title: Antimicrobial and enhancement of the antibiotic activity by phenolic compounds: Gallic acid, caffeic acid and pyrogallol.
abstract: The indiscriminate use of antimicrobial drugs has increased the spectrum of exposure of these organisms. In our studies, these phenolic compounds were evaluated: gallic acid, caffeic acid and pyrogallol. The antibacterial, antifungal and modulatory of antibiotic activities of these compounds were assayed using microdilution method of Minimum Inhibitory Concentration (MIC) to bacteria and Minimum Fungicide Concentration (MFC) to fungi. The modulation was made by comparisons of the MIC and MFC of the compounds alone and combined with drugs against bacteria and fungi respectively, using a sub-inhibitory concentration of 128 μg/mL of substances (MIC/8). All substances not demonstrated clinically relevant antibacterial activity with a MIC above ≥1024 μg/mL. As a result, we observed that the caffeic acid presented a potentiating antibacterial effect over the 3 groups of bacteria studied. Pyrogallol showed a synergistic effect with two of the antibiotics tested, but only against Staphylococcus aureus. In general, caffeic acid was the substance that presented with the greatest number of antibiotics and with the greatest number of bacteria. In relation to the antifungal activity of all the compounds, the verified results were ≥1024 μg/mL, not demonstrating significant activity. Regarding potentiation of the effect of fluconazole, was observed synergistic effect only when assayed against Candida tropicalis, with all substances. Therefore, as can be seen, the compounds presented as substances that can be promising potentiating agents of antimicrobial drugs, even though they do not have direct antibacterial and antifungal action.
authors: Laboratório de Microbiologia e Biologia Molecular, Universidade Regional do Cariri, Crato, CE, Brazil.
authors: Valéria N
authors: VN
authors: Lima
authors: Laboratório de Farmacologia e Química Molecular, Universidade Regional do Cariri, Crato, CE, Brazil.
authors: Cícera D M
authors: CD
authors: Oliveira-Tintino
authors: Laboratório de Farmacologia de Produtos Naturais, Universidade Regional do Cariri, Crato, CE, Brazil.
authors: Enaide S
authors: ES
authors: Santos
authors: Laboratório de Fisiofarmacologia de Células Excitáveis, Universidade Regional do Cariri, Crato, CE, Brazil.
authors: Luís P
authors: LP
authors: Morais
authors: Laboratório de Microbiologia e Biologia Molecular, Universidade Regional do Cariri, Crato, CE, Brazil.
authors: Saulo R
authors: SR
authors: Tintino
authors: Laboratório de Microbiologia e Biologia Molecular, Universidade Regional do Cariri, Crato, CE, Brazil.
authors: Thiago S
authors: TS
authors: Freitas
authors: Faculdade Leão Sampaio, Juazeiro do Norte, CE, Brazil.
authors: Yuri S
authors: YS
authors: Geraldo
authors: Laboratório de Microbiologia e Biologia Molecular, Universidade Regional do Cariri, Crato, CE, Brazil.
authors: Raimundo L S
authors: RL
authors: Pereira
authors: Laboratório de Microbiologia e Biologia Molecular, Universidade Regional do Cariri, Crato, CE, Brazil.
authors: Rafael P
authors: RP
authors: Cruz
authors: Laboratório de Farmacologia e Química Molecular, Universidade Regional do Cariri, Crato, CE, Brazil.
authors: Irwin R A
authors: IR
authors: Menezes
authors: Laboratório de Microbiologia e Biologia Molecular, Universidade Regional do Cariri, Crato, CE, Brazil. Electronic address: hdmcoutinho@gmail.com.
authors: Henrique D M
authors: HD
authors: Coutinho
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D002109:Caffeic Acids / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects*; D004357:Drug Synergism; D005707:Gallic Acid / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D011748:Pyrogallol / Q000494:pharmacology*
chemical_list: D000890:Anti-Infective Agents; D002109:Caffeic Acids; D011748:Pyrogallol; D005707:Gallic Acid; C040048:caffeic acid
keywords: Caffeic acid; Gallic acid; Pyrogallol; Synergistic effect