Extraction, antioxidant and antibacterial activities of essential oils from Magnolia wufengensis

ObjectiveThe aim of this study is to establish a set of reliable process system for the extraction of essential oils from Magnolia wufengensis buds and provide technical support as well as theoretical reference for its subsequent development and application. The extraction process of essential oils from M. wufengensis buds was studied, and chemical compositions, antioxidant and antibacterial activities were identified and evaluated.

MethodBased on single-factor experiment, the supercritical CO₂ fluid extraction conditions of essential oils from air-dried buds of M. wufengensis ‘Jiaohong No.1’ were optimized by response surface methodology. Components of essential oils were qualitatively and quantitatively analyzed by automated mass spectral deconvolution and identification system combined with retention index. DPPH free radical scavenging method and reducing power method were used to analyze the antioxidant activity of essential oils. Disk diffusion method and broth microdilution method were used to measure the antibacterial activities.

ResultUnder the air-dried pretreatment condition, the optimum processing conditions for extracting essential oils from M. wufengensis were as follows: extraction temperature 47 ℃, extraction pressure 40.7 MPa, dynamic extraction time 102 min. The extraction yield of essential oils under this condition was (1.217 ± 0.014)%. A total of 30 components were identified, accounting for 70.65% of the total components. DPPH free radical scavenging method showed that the IC₅₀ value of essential oils was 12.82 mg/mL, and the AEAC value was 198.64 mg. The essential oils had certain antioxidant activity, and the reducing power method showed the same results. The inhibitory effect of essential oils on the four tested bacteria was in order of Staphylococcus aureus > Bacillus subtilis > Escherichia coli > Salmonella typhimurium.

ConclusionA feasible supercritical CO₂ extraction process of the essential oils from the air-dried buds of M. wufengensis was established for the first time. Furthermore, the main components of the essential oils were identified and its antioxidant and antibacterial activities were verified.