Fig. 2. Time- and dose-dependent cytotoxicity of fractionated extracts from P. spathulatum SF7354 on HCT116 cells.

(A) Cell viability was measured by MTT assay after 24, 48, 72 h. Different letters (a-c) indicate significant difference among groups (p < 0.01). (B) Phase-contrast microscopy revealed normal morphology in control cells, whereas treated cells displayed shrinkage, detachment, and reduced cell density in a dose-dependent manner.