Single and multiple investigation activity potential luteolin against Candida albicans, Escherichia coli and...

Candida albicans is an opportunistic pathogen that can cause invasive infections, especially under conditions of immunosuppression and dysbiosis. Its presence alongside Pseudomonas aeruginosa and Escherichia coli may lead to polymicrobial biofilm-related infections. Due to rising antimicrobial resistance, alternative therapies are being explored, including luteolin, a natural flavonoid with reported in vitro antimicrobial activity. This study evaluated the in vitro antimicrobial and antibiofilm effects of luteolin against C. albicans, E. coli, and P. aeruginosa, both individually and in combination. Methods involved determining minimum inhibitory concentrations, using scanning electron microscopy, fibroblast viability tests, ELISA-based cytokine measurements, and RT-qPCR analysis of key biofilm- and quorum-sensing-related genes (luxS, lasI, and ALS1). MIC values were 0.011 mg/mL for individual strains and 0.046 mg/mL for the polymicrobial mixture. Luteolin treatment reduced microbial adherence and improved fibroblast viability compared to infected controls. Infection increased IL-1β levels and decreased IL-10 levels, effects that luteolin partially reversed. RT-qPCR showed downregulation of selected biofilm-related genes at 2×MIC. These findings demonstrate luteolin's measurable antimicrobial and anti-biofilm effects in vitro under controlled laboratory conditions, supporting further validation in preclinical models to assess translational potential.