Bioavailability and Metabolism of Ellagic Acid and Ellagitannins - Chemistry and Biology of Ellagitannins - page 275

ellagic acid upon hydrolysis, although other metabolites can also be
produced and are distinctive of individual ellagitannins ( i.e. , gallagic and
tergallagic acids) (Porter, 1989).

7.3 Do Ellagitannins and Ellagic Acid Show Biological Activity?

ET-rich foods exhibit, in general, high in vitro free-radical scavenging
activity . Of special interest is the antioxidant activity of pomegranate
juice (Gil et al. , 2000). In this study, it was shown that pomegranate juice
has twice the antioxidant activity of red wine and it was attributed to the
ETs extracted from the fruit husk during juice manufacturing (Gil et al. ,
2000). This remarkable activity has been the driving force for research
looking at the biological activity of these powerful antioxidants in
pomegranate and is used by food manufacturers to market pomegranate
juice products as super-antioxidant foods. ETs are also responsible for a
significant part of the antioxidant activity observed in strawberries
(Hannun, 2004), raspberries (Zafrilla et al. , 2001), blackberries, walnuts
(Blomhoff et al. , 2006) and pecans (Villarreal-Lozoya et al. , 2007). This
antioxidant activity may be related to the biological activity reported for
these food products.

Table 7.1 Ellagitannins content in various food products.

Food Content Reference

Pomegranate juice 1500-1900 mg/L Gil et al ., 2000

Raspberries 263-330 mg/100 g f.w. Koponen et al. , 2007

Raspberry jam 76 mg/100 g f.w. Koponen et al. , 2007

Strawberries 77-85 mg/100 g f.w. Koponen et al. , 2007

Strawberry 25 mg/100 g f.w. Abby et al. , 2007

Strawberry jam 24 mg/100 g f.w. Koponen et al. , 2007

Cloudberry 315 mg/ 100 g f.w. Koponen et al. , 2007

Blackberry 1.5-2.0 mg/g d.w. Clifford and Scalbert, 2000

Muscadine grape juice 8-84 mg/L Lee et al. , 2002

Muscadine grape wine 2-65 mg/L Lee et al. , 2002

Walnut 802 mg / 50g (8 nuts) Anderson et al. , 2001

Whiskey 1-2 mg/L Glabasnia and Hofmann, 2006

Cognac 31-55 mg/L Clifford and Scalbert, 2000

Oak aged red wine 9.4 mg/L Glabasnia and Hofmann, 2006

Oak aged red wine 50 mg/L Clifford and Scalbert, 2000