Abstract: To optimize the ultrasound-assisted extraction of polysaccharides from Artemisia lavandulaefolia leaves and stems, a multiple quadratic regression describing the relationship between the extraction rate of polysaccharides and extraction parameters such as extraction time, temperature and ratio of water to material was established using a 3-factor, 3-level Box-Behnken statistical design, and response surface and contour plots with the extraction rate of polysaccharides as the response were drawn based on the model. The optimum conditions for extracting polysaccharides from Artemisia lavandulaefolia leaves and stems were determined as follows: ultrasound treatment time 35 min, temperature 70 ℃ and ratio of water to raw material 40 mL/g. Under such conditions, the relative error between the experimental and theoretical extraction rates of polysaccharides was 4.02%, indicating that the goodness of fit of the established regression model is quiet good. Polysaccharides from Artemisia lavandulaefolia leaves and stems had strong total antioxidant capacity and showed scavenging ability towards DPPH free radicals.

Key words: Artemisia lavandulaefolia, polysaccharides, response surface analysis methodology (RSM), ultrasound-assisted extraction, antioxidant activity