Abstract Candida albicans is an opportunistic pathogen whose virulence factors, such as polymorphism and biofilm formation, facilitate infection. Due to rising antifungal resistance, essential oils (EOs) from Citrus limon and Citrus sinensis are being investigated for their antimicrobial potential. This study analyzes the chemical composition, antifungal activity against Candida albicans in planktonic and biofilm forms, cytotoxicity on human erythrocytes, and pharmacokinetic properties of Citrus limon and Citrus sinensis essential oils. The essential oils were extracted from the leaves by hydrodistillation, and their composition was analyzed by GC-MS. Antifungal activity was assessed using broth microdilution and time-kill kinetics. Combined effects were assessed using checkerboard assays, while antibiofilm tests were evaluated using polystyrene plate assays and microscopy. Hemolytic activity tests were performed using percentage hemolysis. C. limon essential oil had limonene 40.8%, β-pinene 16.5%, and citronellal 12.3%, while C. sinensis had limonene 36.7%, β-pinene 14.6%, and eucalyptol 10.5% as its main constituents. The MIC was 0.312 – 1.25 mg/mL, with kill kinetics of up to 10 h. It showed additive effects for C. limon/fluconazole and synergistic effects for C. sinensis/fluconazole. It exhibited anti-adhesion and anti-polymorphism effects, inhibiting biofilm formation. It also exhibited low cytotoxicity, with an LC50 of 14 000 µg/mL for C. limon and 13 000 µg/mL for C. sinensis. ADMET and BOILED-egg pharmacokinetic predictions indicated safety for systemic use, with caution for topical application of limonene, citronellal, and eucalyptol. Both EOs exhibited strong anti-Candida activity with minimal cytotoxicity. Its additive/synergistic effects with fluconazole highlight its potential as an alternative or adjuvant therapy against C. albicans infections.
Fernandes et al. (Mon,) studied this question.