The present study focuses on the phytochemical composition and in vitro and in vivo antioxidant properties of A. senegalensis root bark. Phenolic total compounds and tannins were quantified by Folin-Ciocalteu, and flavonoids by described by Arvouet-Grand et al. Alkaloids were determined using atropine as a reference. For antioxidant activities, FRAP assay; DPPH, RPA, and RHS were evaluated by standard methods. Thus, A. senegalensis root barks were collected for the different analyses. The results showed a very diversified phytochemical composition. Thus, the total phenolic content varied from 21.16 ± 1.22 to 57.30 ± 0.09 mg GAE/g fraction. The total flavonoid content varied from 2.18 ± 1.71 to 12.47 ± 1.36 mg EQ/g. Total tannin content ranged from 18.46 ± 0.53 to 44.54 ± 0.01 mg WT/g diffraction and total alkaloid content ranged from 2.71 ± 1.53 to 10.61 ± 0.53 mg AE/g fraction. Ethyl acetate fraction (EAF) showed the best contents of bioactive compounds. This fraction thus showed very good antioxidant activities for the four (04) methods of evaluation of the antioxidant activity in vitro used which are: DPPH, FRAP, "Reducing Power Assay" and "Hydroxyl radical scavenging activity"; and the three in vivo methods which are: catalase (CAT), superoxide dismutase (SOD) and lipid peroxidation (LOP) activity. These results highlight the therapeutic effects of A. senegalensis root bark and explain their traditional use to treat certain diseases. These roots can constitute sources of natural antioxidants. Further studies would reveal the bioactive molecules responsible for this high antioxidant potential and therapeutic properties.

Keywords: Annona senegalensis (Annonaceae), phenolic compounds, antioxidant activity, root bark, oxidative stress.