Synergistic anticancer effects of metformin and Achillea vermicularis Trin-loaded nanofibers on human pancreatic cancer cell line: An in vitro study

•Metformin (Met)/Achillea vermicularis (AV)-loaded NFs were fabricated by ES.•Their chemical, mechanical, thermal, and drug release properties were investigated.•All NFs showed an initial burst release followed by a sustained release for 7 days.•Met/AV-loaded NFs decreased cell viability and induced apoptosis in insulinoma cells.•LDH leakage was higher in Met/AV-loaded NF-treated cells (∼50% on days 1, 3, and 7).