Ellagic Acid's Properties
Ellagic Acid is a phenolic compound that has become a known as a potent anti-oxdiant compound. Ellagic acid itself is not thought to be naturally present in plants. Instead, polymers of gallic acid and hexahydroxydipenoyl (HHDP) are linked to glucose centers to form the class of compounds known as ellagitannins. When two gallic acid groups become linked side-by-side within a tannin molecule and HHDP group is formed.
Ellagic acid is the result when the HHDP group is cleaved from the tannin molecule and spontaneously rearranges. It is the ellagitannins that are present in red raspberries. Some articles in which ellagitannins are quantified refer to ellagic acid because quantitation of ellagitannins is done by breaking them down into ellagic acid subunits and quantifying the subunits.
The Meeker red raspberry is the best source of ellagic acid followed by Chilliwack and Willamette. The Meeker variety is specific to the Pacific Northwest---grown primarily for commercial use in Washington State.
The Chilliwack and Willamette varieties contain lesser variations of ellagic acid. Both of these varieties are grown in the Pacific Northwest and may be found in lesser volumes outside the United States. Ellagic acid (micrograms/gram dry weight.