Cytotoxic Effect of Pyomelanin Pigment Produced from Local Pseudomonas aeruginosa Isolates on Different Cell Lines Using MTT Assay


This study was designed to determine the most significant (IC50) values of purified pyomelanin pigment which was produced by local isolates of Pseudomonas aeruginosa on four cell lines using3-(dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT assay). 143 samples from burns, urine and sputum were collected from patients hospitalized into eleven hospitals which are located in Baghdad, Al-Anbar and Karbala provinces during the period of July 2013 to April 2014. All isolates were identified as Pseudomonas aeruginosa according to morphological, cultural, biochemical characteristics, VITEK-2 and 16S rRNA . Eight pyomelanogenic isolates (5.6%) were produced pyomelanin pigment on pyomelanin production medium. The results were showed that the isolate of sputum from cystic fibrosis (CF) was greatest in production of pyomelanin. The cytotoxicity of extracted and purified pyomelanin was assessed on Lung A 549, Skin A375, Macrophage RAW264.7 and VERO cell lines. The results showed that pyomelanin has cytotoxic effect on all tested cell lines but the most significant was on Skin A375 cell line with dose dependent effect.