Ethanolic Extract of Sophora moorcroftiana Seeds Attenuates LPS-Induced Inflammation and Oxidative Stress in RAW 264.7 Macrophages via Modulation of the p62/Keap1/Nrf2 Signaling Pathway

Despite the traditional application of Sophora moorcroftiana seeds (SMS) in Tibetan medicine for heat-clearing, damp-drying, anti-inflammatory and detoxifying properties, the anti-inflammatory mechanisms of SMS remain insufficiently understood and warrant systematic investigation. This study evaluated the protective effects of an ethanolic SMS extract against lipopolysaccharide (LPS)-induced oxidative stress and inflammation in RAW 264.7 macrophages, with emphasis on the p62/Keap1/Nrf2 signaling pathway. In vitro, the extract exhibited significant DPPH, ABTS and ·OH radical scavenging activities, as well as ferric-reducing antioxidant power, in a clear concentration dependent manner. An inflammatory model was established by stimulating RAW 264.7 cells with LPS, followed by treatment with graded concentrations of the ethanolic SMS extract. The extract significantly reduced LPS-induced nitric oxide production and decreased the secretion of TNF-α, IL-6 and IL-1β, while suppressing iNOS and COX-2 expression at both mRNA and protein levels. In parallel, the extract alleviated oxidative stress, as evidenced by reduced intracellular reactive oxygen species (ROS) and MDA levels, increased antioxidant defenses including SOD, GSH and CAT, and decreased LDH release. At the protein-expression level, SMS treatment was accompanied by differential changes in p62, Keap1, total Nrf2 and HO-1 expression, suggesting that its effects may involve regulatory processes associated with cellular stress and antioxidant defense. Collectively, the ethanolic extract of SMS attenuated LPS-induced inflammatory and oxidative stress responses in RAW 264.7 macrophages. These effects may be associated with the suppression of inflammatory mediator production, reduction in the cellular oxidative stress burden and modulation of proteins involved in cellular stress responses and antioxidant defense.