GC-MS Based Phytochemical Profiling and Complementary Antioxidant Activities of Ethanol Extract of Garcinia kola Seeds Collected from Kogi State, Nigeria
TL;DR
Findings indicate measurable antioxidant capacity and chemical diversity, but GC-MS library matching alone does not establish definitive compound identity, biological activity, or causal contribution to the antioxidant response.
Abstract
Garcinia kola Heckel (bitter kola) is widely used in West African traditional medicine and is valued for its diverse phytochemical constituents. This study evaluated the antioxidant activity and chemical composition of an ethanolic seed extract of G. kola using complementary in vitro antioxidant assays and gas chromatography-mass spectrometry (GC-MS). Qualitative phytochemical screening indicated the presence of flavonoids, phenols, tannins, alkaloids, saponins, and phytates. Antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging, total antioxidant capacity (TAC), and ferric reducing antioxidant power (FRAP) assays. The extract showed concentration-dependent DPPH scavenging, ranging from 43.24% at 100 µg/mL to 69.38% at 500 µg/mL, with an IC₅₀ of 284.09 µg/mL. The TAC and FRAP values were 96.61 µg ascorbic acid equivalents (AAE)/g and 84.89 µg AAE/g at 500 µg/mL, respectively. GC-MS tentatively identified 26 constituents, with n-hexadecanoic acid (27.84%), 2,4-di-tert-butylphenol (10.97%), and 9,12-octadecadienoic acid (approximately 4- 5%) among the more abundant components. These findings indicate measurable antioxidant capacity and chemical diversity, but GC-MS library matching alone does not establish definitive compound identity, biological activity, or causal contribution to the antioxidant response. Further isolation, structural confirmation, quantitative analysis, and mechanistic studies are warranted.