Synergistic effect of paeoniflorin combined with luteolin in alleviating Lipopolysaccharides-induced acute lung injury

Acute lung injury (ALI) is an acute multifactorial infectious disease caused by trauma, pneumonia, shock and sepsis. Paeoniae Radix Rubra (Paeonia lactiflora Pall. or Paeonia veitchii Lynch, Chishao in Chinese, CS) and Salviae Miltiorrhizae Radix et Rhizoma (Salvia miltiorrhiza Bge., Lamiaceae, Danshen in Chinese, DS) are common traditional Chinese medicines (TCMs). CS-DS herb pair has been widely used to promote blood circulation and eliminate blood stasis in Chinese clinical practice, appearing in a variety of prescriptions. However, it is still unclear for the effect and active ingredients of the herb pair on ALI. The study investigated the effect and active ingredients of CS-DS herb pair and demonstrated the synergistic effect and mechanisms of the active ingredients. Lipopolysaccharides (LPS)-stimulated RAW264.7 macrophage cells and BALB/c mice were used to establish an ALI model to investigate the effect of CS-DS herb pair on ALI. Network pharmacology and molecular docking were used to analyze the active ingredients and potential mechanisms of the herb pair. The synergistic effects and mechanisms of active ingredients on ALI were validated by in vitro and in vivo experiments. CS-DS herb pair had a synergistic effect on LPS-induced ALI. Based on the network pharmacology, the compounds paeoniflorin and luteolin were screened. Both paeoniflorin and luteolin had good affinity for NF-κB and MAPK by molecular docking. LPS stimulation of RAW264.7 cells resulted in a significant increase in ROS, NO, TNF-α, IL-6 and IL-1β, while the paeoniflorin combined with luteolin significantly reduced their expressions. In the LPS-induced ALI model, the combination also reduced the expression of inflammatory factors and oxidative stress levels. Furthermore, LPS activated the NF-κB and MAPK signaling pathways, whereas the combination decreased the expression of proteins in both pathways. CS-DS herb pair alleviated LPS-induced ALI with the active ingredients paeoniflorin and luteolin, which suppressed inflammation and oxidative stress via regulation of NF-κB and MAPK signaling pathways.