Protective effects of inhalation of essential oils from Mentha piperita leaf on tight junctions and inflammation in allergic rhinitis

Updated epithelial barrier dysfunction in chronic rhinosinusitis: Targeting pathophysiology and treatment response of tight junctions

Tight junction (TJ) proteins establish a physical barrier between epithelial cells, playing a crucial role in maintaining tissue homeostasis by safeguarding host tissues against pathogens, allergens, antigens, irritants, etc. Recently, an increasing number of studies have demonstrated that abnormal expression of TJs plays an essential role in the development and progression of inflammatory airway diseases, including chronic obstructive pulmonary disease, asthma, allergic rhinitis, and chronic rhinosinusitis (CRS) with or without nasal polyps. Among them, CRS with nasal polyps is a prevalent chronic inflammatory disease that affects the nasal cavity and paranasal sinuses, leading to a poor prognosis and significantly impacting patients' quality of life. Its pathogenesis primarily involves dysfunction of the nasal epithelial barrier, impaired mucociliary clearance, disordered immune response, and excessive tissue remodeling. Numerous studies have elucidated the pivotal role of TJs in both the pathogenesis and response to traditional therapies in CRS. We therefore to review and discuss potential factors contributing to impair and repair of TJs in the nasal epithelium based on their structure, function, and formation process.

Peppermint and menthol: a review on their biochemistry, pharmacological activities, clinical applications, and safety considerations

In this manuscript, we conducted a comprehensive review of the diverse effects of peppermint on human health and explored the potential underlying mechanisms. Peppermint contains three main groups of phytochemical constituents, including essential oils (mainly menthol), flavonoids (such as hesperidin, eriodictyol, naringenin, quercetin, myricetin, and kaempferol), and nonflavonoid phenolcarboxylic acids. Peppermint exhibits antimicrobial, antioxidant, anti-inflammatory, immunomodulatory, anti-cancer, anti-aging, and analgesic properties and may be effective in treating various disorders, including gastrointestinal disorders (e.g., irritable bowel syndrome, dyspepsia, constipation, functional gastrointestinal disorders, nausea/vomiting, and gallbladder stones). In addition, peppermint has therapeutic benefits for psychological and cognitive health, dental health, urinary retention, skin and wound healing, as well as anti-depressant and anti-anxiety effects, and it may improve memory. However, peppermint has paradoxical effects on sleep quality and alertness, as it has been shown to improve sleep quality in patients with fatigue and anxiety, while also increasing alertness under conditions of monotonous work and relaxation. We also discuss its protective effects against toxic agents at recommended doses, as well as its safety and potential toxicity. Overall, this review provides the latest findings and insights into the properties and clinical effects of peppermint/menthol and highlights its potential as a natural therapeutic agent for various health conditions.