OBJECTIVE: To investigate the effect of zerumbone on HDM extract-induced airway epithelial barrier dysfunction.
MATERIALS AND METHODS: Human bronchial epithelial cells 16HBE14o- were incubated with 100 μg/mL HDM extract and treated with non-cytotoxic concentrations of zerumbone (6.25 μM, 12.5 μM, and 25 μM) for 24 h. The epithelial junctional integrity and permeability were evaluated through transepithelial electrical resistance (TEER) and fluorescein isothiocynate (FITC)-Dextran permeability assays, respectively. The localization of junctional proteins, occludin and zona occludens (ZO)-1, was studied using immunofluorescence (IF) while the protein expression was measured by western blot.
RESULTS: Zerumbone inhibited changes in junctional integrity (6.25 μM, p ≤ .05; 12.5 μM, p ≤ .001; 25 μM, p ≤ .001) and permeability (6.25 μM, p ≤ .05; 12.5 μM, p ≤ .01; 25 μM, p ≤ .001) triggered by HDM extract in a concentration-dependent manner. This protective effect could be explained by the preservation of occludin (12.5 μM, p ≤ .01 and 25 μM, p ≤ .001) and ZO-1 (12.5 μM, p ≤ .05 and 25 μM, p ≤ .001) localization, rather than the prevention of their cleavage.
DISCUSSION AND CONCLUSION: Zerumbone attenuates HDM extract-induced epithelial barrier dysfunction which supports its potential application for the treatment of inflammation-driven airway diseases such as asthma.
MATERIALS AND METHODS: The MEZZ was prepared by macerating oven-dried (50 degrees C) powdered rhizomes (1.2 kg) of Z. zerumbet in 80% methanol in a ratio of 1:20 (w/v) for 48 h. The supernatant was collected, filtered and evaporated to dryness under reduced pressure (50 degrees C) yielding approximately 21.0 g of the crude dried extract. The crude dried extract was stored at -20 degrees C prior to use and was dissolved in normal saline (0.9% NaCl) immediately before administration at concentrations required to produce doses of 25, 50 and 100 mg/kg.
RESULTS: All dosages of MEZZ showed significant (p < 0.05) antiedema activity when assessed using the carrageenan-induced paw edema test and the cotton-pellet-induced granuloma test. The MEZZ exhibited significant (p < 0.05) antinociceptive activity when assessed by the writhing, hot plate and formalin tests. Pretreatment with naloxone (5 mg/kg) significantly decreased the latency of discomfort produced by the 100 mg/kg dose of MEZZ in the hot plate test.
CONCLUSION: MEZZ produced antiinflammatory and antinociceptive activities which may involve the inhibition of bradykinin-, prostaglandin-, histamine- and opioid-mediated processes.