Investigating the flavonoid compounds of citrus peel and their pharmacological mechanism to combat breast cancer through system pharmacology and experimental verification

Breast cancer remains one of the most prevalent malignancies in women globally. Traditional treatment approaches are often limited by drug resistance and systemic toxicity, whereas multi-targeted treatments offer a promising alternative to overcome these limitations. Flavonoid compounds derived from citrus peel are widely recognized for their antioxidant, anti-inflammatory, and anticancer properties. This study aims to investigate the potential flavonoids present in citrus peel and to elucidate their molecular targets and underlying pharmacological mechanisms against breast cancer using a network pharmacology approach. Compound prescreening and target prediction identified 17 potential flavonoid compounds, based on Lipinski’s Rule of Five and 61 candidate targets associated with breast cancer. Furthermore, based on the compounds pharmacological properties—specifically, a drug-likeness score ≥ 0.5 and enzyme inhibition (Ei) > 2) —as well as network and pathway analyses, we identified four potential compounds (catechin, kaempferol, naringenin, and quercetin) and major targets (EGFR, SRC, PIK3CA, and ESR1), along with their involvement in breast cancer-related pathways. Molecular docking and toxicity analyses revealed that naringenin exhibited strong binding affinities with EGFR, SRC, PIK3CA, and ESR1, and demonstrated cytotoxic effects. Additionally, the suppressive effects of naringenin were verified by in vitro assay using two breast cancer cell lines (MCF-7 and MDA-MB-231). Collectively, our results demonstrated the flavonoids interactions with major breast cancer–related targets and pathways, and offering novel insights into their multi-targeted mechanisms and provided a foundation for future in vivo and clinical studies.