Abstract:The ultrasonic-assisted extraction with 95% ethanol was used to generate a crude extract from Artemisia lavandulaefolia. Then the dried crude extract paste was treated sequentially with petroleum ether, ethyl acetate and n-butanol to obtain different extraction fractions. Steam distillation was used to extract the volatile oil from Artemisia lavandulaefolia. The in vitro antibacterial activity of each fraction of the crude extract and the volatile oil against Staphylococcus aureus was examined using the filter paper dilution system and double diluting method. The effect of Artemisia vlavandulaefolia extract on the growth curve of Staphylococcus aureus was studied. The in vivo antibacterial activity was investigated using Kunming mice. In vitro experiments revealed that the antibacterial ability of each fraction of the crude extract or volatile oil followed this order: ethyl acetate phase > n-butanol phase > petroleum ether phase = volatile oil. No antibacterial activity was detected for the aqueous fraction. The minimum inhibitory concentrations (MICs) of the petroleum ether phase, ethyl acetate phase, n-butanol phase, and volatile oil were 10.00, 2.50, 5.00, and 10.00 mg/mL respectively. The ethyl acetate and n-butanol fractions exhibited significant inhibitory effects on the growth of Staphylococcus aureus (p<0.05). The results of in vivo experiments showed that the highest in vivo antibacterial activity was detected when the mice were fed 0.50 g/kg of wild Artemisia lavandulaefolia extract, with the mortality rate being 77.78% lower than the model group. Thus, the extract of Artemisia lavandulaefolia has antibacterial activity against Staphylococcus aureus.
