5463
Marwa Omar Hussein Elnahas
Microbiological and Physiological Studies on the Production of Polysaccharides from Local Actinomycetes.
Streptomyces, polysaccharides, antioxidant activities, tumor inhibition, metal chelation, emulsification.
Two Streptomyces strains were isolated from soil samples and the sequence of ~ 1500 nucleotides of their 16S rDNA showed 99% identity to Streptomyces sp. HV10 and 100% identity to Streptomyces chattanoogensis respectively. These newly isolated Streptomyces strains produced extracellular polysaccharides (EPS) named MOE6-EPS and MOE7-EPS respectively. The two EPS were characterized by various spectroscopic techniques including fourier transform infrared (FTIR), HPLC, 1HNMR as well as UV visible spectroscopy. MOE6-EPS composed of 71 ± 1% carbohydrate by weight, 3.6 ± 0.1% uronic acid and 0.78 ± 0.1% protein, while MOE7-EPS composed of 98± 0.5% carbohydrate by weight, 0.2 ±0.1 % uronic acid and 0.3± 0.1 % protein. MOE6-EPS and MOE7-EPS showed antioxidant activities by scavenging the hydroxyl free radical scavenging activity and 2,2-diphenyl-2-picryl-hydrazyl (DPPH) radicals. In addition, MOE6-EPSshowed high ferrous ion (Fe2+) chelation activity which is another antioxidant activity. Interestingly, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays that were colorimetric assays for NAD(P)H-dependent cellular oxidoreductases and a proxy of the number of viable cells, showed that MOE6-EPS and MOE7-EPS inhibited the proliferation of the human breast cancer cells (MDA-MB-231). Moreover, the scratch wound assay showed that MOE6-EPS and MOE7-EPS reduced the migration of human breast cancer cells (MDA-MB-231) in EPS concentration dependent manner. MOE6-EPS showed promising emulsifying activities against various hydrophobic phases (olive oil, corn oil, benzene and toluene) and it also demonstrated its capacity to remove toxic heavy metals (Cu(II), Co(II), U(VI), Cr(VI)) from their solution either by chelation and/or reduction to less toxic form. This study reports the production of EPSfrom two Streptomyces species with promising antioxidant, mammalian cell inhibitory, metal chelating and emulsifying activities.
2017
Ph.d
Cairo
Pharmacy