Bigger Data Approach to Analysis of Essential Oils and Their Antifungal Activity against <i>Aspergillus niger</i>, <i>Candida albicans</i>, and <i>Cryptococcus neoformans</i>

Abstract

With increasing drug resistance and the poor state of current antifungals, the need for new antifungals is urgent and growing. Therefore, we tested a variety of essential oils for antifungal activity. We report the minimum inhibitory concentrations (MIC) values for a common set of 82 essential oils against Aspergillus niger, Candida albicans, and Cryptococcus neoformans. Generally, narrow-spectrum activity was found. However, C. neoformans was much more susceptible to inhibition by essential oils with over one-third of those tested having MIC values below 160 ppm. GC-MS analysis showed the essential oils to be chemically diverse, yet, the potentially active major constituents typically fell into a few general categories (i.e., terpenes, terpenoids, terpenols). While essential oils remain a rich source of potential antifungals, focus should shift to prioritizing activity from novel compounds outside the commonalities reported here, instead of simply identifying antifungal activity. Further, capitalizing on bigger data approaches can provide significant returns in expediting the identification of active components.

Keywords

• <i>Aspergillus niger</i>
• <i>Candida albicans</i>
• <i>Cryptococcus neoformans</i>
• essential oil
• antifungal
• minimum inhibitory concentration
• natural product
• exclusionary principle
• phytochemicals
• bioactivity
• drug discovery