Context: Breast cancer expresses high levels of the estrogen receptor alpha (ER-α). Aims: To investigate the potential anticancer activity of nanoliposome Hedyotis corymbosa in breast cancer cells by specifically targeting the ER-α through a combination of in silico and in vitro studies. Methods: This study used molecular docking to analyze the interaction between ER-α and active compounds from H. corymbosa. In vitro studies, the H. corymbosa extract was converted into nanoliposomes. The nanoliposomes' characteristics were examined, combined with tamoxifen, and applied to breast cancer cell cultures. Viability, proliferation, and ER-α expression were assessed, and statistical analysis was performed (p<0.05). Results: The findings show that H. corymbosa compounds, especially rutin, inhibit ER -α binding and act as a substrate for P-glycoprotein. Extract H. corymbosa selectively decreases viability in breast cancer cells (T47D) compared to non-cancerous cells (NIH3T3). Combining extracts with tamoxifen at 10 mg/mL enhances treatment efficacy. The combined treatment is effective for up to 72 h, reducing T47D breast cancer cell proliferation. Nanoliposomes derived from extract exhibit favorable characteristics, including a spherical shape, uniform size distribution, and stability. Using these nanoliposomes at 100 μg/mL with tamoxifen significantly reduces ER-α expression (p<0.05) without affecting cell viability. Conclusions: Compounds from H. corymbosa, especially rutin, inhibit ER-α binding. H. corymbosa nanoliposomes are stable for drug delivery. Combining tamoxifen with nanoliposomes at 100 μg/mL reduces ER-alpha expression. This shows potential for breast cancer treatment, but validation through further research and clinical trials is necessary.