Anthocyanins as antioxidants

LAPIDOT T, HAREL s, AKivi B, GRANITE R and KANNER J (1999) pH-dependent forms of red wine anthocyanins as antioxidants, JAgric Food Chem, 47, 67-70. 

Satue-Gracia MT, Heinonen M and Frankel EN. 1997. Anthocyanins as antioxidants on human low-density lipoprotein and lecithin-liposome systems. J Agric Food Chem 45 3362—3367. 

Anthocyanins and anthocyanidins, compounds present with high structural diversity in fruits and wines, showed a pattern as antioxidants different from that of the tea catechins with respect to the effect of substituents. In a liposomal model system induced peroxidation was inhibited increasingly by anthocyanins/ anthocyanidins with an increasing number of hydroxyl groups in the B-ring (Fig. 16.6), while the opposite was seen for the catechins (Seeram and Nair, 2002). For anthocyanidins, the presence of a 3-hydroxy group is important... 

Cyanidin is the most common anthocyanin in foods. In addition, anthocyanins are stabilized by the formation of complexes with other flavonoids (co-pigmentation). In the United States, the daily anthocyanin consumption is estimated at about 200 mg. Several promising studies have reported that consumption of anthocyanin-rich foods is associated with reductions of the risks of cancers - and atherosclerosis and with preventive effects against age-related neuronal and behavioral declines. These beneficial effects of anthocyanins might be related to their reported biological actions such as modulators of immune response and as antioxidants. Knowledge of anthocyanin bioavailability and metabolism is thus essential to better understand their positive health effects. 

Gould, K.S., McKelvie, J., and Markham, K.R., Do anthocyanins function as antioxidants in leaves Imaging of H2O2 in red and green leaves after mechanical injury. Plant Cell Environ., 25, 1261, 2002. 

Bohm, FI. et al., Flavonols, flavone and anthocyanins as natural antioxidants of food and their possible role in the prevention of chronic diseases, Z. Ernahrungsw., 37, 147, 1998. 

A major group of citrus compounds interacting with drugs are phenolics, which include hydroxycinnamic acids, flavonoids such as flavanones, fla-vones, and flavonols, and anthocyanins, as well as coumarins (Table 1, Fig. 1) (30). Many of these phenolic compounds have been shown to have antioxidant and anticancer properties that may play an important role in cancer prevention, but also in prevention of other chronic diseases such as coronary heart disease, gout, and arthritis (58 60). 

Anthocyanins are a class of flavonoids separated from proanthocyani-dins. Anthocyanins have been known to be highly protective and therapeutic against especially age-related diseases such as hypertension, cardiac infraction and cerebral infarction. Additionally, because the colors of anthocyanins could help to ease psychic and physical troubles or tiredness, the anthocyanins could not only relax us, but also the colors themselves could prevent and remedy many diseases, especially, age-related diseases such as hypertension, heart failure, stroke and diabetes. Generally, anthocyanins have antioxidant properties, which could protect and enhance our body systems with bioactive abilities such as the immuno-, anticancer-, antimicrobial potencies and others. 

The first chapter, Functionality of Anthocyanins as Alternative Medicine by Noboru Motohashi and Hiroshi Sakagami, presents their antioxidant mechanism for anthocyanidins, which are present in common foods. It is possible that anthocyanins may have been used both preventatively and clinically as part of many folklore medicines worldwide and may have provided healthcare benefits since the appearance of mankind some 7.5 million years ago. The review will inform the reader as to their functionality and mechanism. 

It is clear that under in vitro assay conditions, anthocyanins can function as antioxidants. However, in vivo, anthocyanin absorption appears to be low. In animal models, dietary anthocyanins at relatively high doses (1 to 2 mg/kg diet) are protective against oxidative stress induced in a number of models, including ischemia reperfusion, paraquat, CCL4, and t-BHP. In humans, anthocyanins appear to have some vasopro-tective effects, but whether these are the result of antioxidant mechanisms is not clear. It appears that in most of the studies reviewed, the dose of anthocyanins was well above that which might be normally consumed in the diet with natural foods, except for perhaps one study in which 1 cup of blueberries was consumed for 30 days and small increases in plasma antioxidant capacity were observed." ... 

Tsuda, T., Horio, F., and Osawa, T., The role of anthocyanins as an antioxidant under oxidative stress in rats. Biofactors, 13, 133-139, 2000. 

Compared with anthocyanins, the information available on stability of flavonols, flavanols and phenolic acids is limited. As these compounds until recently had only minor interests as food components, investigations were mostly performed for the purpose of biological screening and identification, less for studying stability during processing and storage. However, the mere definition of flavonoids and phenolic acids as antioxidants indicates that the compounds react easily and should be handled as unstable compounds. 

Research into food safety, both microbial and chemical food safety, has been accompanied by a parallel effort to identify, test, and optimize healthy constituents of foods. The interest in chemicals in foods extends beyond traditional areas - vitamins, essential minerals, etc. - to secondary chemicals sometimes termed phytonutrients or neutraceuticals which have positive health benefits including prevention or alleviation of diabetes, heart disease, Alzheimer s disease, cancer, arthritis, and many other diseases. Food producers use this information as a marketing tool. Compounds of interest include phenols/polyphenols, flavonoids, carotenoids, anthocyanins, and several other classes that function as antioxidants,... 

Like other flavonoids, anthocyanins are also expected to have antioxidant and antimutagenic properties in vivo, although only limited data are available. From the published data, it appears that anthocyanins can be effective in vivo as antioxidants when included in the diet at 1 or 2g/kg diet in animal experiments. These levels in the diet provide 20 to 40 mg per day, levels that are much higher on a body-weight basis than found in the typical diet of humans. " ... 

It is known that when vitamin C is mixed with anthocyanin as an antioxidant, the two substances form a condensation product. If vitamin C is present in various functional health foods, this quality deterioration is a problem. Furthermore, since vitamin C is highly soluble in water, it is impossible to stabilize it by CyD inclusion. However, a method of stabilizing vitamin C has been developed in which the antioxidant is included in a CyD to keep it remote from the vitamin C. In such cases, depending on the type of anthocyanin, either yS- or y-CyD is more effective. 

Clifford, M.N., Anthocyanins in foods. Presented at Symposium on Polyphenols and Anthocyanins as Food Colourants and Antioxidants, Pfannhauser, W. and Strigl, A., Eds., Wien, Austria, 1996, 1. 

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