Fig. 1

Time- and dose-dependency of resveratrol (Res) and pterostilbene (Ptero) in inhibiting cellular viability. Different concentrations of resveratrol and pterostilbene were used singly as well as in combination for 24 h (one day) and 72 h (three day) to determine time- and dose- dependent inhibition in both the breast cancer cell lines. With 72 h treatments, the combinatorial resveratrol and pterostilbene showed a highly significant inhibition in comparison to the DMSO control, both single and combinatorial treatments at 24 h and single doses at 72 h. After determining the significance, the combination index (CI) of these two drugs at 72 h was determined using CompuSyn software. Resveratrol at 15 μM and pterostilbene at 5 μM in combination were found to exhibit synergism (indicated by triangle) with the lowest CI value among all of the combinations used (See Additional files 1 and 2). a Effects of resveratrol and pterostilbene single and combinatorial treatments on HCC1806 breast cancer cells. With 72 h of combinatorial treatment, these cells incurred a highly significant inhibition in comparison to the DMSO control and different treatments at 24 h. b Effects of resveratrol and pterostilbene single and combination treatments on MDA-MB-157 breast cancer cells. This cell line also showed a highly significant inhibition at 72 h (three days) treatments in comparison to the DMSO and different treatments at 24 h. Both the cancer cell lines showed time- and dose-dependent inhibition and combinatorial 15 μM of resveratrol and 5 μM of pterostilbene was also found to exhibit synergism as determined by CI values. c Different concentrations of resveratrol and pterostilbene were used to treat MCF10A control cell breast cells for 72 h to determine toxicity. No significant inhibition was observed in comparison to vehicle control. Values are representative of three independent experiments and are shown relative to control ± SE; *P <0.05, **P <0.01. Res, resveratrol; Ptero, pterostilbene