Dietary ellagitannins

Ellagitannins (ETs) are widely distributed secondary metabolites classified as hydrolyzable tannins found mainly in berries such as raspberries, blueberries (BBs), black raspberries (BRBs), strawberries, and pomegranates. A plethora of reports tend to show that ETs can impact positively on human health by promoting therapeutic activities such as being an antioxidant, antimicrobial, antiinflammatory, and anticancer. Studies showed that ETs found in the seeds of black raspberries (BRBs) increase the functional activity of juices or wines which used BRBs as ingredients. It has been reported that berries have the potential to reduce the systolic and diastolic blood pressure and increase superoxide dismutase activity after the consumption of BBs. Numerous studies showed that ETs isolated from pomegranates possess good antimicrobial activities against a panel of microbes including human pathogens such as Escherichia coli, Salmonella enteritidis, Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Yersinia enterocolitica, Listeria monocytogenes, and Candida albicans. Interestingly, it was shown that these therapeutic values are attributed to the presence of ETs. Furthermore, ETs are also distributed in various nuts, namely, pecans, cashews, walnuts, pistachios, or hazelnuts. It is known clinically that frequent nut intake is associated with protective effects against cardiovascular diseases. Although it is mentioned that ETs can also be found in vegetables, however as far as our literature search could establish, there are no scientific validation of ETs in vegetables. Thus, it is proposed that more scientific investigations be geared to shed light on the potential of ETs found in vegetables. Overall, foods containing ETs are recommended to be consumed on a regular basis since a panoply of scientific investigations showed that they are associated with promising health benefits.