Extraction, biological evaluation and GC-MS characterization of ethyl acetate extract of the stem bark of newbouldia laevis

Abstract

The increasing resistance to conventional antibiotics and the demand for effective natural remedies have prompted the exploration of medicinal plants for bioactive compounds. This study aimed to extract and characterize secondary metabolites from the stem bark of Newbouldia laevis and evaluate their antimicrobial and antioxidant activities. The stem bark was collected from Dambai-Zongo in the Oti Region of Ghana and extracted using ethyl acetate via maceration. The crude extract was subjected to Gas Chromatography-Mass Spectrometry (GC-MS) analysis, which identified various compounds, including fatty acids (linoleic acid, octadecanoic acid), sterols (stigmasterol, stigmast-5-en-3-ol), triterpenoids (olean-12-en-3-ol), and esters. The antimicrobial activities of the extract were evaluated using the Kirby-Bauer agar diffusion method and broth microdilution assays against bacterial strains such as Staphylococcus aureus, Escherichia coli, and Salmonella typhi, as well as fungal strains like Candida albicans. The extract demonstrated significant antimicrobial activity, particularly against S. aureus, with zones of inhibition ranging from 8.33 to 19.33 mm. Minimum Inhibitory Concentrations (MICs) ranged from 0.078 to 25 mg/mL, confirming the extract’s bactericidal and fungicidal effects. Antioxidant activity was assessed using DPPH and ABTS scavenging assays. The extract exhibited notable free radical scavenging potential, with IC50 values of 0.322 mg/mL and 0.329 mg/mL, respectively, comparable to the standard vitamin C. These findings validate the traditional use of Newbouldia laevis in treating microbial infections and oxidative stress-related conditions. The presence of bioactive compounds highlights their potential for pharmaceutical applications, particularly in developing natural antibiotics and antioxidants. Further studies are recommended to evaluate the pharmacokinetics, toxicity, and clinical efficacy of the identified compounds to facilitate their development into therapeutic agents.