Evaluation of the Interaction among Yeast β-Glucan and Polyphenols derived from Cinnamic and Benzoic acids

VILLALBA, G.; LÓPEZ ALSOGARAY, S.; NAZARENO, M. A .

San Miguel de Tucumán

Congreso; XI Congreso Argentino de Microbiología General; 2015

Asociación Civil de Microbiología General

The B-(1-3)-D-glucan is a homo-polysaccharide of D-glucose with insoluble alkali-acid characteristics. It is widely used to activate the immune system, for its antiviral and antimicrobial properties. Considering its use by the food industry, the FDA (Food and Drug Administration-USA) has been recognized as GRAS. One of the most important sources of B-glucan is the cell wall of yeast, especially of Saccharomyces cerevisiae. Phenolic compounds are secondary plant metabolites occurring in fruits and vegetables. They are involved in the defence system against invading pathogens (including Escherichia coli and Campylobacter jejuni). Many of these phenolic compounds have valuable chemical and biological activities, as antioxidants, metal chelators as well as antimicrobial and antiviral agents. This study focuses on obtaining biomaterials with metal complexing and antioxidants properties based on secondary interactions between B-glucan from S. cerevisiae and a series of phenolic compounds (caffeic, ferulic, and gallic acids). The aim of this work is to develop antioxidant solid filters to remove free radicalsand metal ions to be used in environmental remediation and food and pharmaceutical industry. YPD growth medium was supplemented with EDTA and adjusted to pH 4.00 with tartaric acid. Cells were incubated at 30 °C with shaking at 200 rpm for 24 h. The number of viable cells was analysed using the McFarland turbidity standards. The cell wall was obtained by cell autolysis at 50 °C for five days. The alkalis-acid soluble components of the cell wall were removed by alkali treatment (incubation in NaOH at 90 °C) and acidic treatment (incubation in H 3PO4 at room temperature). Mannoproteins removal was performed by autoclaving at McIlvane pH 7.00 buffer for 90 min. The -glucan extracted was analysed by IR and NMR. The interactions were assessed by monitoring the UV-Vis spectral changes for different ratios of polyphenol/glucan mass at pH 5 to 8 and its stability for one hour. The presence of 1,5x1012 viable cells/mL was observed. Amounts of 0.31 g of glucan per liter of culture were obtained. The yield obtained is low considering the physical size of the microorganism, as well as the energetic conditions used during extraction. The quantification of viable cells was null after autolysis. The purity of the material was analysed by IR and NMR spectroscopy, and results were satisfactory. For interactions between B-glucan and polyphenols the UV-Vis spectral changes indicated the existence of interaction between B-glucan and caffeic acid as well as between B-glucan and gallic acid. The evaluation of changes in the antiradical activity and metal complexing abilities when the polyphenols were combined with B-glucan was carried out. Further studies of high biological ongoing interest are in progress concerning the chemical modification of B-glucan to enhance the interaction with polyphenols.