Phytochemical investigation and molecular docking studies of <i>Ruellia simplex</i> extract on human breast cancer cell line

This study investigated phytochemical constituents of <i>Ruellia simplex</i> extract and evaluated their molecular interactions with estrogen receptor alpha (ERα) and cytotoxic effects against MCF-7 breast cancer cells. The whole plant was extracted with ethanol and fractionated into methanolic (ME01) and chloroform (CH02) fractions. HR-LCMS identified 11 compounds in ME01 and 8 in CH02, with flavonoids predominating in ME01 and terpenoids in CH02. Molecular docking against ERα (PDB ID: 3ERT) revealed five potent compounds: stigmasterol (-9.0 kcal/mol), apigenin (-8.6 kcal/mol), rosmarinic acid (-8.6 kcal/mol), luteolin (-8.4 kcal/mol), and β-sitosterol (-8.3 kcal/mol). MTT assay demonstrated superior cytotoxicity of ME01 (IC₅₀ = 38.42 ± 2.16 μg/mL) compared to CH02 (52.64 ± 3.05 μg/mL), approaching 5-Fluorouracil (32.18 ± 1.87 μg/mL). Results demonstrate that <i>Ruellia simplex</i> contains bioactive compounds with significant ERα binding affinities and notable cytotoxic activity against breast cancer cells. The ME01 fraction shows promise for developing natural anticancer agents targeting hormone-dependent breast cancers.