Characterization of Phenolic Acid Antimicrobial and Antioxidant Structure-Property Relationships.

Jingyi Liu,Mary Beth B Monroe,Henry T Beaman,Changling Du

doi:10.3390/pharmaceutics12050419

Jingyi Liu, Mary Beth B Monroe + Show 2 more

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https://doi.org/10.3390/pharmaceutics12050419

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Journal: Pharmaceutics	Publication Date: May 2, 2020
Citations: 79	License type: CC BY 4.0

Affiliation: Syracuse University

Abstract

Plant-derived phenolic acids (PAs) are small molecules with antimicrobial, antioxidant, anti-inflammatory, and pro-coagulant properties. Their chemistry enables facile potential incorporation into biomaterial scaffolds to provide naturally-derived functionalities that could improve healing outcomes. While PAs have been previously characterized, their structure-property relationships in terms of antioxidant and antimicrobial properties are not well-understood, particularly in the context of their use in medical applications. To that end, a library of PAs with varied pendant groups was characterized here. It was found that increasing the number of radical-scavenging hydroxyl and methoxy groups on PAs increased antioxidant properties. All PAs showed some antimicrobial activity against the selected bacteria strains (Escherichia coli, Staphylococcus epidermidis (native and drug-resistant), and Staphylococcus aureus (native and drug-resistant)) at concentrations that are feasible for incorporation into polymeric biomaterials. In general, a trend of slightly decreased antimicrobial efficacy with increased number of pendant hydroxyl and methoxy groups was observed. The carboxylic acid group of a selection of PAs was modified with a polyurethane monomer analog. Modification did not greatly affect antioxidant or antimicrobial properties in comparison to unmodified controls, indicating that the carboxylic acid group of PAs can be altered without losing functionality. These results could be utilized for rational selection of phenolic moieties for use as therapeutics on their own or as part of a biomaterial scaffold with desired healing outcomes.

Highlights

A majority of hospital-acquired infections are related to medical devices
The addition of hydrogen donating groups onto the other cinnamic acid (CA)-based phenolic acids (PAs) resulted in significantly improved antioxidant capabilities
In comparing the BA- and CA-based PAs, it should be noted that the addition of one OH group to CA (P-coumaric acid) resulted in a much higher increase in H2O2 scavenging than the corollary BA-based 4-hydroxy benzoic acid with one OH group

Summary

Introduction

A majority of hospital-acquired infections are related to medical devices. In a 1999 study, 95% of cases of urinary tract infections were catheter-related, and 87% of bloodstream infections originated from a vascular catheter [1]. An added complication of infection is the grand challenge of antibiotic-resistant bacteria strains, which is caused in part by antibiotic overuse. Antibiotic resistant infections contribute to ~100,000 deaths each year in the US, and “superbugs” are expected to cause more deaths than all cancers combined by 2050 if no effective alternative treatments are developed [5,6]. Based on these trends, implantable medical devices that are resistant to infection could provide enhanced safety and efficacy, and non-drug-based antimicrobials must be pursued to reduce these risks and complications

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