Publication Details
Abstract
Objective: Menthol and eucalyptus-derived 1,8-cineole are widely used in cooling-aromatic respiratory products, but their physiological relevance depends on both sensory delivery and preservation of volatile constituents during manufacture. We evaluated a sugar-free herbal hard candy containing eucalyptus oil microcapsule powder and menthol, with emphasis on 1,8-cineole retention, flavor uniformity and the human evidence linking menthol/cineole exposure to cough sensitivity and respiratory comfort. Method: In the optimized process, eucalyptus oil was microencapsulated with maltodextrin and gum arabic, spray-dried, and added together with menthol only after the candy mass had cooled to 92°C. Results: Relative 1,8-cineole retention reached 82.1%, compared with 64.5% when an equivalent amount of liquid eucalyptus oil was directly incorporated and 68.2% when the microcapsule fraction was added at 128°C. The optimized candy also produced highly uniform eucalyptus flavor and high overall sensory acceptance. Human challenge studies show that menthol can increase capsaicin or citric-acid cough thresholds in healthy subjects and in patients with chronic cough, with cough-count responses varying across studies. Separately, oral cineole at pharmacological doses has demonstrated symptom-related effects in randomized studies of acute bronchitis, asthma and chronic obstructive pulmonary disease. Novelty: The NVTIA formulation therefore combines a manufacturing strategy that preserves a volatile eucalyptus marker with a menthol-cineole sensory architecture that has independently measurable human physiological correlates. The current findings provide a formulation-level basis for future studies using cough-urge, cough-challenge, perceived airway cooling and respiratory-comfort endpoints under product-specific exposure conditions.