Medicinal plants were used to prevent and treat numerous gastrointestinal disorders owing, in part, to their antioxidant capacity. The protective effects of Diospyros kaki fruit aqueous extract (DKFAE) against castor oil (CO)-induced diarrhea was studied. The in vitro antioxidant and antibacterial properties were investigated using colorimetric and biochemical analyses. In vivo, 60 male rats were divided into 6 groups of 10 animals each (n = 10): control (C), CO, CO+various doses of DKFAE (100, 200, and 400 mg/kg, b.w., p.o.), and CO+loperamide (LOP, 10 mg/kg, b.w., p.o.).The DKFAE was rich in tannins and showed interesting antioxidant and antibacterial activities. The liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis resulted in the identification of 16 phenolic compounds, among which quinic acid was the main one. The in vivo study showed that diarrhea was accompanied by an oxidative stress status as measured by an increase of lipid peroxidation, a decrease of glutathione and thiol group levels, as well as antioxidant enzyme activity depletion, such as glutathione peroxidase, superoxide dismutase, and catalase. The DKFAE administration significantly decreased the gastrointestinal transit in a dose-dependent manner. Besides, DKFAE protected against CO-induced diarrhea and intestinal fluid accumulation. Interestingly, DKFAE pretreatment counteracted all the oxidative stress status deregulation induced by CO intoxication. D. kaki fruit could be suggested for its strong protective effect against CO-induced acute diarrhea, which could be explained, in part, to its antimicrobial and antioxidant properties.
Keywords: Diospyros kaki; antimicrobial activity; antioxidant properties; diarrhea; oxidative stress; rat.