Anti‑Fatigue Activities and Phytochemical Compositions of Turnip (Brassica rapa L.) Extracts

Objectives: The objective is to evaluate the anti‑fatigue properties and characterize the phytochemical compositions of turnip. Materials and Methods: Different proportions of turnip extract, including the total aqueous extract (50 mg/kg, per oral, [p. o.]), supernatant (50 mg/kg, p. o.), and polysaccharide (50 mg/kg, p. o.), were administered to mice, once a day for 20 days; following which, the exhaustive swimming time, liver and muscle glycogen, lactate dehydrogenase (LDH), creatine kinase (CK), blood lactic acid (BLA), and blood urea nitrogen (BUN) levels were tested. Ultra‑high‑performance liquid chromatography and Q‑Exactive Orbitrap high‑resolution mass spectrometry were used to analyze the turnip compounds. Results: Turnip, especially the supernatant portion, increased the exhaustive swimming time (476.01 ± 59.63 vs. 217.89 ± 32.70 s, P < 0.01), levels of liver glycogen (87.22 ± 16.28 vs. 18.53 ± 4.82 mg/kg, P < 0.01), and muscle glycogen (5.93 ± 0.51 vs. 2.56 ± 0.62 mg/kg, P < 0.01); decreased the activities of LDH (6,351.84 ± 344.81 vs. 7,359.54 ± 382.48 U/L, P < 0.01) and CK (974.66 ± 112.89 vs. 1,115.69 ± 113.52 U/L, P < 0.05); and decreased the levels of BLA (8.68 ± 1.86 vs. 10.99 ± 1.52 mmol/L, P < 0.05) and BUN (4.40 ± 0.44 vs. 5.21 ± 0.52 mmol/L, P < 0.01) when compared to the control group, and exhibited the best performance in relieving fatigue. Fourteen low‑molecular‑weight chemicals were detected in the supernatant portion, some of which had anti‑fatigue effects. Conclusion: Our findings suggest that turnip prevents fatigue in mice and has the potential to be developed into health products to reduce fatigue.