Quercetin in Idiopathic Pulmonary Fibrosis and Its Comorbidities: Gene Regulatory Mechanisms and Therapeutic Implications.

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive interstitial lung disease associated with high morbidity and mortality. Both pulmonary and extrapulmonary comorbidities significantly influence disease progression and patient outcomes. Despite current therapeutic options, effective treatments remain limited. Quercetin, a naturally occurring flavonoid, has emerged as a promising compound due to its antioxidant, anti-inflammatory, and antifibrotic properties. Preclinical and clinical studies have demonstrated its ability to modulate key molecular pathways involved in IPF, including Nrf2, SIRT1/AMPK, and the regulation of fibrosis-associated microRNAs (miRNAs). Furthermore, quercetin shows therapeutic potential across a range of IPF-related comorbidities, including chronic obstructive pulmonary disease, pulmonary hypertension, lung cancer, cardiovascular disease, diabetes, and psychiatric disorders. Under these conditions, quercetin acts via epigenetic modulation of miRNAs and regulation of oxidative stress and inflammatory signaling pathways. This review highlights the multifunctional role of quercetin in IPF and its comorbidities, emphasizing its gene regulatory mechanisms and potential as an adjunctive or alternative therapeutic strategy.