Phytochemical profile, antioxidant activity, and acute toxicity of methanolic extracts of Annickia affinis (Exell) Versteegh & Sosef leaves stem bark and roots

Abstract

This study aimed to determine the phytochemical profile, acute toxicity, and antioxidant activity of leaves, stem bark, and roots of methanolic extracts of Annickia affinis. Phytochemical screening was done to highlight the secondary metabolites present in the plant. The in vitro antioxidant activity was carried out using the DPPH free radical trapping method based on our extracts' reduction of the DPPH radical. This was evaluated by measuring the absorbance of all concentrations of extracts tested at 517 nm. Whereas the total phenol content was quantified using the reagent of “Folin-Ciocalteu,” measurable using a spectrophotometer at 765 nm. The in vivo acute toxicity study was conducted according to guideline 423 of the Organisation for Economic Co-operation and Development (OECD) protocol at a fixed dose in Wistar rats. Phytochemical screening of the different extracts revealed the presence of alkaloids, saponins, triterpenoids, anthraquinones, anthocyanins, and coumarins. The extracts of the leaves, stem bark, and roots showed good DPPH radical scavenging activity with IC₅₀ values of 0.34 µg/mL, 0.37 µg/mL, and 0.22 µg/mL, respectively; these values were very close to that recorded for the standard, Butyl hydroxytoluène (BHT) (0.14 µg/mL). The total phenolic contents were 122.11 µgEqGA/g for the leaves, 47.11 µgEqGA/g for the stem bark, and 109.95 µgEqGA/g for the roots. An oral administration of all extracts did not cause an abnormal variation of the physiological parameters in female Wistar laboratory rats at doses of 2000 and 5000 mg/kg body weight up to 14 days after administration. The methanolic extracts of the leaves, stem bark, and roots of A. affinis are thus non-toxic at a dose as high as 5000 mg/kg body weight. They all have good antioxidant activity, the best activity recorded for the roots. It would be beneficial to suggest A. affinis to local populations against pathologies linked to oxidative stress after the preclinical and clinical tests.