In-Vitro Anticancer and Antioxidant Evaluation of Ethanolic Allium cepa Seed Extract against MCF-7 Breast Cancer Cells with In-Silico ADME-Toxicological Profiling of Principal Bioactive Constituents

AbstractBackground: Breast cancer remains the most frequently diagnosed malignancy in womenglobally, with current therapeutic strategies limited by systemic toxicity, drug resistance, andhigh treatment costs. Natural products, particularly those derived from underexplored plantparts such as seeds, represent promising sources of novel anticancer agents. Allium cepa(onion) seeds, though phytochemically rich, remain significantly underinvestigated foranticancer potential.Objective: This study aimed to evaluate the in-vitro anticancer and antioxidant activities ofethanolic onion (Allium cepa) seed extract (OSE) against the MCF-7 human breast cancercell line, and to computationally profile the absorption, distribution, metabolism, excretion(ADME), and toxicological properties of its principal bioactive constituents.Methods: Ethanolic OSE was prepared by Soxhlet extraction and subjected tophysicochemical standardization, qualitative and quantitative phytochemical screening, andHPTLC fingerprinting. Antioxidant activity was assessed using DPPH, ABTS, and FRAPassays. Cytotoxicity against MCF-7 cells was evaluated by the MTT assay, withmorphological assessment by inverted microscopy. Computational ADME profiling wasperformed using SwissADME and pkCSM, while toxicological prediction was conductedusing ProTox-II.Results: The extract yield was 8.62% w/w, with total phenolic content of 84.32 ± 2.76 mgGAE/g and total flavonoid content of 52.14 ± 1.93 mg QE/g. OSE demonstratedconcentration-dependent antioxidant activity (DPPH IC50: 148.5 ± 3.21 μg/mL; ABTS IC50:132.4 ± 2.87 μg/mL; FRAP: 215.8 ± 8.43 μM Fe2+ eq/g). Significant cytotoxicity againstMCF-7 cells was observed with an IC50 of 178.3 ± 4.87 μg/mL at 48 hours, accompanied byapoptotic morphological changes. In-silico analysis confirmed that quercetin, kaempferol,and thymoquinone satisfied Lipinski's Rule of Five. Thymoquinone exhibited the most favorableADME profile, while all three compounds showed absence of predictedhepatotoxicity, carcinogenicity, and mutagenicity.Conclusion: Ethanolic onion seed extract demonstrates significant in-vitro anticancer and antioxidant activities, with its principal bioactive constituents exhibiting favorable drug-likeness and safety profiles. These findings establish a scientific basis for further preclinical development of onion seed-derived formulations for breast cancer management.