The Olive Compound 4‐Hydroxytyrosol Inactivates Staphylococcus aureus Bacteria and Staphylococcal Enterotoxin A (SEA)

Abstract

The foodborne pathogen Staphylococcus aureus produces the virulent staphylococcal enterotoxin A (SEA), a single chain protein which consists of 233 amino acid residues with a molecular weight of 27078 Da. SEA is a superantigen that is reported to contribute to animal (mastitis) and human (emesis, diarrhea, atopic dermatitis, arthritis, and toxic shock) syndromes. Changes in the native structural integrity may inactivate the toxin by preventing molecular interaction with cell membrane receptor sites of their host cells. In the present study, we evaluated the ability of the pure olive compound 4-hydroxytyrosol and a commercial olive powder called Hidrox-12, prepared by freeze-drying olive juice, to inhibit S. aureus bacteria and SEA's biological activity. Dilutions of both test substances inactivated the pathogens. Two independent cell assays (BrdU incorporation into newly synthesized DNA and glycyl-phenylalanyl-aminofluorocoumarin proteolysis) demonstrated that the olive compound 4-hydroxytyrosol also inactivated the biological activity of SEA at concentrations that were not toxic to the spleen cells. However, efforts to determine inhibition of the toxin by Hidrox-12 were not successful because the olive powder was cytotoxic to the spleen cells at concentrations found to be effective against the bacteria. The results suggest that food-compatible and safe antitoxin olive compounds can be used to inactivate both pathogens and toxins produced by the pathogens. Practical Application: The results of this study suggest that food-compatible and safe antitoxin olive compounds can be used to reduce both pathogens and toxins produced by the pathogens in foods.

Combating Pathogenic Microorganisms Using Plant-Derived Antimicrobials: A Minireview of the Mechanistic Basis

“…Transcriptional analysis conducted by these researchers revealed a reduction in the expression of critical virulence genes ( sea, seb, tst, and hla ) involved in various aspects of S. aureus toxin production. Similarly, a compound from olive, 4-hydroxytyrosol, was found to successfully inactivate S. aureus endotoxin production in vitro [179]. …”

Low Levels of Aflatoxin B1, Ricin, and Milk Enhance Recombinant Protein Production in Mammalian Cells

“…In a previous study, we have demonstrated that adding low concentrations of the olive compound 4-hydroxytyrosol or the commercial olive powder isolated from olive juice called Hidrox-12 enhanced the growth of the bacterial pathogen Staphylococcus aureus [6]. By contrast, higher concentrations of these natural products were bactericidal against the pathogen.…”

3,4-DHPEA-EA from Olea Europaea L. is effective against standard and clinical isolates of Staphylococcus sp

“…Another investigation on the antimicrobial effect of an olive leaf extract showed that Bacillus subtilis was less susceptible than E. coli , Pseudomonas aeruginosa , Klebsiella pneumoniae and S. aureus [25]. A commercial olive powder and 4-hydroxytyrosol were able to inactivate S. aureus and its enterotoxin A, secreted by the bacteria in 78% of the outbreaks [26]. Although no reports have identified the possible mechanisms of action of the phenolic compounds present in olive leaf, some authors report the activity of phenolics on Gram-positive bacteria may be due to the cell wall or cell membrane disruption together with cell enlargement, which is more susceptible compared to Gram-negative strains [27].…”