Bioprospecting the liver protective activity of betulinic acid isolated from the stem bark of Ziziphus mucronata Willd. subsp. mucronata

In traditional African medicine, Ziziphus mucronata Willd. subsp. mucronata is used in the treatment of chronic cough, boils, toothache, rheumatism, diabetes, hypertension, snake bite, dysentery, sexually transmitted infections and many other diseases. The present study sought to explore the hepatoprotective potential of the ethyl acetate extract of the stem bark of Z. mucronata and its isolated component, betulinic acid (BA), using carbon tetrachloride (CCl4) to induce acute damage in Sprague-Dawley rats. Thirty-five (35) male Sprague Dawley rats, were divided into seven (7) treatment groups of five (5) rats per group. The in vitro hepatoprotective effect of BA on human hepatocellular carcinoma (HepG2) hepatoblastoma was also investigated at concentrations of 0.01, 0.1 and 1 mu g/mL was investigated against paracetamol-mediated toxic induction. Treatment with the crude extract of Z. mucronata ethyl acetate and BA showed comparable results with rats treated with silymarin, significantly different (p < 0.05) from the induction control group in terms of reduction in serum aspartate, alanine amino transaminases, and alkaline phosphatase activities. Similarly a corresponding decrease in serum concentrations of cholesterol, total bilirubin, and triglycerides, as well as creatinine, uric acid, and urea, significantly (p < 0.05) different from the induction control was observed with our test samples. Rats co-administered with the crude extract or BA showed also increased glutathione (GSH) levels, catalase (CAT), and superoxide dismutase (SOD) activities and a concomitant decrease in malondialdehyde contents at a high dosage of crude extract or BA ethyl acetate, significantly (p < 0.05) different from untreated liver homogenates. The liver histology of the cotreatment groups revealed promising marked regeneration of the altered hepatocytes compared to the induction group. Furthermore, BA showed percentage protection of 7.77 %, 14.86 % and 17.78 %, comparatively at low concentrations with silymarin (34 %). Finally, molecular docking identified potential proteins, targeted by the isolated compound. The findings justify the crude extract of Z. mucronata stem bark ethyl acetate as complementary hepatoprotective agents and BA as the lead compound for the development of a potent hepatoprotective molecule.