Antiinflammatory effects of euclyptol (1.8-cineole) in bronchial asthma: inhibition of arachidonic acid metabolism in human blood monocytes ex vivo.

Monoterpenes are prescribed to treat chronic obstructive airway disorders mainly because of their familiar secretolytic properties. The aim of this study was to investigate the effect of 1.8-cineole (Soledum) on arachidonic acid (AA) metabolism in blood monocytes of patients with bronchial asthma. Patients with bronchial asthma (n = 10) and healthy test subjects (n = 12) were included in the study. Production of the representative AA-metabolites LTB4 and PGE2 from isolated monocytes stimulated with the calcium ionophore A23187 were measured ex vivo before therapy with 1.8-cineole (3 x 200 mg/day), after three days of treatment (day 4) and four days after discontinuation of 1. 8-cineole (day 8). The production of LTB4 and PGE2 from monocytes ex vivo was significantly inhibited on day 4 in patients with bronchial asthma (-40.3%, n = 10 and -31.3%, p = 0.1, n = 3 respectively) as well as in healthy volunteers (-57.9%, n = 12 and -42.7%, n = 8 respectively). In conclusion, 1.8-cineole was shown to inhibit LTB4 and PGE2, both pathways of AA-metabolism. Further studies are needed to show that 1.8-cineole is suitable in the treatment of bronchial asthma.