Phenolic profile and chronic gastric ulcer healing effects of Cameroonian propolis

Gastric ulcers continue to affect millions of people worldwide, with reported cases of fatalities and the diagnosis, prevention and treatment constitute a burden on the patients especially in case of chronic ulcers which are difficult to treat. Natural medicines such as propolis provide suitable therapeutic alternatives in the treatment and curation of ulcers. This work focused on the evaluation of the phenolic profile and healing effect of Cameroonian propolis on gastric ulcers in rats. Identification and quantification of phenolic compounds in the propolis extract was done using HPLC-DAD. Chronic gastric ulcers were induced using ethanol (70%; 1 mL/200 g p.o.)/indomethacin (1 mg/kg p.o.), and "unhealed" gastric ulcerations were induced using acetic acid (30%)/indomethacin (1mg/kg p.o.). The animals were administered with the vehicle (tween 20, 1 mL/100 g p.o.), propolis extract (200, 400 and 600 mg/kg p.o.) or sucralfate (50 mg/kg p.o.), once daily for ten to fourteen days. At the end of each treatment period, the animals were sacrificed and ulcer indices, gastric mucus weight, histological and oxidative stress parameters were assessed. Eight phenolic compounds were identified and quantified and most abundant were Caffeic acid (45.31±0.25 µg/g), Chrysin (37.65±0.17 µg/g) and p-Hydroxy benzoic acid (34.14±0.21 µg/g). The treatment of ulcerated rats (chronic and unhealed gastric ulcer models) with propolis extract at 200, 400 and 600 mg/kg resulted in reduction of ulcer index compared to negative controls in both models. Histological observation of stomach tissues showed that treatment with propolis extract led to a dose-dependent normalization of the mucosa. There was a significant increase (P < 0.5; P < 0.01 and P < 0.001) in mucus weight that accompanied the healing of the ulcers. Furthermore, doses of 200, 400 and 600 mg/kg of the propolis extract induced an increase in the amounts of SOD, catalase, nitrite and GSH while MDA concentrations decreased in both models. The healing effect of propolis extract is due to the stimulation of mucus production followed by an improvement of in vivo antioxidant status. These results support the use of propolis in the development of new pharmacological strategies for the management of peptic ulcers disease.