Effect of Propolis on clinical and physiological parameters of moderate Asthma. A double blind randomized placebo- controlled clinical trial.

Introduction: Propolis is produced by honey bee, but it seems that its constituent is different from honey. Propolis was used by folk medicine for treatment of asthma but most of the studies were experimental. The objective of this study was to determine the effect of Propolis on clinical and physiological findings of moderate persistent asthma.
Design: Prospective, randomized, double blind, placebo-controlled, clinical trial.
Participants including major eligibility criteria: We enrolled patients aged 15-90 years with moderate asthma and FEV1 of 60-79% of predicted at a sub-specialty clinic of pulmonary medicine. We randomly allocated subjects to receive either Propolis (75 mg three times a day) or matched placebo for one month.
Primary outcome was ACT (Asthma control test) score and secondary outcomes included dyspnea, Spirometry, FENO (Fractional Exhaled Nitric Oxide) and Sputum cytology including inflammatory cell. Sputum induction was made by hypertonic saline and cytology slides were stained by Papa Nicolaou stain.
Results: Fifty two subjects were enrolled in this study and completed the course of therapy. Clinical findings including cough, dyspnea, wheezing, Sputum, post nasal drip, Nocturnal symptoms, Acute attack and wheezing were significantly improved after the treatment. ACT score was also significantly increased by Propolis (12.8±5.5 before and 18.1±4.99 after the trial) which was significantly higher than placebo (14.4±6.6 after the trial). The most significant physiological improvements were significant increase of FEV1, FEFV1/FVC, FEF25-75 and PEFR. FENO showed significant decrease in Propolis group, on the contrary it was increased in placebo group. Cytological examination of sputum showed that the pattern of inflammation was eosinophilic in 44% of subjects with average eosinophil of 7.2±1.01%. The eosinophilia was significantly decreased by Propolis after the trial (4.3±3.1%), but it was significantly increased in placebo group (11.1±6.6%).
Conclusion: Propolis improved the clinical and physiological findings of moderate persistent of asthma, and it was also able to suppress the eosinophilic inflammation.