The impact of oleanolic and ursolic acid on corneal epithelial cells in vitro

Abstract

INTRODUCTION. Oleanolic (OA) and ursolic (UA) acids belong to the triterpene group widely present in plants. These compounds are recognised to have anti-inflammatory properties and thus are considered to be used in therapies as well as in cosmetic, natural health, or diet products.

AIM. The scientific hypothesis of our study was to show that OA and UA influence corneal epithelial cells cultured in vitro.

METHODS. Toxicity tests, based on MTT and Neutral Red (NR) uptake, measurement of nitric oxide (NOx) level, as well as analysis of metalloproteinases (MMP-2 and MMP-9) amount and activity were performed.

RESULTS . UA expressed significantly higher toxicity on cells than OA. At the lowest concentration applied (5 μM), UA limited cellular metabolism and viability on average by 22% as compared to untreated control, while 25 μM resulted in values lower than 10%. On the other hand, OA at the highest (100 μM) concentration limited cellular metabolism and viability by about 20%. NOx level significantly increased when OA and UA were applied at concentrations of 25 and 100 μM, respectively. OA and UA had a stronger impact on the level of MMP-2 than MMP-9. OA and UA reduced MMP-2 and MMP-9 in the whole range of concentrations. Tested triterpenoids had no significant impact on MMP activity.

CONCLUSIONS. OA and UA have a different impact on human corneal epithelial cells. UA is toxic for corneal epithelial cells, while OA exhibits milder activity, which may be useful for further analysis in ocular pharmacology.