none 10.31254/phyto.2025.14307 BioMed Research Publishers BioMed Research Publishers 16195 182219415 316921 20250913114628951 10.31254 2025-09-13T11:46:35Z 2025-09-13T11:46:34Z 0 The Journal of Phytopharmacology J Phytopharmacol 2320480X 10.31254/phyto https://phytopharmajournal.com/ 07 31 2025 14 3 Dickson Aboagye https://orcid.org/0009-0006-2780-6989 Caleb Ofori Bandoh https://orcid.org/0009-0000-0297-1677 Kingsley Ofolikwei Quaye https://orcid.org/0009-0009-9471-2722 Josephine Frimpomaa Oppong https://orcid.org/0009-0008-1633-6402 Justice Yao Akakpo https://orcid.org/0009-0004-7507-6277 Emmanuel Ogwoh Chisom https://orcid.org/0009-0002-4206-6254 Kelvin Amankwah Sarfo https://orcid.org/0009-0001-2804-9960 Prince Nartey-Addy Amoyaw Background: Allium cepa (onion) is a widely cultivated plant, known for its rich phytochemical composition and diverse medicinal properties. As global antibiotic resistance continues to rise, there is an increasing interest in exploring natural sources, such as medicinal plants, for the discovery of novel bioactive compounds. This study investigated the extraction, isolation, and antimicrobial activity of chemical constituents from the ethanolic extract of Allium cepa. Aims and Objectives: This study aimed to extract and isolate bioactive compounds from the ethanolic extract of Allium cepa and evaluate their antimicrobial activities against Escherichia coli and Staphylococcus aureus. Materials and Methods: Fresh Allium cepa bulbs were obtained from Aburi, Ghana. A total of 316 g of dried powdered bulbs were extracted via cold maceration using 95% ethanol and 5% water. The extract was filtered and concentrated using a rotary evaporator, and then analyzed by TLC, revealing three spots (Rf: 0.29, 0.33, and 0.5). Further purification using flash column chromatography and HPLC yielded the pure compound AC (Rf = 0.5). Compound AC’s antimicrobial activity was evaluated using the micro broth dilution method against E. coli and S. aureus, using ciprofloxacin and clindamycin as controls. Results: Phytochemical screening of the crude extract confirmed the presence of alkaloids, tannins, flavonoids, quercetin, and saponins. TLC analysis of the crude extract yielded three spots, and flash chromatography isolated AC with Rf = 0.5. The isolated compound, AC, had a melting point of 317°C and was soluble in DMSO and methanol. The MIC values of compound AC were 0.5 mg/mL against S. aureus and 3.91 mg/mL against E. coli, which are comparable to standard antibiotics such as ciprofloxacin (MICs:< 0.1 mg/mL and <0.1 mg/mL respectively) and clindamycin (MICs: <0.1 mg/mL and <0.5 mg/mL respectively). Conclusion: The ethanolic extract of Allium cepa contained bioactive compounds with significant antimicrobial activity, particularly against S. aureus. The isolated compound AC showed promising results, supported by TLC, flash chromatography, HPLC, and MIC determination. 07 31 2025 170 176 1 10.31254/biomed-crossmark-policy www.biomedresearch.org false 10.31254/phyto.2025.14307 https://phytopharmajournal.com/articles/abstracts/820/year=2025&vol=14&issue=3