Phytochemical Screening and Antibacterial Assay of the Stem Bark of Hagenia abyssinica and Vernonia amygdalina

Abstract

Introduction: Traditional medicine remains an essential part of healthcare, particularly in regions with limited access to modern medical facilities. Hagenia abyssinica and Vernonia amygdalina are widely used in Ethiopia for managing infectious diseases, but comprehensive studies on their phytochemical composition and antibacterial activity are limited. Objective: This study aimed to evaluate the phytochemical constituents and antibacterial activities of stem bark extracts of H. abyssinica and V. amygdalina to validate their traditional uses and identify potential bioactive compounds. Methods: Stem bark samples were collected, dried, and sequentially extracted with petroleum ether, chloroform, acetone, and methanol. Standard qualitative phytochemical screening tests were performed on the crude extracts. Antibacterial activity was assessed against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) using the agar well diffusion method at concentrations of 50, 100, and 150 mg/mL. Ciprofloxacin was used as a positive control, while dimethyl sulfoxide (DMSO) served as a negative control. Results: Phytochemical screening revealed the presence of saponins, tannins, glycosides, terpenoids, flavonoids, and alkaloids, depending on the solvent and plant species. Methanol extracts yielded the highest percentages (3.32% for H. abyssinica and 3.48% for V. amygdalina). The acetone and methanol extracts exhibited the strongest antibacterial effects, with inhibition zones ranging from 24.67 ± 1.53 to 30.33 ± 0.58 mm against both bacterial strains, in some cases comparable to or greater than ciprofloxacin (25.00 ± 0.00 mm). Non-polar extracts displayed weak or no activity. Statistical analysis (ANOVA, p < 0.05) confirmed significant differences between extracts. Conclusion: The results confirm that H. abyssinica and V. amygdalina stem barks are rich in phytochemicals with significant antibacterial potential. These findings support their traditional applications and suggest that polar extracts, particularly acetone and methanol fractions, may provide promising leads for the development of new antimicrobial agents.