Proteomic of goat milk whey and its bacteriostatic and antitumour potential

Goat whey is normally discarded in the milk processing industry. However, several studies have addressed its biological properties and possible use in human or animal diet. The present study aimed to analysis the protein profile of goat whey to evaluate its possible oxidant, antioxidant, antibacterial, antitumour, and cytotoxic activities in vitro against human erythrocytes. Goat whey was skimmed, and crude protein extract (CPE) was obtained. Next, protein fractions (F) were obtained using ammonium sulphate precipitation method. The proteins were characterized by SDS-PAGE, two-dimensional electrophoresis and soluble protein measurements. No significant differences were observed in protein profile of CPE, F 30-60% and F 60-90%. The highest protein content was found in F 60-90% (0.41 mgP/mL). All samples, except F 0-30% showed bacteriostatic activity against different bacterial strains. Only CPE at a concentration of 1000 μg/mL was haemolytic against human erythrocytes. Oxidant activity against erythrocytes was not observed. Antioxidant activity was observed only for CPE. Cytotoxicity against C6 rat glioma cell line that was performed with CPE revealed tumour cell death > 70% at concentrations of 0.05 and 0.1 μg/mL. These results demonstrate at first time that CPE may be used as an antioxidant, bacteriostatic and cytotoxic compound against tumour cells.