Context: Essential oil (EO) is a concentrated form of extract. Drug discovery from natural products to address antimicrobial resistance (AMR) is now considered crucial in tackling the global threat to human health. Eremophila mitchellii is an endemic Australian plant which has been used by Indigenous populations for treating infections and inflammation. The oil has been produced from the wood of this plant is known as ‘buddha wood oil’ commercially. However, its biological properties and clinical significance have not been studied extensively.
Objective: To evaluate the composition and in vitro antimicrobial activity of Buddha wood oil emulsion against Staphylococcus aureus biofilms.
Methods: The chemical composition of the pure oil was analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). The oil emulsion was prepared using ultrasonication and characterization of the emulsified oil was performed using droplet size distribution and phase separation. The emulsified oil was then evaluated for its antimicrobial as well as anti-biofilm properties against S. aureus using minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) assays.
Results: Buddha wood oil comprised almost 50 different compounds on GC-MS. The emulsified formulation exhibited good stability (no phase separation) during 3 months of evaluation. The emulsified oil showed significant anti-microbial and anti-biofilm activity against S. aureus including clinical isolates. The MIC for planktonic culture was less than 1ug/uL and the MBIC was 1ug/uL.
Conclusion: The findings suggest that Buddha wood essential oil emulsion has antibacterial properties against S. aureus and thus warrants further investigation on its pharmacological value and traditional practices.