Phytochemical Screening, Antioxidant and Anti-inflammatory Activities and in silico Studies of the Root Bark Extract of Terminalia catappa Linn
Arinze C. Ikeh *
Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria.
Adaora S. Ogbuagu
Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria.
Onyeka F. Obumselu
Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria.
Emmanuella O. Oguguongene
Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria.
Innocent A. Okagu
Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Background: Oxidative stress and persistent inflammation are associated with chronic disease, while the root bark of Terminalia catappa remains less investigated than other plant parts.
Aims: This study evaluated the phytochemical composition, antioxidant, and anti-inflammatory properties of the methanol root bark extract of Terminalia catappa, a plant used in traditional medicine. Conventional anti-inflammatory drugs have serious side effects, while oxidative stress and inflammation contribute to chronic diseases. The root bark remains underexplored, and this research aimed to address this gap.
Study Design: An experimental approach involving phytochemical screening, antioxidant and anti-inflammatory assays, HPLC analysis, and in silico docking and ADMET prediction was employed.
Place and Duration of Study: Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria, and Docchy Laboratory, Awka, Anambra State, Nigeria, between March 2026 and August 2026.
Methodology: Root bark samples were extracted with methanol by cold maceration. Phytochemical screening for alkaloids, flavonoids, saponins, tannins, glycosides, carbohydrates, terpenoids, and phenolics was conducted. HPLC analysis identified and quantified bioactive compounds. Antioxidant activity was evaluated using DPPH, H₂O₂, and FRAP assays. Anti-inflammatory activity was assessed through protein denaturation, membrane stabilisation, and proteinase inhibition assays. In silico docking against Keap1-Nrf2 and COX-2 and ADMET prediction using SwissADME, pkCSM, and ProTox-3.0 were performed002E
Results: Alkaloids, flavonoids, saponins, tannins, glycosides, phenols, and carbohydrates were present. HPLC confirmed phenolic and flavonoid compounds. The extract showed IC₅₀ values of 527.1 µg/mL in the DPPH assay, 184.7 µg/mL in the FRAP assay, and 367.0 µg/mL in the H₂O₂ assay. Anti-inflammatory activity showed IC₅₀ values of 489.8 µg/mL for membrane stabilisation, 258.2 µg/mL for protein denaturation, and 1192.5 µg/mL for proteinase inhibition. Docking revealed favourable binding affinities, and ADMET predictions indicated favourable drug-like properties.
Conclusion: The extract showed antioxidant and anti-inflammatory activities, supported by HPLC and in silico findings. Further in vivo studies are recommended.
Keywords: Terminalia catappa, root bark, methanol extract, phytochemicals, HPLC, antioxidant, anti inflammatory, molecular docking