Antioxidant Evaluation of Jatropha gossypiifolia Leaf and Stem Bark Extract: Phytochemical Assays, Chemical Fingerprinting, and Molecular Docking Studies
Musa Runde *
Department of Chemistry, National Open University of Nigeria, Abuja, Nigeria.
Onyinyechi V. Ugochukwu
Department of Chemistry, National Open University of Nigeria, Abuja, Nigeria.
Nguuma I. Gber *
Department of Microbiology University of Calabar, Calabar, Nigeria.
Aminah L. Tanimu
Department of Chemistry, National Open University of Nigeria, Abuja, Nigeria.
Ernest Onugwu
Department of Chemistry, National Open University of Nigeria, Abuja, Nigeria.
Idris Abubakar
Department of Chemistry, National Open University of Nigeria, Abuja, Nigeria.
Efeoma Omobude
Department of Chemistry, National Open University of Nigeria, Abuja, Nigeria.
Francisca Bassey
Department of Chemistry, University of Cross River State, Calabar, Nigeria.
Hitler Louis
Department of Chemistry, University of Cross River State, Calabar, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Jatropha gossypiifolia is used in traditional medicine for the management of wounds, infections, inflammation, fever, and gastrointestinal disorders; however, comparative information on the chemical profile and antioxidant activity of its leaf and stem bark extracts remains limited. This study evaluated the phytochemical composition, in vitro antioxidant activity, FTIR-based chemical fingerprinting, and molecular docking profile of J. gossypiifolia leaf and stem bark extracts. The extracts were prepared and analysed in triplicate. Quantitative phytochemical assessment showed that the leaf extract recorded higher values for tannins (0.190 a.u), phenols (0.368 a.u), and alkaloids (0.050 a.u) than the stem bark extract, which recorded tannins (0.168 a.u), phenols (0.311 a.u), and alkaloids (0.048 a.u). In contrast, the stem bark extract had a higher flavonoid value (0.012 a.u) than the leaf extract (0.002 a.u). Antioxidant activity was assessed using the DPPH radical scavenging assay, with absorbance measured at 517 nm and inhibition calculated relative to the methanol control. The stem bark extract showed stronger radical scavenging activity, increasing from 54.39% to 77.03%, with an IC₅₀ of 1.5 µL, whereas the leaf extract increased from 44.48% to 71.68%, with an IC₅₀ of 37.3 µL. FTIR analysis indicated hydroxyl, carbonyl, aromatic, glycosidic, aliphatic, and nitrile-associated functional groups in the extracts and DPPH-treated complexes. The observed spectral changes after DPPH treatment supported the involvement of oxygen- and nitrogen-containing functional groups in radical scavenging. Molecular docking results reported for DNA gyrase B (PDB ID: 4GGL) showed that lupeol had the most favourable MolDock score (−168.539 kcal/mol), followed by ellagic acid and gallic acid.
Keywords: Jatropha gossypiifolia, antioxidant activity, DPPH assay, phytochemical profiling, leaf extract, stem bark extract, FTIR spectroscopy, chemical fingerprinting, molecular docking, lupeol, phenolic compounds.