Is it Worth Combining <i>Solidago virgaurea</i> Extract and Antibiotics against Uropathogenic <i>Escherichia coli</i> rods? An In Vitro Model Study

• Main Authors: Dorota Wojnicz, Dorota Tichaczek-Goska, Michał Gleńsk, Andrzej B. Hendrich
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Pharmaceutics
• Subjects: <i>Solidago virgaurea</i> extract; amikacin; ciprofloxacin; biofilm; uropathogenic <i>Escherichia coli</i>
• Online Access: https://www.mdpi.com/1999-4923/13/4/573

European goldenrod (<i>Solidago virgaurea</i> L.) has long been applied in traditional medicine and recommended in the prophylaxis of urinary tract infections (UTIs). However, research describing the antibacterial properties of goldenrod is very limited. Therefore, the aim of the study was to determine the effect of <i>S. virgaurea</i> extract on the survival and biofilm formation of uropathogenic <i>Escherichia coli</i>. The interactions between the goldenrod extract and antibiotics used in UTIs were established. The influence of the extract on the duration of the post-antibiotic effects (PAE) and post-antibiotic sub-MIC effects (PASME) of amikacin and ciprofloxacin were determined. Extract composition was analyzed using coupled UHPLC/MS and the spectrophotometric method. The survival of bacteria was established using the serial dilution assay. The crystal violet assay for biofilm quantification was also used. PAE and PASME were investigated using the viable count method. The obtained results indicate that <i>S. virgaurea</i> extract limits the survival of planktonic forms of bacteria and reduces 24-h biofilm. However, the combination of <i>S. virgaurea</i> extract with antibiotics weakens their antibacterial activity and shortens the duration of PAE and PASME. Therefore, when deciding to use a combination of <i>S. virgaurea</i> extract and amikacin/ciprofloxacin, it is necessary to take into account their antagonistic activity.