Cranberries antioxidant activity

Flavonoids are present in other beverages besides wine and tea. For example, pomegranate and cranberry juice contain high concentrations of polyphenols and a strong antioxidant activity against LDL oxidation. Their antioxidant capacity depends not only on the amount but also on the type of flavonoids present (Aviram and Fuhrman 2003). 

Gunes, G. Liu, R. H. Watkins, C. B. Controlled-Atmosphere Effects on Postharvest Quality and Antioxidant Activity of Cranberry bruits. J. Agric. Food Chem. 2002, 50, 5932-5938. 

Vattem DA, Shetty K. EUagic acid production and phenolic antioxidant activity in cranberry pomace Vaccinium macrocarpon) mediated by Lentinus edodes using a solid-state system. Process Biochem 2003 39 367-79. 

The beneficial health eflfects attributed to the consumption of fruits and vegetables are related at least in part to their antioxidant activity. Of special interest is the inverse relationship between intake of dietary nutrients rich in flavonoids and cardiovascular diseases. This elfect is attributed to the flavo-noids capability to inhibit LDL oxidation, macrophage foam cell formation, and atherosclerosis. Fig. 7 summarizes some of our studies of total polyphenol concentration in several fmit juices or wines and the capacity of the juices, when compared on a similar total polyphenol concentration basis, to inhibit LDL oxidation. Pomegranate juice, red wine, and cranberry juice contained the... 

Fractionation, Antioxidant Activity, and Cytotoxicity of Cranberry Fruit Extracts... 

Cranberries (Vaccinium macrocarpon) are potentially an excellent dietary source of phenolic confounds such as flavonoids, anthocyanins and caffeic acid derivatives which are potent antioxidants. Studies also link a lowered incidence of breast cancer to cranberry juice consumption. In this study, cranberry fruits were fractionated by several methods and tested for radical-scavenging activity in an effort to begin establishing a link between chemical composition and antioxidant activity. The strongest activity was observed in flavonoid-rich extracts. Cytotoxicity assays in several tumor cell lines showed some specificity for HT-29 tumor cells and K562 cells from a methanolic cranberry extract containing several phenolic compounds. 

Table I shows the results of a DPPH radical-scavenging assay on each of the whole-cranberry extracts prepared by Mediods 1 and 2. For whole cranberries, the highest antioxidant activity was observed in ethyl acetate extracts prepared by both methods, with an IC50 value of 0.033 mg/mL for the ethyl acetate extract prepared by Method 2. The ethyl acetate fraction was about twice as effective at radical scavenging as the whole-berry extract (IC50 = 0.078 mg/mL). Kinetics of these reactions were slow compared to the standard. Vitamin E for all cranberry extracts, radical scavenging occurred over a period of approximately one hour as compared to several minutes for vitamin E.

Table I. Comparative antioxidant activities of extracts of whole cranberries measured by a DPPH radical-scavenging assay...

The conq)arative antioxidant activities of extracts from the peels, solids and juice are shown in Table V. Table VI shows the con5>osition of different anthocyanins in cranberry. Cyanidin and peonidin were the principal anthocyanins present in all parts including juice each existed in two main glycosidic forms. Two glycosides of a third anthocyanin, petunidin, were found only in the peels which accoimted for about 14% of the total anthocyanin content in cranberry peels. 

Table II. Contribution of Important Phenolic Acids and Flavones to Antioxidant Activity in Blackberries (Chester thornless), Blueberries (Sierra), Chokeberries (Wild), Cranberries (Ben Lear), Lingonberries (Amber land). Black...

Vattem, D.A., Lin, Y.T. Labbe, R.G., and Shetty, K. 2003. Antimicrobial activity against select food-home pathogens by phenoUc antioxidants enriched in cranberry pomace by solid-state bioprocessing using the food grade fungus Rhizopus oligosporus Process Biochem 39 1939-1946. 

The DPPH assay (5) was used to evaluate the free-radical-scavenging capacity of extracts prepared by the methods outlined above, whole berry extract and commercial cranberry juice cocktail (Ocean Spray Inc.). Activity was compared to that of a standard antioxidant (Vitamin E, Aldrich Chemical Co.) measured using the same methods. Varying concentrations of cranberry extracts were mixed with a 60 pM solution of DPPH in methanol. Quenching of the violet DPPH radical was observed as a decrease in absorbance at 515 nm over one hour. EC50 values are measured as the sample concentration required to decrease DPPH absorption by 50%. Results are shown in Table I. The DPPH assay was also used to evaluate the extracts of peel, solids and juice EC50 values are reported in Table V. 

Further studies will address the structures of the major bioactive con )onents of the antioxidant and cytotoxic cranberry extracts, their compositions in extracts from peel, solids and juice, and their specific molecular and radical targets of activity. 

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