Preparation of Various Glycoside Hydrolase Enzyme Extracts from Durvillaea antarctica and Evaluation of the Neuroprotective Efficacy

In this study, three distinct hydrolysates which designated Dur-I, Dur-II, and Dur-III, were generated from extrusion-pretreated Durvillaea antarctica biomass by applying viscozyme, cellulase, and α-amylase, respectively. Dur-III had a higher proportion of low-molecular-weight polysaccharides as compared to Dur-I and Dur-II. Chemical composition determination and FTIR analyses revealed that Dur-I, Dur-II, and Dur-III contained fucose-containing sulfated polysaccharides. To investigate neuroprotective properties of Dur-I, Dur-II, and Dur-III, rotenone (Rot) was added to SH-SY5Y cells that had been pretreated with Dur-I/II/III. Here, flow cytometry was employed to assess changes in mitochondrial membrane potential (MMP), Bcl-2 expression, cytochrome c release, caspase-9, -8, and -3 activation, as well as DNA fragmentation. The protective effect of Dur-I/II/III pretreatment of SH-SY5Y cells on the Rot-induced death process was further investigated using cell cycle and annexin V-fluorescein isothiocyanate (FITC) / PI (propidium iodide) double staining analyses. The results reveal that the Rot-induced apoptotic factors were all recovered by the pretreatment of Dur-I/II/III. Moreover, cell cycle and annexin V-FITC/PI double staining analyses also indicated that Dur-I/II/III were capable of protecting SH-SY5Y cells from Rot-induced cytotoxicity. Therefore, these Dur extracts are considered as good candidates for the prevention and treatment of neurodegeneration induced by oxidative stress.