ABSTRACT
Aim: This study was carried out to assess the antioxidant and hepatoprotective properties of the extract and fractions of Annona senegalensis stem bark through in vitro and in vivo experimental models. Study Design: The study followed a completely randomized design (CRD) of groups of treatments and control samples for all the tests. Place and Duration of Study: Department of Pharmacognosy and Environmental Medicines, University of Nigeria, Nsukka, between January and September 2016. Methodology: Phytochemical constituents and in vitro antioxidant activities using different models (reducing power, DPPH free radical scavenging, ABTS radical scavenging, Hydroxyl radical scavenging, Hydrogen peroxide scavenging, β-carotene bleaching, FRAP scavenging and superoxide radical scavenging assays) were carried out. In vivo antioxidant activity was determined from the assays of lipid peroxidation, superoxide dismutase and total protein while hepatoprotective activity was evaluated against CCI4 induced liver damage and elevated serum marker enzymes. Results: The results showed that the extract and fractions of stem bark of A. senegalensis had appreciable amounts of total flavonoids (845.67±93.62 mg/g) and total phenols (866.67±8.41), and exhibited good antioxidant activities at higher concentrations. Doses of the extract and fractions administered at 400 mg/kg protected the CCI4–induced lipid peroxidation and significantly (P = .05) reduced the elevated serum marker enzymes - aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphate (ALP), and bilirubin level on a dose and solvent dependent fashion. At 200 and 400 mg/kg extract, the serum AST was reduced (by 40.34% and 45.66% respectively) as much as the MeOH fraction (43.88%) and control (43.44%), whereas EtOAc fractions gave significantly the best reduction (52.49%). The ethyl acetate fraction gave the best activity among all the fractions. Conclusion: The results showed that the stem bark is a potential source of natural antioxidants and hepatoprotective agents, and justifies its use in traditional herbal practice.