Plant-Derived Polyphenols Interact with Staphylococcal Enterotoxin A and Inhibit Toxin Activity

Abstract

This study was performed to investigate the inhibitory effects of 16 different plant-derived polyphenols on the toxicity of staphylococcal enterotoxin A (SEA). Plant-derived polyphenols were incubated with the cultured Staphylococcus aureus C-29 to investigate the effects of these samples on SEA produced from C-29 using Western blot analysis. Twelve polyphenols (0.1–0.5 mg/mL) inhibited the interaction between the anti-SEA antibody and SEA. We examined whether the polyphenols could directly interact with SEA after incubation of these test samples with SEA. As a result, 8 polyphenols (0.25 mg/mL) significantly decreased SEA protein levels. In addition, the polyphenols that interacted with SEA inactivated the toxin activity of splenocyte proliferation induced by SEA. Polyphenols that exerted inhibitory effects on SEA toxic activity had a tendency to interact with SEA. In particular, polyphenol compounds with 1 or 2 hexahydroxydiphenoyl groups and/or a galloyl group, such as eugeniin, castalagin, punicalagin, pedunculagin, corilagin and geraniin, strongly interacted with SEA and inhibited toxin activity at a low concentration. These polyphenols may be used to prevent S. aureus infection and staphylococcal food poisoning.

Interaction between Various Apple Procyanidin and Staphylococcal Enterotoxin A and Their Inhibitory Effects on Toxin Activity

“…The polyphenol that interacts strongly with the protein is small enough to pass through the protein molecules and must be large enough to crosslink the peptide chains [ 13 ]. Additionally, in our previous study, the molecular weight of the polyphenols that weakly interacted was more than 1000, whereas the molecular weight of the polyphenols that strongly interacted was 1000 or less [ 14 ]. In the dimer to tetramer group, it was suggested that the interaction was weak when the molecular weight of polyphenol was less than or equal to 1000.…”

“…The interaction affinities of AP with SEA toxin active sites (emetic and superantigenic activities) were analyzed using four different synthetic peptides and rabbit antibodies with their corresponding peptides (A-2, 21–40; A-3, 35–50; A-6, 81–100; or A-10, 161–180) [ 15 ]. Amino acid residues 21–50 and 81–100 of SEA molecule are necessary to superantigenic and emetic activities in house musk shrews [ 14 ]. Treatment with AP resulted in a dose-dependent interaction of SEA active sites.…”

“…There are four SEA functional regions (peptides) that are responsible for superantigenic and emetic activities on SEA structures [ 14 ]. According to the amino acid sequence of SEA reported previously, these four peptides (20 amino acid residues in length), corresponding to the fragment of the primary sequence of SEA, were synthesized.…”

“…The binding affinities of AP to SEA toxin active sites were analyzed using four synthetic peptides equivalent to SEA toxin active sites, and rabbit antibodies to their corresponding peptides (A-2, A-3, A-6 and A-10). A-2, A-3, A-6 and A-10 peptides, corresponding to the regions 21–40, 35–50, 81–100, or 161–180 in SEA toxin active sites [ 14 ], were obtained from Sigma-Aldrich Corporation (St. Louis, MO, USA). The synthetic peptides are as follows: CALGNLKQIYYYNEKAKTEN (A-2), CKAKTENKESHDQFLQH (A-3), KGKKVDLYGAYYGYQC (A-6), CRYLQEKYNLYNSDVFDGKV (A-10).…”

Quantitative Proteomic Analysis of Staphylococcus aureus Treated With Punicalagin, a Natural Antibiotic From Pomegranate That Disrupts Iron Homeostasis and Induces SOS

“…Punicalagin can chelate iron and can interfere with antibody binding to the S. aureus enterotoxin, but its biochemical mechanistic action on microbial proteins is unknown. Aspiring to understand the mechanistic action of punicalagin on S. aureus , we performed a quantitative, comparative analysis of the proteome of S. aureus exposed to punicalagin.…”