Abstract:Sea cucumber freeze-dried powder was prepared by vibration-assisted milling combined with enzymatic hydrolysis.The antioxidant activity of the sea cucumber freeze-dried powder was evaluated based on the DPPH and hydroxyl radical scavenging rates and reducing power.The anti-tumor activity was examined based on the proliferation inhibition rate of HeLa cells.The rotarod test of mice and the blood lactic acid（LA）content were employed to measure the anti-fatigue activity.The mouse model of cyclophosphamide（CY）-induced immune deficiency and the immunoglobulin G（IgG）content were employed to assess the immunity-enhancing activity of the powder.The prepared sea cucumber freeze-dried powder showed the IC50 of 12.46 mg/mL and 15.22 mg/mL for scavenging DPPH and hydroxyl free radicals，respectively，and the reducing power of 0.35，which indicated that the sea cucumber freeze-dried powder possessed antioxidant activity.The sea cucumber freeze-dried powder showed the IC50 of 556.2 μg/mL on the proliferation of HeLa cells，demonstrating anti-tumor activity.The administration of sea cucumber freeze-dried powder prolonged the duration of rotarod exercise of mice in a dose-dependent manner，and the LA content（19.15 mmol/L）in the high-dose group piled up less after exercise，which suggested that the powder improved the exercise endurance of mice.Furthermore，the sea cucumber freeze-dried powder slowed down the body weight loss in the mouse model of CY-induced immune deficiency in a dose-dependent manner，and the IgG content in the high-dose group was restored to 11.98 mg/mL.In conclusion，sea cucumber freeze-dried powder has antioxidant，anti-tumor，anti-fatigue，and immunity-enhancing activities.