title: Antifungal activity of geraniol and citronellol, two monoterpenes alcohols, against Trichophyton rubrum involves inhibition of ergosterol biosynthesis.
abstract: BACKGROUND
  Trichophyton rubrum is the most common fungus causing chronic dermatophytosis in humans. Antifungal activity of promising agents is of great interest. Geraniol and citronellol are monoterpenes with antimicrobial properties.
  
  
  OBJECTIVE
  This study aimed to investigate the inhibitory effects and possible mechanism of antifungal activity of geraniol and citronellol against strains of T. rubrum.
  
  
  METHODS
  The minimum inhibitory concentration (MIC) of each drug against 14 strains was determined by broth microdilution. The effects of the drugs on dry mycelial weight, conidial germination, infectivity on human nail fragments, and morphogenesis of T. rubrum were analyzed. The effects on the cell wall (test with sorbitol) and cell membrane (release of intracellular material and ergosterol biosynthesis) were investigated.
  
  
  RESULTS
  MIC values of geraniol ranged between 16 and 256 µg/mL while citronellol showed MIC values from 8 to 1024 µg/mL. The drugs (MIC and 2 × MIC) inhibited the mycelial growth, conidia germination, and fungal growth on nail fragments. The drugs (half of MIC) induced the formation of wide, short, and crooked hyphae in T. rubrum morphology. With sorbitol, geraniol MIC was increased by 64-fold and citronellol by 32-fold. The drugs caused leakage of intracellular material and inhibited ergosterol biosynthesis.
  
  
  CONCLUSIONS
  The results suggest that the drugs damage cell wall and cell membrane of T. rubrum through a mechanism that seems to involve the inhibition of the ergosterol biosynthesis.
  
  
  CONCLUSIONS
  This study confirms that geraniol and citronellol can be regarded as potential drugs for controlling T. rubrum growth, with great potential against agents of dermatophytosis.
authors.affiliation: Unidade Acadêmica de Saúde, Centro de Educação e Saúde, Universidade Federal de Campina Grande , Cuité , Brasil and.
authors.forename: Fillipe de Oliveira
authors.initials: Fde O
authors.lastname: Pereira
authors.forename: Juliana Moura
authors.initials: JM
authors.lastname: Mendes
authors.forename: Igara Oliveira
authors.initials: IO
authors.lastname: Lima
authors.forename: Kelly Samara de Lira
authors.initials: KS
authors.lastname: Mota
authors.forename: Wylly Araújo de
authors.initials: WA
authors.lastname: Oliveira
authors.forename: Edeltrudes de Oliveira
authors.initials: Ede O
authors.lastname: Lima
mesh_terms: D000080462:Acyclic Monoterpenes; D000438:Alcohols / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology*; D004875:Ergosterol / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008826:Microbial Sensitivity Tests; D039821:Monoterpenes / Q000494:pharmacology*; D009262:Nails / Q000382:microbiology; D013729:Terpenes / Q000494:pharmacology*; D014249:Trichophyton / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D000080462:Acyclic Monoterpenes; D000438:Alcohols; D000935:Antifungal Agents; D039821:Monoterpenes; D013729:Terpenes; C007836:geraniol; C007078:citronellol; D004875:Ergosterol
keywords: Dermatophytes; essential oil; mechanism of action; natural drugs