Understanding the interactions between metabolites isolated from Achyrocline satureioides in relation to its antibacterial activity

• Published in: Phytomedicine (Stuttgart) Vol. 20; no. 3-4; pp. 258 - 261
• Main Authors: Joray, Mariana Belén, Palacios, Sara María, Carpinella, María Cecilia
• Format: Journal Article
• Language: English
• Published: Germany Elsevier GmbH 15.02.2013; Urban & Fischer Verlag
• Subjects: Achyrocline - chemistry; Achyrocline satureioides; Anti-Bacterial Agents - isolation & purification; Bacterial infections; Care and treatment; Chemical properties; Compositae; Drug Interactions; Escherichia coli; Escherichia coli - drug effects; Health aspects; Medicine, Botanic; Medicine, Herbal; Microbial Sensitivity Tests; Natural antibiotics; Phytotherapy; Plant metabolites; Plants, Medicinal - chemistry; Staphylococcus aureus; Staphylococcus aureus - drug effects; Synergism; Argentina; Achyrocline satureioides; Synergism; Natural antibiotics
• ISSN: 0944-7113; 1618-095X
• DOI: 10.1016/j.phymed.2012.10.015

Combinations of compounds 23-methyl-6-O-desmethylauricepyrone (1), quercetin (2) and 3-O-methylquercetin (3), obtained through bioguided fractionation from Achyrocline satureioides, showed synergistic or additive effect for inhibiting growth of Escherichia coli and Staphylococcus aureus. As part of our ongoing research on the antibacterial activity of Achyrocline satureioides, this study seeks to better understand the interactions between the metabolites isolated from this plant. For this purpose, the combined effect of 23-methyl-6-O-desmethylauricepyrone (1), quercetin (2) and 3-O-methylquercetin (3), obtained through bioguided fractionation from A. satureioides ethanol extract, was evaluated against Staphylococcus aureus and Escherichia coli. In first place, the antibacterial effect of the combination of flavonols 2 and 3 was assessed, as these showed individual effectiveness lower than or equal to that of the fraction from which they were obtained. When the flavonols were applied together at concentrations below their minimum inhibitory concentration (MIC) values, a synergistic effect (FICI<0.30) against S. aureus was observed. In addition, compounds 2 and 3 in combination reduced 1000 times the MIC of compound 1, showing a clear synergistic interaction (FICI<0.15) in treatments against the Gram (+) bacterium. The most active combination against E. coli showed an additive interaction (FICI<0.62) between the three assayed compounds 1–3. These results indicated the existence of concerted action between these metabolites, evidence of the importance of the synergistic interactions between the components of plant-derived extracts for the control of pathogenic bacteria.