In traditional medicine, Annnickia chlorantha (Annonaceae)is used in many parts of Africa to treat several pathologies. It is used for the management of stomach problems, for the treatment of jaundice, tuberculosis, urinary tract infections, malaria, hepatitis and ulcers forms, for gallstones or even diarrhea. The phytochemical analysis and determination of the antiradical activity of the methanolic extract of the trunk bark from Annickia chlorantha from Gabon was the subject of this study. Phytochemical screening revealed the abundance of alkaloids, polyphenols and catechics tannins.The total polyphenol content released by the Folin-Ciocalteu method was 309.17 ± 38.05 g of gallic acid equivalent per 100 mg of dry matterand the total flavonoids content performed with AlCl3 was 155.16 ± 21.06 g of quercetin equivalent per 100 mg of dry matter. The antiradical activity was limited to 81.58% ± 1.25 without disappearance of the ABTS•+ radical after 6 minutes of incubation. These results confirm the correlation between the polyphenol content and the antiradical activity.