Effects of organic acid in Folium Isatidis on the immune organ index and activity of enzymes involved in free radicals of immunosuppressed mice

This study aimed to investigate the effects of organic acid in Folium Isatidis (OAFI) on the antioxidant capacity of immunosuppressed mice. The immunosuppression model was established by administering dexamethasone (Dex) 1.25 mg·kg^-1, in vivo by subcutaneous injection. The thymus and spleen indices, MDA and H₂O₂ levels, and the activities of 4 enzymes that are related to free radical production and scavenging were measured after the mice were treated with 250 mg kg^-1 OAFI by gavage. OAFI significantly increased the spleen index of immunosuppressed mice, and it also decreased MDA and increased T-SOD, T-AOC, POD, and XOD levels of immunosuppressed mice. These results suggest OAFI can affect the production and elimination of free radicals by changing the activity of related enzymes, increasing the spleen index and decreasing MDA levels of peroxidation products. This would accordingly protect the immunological organs, so that they can resist the immunosuppression caused by Dex and strengthen immunity to diseases.