Fig. 2.

Cytotoxic effect of morin-cisplatin combination on a TOV-21G (cisplatin-sensitive) and b SK-OV-3 (cisplatin-resistant) human ovarian cancer cells. The cells were treated with different combinations of morin–cisplatin according to three approaches: APP:1—simultaneous treatment with both drugs for 24 h; APP:2—pre-treatment with morin for 24 h, followed by treatment with cisplatin alone for the another 24 h; APP:3—pre-treatment with morin for 24 h, followed by co-treatment with morin and cisplatin for another 24 h. After the treatments the cell viability was determined (XTT assay), followed by the calculation of combination index (CI). The CI values are shown as heat maps, where the effect of a drug combination is synergistic if CI < 0.9 (green colour); additive if 0.9 ≤ CI ≤ 1.1 (yellow colour); antagonistic if CI > 1.1 (red colour)