Comparative Phytochemical, Antioxidant, and GC–MS Profiling of Polar Leaf and Stem Bark Extracts of Khaya senegalensis

Abstract

Background: Medicinal plants are important sources of bioactive compounds with therapeutic potential and are increasingly being investigated as alternatives to synthetic drugs for managing oxidative stress, microbial infections, and other health disorders. Khaya senegalensis (African mahogany), a widely used medicinal plant in tropical Africa, has a long history of ethnomedicinal use in the treatment of malaria, fever, diarrhea, jaundice, rheumatism, and infectious diseases. Aim: To evaluate the phytochemical composition, antioxidant activities, and GC–MS bioactive profiles of aqueous and ethanol extracts of the leaves and stem bark of Khaya senegalensis. Study Design: Experimental laboratory-based study. Place and Duration of Study: Department of Science Laboratory Technology/Directorate of Laboratory Services and Biosecurity, Federal College of Animal Health and Production Technology, National Veterinary Research Institute (NVRI), Vom, Plateau State, Nigeria, between July and October 2025. Methodology: Fresh leaves and stem bark of Khaya senegalensis were collected, air-dried, pulverized, and separately extracted using distilled water and ethanol through cold maceration. Percentage extraction yield was determined gravimetrically. Qualitative phytochemical screening was carried out for alkaloids, flavonoids, tannins, phenols, saponins, glycosides, anthraquinones, and terpenoids using standard analytical procedures. Antioxidant activity was evaluated using the DPPH radical scavenging assay, while bioactive compounds were identified using Gas Chromatography–Mass Spectrometry (GC–MS). Statistical analysis was performed using one-way analysis of variance followed by Duncan’s Multiple Range Test at p < 0.05. Results: Extraction yield differed significantly among the extracts, with aqueous leaf extract showing the highest yield (9.80 ± 0.12%) and ethanol stem bark extract the lowest (8.00 ± 0.08%). Phytochemical screening revealed the presence of flavonoids, alkaloids, tannins, phenols, glycosides, saponins, and anthraquinones in all extracts, while terpenoids were predominantly detected in stem bark extracts. Ethanol leaf extract exhibited the highest DPPH radical scavenging activity (76.00 ± 0.38%), whereas aqueous stem bark extract showed the lowest activity at lower concentrations. GC–MS profiling identified forty-five bioactive compounds mainly comprising fatty acid esters, diterpenes, phytosterols, hydrocarbons, tocopherols, fatty alcohols, and phenolic compounds. Major metabolites identified included phytol, hexadecanoic acid methyl ester, β-sitosterol, stigmasterol, squalene, and vitamin E. Conclusion: The findings demonstrate that Khaya senegalensis possesses substantial phytochemical richness, significant antioxidant potential, and diverse bioactive metabolites of pharmacological relevance, supporting its traditional medicinal applications and potential use in natural antioxidant and nutraceutical development.