Rosemary Extract: Phytochemical Composition and Potential for Eliminating Polymicrobial Biofilm of Candida albicans and Multidrug-Resistant Bacteria

Abstract

Herbal medicines can be promising for the treatment of infections caused by multidrug-resistant microorganisms. This study aimed to evaluate <i>Rosmarinus officinalis</i> (Rosemary) hydroalcoholic extract (RHE) regarding its phytochemical composition and potential for eliminating polymicrobial biofilm of <i>Candida albicans</i> with multidrug-resistant bacteria (<i>Acinetobacter baumannii</i>, <i>Klebsiella pneumoniae</i>, and <i>Pseudomonas aeruginosa</i>). The extraction and quantification of the extract (flavonoids and phenols) were performed, and its antioxidant activity (DPPH) and the presence of bio-active compounds were investigated using high-performance liquid chromatography with Diode Array Detection (HPLC-DAD) and Gas Chromatography-Mass Spectrometry (GC-MS). The minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) were determined, and the extract's action on polymicrobial biofilms was evaluated using the MTT assay. Data were analyzed using one-way ANOVA and Tukey's tests, as well as Kruskal-Wallis and Dunn's tests, with a significance level of 5%. RHE showed compatible amounts of flavonoids and phenols, with an EC50 of 19.53 µg/mL. Through HPLC-DAD and GC-MS, biomolecules such as rosmarinic acid and α-Pinene were identified. The extract exhibited microbicidal activity and antibiofilm action, with reduction percentages of up to 69.6% (<i>p</i> &lt; 0.05), showing superior performance compared to 0.12% chlorhexidine against <i>C. albicans</i> + <i>A. baumannii</i>. In conclusion, RHE may be a promising therapeutic agent against multidrug-resistant pathogens.