Amino Acid Analysis and Cytotoxicity Study of Iraqi <em>Ocimum basilicum</em> Plant

Context: Medicinal plants have long been a cornerstone of traditional medicine and modern pharmacology, offering a rich source of biologically active compounds with diverse therapeutic applicationsObjective: Detection and identification of amino acid composition of Iraqi Ocimum basilicum (basil) leaves and evaluation the cytotoxic effects of the plant leaf extract on human colorectal cancer cells (HRT-18).Methods: Leaves of Ocimum basilicum were collected from Tikrit in November 2024. After drying and powdering, the plant material goes through cold methanol extraction. Initial phytochemical screening was conducted to identify the presence of alkaloids, flavonoids, coumarins, and terpenoids. Amino acids analysis was completed by amino acid analyzer with fluorescence detection. Cytotoxic effect was evaluated via the MTT assay on HRT-18 cell lines exposed to various concentrations of the plant extract. Morphological changes were further tested using dual Propidium Iodide/Acridine Orange assay fluorescent staining.Results: Seventeen amino acids were detected in the plant extract. The extract showed dose-dependent cytotoxic effects on HRT-18 cells, with significant reduction in cell viability at concentrations of more than 25 µg/mL. Morphological alterations of membrane blebbing and cell shrinkage were observed suggesting apoptotic activity. The IC₅₀ value confirmed strong cytotoxic potential.Conclusion: The extract of Ocimum basilicum leaf cultivated in Iraq shows a rich amino acid profile and significant cytotoxic activity against colorectal cancer cells that highlights its potential effect as a natural source of anticancer compounds and permit further analysis into its active constituents and the mechanisms of action.