Abstract
Acute pharyngitis is an inflammation of the pharyngeal mucous membrane and submucous lymphoid tissues. Unsatisfactory treatment and repeated occurrences might cause chronic pharyngitis and other complications. Syringa oblata L. (S. oblata) is a traditional Chinese medicine that exhibited a significant therapeutic effect on various inflammatory diseases. Its commercial drug Yan Li Xiao (YLX) capsule is used as a cure for the treatment of inflammatory diseases, such as bacillary dysentery, tonsillitis, bronchitis, and acute gastroenteritis. However, studies about S. oblata relieving acute pharyngitis are rare. In this study, high-performance liquid chromatography (HPLC) was used to analyze the chemical profile of S. oblata, and the bioactive phytoconstituents were isolated and identified by nuclear magnetic resonance (NMR) and mass spectrometry. An ammonia-induced acute pharyngitis rat model was established to estimate the protective effect of S. oblata in vivo for the first time. The severity of pharyngitis was observed by appearance index and HE staining. The cytokines expression was performed by ELISA. Crucial proteins expression associated with TLR4/NF-κB/MAPK and NLRP3 inflammasome signaling pathways were analyzed by western blotting and immunohistochemistry. Furthermore, the anti-inflammatory effect of isolated compounds was evaluated by suppressing lipopolysaccharide- (LPS-) induced NO generation and regulating the cytokines levels in RAW 264.7 cells. The results showed that S. oblata exhibited a protective effect in the ammonia-induced acute pharyngitis rat model, and the compounds exert potential anti-inflammatory properties against LPS-activated RAW 254.7 cells.
Highlights
Acute pharyngitis is the most common seasonal nonspecific inflammation among upper respiratory tract diseases [1,2,3]
Four main compounds with sharp peaks were shown in chromatography and the retention times were 22.65, 22.99, 25.54, and 26.13 min, respectively. e chemical profile of S. oblata was analyzed by highperformance liquid chromatography (HPLC) and is shown in Figure 3(a). 13C nuclear magnetic resonance (NMR) spectra and HR-ESI-MS [M-H]- peaks at m/z (Figures 3(b) and 3(c)) confirmed their molecular formulae. e structures of compounds were determined by comparing the NMR data with previous studies [25,28]
S. oblata is a traditional herbal medicine that has anti-inflammatory property, and its commercial drug Yan Li Xiao (YLX) capsule is extensively applied in a variety of acute and chronic inflammatory diseases [29]. e ammonia-induced acute pharyngitis rat model has been widely used as an experimental model in pharyngitis pathogenesis studies due to being highly consistent with clinical indicators as well as the characteristics of easy, reliable, and short duration. erefore, an ammoniainduced acute pharyngitis rat model was applied to evaluate the therapeutic effects of S. oblata in vivo in the present study for the first time. e administration dosage was calculated by coefficient commutation of somatotypes according to the human clinical dosage of the YLX capsule
Summary
Acute pharyngitis is the most common seasonal nonspecific inflammation among upper respiratory tract diseases [1,2,3]. Patients with pharyngitis mainly manifest severe itchy throat, cough, pain, congestion, swelling, fever, dryness, and loss of appetite [4]. Several treatment strategies, including antibiotics, antiviral drugs, and glucocorticoid hormones, are used for pharyngitis in clinical to relieve pain. These drugs have potential risks and side effects [7,8,9]. Current research mainly focused on infectious pharyngitis induced by virus and bacteria, while both preclinical and clinical epidemiological studies for noninfectious pharyngitis caused by an allergic reaction, smoking, alcohol intake, and so on are lacking [10]. Erefore, the development of safer and more effective therapeutic alternatives for noninfectious pharyngitis was limited under this situation Current research mainly focused on infectious pharyngitis induced by virus and bacteria, while both preclinical and clinical epidemiological studies for noninfectious pharyngitis caused by an allergic reaction, smoking, alcohol intake, and so on are lacking [10]. erefore, the development of safer and more effective therapeutic alternatives for noninfectious pharyngitis was limited under this situation
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