Related Experiment Video
Updated: Feb 9, 2026

Expression, Purification, and Antimicrobial Activity of S100A12
Published on: May 13, 2017
Growth Media Affect Assessment of Antimicrobial Activity of Plant-Derived Polyphenols
Xin Xu1,2, Zhen M Ou1, Christine D Wu1
1Department of Pediatric Dentistry, College of Dentistry, University of Illinois at Chicago, Chicago, IL, USA.
Abstract:
This study aimed to investigate the effects of different microbial growth media on the laboratory assessment of antimicrobial activity of natural polyphenolic compounds. The inhibition of the tea polyphenol EGCG on growth of selected oral microorganisms was evaluated in complex media and a protein-free chemically defined medium (CDM). Other antimicrobial agents (polyphenolic grape seed extract, plant alkaloid berberine, methyl salicylate, and chlorhexidine gluconate) were also tested in the study. The presence of proteins and their effects on the antimicrobial activity of EGCG were investigated by the addition of BSA to the CDM. The MICs of EGCG against test oral microorganisms were 4 to 64 times higher in complex media than in CDM. The polyphenolic grape seed extract exhibited similar discrepancies. However, the MICs of the nonpolyphenolic compounds (berberine, methyl salicylate, and chlorhexidine) were not significantly different between the two growth media. The MIC of EGCG against S. mutans UA159 in CDM with added BSA was 16 times higher than that in CDM alone. Therefore, nonproteinaceous CDM should be used to avoid interference of proteins with the active ingredients when testing the antimicrobial activity of plant-derived polyphenolic compounds against microorganisms. This will also minimize the discrepancies noted in results obtained by different investigators.
More Related Videos
Related Concept Videos
Meristems and Plant Growth
Microbial Growth Media
Role of Affect in Interpersonal Attraction
Photoreceptors and Plant Responses to Light
Key Elements for Plant Nutrition
Plant Hormones

