Acute Toxicity Assessment, In Vitro Antacid and Cytoprotective Effects of Root Bark Aqueous Extract of Diospyros mespiliformis on Water Immersion Stress-Induced Gastric Ulcers in Rats.

Abstract

Objective: The objective of the present study was to evaluate the antacid and cytoprotective effects of root bark aqueous extract of Diospyros mespiliformis (RBAEDM). Materials and Methods: Thirty rats were grouped into six groups of five rats each, namely, three control groups (normal, negative and positive) and three test groups. These animals were treated with distilled water (normal and negative controls), verapamil (positive control) and the extract at doses of 100, 200 and 400 mg/kg (test groups). One hour after treatment, gastric ulcers were induced in all animals by immersion in water (22 ± 1°C) for 5 h except for the normal control. The ulcerated surface, mucus mass, in vivo oxidative stress parameters and nitrite levels were determined. In vitro antacid activity of the extract was evaluated on artificial gastric juice by the determination of pH, neutralization time and antacid capacity. Acute toxicity of extract was evaluated. Results: Treatment with RBAEDM showed a significant (p < 0.01, p < 0.001) decrease of ulcerated surface with a percentage of inhibition between 5.58% and 60.46%. The decrease in the ulcerated surface was accompanied by a significant (p < 0.001) increase in mucus production at 400 mg/kg. Treatment with RBAEDM also showed a significant (p < 0.001) decrease in malondialdehyde (MDA) levels and a significant increase in superoxide dismutase (SOD) level, catalase (CAT) activities, in addition to nitrite levels in stomachs. In artificial gastric juice, the RBAEDM caused a significant increase (p < 0.001) of neutralizing time and the number of neutralized H⁺ ions compared to distilled water. No change in behavioural parameters and no death was observed after administration of the extract at 2000 mg/kg. Conclusion: RBAEDM inhibited ulcer occurrence by the stimulation of mucus production, increase of antioxidant enzyme activity and NO production. Moreover, this study revealed that the studied extract could exert a strong anti-acid capacity in vitro due its ability for the neutralization of H⁺ ions. DL₅₀ of RBAEDM was greater than 2000 mg/kg.