'Pterocephalodes hookeri-Onosma hookeri' decoction protects against LPS-induced pulmonary inflammation via inhibiting TLR4/NF-κB signaling pathway

Ethnopharmacological relevance: As the second-largest traditional medical system in China, Tibetan medicine has a long history and abundant resources. To promote the development of the Tibetan medicine industry, it is essential to study the pharmacological activities of Tibetan medicine based on its traditional usage methods. Aim of the study: Pneumonia has been a worldwide health problem with high morbidity and mortality rates, especially in the context of the COVID-19 epidemic. Given the unique advantages of traditional Tibetan medicine in treating pulmonary diseases, further research is warranted to develop potential anti-pneumonia drugs. Materials and methods: In our study, the potential combined decoction from traditional Tibetan medicine was determined by the data mining method. The antioxidant activity in vitro, anti-inflammatory effects on the macrophage cell model, as well as the anti-pulmonary inflammation effects on the LPS-induced mice model, have been explored to investigate the potential anti-pneumonia role of the decoction. Additionally, we conducted network pharmacology analysis to identify the potential targets against pneumonia, which were further confirmed by western blot assays. Results: Following the combination therapy of Pterocephalodes hookeri (C.B.Clarke) V.Mayer & Ehrend. and Onosma hookeri var. longiflora (Duthie) A.V.Duthie ex Stapf ('P-O'), the clearance of DPPH radical and the total reducing power were all improved, as well as alleviated the toxicity. On the in vitro level, 'P-O' pre-treatment reduced the secretion of NO, TNF-alpha, IL-6, and IL-1 beta in LPS-stimulated RAW264.7 cells, while promoting the concentration of IL-10. Meanwhile, on the in vivo level, the 'P-O' pre-treating also could alleviate LPS-induced pulmonary inflammation by reducing the pulmonary edema and leakage of the lung microvascular, improving the pathological change of lung tissue and regulating the cytokines content in bronchoalveolar lavage fluid (BALF). Furthermore, network pharmacology analysis revealed that the mechanism of 'P-O' in treating pneumonia in a multi-component, multi-target, and multi-pathway network, with the TLR4/NF-kappa B signaling pathway playing a crucial role, as demonstrated by the western blot assay results. Conclusion: In summary, the combination therapy of 'P-O' exhibited good antioxidant activity and anti-inflammatory activity in vitro, as well as a therapeutic effect against pulmonary inflammation in vivo. These findings provide evidence for the clinical application of 'P-O' and offer new approaches for treating pneumonia.