Chemical Profiles and Antioxidant Potential of Extracts from Nauclea diderichii (De Wild. & T. Durand) Merr., Collected in the Republic of the Congo

The chemical profiles of methanolic extract from the leaves, trunk, and roots of Nauclea diderrichii were determined by liquid chromatography coupled with mass spectrometry (LC-MS). Total polyphenol content was determined using the Folin-Ciocalteu reagent method, and total flavonoid content using the aluminum trichloride method. Antioxidant potential was evaluated via DPPH free radical scavenging, ferric reducing antioxidant power (FRAP), and HPTLC bioautography. Extraction yields were highest for the roots (13.17%) and leaves (12.68%). Total polyphenol content was highest in the leaves (270.68 mg GAE/g), followed by the roots (244.26 ± 0.01 mg GAE/g). Total flavonoid content followed the same trend as total polyphenol content; specifically, the leaves (142.27 mg QE/g) contained higher levels than the roots (29.03 ± 0.01 mg QE/g). Quinic, chlorogenic, protocatechuic, and caffeic acids were identified in the leaves. In contrast, the trunk and roots were rich in triterpene compounds such as quinovic, quafrinoic, and emmolic acids. Antioxidant potential was most pronounced in the leaves (DPPH (IC₅₀) = 90.90 ± 0.03 µg/mL; FRAP = 814.25 ± 0.08 mg BHA-E/g) and roots (DPPH (IC₅₀) = 92.16 ± 0.04 µg/mL; FRAP = 723.36 ± 0.03 mg BHA-E/g).