title: Hydroxytyrosol expresses antifungal activity in vitro.
abstract: Hydroxytyrosol (HT) is a potent antioxidant found in olive oil and leaves. Using several in vitro approaches, we tested antifungal activity of HT. HT showed broad spectrum of antifungal activity against medically important yeasts and dermatophyte strains with MIC values ranging between 97.6 µgml⁻¹ and 6.25 mgml⁻¹. The antimicrobial activity of HT was also tested using the time-kill methodology. Below the MIC value, HT showed potent damage of cell wall of Candida albicans ATCC 10231 using fluorescent dye-exclusion method. At the subinhibitory concentration, HT also influenced dimorphic transition of Candida indicating that HT is inhibitor of germ-tube formation as one of the most important virulence factor of C. albicans. Furthermore, HT showed disturbances in cell surface hydrophobicity (CSH) of C. albicans. The in vitro results indicate that HT caused a significant cell wall damage and changes in CSH as well as inhibition of germ-tube formation as virulence factor of C. albicans. The study indicates that HT has a considerable in vitro antifungal activity against medically important yeasts.
authors.affiliation: Agency for Medicinal Products and Medical Devices of Croatia, Ksaverska cesta 4, HR- 10000 Zagreb, Croatia. natasa.zoric@halmed.hr
authors.forename: Natasa
authors.initials: N
authors.lastname: Zoric
authors.forename: Igor
authors.initials: I
authors.lastname: Horvat
authors.forename: Nevenka
authors.initials: N
authors.lastname: Kopjar
authors.forename: Ante
authors.initials: A
authors.lastname: Vucemilovic
authors.forename: Dario
authors.initials: D
authors.lastname: Kremer
authors.forename: Sinisa
authors.initials: S
authors.lastname: Tomic
authors.forename: Ivan
authors.initials: I
authors.lastname: Kosalec
mesh_terms: D000935:Antifungal Agents / Q000627:therapeutic use*; D003883:Arthrodermataceae / Q000187:drug effects* / Q000502:physiology; D002176:Candida albicans / Q000187:drug effects* / Q000472:pathogenicity / Q000502:physiology; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D000069463:Olive Oil; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000627:therapeutic use; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry; D010946:Plants, Medicinal; D015003:Yeasts / Q000187:drug effects* / Q000502:physiology
chemical_list: D000935:Antifungal Agents; D000069463:Olive Oil; D010936:Plant Extracts; D010938:Plant Oils; C005975:3,4-dihydroxyphenylethanol; D010626:Phenylethyl Alcohol