NFKB1 and idiopathic pulmonary fibrosis: While the flavonol quercetin exhibits established anti-inflammatory and antioxidant properties, its therapeutic mechanisms against IPF—particularly regarding epithelial-mesenchymal transition (EMT) and inflammation regulation via the follistatin-like 1 (FSTL1)/nuclear factor kappa B (NF-κB) axis—remain incompletely elucidated.