A new method of standartization of health-promoting pomegranate fruit (Punica granatum) extract

This study analyzes the major phenolic constituents of pomegranate fruit juice and pericarp feedstock, and dry extracts thereof, using high-performance liquid chromatography. Pomegranate pericarp was extracted with water (WE) and alcohol (AE) as solvents, and liquid extracts were subsequently freeze-dried. The results indicate that ellagitannins punicalagin A and punicalagin B are the major constituents in the primary pomegranate feedstock and in both types of extracts. Ellagic acid, a common botanical constituent that is currently used to standardize pomegranate extracts, as well as ellagitannin punicalin, were found to be only minor constituents. Total punicalagins (the sum of punicalagins A+B and punicalin) and ellagic acid content in the pomegranate fruit pericarp feedstock WE were 7,6+/-0,3% and 0,2+/-0,1% by dry weight, respectively, and in the AE feedstock 7,0+/-0,2 and 0,4+/-0,1%, respectively. Total phenolic content (the sum of punicalagins and ellagic acid) in the pomegranate WE and AE were 45,8+/-1,2% and 42,3+/-1,1%, respectively. The concentrations of ellagic acid in the pomegranate WE and AE were 0,8+/-0,2% and 3,9+/-0,2%, respectively. Total phenolics in fresh single-strength pomegranate whole fruit juice contained 2,216+/-70 mg/L (95% punicalagins), whereas commercial pomegranate juice that was purchased from local stores was 317+/-13 mg/L (70% punicalagins). Our results strongly suggest that the commercially produced pomegranate extracts should be standardized to the content of total punicalagins as well as ellagic acid. The current standard uses only ellagic acid, which is unreliable, potentially misleading and vulnerable to commercial adulteration.