In Silico Evaluation of Tamarind Leaf Flavonoids Targeting ERα as Anti-Breast Cancer Agents Using Molecular Docking

Breast cancer particularly the estrogen receptor–positive (ER+) luminal subtype remains a major cause of mortality. Although tamoxifen is the gold-standard therapy, resistance and adverse effects motivate the discovery of new agents. This study identified tamarind (Tamarindus indica L.) leaf flavonoids with potential ERα inhibition using in-silico molecular docking. Twenty-two ethanol-extract compounds were screened by Lipinski’s Rule of Five, docked to ERα (PDB: 1SJ0) with PyRx/AutoDock Vina, and analyzed in Discovery Studio; redocking of the native ligand yielded an RMSD of 0.68 Å, and tamoxifen served as the reference ligand. Four flavonoids exhibited strong ERα binding relative to tamoxifen (−9.1 kcal/mol): apigenin (−9.2), chrysin (−8.9), cynaroside (−8.4), and kaempferol (−8.0), forming stabilizing hydrogen bonds and hydrophobic contacts while largely complying with Lipinski criteria. These findings indicate that tamarind-derived flavonoids—particularly apigenin and chrysin—are promising ERα-targeting candidates and warrant in vitro/in vivo validation for anti-breast cancer development.