Metformin Plus a Pomegranate Compound Made Resistant Breast Tumors Respond to Chemo Again — in Mice
Ellagic acid and metformin showed strong synergy against cisplatin-resistant breast cancer; added to cisplatin in mice, tumors shrank by about half.
By Sanare Lab · September 30, 2026 · 2 min read
Key Takeaway
When breast cancer stops responding to cisplatin (a common chemotherapy drug), options run out. In a new study, the diabetes drug metformin and ellagic acid (a natural compound from pomegranates and berries) worked as a strong team against resistant tumors: added to cisplatin in mice, they shrank tumors by about half. This is preclinical (animal-stage) research.
The team used two mouse breast-cancer cell lines: a standard one and a version trained to survive cisplatin. They measured synergy with the combination index — a score below 1 means two drugs reinforce each other. Metformin plus ellagic acid scored 0.45 against standard cells and 0.29 against resistant ones — so the teamwork was strongest exactly where chemotherapy fails. Related reading: metformin and antiandrogen resistance in prostate cancer models.
In mice, adding the pair to cisplatin cut tumor size by 73.8% in standard tumors and 56.3% in resistant ones, with tumor regressions (shrinkage of individual tumors) reported in 66.6% and 50% of the animals, respectively. Liver and kidney blood markers were checked for toxicity, the authors report.
Context: the first study of this pair in cisplatin-resistant breast cancer, but cell-and-mouse work — no patients were treated, and doses would need human trials. For related reading, see metformin combinations studied in breast cancer and metabolic therapy with repurposed drugs in breast cancer; for dosing questions, our dosing calculator.
In plain words
What happened: Scientists combined metformin, a diabetes drug, and ellagic acid, a natural compound from pomegranates and berries, with chemotherapy in mice with breast cancer, including tumors resistant to the chemo drug cisplatin.
Why it matters: Chemotherapy often stops working because cancer cells adapt. The pair together hurt cancer cells far more than either one alone — like two people pushing a stuck door at the same time — and the effect was strongest against the chemo-resistant tumors.
How strong is the evidence: Early-stage animal research: cells in dishes and mice. Tumors shrank by about half to three-quarters, but mice are not people — no patient has received this combination.
What it means for you: Nothing changes for treatment today — do not try drug combinations on your own. If you face chemo-resistant breast cancer, ask the oncology team about clinical trials.
References
- Jdaitawi B, Alasmari MM, Alshaeri HK, et al. Ellagic Acid and Metformin: In Vitro Synergy and Enhanced Cisplatin Efficacy In Vivo in Resistant Breast Cancer (in vitro = cell cultures; in vivo = live animals). Nutrients. 2026 Sep 17. doi:10.3390/nu18183047. PMID: 42797030.
Medical Disclaimer
This article is for informational purposes only and is not medical advice. The study was done in cells and mice, not humans. Never start, stop or change any medication or supplement without consulting a licensed healthcare provider.
Sanare Lab
Science-based health education team reviewing published research on repurposed drugs, integrative oncology, and evidence-based protocols.