Optimization of ultrasound-assisted alcohol extraction process of Mori Fructus anthocyanins and its anti-exercise fatigue effect

This study aims to optimize the ultrasound-assisted ethanol extraction process of anthocyanins from Mori Fructus and evaluate their anti-exercise fatigue activity. Using Mori Fructus as the raw material, the extraction process was optimized through single-factor experiments combined with Box-Behnken response surface methodology, focusing on ethanol concentration, ultrasonic time, and liquid-to-solid ratio. A mouse model of weight-loaded swimming fatigue was established. SPF-grade male mice were randomly divided into a blank control group and low-, medium-, and high-dose groups (1.7, 16.8, and 50.0 mg/kg·BW). After 30 days of continuous intragastric administration, the exhaustive swimming time and related biochemical indicators including blood lactic acid, hepatic glycogen, hemoglobin, and blood urea nitrogen were measured. The results showed that the optimal extraction conditions were as follows: ethanol concentration of 64%, ultrasonic time of 42 min, and a liquid-to-solid ratio of 27∶1 (mL/g). Under these conditions, the anthocyanin yield reached 44.91 ± 1.03 mg/g (n=3). Animal experiments revealed that, compared with the blank control group, the low-dose Mori Fructus anthocyanins significantly increased hepatic glycogen content (P < 0.05). The medium- and high-dose Mori Fructus anthocyanins extremely significantly prolonged the exhaustive swimming time of mice, reduced blood lactic acid levels, and increased hepatic glycogen content (P < 0.01), while significantly decreasing blood urea nitrogen levels (P < 0.05). All dosage groups showed a significant increase in hemoglobin content (P < 0.05), and all observed effects exhibited a good dose-dependent manner. This indicates that Mori Fructus anthocyanins extracted by the ultrasound-assisted ethanol method possess good anti-exercise fatigue effects.