Camphor and Eucalyptol—Anticandidal Spectrum, Antivirulence Effect, Efflux Pumps Interference and Cytotoxicity

Abstract

Candidaalbicans represents one of the most common fungal pathogens. Due to its increasing incidence and the poor efficacy of available antifungals, finding novel antifungal molecules is of great importance. Camphor and eucalyptol are bioactive terpenoid plant constituents and their antifungal properties have been explored previously. In this study, we examined their ability to inhibit the growth of different Candida species in suspension and biofilm, to block hyphal transition along with their impact on genes encoding for efflux pumps (CDR1 and CDR2), ergosterol biosynthesis (ERG11), and cytotoxicity to primary liver cells. Camphor showed excellent antifungal activity with a minimal inhibitory concentration of 0.125–0.35 mg/mL while eucalyptol was active in the range of 2–23 mg/mL. The results showed camphor’s potential to reduce fungal virulence traits, that is, biofilm establishment and hyphae formation. On the other hand, camphor and eucalyptol treatments upregulated CDR1;CDR2 was positively regulated after eucalyptol application while camphor downregulated it. Neither had an impact on ERG11 expression. The beneficial antifungal activities of camphor were achieved with an amount that was non-toxic to porcine liver cells, making it a promising antifungal compound for future development. The antifungal concentration of eucalyptol caused cytotoxic effects and increased expression of efflux pump genes, which suggests that it is an unsuitable antifungal candidate.

Fungal Biofilms as a Valuable Target for the Discovery of Natural Products That Cope with the Resistance of Medically Important Fungi—Latest Findings

“…At ¼ MBIC 90 , CBD produced upregulation of yeast-associated genes and downregulation of hyphae-specific genes. As reported by Ivanov et al [ 166 ], camphor inhibited more than 50% of the biofilm biomass in C. albicans strains at 62–250 µg/mL, while in C. tropicalis, the inhibition was achieved at 175 µg/mL. On the other hand, eucalyptol showed the same effect in the tested C. albicans strains at higher concentrations (>3000 µg/mL) and in C .…”

“…On the other hand, eucalyptol showed the same effect in the tested C. albicans strains at higher concentrations (>3000 µg/mL) and in C . tropicalis , C. parapsilosis and C. krusei at >1000 µg/mL [ 166 ]. Camphor, applied at 125 µg/mL, reduced ROS generation in one strain of C. albicans , although eucalyptol failed to exert this effect.…”

Protective Effect of Amber Extract on Human Dopaminergic Cells against 6-Hydroxydopamine-Induced Neurotoxicity

“…Moreover, sesquiterpenoids have also been reported to have anti-inflammatory [ 27 ] and neuroprotective effects [ 28 ]. Previous studies have shown that Baltic amber contains several different active compounds [ 16 , 29 ], such as p-cymene and dehydroabietic acid, which have been reported to have anti-inflammatory effects [ 30 , 31 ]; camphor, which has been reported to have antifungal activity [ 32 ]; pimaric acid, which has been reported to have anti-atherosclerotic activity [ 33 ], etc. However, there are still many other unknown components in amber, and future studies should focus on identifying all components of the amber extract and elucidating the exact components that have potential neuroprotective effects.…”

Emerging Antifungal Targets and Strategies

“…Anti-hyphal potential of camphor (0.125 mg/mL) and eucalyptol (23 mg/mL) against clinical isolate of C. albicans were evaluated [ 66 ]. Both compounds triggered a marked decrease in the number of hyphal cells and block hyphal transition along with antibiofilm properties.…”