Estrone‐α‐2‐Deoxy‐Glucoside as a Targeted Therapy for Triple‐Negative Breast Cancer: Aromatase Inhibition and Cytotoxicity

ABSTRACT Aromatase inhibitors (AIs) are vital in the treatment of estrogen‐dependent breast cancer, especially in postmenopausal women. In this study, a series of steroidal glycosides (SGs) derived from trans ‐androsterone ( t AND), estrone (E1), and estradiol (E2) were synthesized using a one‐pot multi‐enzyme glycosylation approach and structurally characterized via HPLC, MS, and NMR. Among the synthesized compounds, E1‐α‐2DG ( 2b ) and E2‐α‐2DG ( 3b ) demonstrated the most potent aromatase inhibition, with IC 50 values of 0.101 ± 0.001 μM and 0.159 ± 0.009 μM, respectively. Molecular docking revealed that these glycosides form key hydrogen bonds with catalytic residues and the heme group of CYP19A1. In vitro cytotoxicity showed that E1‐α‐2DG selectively inhibited the growth of MCF‐7 and MDA‐MB‐231 breast cancer cells in a dose‐dependent manner, with the highest potency observed against triple‐negative MDA‐MB‐231 cells (IC 50 = 20.46 ± 2.92 μM), while exhibiting no toxicity toward non‐cancerous HEK293 cells. These findings suggest that glycosylation enhances the pharmacological potential of steroidal scaffolds and highlights E1‐α‐2DG as a promising lead compound for the development of safer, dual‐function breast cancer therapies.