Antifungal Activity of the Essential Oils of Osteophloeum platyspermum (Myristicaceae) against Malassezia spp. and Candida albicans Influenced by Seasonality and Climatic Factors

Aims: Malassezia spp. are involved in a wide range of mammalian skin diseases. The introduction of new drugs is a need. Natural products are known to be effective in the treatment of microbial pathogens. The present study analyzed the O. platyspermum leaf essential oils (EOs) antifungal activity.

Study Design: 18 terpenes from 13 O. platyspermum leaf EOs are related to seasonal and climatic variations occurring during the dry (DS) and rainy (RS) seasons in the Amazon Rain-Forest, verified by means of multivariate analyses.

Place and Duration of the Study: the study was conducted at the Center for Research in Biodiversity (Microbiology Laboratory and Cell Culture Laboratory), Paulista University, biological activity evaluations occurred between January/2019 and December 2019).

Methodology: microdilution broth assay was used in the minimal bactericidal concentration (MBC). Multivariate analyses were used to access the relationship among MBC, seasonality and terpene composition of the EOs.

Results: Malassezia pachydermatis showed higher sensitivity to the EOs than M. furfur or C. albicans. The DS EOs were linked to the presence of limonene, myrcene, α-terpineol, linalool, terpinen-4-ol, cubenol-1-epi, influenced by insolation, temperature and evaporation, while β-elemene, γ-elemene, neo-intermedeol, elemol, α-cadinol, spathulenol, isospathulenol, viridiflorol, δ-amorphene and ledol were linked to the RS EOs, and were influenced by precipitation, relative humidity and wind velocity. DS EOs showed better antifungal activity against both Malassezia species, and the presence of the six discriminative terpenes was essential for the antifungal activity.

Conclusions: The DS EOs are a potential source of new leads to defeat animal dermatological microbes.