Flavonoid-enriched extract from Forsythia suspensa leaf tea (FSLT-FE) attenuates cigarette smoke/lipopolysaccharide-induced COPD-like lung injury in mice: UPLC-MS profiling and network pharmacology analysis

Flavonoids from Forsythia suspensa leaves may benefit Chronic obstructive pulmonary disease (COPD) through anti-inflammatory and antioxidant mechanisms, but the underlying pathways remain poorly defined. We profiled a flavonoid-enriched extract from F. suspensa leaf tea (FSLT-FE) by ultra-performance liquid chromatography–mass spectrometry (UPLC-MS) and evaluated its efficacy in a cigarette smoke/LPS-induced COPD mouse model, complemented by network pharmacology. UPLC-MS identified 62 constituents, including rutin, quercetin, hesperidin, caffeic acid, forsythoside A, and phillygenin. FSLT-FE dose-dependently attenuated lung inflammation and structural damage, reduced IL-6, TNF-α, CXCL1/KC (the murine functional homologue of human IL-8), IL-1β, and malondialdehyde levels, and increased superoxide dismutase and catalase activities. Network pharmacology identified 23 active ingredients targeting 98 COPD-associated proteins, including AKT1, MAPK1, MMP2, and epidermal growth factor receptor (EGFR), with enrichment in NF-κB, PI3K-Akt, MAPK, and IL-17 signalling pathways. These results indicate that FSLT-FE acts on inflammatory and oxidative stress pathways through multiple components, supporting its potential as a protective agent against COPD-like lung injury.