and vegetables. These effects include antioxidant, anti-allergic, anti-inflammatory, anti-viral, antiproliferative, anti-mutagenic, anti-microbial, anti-carcinogenic, protection from cardiovascular damage and allergy, microcirculation improvement, peripheral capillary fragility prevention, diabetes prevention, and vision improvement. Other physiological effects are continually being investigated. The aim of the present article is to summarise the known anti-diabetic and eye function properties of anthocyanins to help in our understanding of their functional mechanism.