Chemosensitization of filamentous fungi to antifungal agents using Nectandra Rol. ex Rottb. species essential oils

Abstract

Chemosentizing of pathogens using natural compounds has been shown to be a promising alternative, resulting in increased efficacy of classical antifungal therapy. This study determines the chemical composition and antifungal, antichemotactic and antioxidant activities of Nectandra Rol species. ex Rottb. essential oils species, and its interaction with commercial antifungals. The chemical composition of N. megapotamica and N. lanceolata essential oils was established by gas chromatography–mass spectrometry (GC–MS). The major compounds identified in N. megapotamica oil were bicyclogermacrene (33.4%) and germacrene D (16.8%), while N. lanceolata were identified β-caryophyllene (32.5%), bicyclogermacrene (27.8%) and spathulenol (11.8%). The oils presented antidermatophytic effect and affinity by ergosterol indicating a possible involvement in fungal membrane. The combination of the essential oil from N. lanceolata and ciclopirox showed synergistic and additive effect on most isolates (75%) reducing the active concentration of the antifungal agents when in combination. The oils were also tested for their ability to inhibit leukocyte migration in vitro stimulated by Escherichia coli lipopolysaccharide and showed antichemotactic effect with reduction in migration in the range of 30.7–96.7%, suggesting that it could act in acute stage of inflammatory process. Antioxidant concentration-dependent activity was observed on both samples. N. lanceolata showed 50% antioxidant effect in the highest concentration tested. The results of the combination between antifungals and N. lanceolata essential oil indicate this oil as a possible complement to conventional therapy for topical treatment of superficial infections caused by dermatophytes, acting in the chemosensitization of the fungal cell and resulting in antifungal effect improvement with the advantage of the anti-inflammatory effect associated.