Assessment of exopolysaccharides, bacteriocins and in vitro and in vivo hypocholesterolemic potential of some Egyptian Lactobacillus spp.

Lactobacilli probiotics have been suggested to reduce cholesterol with low side effects to host. Bacteriocins and exopolysaccharides (EPSs) production are two meaningful examples of functional applications of lactobacilli in the food industry. Eight Lactobacillus strains were isolated from some Egyptian fermented food and tested for their probiotic properties. Analysis of the monosaccharide composition by thin layer chromatography showed the presence of glucose, galactose and unknown sugar. The main functional groups of EPSs were elucidated by Fourier-Transform Infrared Spectroscopy. Their fermentation cultures displayed powerful antioxidant activities extending from 97.5 to 99%, 40-75% for their EPSs and free cells, respectively, and exhibited in vitro cholesterol downgrading from 48 to 82% and 72 to 91% after 48 and 120 h, respectively. Their EPSs showed good anticancer activities against carcinoma cells with low IC50 values for HCT-116, PC-3 and HepG-2 cells. To the best of our knowledge, there have been no previous reports on the potential of Lactobacillus EPSs activity against PC-3. The selected strains, L. plantarum KU985433 and L. rhamnosus KU985436 produced two different bacteriocins as detected by gel permeation chromatography with good antimicrobial activities. In vivo study demonstrated that feeding Westar rats with fermented milk exhibited greater cholesterol, LDL and blood triglyceride reduction for both strains. Whereas, HDL was increased by about 43 and 38%, respectively, and the atherogenic indices decreased.

Structural, physical characteristics and biological activities assessment of scleroglucan from a local strain Athelia rolfsii TEMG.

Athelia rolfsii TEMG (MH 236106) an exopolysaccharide (EPS) producing fungal strain was isolated and identified. Extraction, purification, characterization, antimicrobial, antioxidant, antiviral and antitumor activities of the polysaccharide were investigated. It characterized as a homopolysaccharide of glucose with a molecular weight of 345.622 kDa. The identification of the polysaccharide was conducted using scanning electron microscopy, energy dispersive X-ray analysis, 1H and 13C NMR spectra. The existence of ß-1,3 and ß-1,6 linkages suggests that EPS could be scleroglucan. The purified scleroglucan showed considerable antibacterial and antioxidant activities. The results indicated that, there was no cytotoxicity on normal cell (W138) and no effect on tumor cell lines including HepG2 and PC3 showing IC50 of 5096.83, 5885.80 and 4803.90 µg/mL, respectively. The results showed also that Sclg could reduce the cytopathic effect by 50% (EC50) at 15 and 50 µg/mL of herpes simplex virus type-1 (HSV-1) and influenza virus (H5N1), respectively.