Prodigiosin pigment-producing Streptomyces diastaticus on Semi-solid media and anticancer activity against colorectal...

The present study insights into the copious application of Prodigiosin as a bio-colorant produced by Actinomycetes using semisolid low-cost substrate media. Reddish pink pigment-producing Actinomycetes were isolated from the rhizosphere soil of the peanut plant and characterized by morphological, biochemical, and molecular analysis. Molecular analysis unveiled that the pigment-producing isolate was identified as Streptomyces diastaticus. Prodigiosin was produced in oatmeal media and characterized by UV-Spectrophotometer, Thin layer chromatography, FTIR, GC-MS, and NMR studies to investigate the structure of the pigment. Anti-cancer activity and toxicity of the pigment were studied. The results demonstrated dose-dependent anti-cancer activity against COLO-205 with an IC-50 value 171.36 μg/ml and the toxicity test on the HaCaT cell line showed cytotoxicity at higher concentrations at 1000 μg/ml respectively. The efficiency of anti-cancer activity on COLO-205 was further investigated by colony-forming assay, sphere-forming assay, ROS assay, simple staining, and dual staining. Anti-oxidant activity has increased with the increasing concentration of the pigment. Furtherly, it inhibits the growth of bacterial pathogens Staphylococcus aureus, Pseudomonas sp., Salmonella sp., E. coli and Klebsiella sp. and fungal pathogens Aspergillus niger, Aspergillus flavus, Penicillium sp., and Rhizopus sp. Overall results showed that the Prodigiosin produced from Actinomycetes is found to be toxic to cancer cells. Thus, it could find application as a bio-colorant in the dyeing, cosmetics, and food sectors.