2.1. Preparation of ATMP

Acanthopanax trifoliatus (L.) Merr polysaccharide (ATMP) was extracted as previously described with modifications (14). The dry stem of Acanthopanax trifoliatus (L.) Merr was obtained from Enping (Guangdong, China). The powdered stem of Acanthopanax trifoliatus (L.) Merr was extracted with distilled water 1:10 (w/v) for 2 h at 100°C. The same process was repeated two times. The solvent was concentrated to 1/10 of the total volume under reduced pressure, and then the supernatants were gathered after centrifugation (4,500 r/min for 10 min). Two times absolute ethanol was added to the supernatant fluid, then the precipitations were collected by centrifuging at 4,500 r/min for 10 min after precipitating for 24 h. To remove water, sticky substances, and other impurities from the material, the precipitation was washed with absolute ethanol, diethyl ether, and acetone in turn, and the Acanthopanax trifoliatus (L.) Merr crude polysaccharide (ATMCP) was obtained by vacuum freeze-drying. After removing proteins via the Sevag method (27), ATMCP was dissolved in distilled water and centrifuged (8,000 r/min for 10 min). Consequently, the supernatants were purified successively by chromatography on the DEAE-52 cellulose column and then on the SephadexG-75 gel column. The eluent was collected, freeze-dried, and labeled as Acanthopanax trifoliatus (L.) Merr polysaccharides (ATMP).