Magnolia kobus DC leaf ethanol extract alleviated lipopolysaccharide-induced acute lung inflammation by suppressing NF-κB and Nrf۲ signaling

Introduction: Magnolia kobus DC has been used as herbal medicine to treat coughs and is known to exert biological effects such as anti-inflammatory, antioxidant, and antibacterial properties. We aimed to define the pharmacological effects of M. kobus leaf ethanol extract (MLEE) on acute lung inflammation and explore the underlying mechanisms of action. Methods: For in vitro investigations, RAW ۲۶۴.۷ cells were pretreated with MLEE (۱, ۱۰, and ۱۰۰ μg/mL) and stimulated with lipopolysaccharide (LPS). For in vivo investigations, BALB/c mice were intratracheally administered with LPS for ۲۴ hours after injection of MLEE (۰.۳, ۳, and ۳۰ mg/kg). Hematoxylin and eosin staining was used for histopathology analysis of lung tissue. The phytochemical constituents of MLEE were analyzed using high-performance liquid chromatography. Results: In RAW ۲۶۴.۷ cells, MLEE reduced the activation of the inflammatory mediators (inducible nitric oxide synthase and cyclooxygenase-۲) and the nuclear translocation of nuclear factor (NF)-κB and nuclear factor erythroid-۲-related factor ۲ (Nrf۲). The intraperitoneal injection of MLEE (۳۰ mg/kg) attenuated interstitial edema and immune cell infiltration in LPS-induced acute lung inflammation. MLEE also inhibited the activation of cyclooxygenase-۲, NF-κB, and Nrf۲ in the lung tissue. Conclusion: Taken together, MLEE exerted an anti-inflammatory effect by inhibiting inflammatory and oxidative mediators on acute lung inflammation suggesting that it might be used as a natural drug for treating acute lung inflammatory diseases.