Fig. 3

Cytotoxicity of violacein and deoxyviolacein. MTT assay used to investigate the cytotoxicity of violacein and deoxyviolacein to (a) COS-7 and (b) HepG2 cells, indicated that deoxyviolacein shows no measurable toxicity to mammalian cells, whereas the IC₅₀ for violacein is approximately 2.5 μM and 1.4 μM for COS-7 and HepG2 cells, respectively