Insight on the relationship between the compositions and antimicrobial activities of Osmanthus fragrans Lour. (Oleaceae family) essential oils by multivariable analysis

The study aims to optimise the extraction method of Osmanthus fragrans Lour. (Thunbergii flower) essential oil (EO) and establish the correlation between its chemical compositions and antimicrobial activities. Three extraction methods, Soxhlet extraction (SE), Ultrasound-assisted extraction (UE) and Supercritical Fluid Extraction with CO2 (SFE), were employed to obtain the EO, and its phytochemicals were analysed using gas chromatography and mass spectrometry (GC/MS). Thereafter, the extraction method was optimised through principle component analysis (PCA). Multiple linear regression (MLR) was performed to determine the correlation between the chemical compositions and antimicrobial activities. According to the PCA results, SFE was selected as an appropriate extraction method. MLR analysis successfully showed that Ionone, Linalool oxide, Furaneol, Polybasic acid and Linoleic acid were the major bioactive components responsible for the antimicrobial activity. The relationship between the antibacterial and active compounds provides a theoretical basis for further development of Thunbergii flower EO.