Note: a: control; b: the treatment of S180 with S1; c: the treatment of S180 with S2; d: the treatment of S180 with P1;
e: the treatment of S180 with P2. Concentrations of P1, P2, S1 and S2 were 250 μg /ml. (As followed)
Figure 1: Images of S180 cells observed by invert fluorescence microscope of MTT assay.