Soy yogurt using Lactobacillus plantarum 200655 and fructooligosaccharides: neuroprotective effects against oxidative...

This study aimed to evaluate the effect of Lactobacillus plantarum 200655 and fructooligosaccharides (FOS) on soymilk fermentation and the neuroprotective effects of fermented soymilk (FS). The addition of FOS did not affect the physicochemical properties during fermentation. It helped that L. plantarum 200655 survive for 21 days of storage at 4 °C. FOS increased the β-glucosidase activity of L. plantarum 200655, total phenolic content, and antioxidant activities, such as radical scavenging and reducing power of FS. In addition, FS with FOS exerted neuroprotective effects in SH-SY5Y cells against H₂O₂-induced oxidative stress. FS with 3% and 5% FOS (FS3 and FS5) significantly increased cell viability and gene expression of neuronal markers, such as brain-derived neurotrophic factor and tyrosine hydroxylase. Moreover, FS3 and FS5 significantly reduced lactate dehydrogenase release and the gene expression of Bax/Bcl-2 ratio, caspase-9, and caspase-3. These results indicated that FS3 and FS5, with enhanced antioxidant properties, could protect SH-SY5Y cells against H₂O₂-induced damage. Therefore, soymilk fermented with L. plantarum 200655 and FOS can be used as a prophylactic functional food with neuroprotective effects against oxidative stress.