ABSTRACT

The in vitro antioxidant activity of the ethanolic extract of Coriandrum sativum (C. sativum) leaves was performed by DPPH scavenging and ferrous chelating methods. To induce allergic conjunctivitis, an intraperitoneal injection of 0.6 mL saline containing alum (2 mg), egg albumin (1 mg) and 1010 cells inactivated Bordetella pertussis was administered on the first day. On the fifth day, a booster dose was given subcutaneously, consisting of egg albumin (0.5 mg) injected at 10 sites on the back of rats. From the 14th to the 42nd day, rats were orally administered ethanolic extract of C. sativum eaves (EECS) in doses of 100 mg kg-1, 200 mg kg-1, and 400 mg kg-1, depending on their respective groups. The standard group received 10 mg kg-1 cetirizine hydrochloride orally. 1 h after dosing, local sensitization was performed by applying 5 µL of egg albumin into both eyes using a micropipette. It was noted how frequently eye-scratching behaviours occurred over a five-minute period following the sensitization. Allergic symptoms, including conjunctival redness and swelling, were evaluated at five and twenty minutes, respectively. After 24 h of 14th and 42nd day treatment, one animal from each group was euthanised. The conjunctiva was excised, and 4-µm-thick sections were stained to assess eosinophil infiltration. Results showed that the ethanolic extract of C. sativum leaves produced in vitro antioxidant properties by DPPH scavenging and metal chelating activity against iron, with IC50 values of 200 µg mL-1 and 2000 µg mL-1, respectively. The extract considerably reduced eosinophils infiltrating the conjunctival tissues (p<0.01) and significantly lowered allergy symptoms and eye scratching behaviours (p<0.001). Therefore, we conclude that the ethanolic extract of C. sativum leaves produced a significant anti-allergic conjunctivitis activity.