Comparison of Single and Combined Use of Catechin, Protocatechuic, and Vanillic Acids as Antioxidant and Antibacterial Agents against Uropathogenic Escherichia Coli at Planktonic and Biofilm Levels

• Published in: Molecules (Basel, Switzerland) Vol. 23; no. 11; p. 2813
• Main Authors: Bernal-Mercado, Ariadna Thalia, Vazquez-Armenta, Francisco Javier, Tapia-Rodriguez, Melvin R, Islas-Osuna, Maria A, Mata-Haro, Veronica, Gonzalez-Aguilar, Gustavo A, Lopez-Zavala, Alonso A, Ayala-Zavala, Jesus Fernando
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 30-10-2018; MDPI
• Subjects: Acids; Adhesion; anti-biofilm compounds; Antibacterial agents; antibiotic resistance; Antibiotics; Antiinfectives and antibacterials; antimicrobials; Antioxidants; Bacteria; bacterial adhesion; Biofilms; Catechin; Catheters; Cell adhesion; Cell adhesion & migration; E coli; Escherichia coli; Minimum inhibitory concentration; Nitrofurantoin; Phenolic compounds; Phenols; Protocatechuic acid; Silicones; Synergism; Synergistic effect; urinary catheter infection; Urinary tract infections; Vanillic acid; anti-biofilm compounds; antibiotic resistance; urinary catheter infection; phenolic compounds; synergism; antimicrobials; bacterial adhesion
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules23112813

The objective of this study was to evaluate the effect of combining catechin, protocatechuic, and vanillic acids against planktonic growing, adhesion, and biofilm eradication of uropathogenic
(UPEC), as well as antioxidant agents. The minimum inhibitory concentrations (MIC) of protocatechuic, vanillic acids and catechin against the growth of planktonic bacteria were 12.98, 11.80, and 13.78 mM, respectively. Mixing 1.62 mM protocatechuic acid + 0.74 mM vanillic acid + 0.05 mM catechin resulted in a synergistic effect acting as an MIC. Similarly, the minimum concentrations of phenolic compounds to prevent UPEC adhesion and biofilm formation (MBIC) were 11.03 and 7.13 mM of protocatechuic and vanillic acids, respectively, whereas no MBIC of catechin was found. However, combinations of 1.62 mM protocatechuic acid + 0.74 mM vanillic acid + 0.05 mM catechin showed a synergistic effect acting as MBIC. On the other hand, the minimum concentrations to eradicate biofilms (MBEC) were 25.95 and 23.78 mM, respectively. The combination of 3.20 mM protocatechuic acid, 2.97 mM vanillic acid, and 1.72 mM catechin eradicated pre-formed biofilms. The antioxidant capacity of the combination of phenolics was higher than the expected theoretical values, indicating synergism by the DPPH
, ABTS, and FRAP assays. Effective concentrations of catechin, protocatechuic, and vanillic acids were reduced from 8 to 1378 times when combined. In contrast, the antibiotic nitrofurantoin was not effective in eradicating biofilms from silicone surfaces. In conclusion, the mixture of phenolic compounds was more effective in preventing cell adhesion and eradicating pre-formed biofilms of uropathogenic
than single compounds and nitrofurantoin, and showed antioxidant synergy.