Topically applied water extract of propolis to suppress corneal neovascularization in rabbits

Purpose: Propolis, a natural honey bee hive product, has anti-inflammatory and antioxidative properties. We aimed to assess the possible contribution of topically applied propolis to the suppression of corneal neovascularization (CNV). Methods: The effect of a water extract of propolis (WEP) 1% drops (group 1) in comparison with dexamethasone 0.1% (group 2) and saline (group 3) on CNV was tested in rabbit corneas injured by silver nitrate cauterization. The extent of CNV was quantitated as the area of CNV and the percent area of CNV for each cornea of the three groups (12 right eyes per group) in the first week of the treatment. The mean percent CNV was used for statistical analysis. Results: The corneas treated with the topical WEP 1% had an almost equal percent CNV as compared with the corneas treated with topical dexamethasone 0.1% and had less percent CNV than the control eyes. The quantitative analysis in groups 1, 2 and 3 revealed that the mean percent CNV was 41.0 +/- 14.1, 39.4 +/- 11.0 and 56.9 +/- 18.4, respectively. The differences between both groups 1 and 3 as well as groups 2 and 3 were statistically significant (p = 0.02 and p = 0.01, respectively), whereas the difference between groups 1 and 2 was not significant (p = 0.86). Conclusions The topical application of a WEP 1% has an inhibitory effect on CNV in the rabbit's cornea. The inhibitory effect of propolis was shown to be comparable to that of topical dexamethasone 0.1%, a potent inhibitor of angiogenesis. We suggest that the effect of propolis may partially be due to its inhibitory effect on the activity of both cyclo-oxygenase and lipo-oxygenase.