Fig. 1

Eugenol sensitizes OC cells to cisplatin. a OV2774 and SKOV3 cells were treated with increasing concentrations of cisplatin and eugenol, for 72 h and dose response curves were determined by the WST-1 assay. Combination index (CI) and isobologram were generated using the CompuSyn software. The individual doses of cisplatin and eugenol to achieve 90% growth inhibition (green line, Δ-symbol, Fa = 0.90), 75% growth inhibition (red line, □-symbol, Fa-0.75) and 50% growth inhibition (blue line, Ο-symbol, Fa = 0.50) were plotted on the X and Y-planes. b Cells were treated as indicated, and cell survival was determined by the WST-1 assay. Significant differences were analyzed using Factorial ANOVA between cisplatin and eugenol single treatments. [Top and bottom left panel; Columns 4 and 7-eugenol at 1 μM constant, cisplatin 5 and 10 μM; top and bottom right panel; Columns 4 and 7 eugenol at 2 μM constant, cisplatin at 5 and 10 μM] (n = 3; mean +/− SD, * p 0.05, **p 0.01). c Exponentially growing cells were treated as indicated, and cell death was assessed by Annexin V/PI-associated flow cytometry. d Whole cell lysates were prepared from the indicated cells and were used for immunoblotting analysis using antibodies against the indicated proteins, while GAPDH was used as internal control. e Cells were treated with DMSO (control), cisplatin (10 μM), eugenol (2 μM), and the sequential combination of both drugs. Treated cells were cultured in ultra-low attachment plates for 10 days and spheres were photographed and the number of spheres were counted, analyzed and presented as bar graph (n = 3; mean +/− SD, *p 0.05, ***p 0.001)