MbShea@PWP@English@UMCP

Abstract:
Plants have long synthesized antimicrobial compounds as a mechanism of defense against bacterial attacks. These compounds offer an alternative to conventional antibiotics, especially in the livestock industry where antibiotics are often overfed to animals in an effort to prevent zoonotic infections. This study investigates the phenolic compounds derived from Olea europaea, as they have been shown to confer a variety of human health benefits in addition to their antimicrobial properties. Four olive phenols are used: oleuropein and hydroxytyrosol, the major phenolic compounds in olives, maslinic acid, a byproduct of olive oil extraction, and oleanolic acid, found in the leaves and fruits of olives. While oleuropein and hydroxytyrosol have been shown to exhibit antimicrobial activity against both ATTC and clinical bacterial strains, the antimicrobial properties of maslinic and oleanolic acid are less well known. This study aims to determine the effect these four compounds have on the growth and pathogenicity of two zoonotic pathogens: enterohemorrhagic E. coli (EHEC) and Salmonella enterica serovar Typhimurium (ST), as well as the growth of three probiotics: Lactobacillus casei, Lactobacillus rhamnosus, and Lactobacillus plantarum. In addition, mixed cultures of L. rhamnosus and pathogens will be cultivated with olive compounds to determine if the presence of the phenols enhances the inhibition effect of L. rhamnosus on the pathogens. Predicted results would show that the olive compounds do inhibit growth of the two pathogens while having a lesser effect on Lactobacillus, thus resulting in their ability to supplement the inhibitory effect of L. rhamnosus.

WC: 246

Reader’s Profile: I imagine a reader who does not believe that olive phenols will be able to produce enough of an antimicrobial effect such that they can be used for industrial applications.

Reader’s Response: There is such a wide variety of natural plant extracts that have been shown to exhibit antimicrobial effects, so why study those found in olives? In particular, if used as an alternative to conventional antibiotics, would the effects of these phenols actually provide a feasible barrier against pathogen invasions? I am worried that large or very concentrated quantities of phenols are needed such that it no longer is viable to extract them. While these compounds have been tested in laboratory settings, what about other environments, such as livestock farms and in the gastrointestinal tract of animals? There is a distinct possibility that olive phenols lose their potency when in a more dynamic environment. Your research is enlightening, but I do not see how olive phenols can ever replace conventional antibiotics.

C -- looking forward to this. Any possible concerns about toxicity of these polyphenols at concentrated doses for people? Any rat live studies on this line of inquiry? (Just wondering....)