In vitro antidermatophytic activity of Otacanthus azureus (Linden) Ronse essential oil alone and in combination with azoles.
OBJECTIVE
We determined the chemical composition and investigated the antifungal activity of Otacanthus azureus (Linden) Ronse essential oil (EO) against a range of dermatophytes alone or in combination with azole antifungals.


RESULTS
Aerial parts of the plant were steam-distilled and the obtained oil was analysed by gas chromatography/mass spectrometry and (1) H-NMR. It was shown to be largely composed of sesquiterpenes, with the main component being β-copaen-4-α-ol. Using broth microdilution techniques, this oil was found to have remarkable in vitro antifungal activities. Minimum inhibitory concentrations as low as 4 μg ml(-1) were recorded. The analysis of the combined effect of the O. azureus EO with azoles using chequerboard assays revealed a synergism between the EO and ketoconazole, fluconazole or itraconazole against Trichophyton mentagrophytes. Notably, the O. azureus essential oil showed low cytotoxicity to VERO cells.


CONCLUSIONS
The O. azureus essential oil alone or in combination with azoles is a promising antifungal agent in the treatment for human dermatomycoses caused by filamentous fungi.


CONCLUSIONS
There is much interest in the study of essential oils for the discovery of new antimicrobial drugs. This study has highlighted the antidermatophytic activity of the O. azureus EO.
CNRS-UMR EcoFoG, Cayenne, French Guiana.
E
E
Houël
CNRS-Institut de Chimie des Substances Naturelles, Gif-sur-Yvette, France.
A M S
AM
Rodrigues
CNRS-UMR EcoFoG, Cayenne, French Guiana.
A
A
Jahn-Oyac
UMR 5076, École Nationale Supérieure de Chimie, Montpellier, France.
J-M
JM
Bessière
CNRS-Institut de Chimie des Substances Naturelles, Gif-sur-Yvette, France.
V
V
Eparvier
Université de Toulouse; UPS; UMR 152 Pharma-DEV, Faculté des Sciences Pharmaceutiques, Université Toulouse 3, Toulouse, France.|Institut de Recherche pour le Développement (IRD), UMR 152 Pharma-DEV, Toulouse, France.
E
E
Deharo
CNRS-Institut de Chimie des Substances Naturelles, Gif-sur-Yvette, France.
D
D
Stien
D000818:Animals; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D003883:Arthrodermataceae / Q000187:drug effects*; D001393:Azoles / Q000494:pharmacology*; D002522:Chlorocebus aethiops; D003881:Dermatomycoses / Q000188:drug therapy; D004357:Drug Synergism; D005658:Fungi / Q000187:drug effects; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D035261:Plant Components, Aerial / Q000737:chemistry; D000068377:Plantaginaceae / Q000737:chemistry*; D014249:Trichophyton / Q000187:drug effects; D014709:Vero Cells
D000935:Antifungal Agents; D001393:Azoles; D009822:Oils, Volatile
Otacanthus azureus; antifungal activity; azoles; dermatophytes; essential oil; synergy