Ethnopharmacological relevance: Angelica decursiva Franchet & Savatier is a traditional medicinal plant used to treat asthma, cough, headache, pyrexia and thick phlegm in China, Japan and Korea. A. decursiva contains many types of coumarins, which can exert several pharmacological activities including anti-inflammatory and antioxidant properties for treating various diseases such as pneumonitis, atopic dermatitis, diabetes, and Alzheimer's disease.
Aim of the study: In this study, we analyzed the components of A. decursiva ethanol extract (ADE) by high performance liquid chromatography (HPLC) and investigated the therapeutic effects of ADE against allergic asthma using lipopolysaccharide (LPS) stimulated RAW264.7 cells and an ovalbumin (OVA)-exposed allergic asthma model. To elucidate the mechanism of action of ADE, we examined the protein expression through network pharmacological analysis.
Materials and methods: To establish asthma model, the mice were sensitized on day 0 and 14 via intraperitoneal injection of OVA with aluminum hydroxide. The mice were inhaled with OVA using an ultrasonic nebulizer on day 21, 22 and 23. ADE (50 and 100 mg/kg) was administered to mice by oral gave form day 18-23. On day 24, airway hyperresponsiveness (AHR) was measured using flexivent. On day 25, the mice were sacrificed and collected bronchoalveolar lavage fluids (BALF), serum and lung tissue. In LPS-stimulated RAW264.7 cell, nitric oxide and cytokines were measured. Additionally, expression of nuclear factor erythroid-2-related factor (Nrf2) and suppression of nuclear factor (NF)-κB were detected using double-immunofluorescence.
Results: We detected the five coumarin components which included nodakenin, umbelliferon, (-)-marmesin (=nodakenetin), bergapten, and decursin, in ADE by high performance liquid chromatography. Treatment with ADE decreased the production of nitric oxide, interleukin (IL)-6 and tumor necrosis factor (TNF)-α in LPS-stimulated RAW264.7 cells accompanied by the enhanced expression of nuclear factor erythroid-2-related factor (Nrf2) and suppression of nuclear factor (NF)-κB. In the asthma model, the administration of ADE reduced inflammatory cell count and airway hyperresponsiveness in OVA-exposed animals with decreased levels of IL-4, IL-13, and OVA-specific immunoglobulin E. These results were accompanied by the reduction of pulmonary inflammation and mucus secretion. Furthermore, ADE administration inhibited the expression of NF-κB and matrix metalloproteinase (MMP)-9 in OVA-exposed animals, which was consistent with the results of network pharmacological analysis.
Conclusion: This study demonstrated that ADE effectively attenuated allergic inflammation induced by OVA inhalation through the enhancement of Nrf2 expression and suppression of NF-κB expression. Therefore, ADE may be a potential therapeutic agent for controlling asthma.
Keywords: Angelica decursiva Franchet & Savatier; Asthma; NF-κB; Network pharmacology; Nrf2.
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