Active ingredients targeting Nrf2 in the Mongolian medicine Qiwei Putao powder: Systematic pharmacological prediction and validation for chronic obstructive pulmonary disease treatment

Qiwei Putao powder (Uzhumu-7 in Mongolian) is a traditional Mongolian medicine, which has been widely used for alleviating cough and dyspnea, especially in aged individuals in both Inner Mongolia Autonomous Region and Xinjiang Uygur Autonomous Region of China. However, the active ingredients and exact pharmacological mechanism remain unclear.The protective effect of Qiwei Putao powder (QPP) on mice with cigarette smoke (CS)- and lipopolysaccharide (LPS)-induced chronic obstructive pulmonary disease (COPD) was assessed by histopathological hematoxylin and eosin staining, lung coefficient determination and measurement of cytokine levels. The bioactive ingredients and potential targets of the QPP were screened and detected with network pharmacology method and ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS). The mechanism and efficacy of active ingredients were further validated in COPD mice with immunohistochemistry tests, cytokine level measurement and RT-PCR. The expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) in the nucleus, interleukin (IL)-1β, superoxide dismutase (SOD), malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA) kits to evaluate oxidative stress and inflammatory conditions in vivo after treatment. The expression of Nrf2 and downstream genes was detected by RT-PCR.QPP can alleviate pathological changes in the lung during COPD progression. Sixty-one bioactive molecules were identified in QPP, 42 candidate compounds present in UPLC-Q/TOF-MS and 30 predicted COPD-related targets were generated by in silico analysis. A therapeutic network was constructed with all potential targets to predict the preventive effects of the targets on respiratory disease as well as cardiovascular diseases, nervous system diseases, musculoskeletal diseases and bacterial infections. Targets related to inflammation, immunity and oxidative stress (prostaglandin-endoperoxide synthase 2, PTGS2; Nrf2; heat shock protein 90 alpha class A1, HSP90AA1; nitric oxide synthase, NOS2A; etc.) influenced COPD progression the most. We found that Nrf2 promotes a cell antioxidant response and is a key common target in the response to treatment with isoliquiritigenin (ISL), pterostilbene (PTE) and quercetin (QUE), the highly absorbed active ingredients in the formula. The data showed a strong synergistic protective role of these three molecules against the death of human type II alveolar adenocarcinoma (A549) cells through Nrf2 activation following H₂O₂ exposure and provide pharmacological mechanism of QPP in COPD treatment.