Biochemical and Histochemical Assessment of the Protective Effects of Aqueous and Ethanol Fruit Extracts of Phoenix Dactylifera on Mercury-induced Liver Toxicity

Abstract Background: Mercury is a highly toxic metal that causes severe damage to the body system of humans and animals that establish contact with it. Date palm (Phoenix dactylifera) fruits have been documented to possess several pharmacological abilities and have been used in traditional medicine worldwide. The present study was aimed at assessing the protective effects of aqueous and ethanolic fruit extracts of Phoenix dactylifera L. on mercury-induced liver damage toxicity in Wistar rats. Design; A total of forty-five (45) Wistar rats of male sex (80 – 125g) were randomly divided into nine groups (I-IX) of five (5) rats each. Group 1 served as the control and was administered distilled water (2 ml), group II was administered mercury chloride (HgCl2) only at 5 mg/kg body weight; group III was pretreated with silymarin at 100 mg/kg then followed by HgCl2 at 5 mg/kg; groups IV and V were pretreated with aqueous fruit extract of Phoenix dactylifera (AFPD) at 500 mg/kg and 1000 mg/kg respectively, followed by HgCl2 at 5 mg/kg; groups VI and VII were pretreated with ethanol fruit extract of Phoenix dactylifera (EFPD) at 500 mg/kg and 1000 mg/kg respectively, followed by HgCl2 at 5 mg/kg, while groups VIII and IX were treated with AFPD and EFPD only at 1000 mg/kg respectively. After two weeks of oral administration, the animals were humanely sacrificed using cervical dislocation method, and blood samples were collected through the jugular vein for biochemical studies (liver serum enzymes: Aspartate transaminase (AST), Alanine transaminase (ALT) and Alkaline phosphatase (ALP); and oxidative stress markers, (MDA, SOD, CAT, and GPx). Tissue samples of the liver were collected and processed for histochemical (Gordon and Sweet) stain analysis. Results: The results of the present study showed that toxicity and oxidative stress were induced by the significantly (p < 0.05) increased levels of ALP and MDA when compared to the control. Histochemical analysis revealed severe degenerative changes in the liver. Extracts (AFPD and EFPD) of P. dactylifera preserved liver serum enzymes and antioxidant enzyme activities to levels similar to that of the control. The effects of HgCl2 toxicity were ameliorated as observed by the remarkably decreased levels of MDA and significantly increased activity of SOD, as well as preserved histoarchitecture of the liver parenchyma when compared to the HgCl2-treated group. The protective activities of the extracts of Phoenix dactylifera could be attributed to the antioxidant properties of the constituent phytochemicals, such as flavonoids. Conclusion: Thus, these extracts could be potential candidates for use in the management and treatment of mercury-induced liver diseases in our localities.