Green natural nail polish modified with essential oils to treat onychomycosis

Background: Onychomycosis (OM) accounts for about 50% of nail disorders in industrialised countries. Essential oils (EOs), aromatic natural compounds, are known for their antimicrobial activity. Objective: The aim of this work was to evaluate the antifungal efficacy of seven EOs and a commercial MIX against 10 dermatophytes responsible for OM to select the most effective ones to be included in a preventive or curative formulation based on a green natural nail polish (GNNP). Methods: Micro-broth dilution tests in line with EUCAST guidelines and olfactory satisfaction test were performed to select the best natural compounds previously analysed by SPME coupled with GC-MS. The same method was used to evaluate the release over time of the active compounds present in the two modified-GNNPs made by adding the best natural compound selected (the C. citratus EO) and the MIX. Furthermore, to evaluate the preventive and curative activity of modified-GNNPs, ex vivo experiments on healthy or colonised nails were performed. Results and Conclusions: Data showed that MIX-modified- GNNP had preventive activity as it inhibits the fungal growth by releasing its active ingredients for 7 days, while the OE-modified GNNP acts as a natural drug showing cytocidal activity on nails colonised by dermatophytes, but it requires two weekly applications