NFKB1 and ulcerative colitis: The Flavonoid Extract of Polygonum viviparum L. Alleviates Dextran Sulfate Sodium-Induced Ulcerative Colitis by Regulating Intestinal Flora Homeostasis and Uric Acid Levels Through Inhibition of PI3K/AKT/NF-κB/IL-17 Signaling Pathway