Acetylcholinesterase-inhibitor hydrolysates obtained from 'in vitro' enzymatic hydrolysis of mannoproteins extracted from different strains of yeasts

Abstract

In vitro inhibitory activity against acetylcholinesterase (AChE) of peptides obtained by enzymatic hydrolysis of mannoproteins extracted from strains of yeasts was investigated. Yeast mannoproteins were extracted from strains belonging to the genera Brettanomyces, Candida, Pichia and Saccharomyces isolated from dairy products. They were obtained by heat treatment in citrate buffer and purified by affinity chromatography with concanavalin A. Each purified extract was subsequently hydrolysed with proteolytic enzymes (trypsin, pepsin, chymotrypsin and proteinase K) applied individually or in combination, thus generating smaller peptides. Inhibitory activity of the latter against AChE was determined. The molecular weight of mannoproteins, determined by SDS-PAGE, was between 6.5 and 30 kDa. As regards AChE inhibition, a preliminary screening of all hydrolysed extracts was performed, yielding variable results with 59% maximum inhibition. Subsequently, when inhibitory concentration 50 (IC50) was determined, the extracts showed higher inhibitory activity (between 6.75 and 12.3 mg mL-1). Results showed that the mannoproteins separated from yeast strains of food origin generated bioactive peptides by enzymatic hydrolysis, which can be of interest to the manufacturing of food with potential functional properties. Different peptide extracts were obtained by enzymatic hydrolysis of yeast mannoproteins and their in vitro inhibitory activity against acetylcholinesterase (AChE) was investigated. The most active extracts showed IC50 between 6.75 and 12.3 mg mL-1.