Fine-tuning of the hydrophobicity of caffeic acid: studies on the antimicrobial activity against Staphylococcus aureus and Escherichia coli

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Mafalda Andrade (Author) Other; Sofia Benfeito (Author) Other; Pedro Soares (Author) Other; Diogo Magalhães e Silva (Author) Other; Joana Loureiro (Author) Other; Anabela Borges (Author) FEUP; Fernanda Borges (Author) FCUP; Manuel Simões (Author) FEUP

Journal

Title: RSC Advances

Vol. 5 No. 66

Pages: 1-17

ISSN: 2046-2069

Publisher: Royal Society of Chemistry

Indexing

ISI Web of Knowledge - 46 Citations

ISI Web of Science

Scopus - 49 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

CORDIS: Physical sciences > Chemistry

Associated Projects

LEPABE - Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia

Centro de Investigação em Química da Universidade - Centro de Investigação em Química da Universidade

Other information

Authenticus ID: P-00G-CGD

DOI: 10.1039/c5ra05840f

Abstract (EN): The increased bacterial multidrug resistance caused by inappropriate use and overuse of antimicrobials is a global concern. To circumvent this issue, a quest for the development of new active agents has been widely recognized. Some phytochemical products, produced by plants as part of their chemical defense strategies, are regarded as new stimulii to develop novel antimicrobials that are not as vulnerable as current drugs to bacterial resistance mechanisms. In this study, the antimicrobial activity and mode of action of caffeic acid (CAF) and a series of CAF alkyl esters was assessed against Escherichia coli and Staphylococcus aureus, with the aim of analyzing the influence of the alkyl ester side chain length on the activity. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), changes in physicochemical surface properties and intracellular potassium leakage were used as physiological indices for the antimicrobial mode of action. CAF alkyl esters were found to be effective antimicrobial agents against both bacteria. Their activity was directly dependent on their lipophilicity, which affected bacterial susceptibility, the physicochemical properties of the bacteria and the integrity of the membranes. E. coli was less susceptible than S. aureus to the action of the compounds. Longer alkyl side chains were more effective against the Gram-positive bacterium, while medium length alkyl side chain compounds were more effective against the Gram-negative bacterium. Caffeic acid derivatives are proposed to act as cell permeabilizers, inducing membrane alterations, causing rupture with potassium leakage, particularly on the Gram positive bacterium, and consequent cell death.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 17