Author
Prior, Ronald | |
WU, XIANLI - ACNC/UAMS |
Submitted to: Encyclopedia of Dietary Supplements
Publication Type: Book / Chapter Publication Acceptance Date: 10/15/2004 Publication Date: 12/10/2004 Citation: Prior, R.L., Wu, X. 2004. Anthocyanins. In: Coates, P., Coates, P.M., editors. Encyclopedia of Dietary Supplements. New York, NY: Marcel Dekker. p 840-849. Interpretive Summary: Anthocyanins are water soluble plant secondary metabolites responsible for the blue, purple, and red color of many plant tissues. Over 600 naturally occurring anthocyanins with various sugar attached have been reported and they are known to vary in complexity in their chemical structure. Anthocyanins have an important function in plant physiology. They are believed to play a major role in both pollination and seed dispersal. Because of their intense color, anthocyanins are also regarded as potential candidates for natural colorants in the food industry. However, recently, increased attention has been focused on their possible health effects. Anthocyanins have been shown to be strong antioxidants, and may exert a wide range of health benefits through antioxidant or other mechanisms. Of the various classes of flavonoids, the potential dietary intake of anthocyanins is perhaps the greatest (100+ mg/day). The concentrations as well as the specific anthocyanins vary considerable among different fruits and berries. Information is limited as to possible metabolites of anthocyanins in the human. Anthocyanins have been shown to provide protection against various forms of oxidative stress. Technical Abstract: Anthocyanins are water soluble plant secondary metabolites responsible for the blue, purple, and red color of many plant tissues. They occur primarily as glycosides of their respective anthocyanidin with a sugar moiety attached at the 3-position on the C-ring. Glucose, galactose, arabinose, rhamnose and xylose are the most common sugars that are bonded to anthocyanidins as mono-, di- or trisaccharide forms. Aglycones are rarely found in fresh plant materials. There are about seventeen anthocyanidins found in nature, whereas only six of them, cyanidin, delphinidin, petunidin, peonidin, pelargonidin, and malvidin are ubiquitously distributed. The differences in chemical structure of these six common anthocyanidins occur at the 3' and 5' positions of the B-ring. The sugar moieties may also be acylated by a range of aromatic or aliphatic acids. Common acylating agents are cinnamic acids. Over 600 naturally occurring anthocyanins have been reported and they are known to vary in: 1) the number and position of hydroxyl and methoxyl groups on the basic anthocyanidin skeleton; 2) the identity, number and positions at which sugars are attached; and, 3) the extent of sugar acylation and the identity of the acylating agent. Anthocyanins have an important function in plant physiology. They are believed to play a major role in both pollination and seed dispersal. Because of their intense color, anthocyanins are also regarded as potential candidates for natural colorants in the food industry. However, recently, increased attention has been focused on their possible health effects. Anthocyanins have been shown to be strong antioxidants, and may exert a wide range of health benefits through antioxidant or other mechanisms. Of the various classes of flavonoids, the potential dietary intake of anthocyanins is perhaps the greatest (100+ mg/day). The content in fruits varies considerably between 0.25 to 700 mg/100 g fresh weight. Not only does the concentration vary, but the specific anthocyanins present in foods are also quite different. Anthocyanins are absorbed intact without cleavage of the sugar to form the aglycones. The proportion of the dose that appears in the urine is quite small (<0.1 % of dose). Plasma levels of anthocyanins are in the range of 1-120 nM following a meal high in anthocyanins, but fasting plasma levels are generally non-detectable. Information is limited as to possible metabolites of anthocyanins in the human. Anthocyanins have been shown to provide protection against various forms of oxidative stress in animal models. |