Apoptosis induction in cancer cell lines by the carotenoid Fucoxanthinol from Pseudomonas stutzeri JGI 52

CONTEXT: Microorganisms produce a variety of pigments and many pigments from bacteria were reported to have therapeutic potential including anticancer effects. AIM: The aim of this study is to evaluate the anticancer potential a yellow pigment from newly isolated Pseudomonas stutzeri JGI 52. MATERIALS AND METHODS: Serial dilution method was adopted for the isolation of pigmented bacteria from soil sources. Pigment extraction was carried out from bacterial isolates using methanol as the solvent and the pigment was purified by thin layer chromatography. Through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, the effect of the pigment fraction on cancer cells was analyzed. Apoptosis induction was evaluated by caspase-3 activity assay, DNA fragmentation analysis, cell morphology observation by AO-EB staining under the fluorescence microscope, and cellular cytotoxicity was analysed by lactate dehydrogenase (LDH) release assay. Characterization of the purified pigment was by high-performance liquid chromatography and electrospray ionization-mass spectrometry analysis. STATISTICAL ANALYSIS: Significance of the results was confirmed by performing one-way analysis of variance. RESULTS: The pigment (PY3) from P. stutzeri inhibited the proliferation of HeLa, HepG2, and Jurkat cells and found to be less toxic to lymphocytes and CHO cells. PY3 exhibited apoptotic potential in the cancer cell lines, as evidenced by cleavage of DNA, LDH release, activation of caspase-3, and decrease in cell count. Results of mass spectra indicated the presence of “fucoxanthinol” which was earlier reported as an anticancer compound from seaweeds. CONCLUSIONS: This study revealed that the pigment PY3 from P. stutzeri has anticancer potential and induced cell death by apoptosis. It was found to have the carotenoid fucoxanthinol, responsible for its observed anticancer activity.