Therapeutic potential of nanofabricated Melissa officinalis L. essential oil against Trichophyton mentagrophytes mediated dermatophytosis

The present study aims to investigate the anti-dermatophytic activity of Melissa officinalis L. essential oil loaded chitosan nanoemulsion (MOEO-CsNm) for treating Trichophyton mentagrophytes mediated dermatophytosis. MOEO-CsNm was fabricated using ionic gelation method and physcio-chemically characterized through SEM, AFM, XRD, and FT-IR to observe their morphology, structural integrity, and effective loading of MOEO into MOEO-CsNm. Moreover, the in vitro controlled release behavior of MOEO from MOEO-CsNm is crucial for its prolonged efficacy. The chemical profile of MOEO was analyzed by GC-MS which revealed geranial (31.74%) as the primary components. MOEO-CsNm showed higher anti-dermatophytic activity against T. mentagrophytes (minimum inhibitory concentration (MIC): 0.08 µL/mL) as compared to unencapsulated M. officinalis essential oil (MOEO) (MIC: 0.16 µL/mL), geranial (major component of MOEO) (MIC: 0.3 µL/mL) and synthetic drug imidazole (MIC: 0.5 µL/mL). The plasma membrane was found to be the target site of MOEO and MOEO-CsNm. However, poor viscosity of MOEO-CsNm limits its practical applicability as a topical formulation. Hence, MOEO-CsNm nanoemulgel was prepared by incorporating MOEO-CsNm with Carbopol hydrogel. In vivo experiments using guinea pig model showed that the topical application of MOEO-CsNm nanoemulgel completely cured the T. mentagrophytes infection in guinea pigs after 15 days. The histopathological examination suggested complete recovery of the epidermal layer without active fungal invasion, and remarkable appearance of new hair follicles in the dermal region. Therefore, findings propose the MOEO-CsNm nanoemulgel as a novel plant- based topical antifungal formulation for treating dermatophytosis as an alternative to synthetic drugs with the advantage of reduced chance of drug resistance.