Structural features of glycoprotein purified from Saccharina japonica and its effects on the selected probiotic properties of Lactobacillus plantarum in Caco-2 cell

The aim of this study was to characterise the structural features of glycoprotein isolated from the brown alga Saccharina japonica (SJGP) and to evaluate its effects on the probiotic properties of Lactobacillus plantarum in Caco-2 cells. The amino acid profile, protein backbone and monosaccharides were analysed by amino acid analysis, Fourier transform infrared spectroscopy (FT-IR) and high-performance liquid chromatography (HPLC), respectively. The pretreatment of L. plantarum with SJGP increased cell adhesion, auto-aggregation and growth in Caco-2 cells, as observed by plate counting, light microscopy and scanning electron microscopy. Auto-aggregation and cell surface hydrophobicity of L. plantarum was also increased following pretreatment with SJGP. SJGP was shown to improve adhesiveness through its lipase inhibitory activity. Adhesion-related genes of L. plantarum showed upregulated expression in the presence of SJGP confirmed by reverse transcriptase-PCR assay. In summary, SJGP could be used as a bioactive compound to improve the probiotic properties of L. plantarum and could be relevant to the preparation of functional foods.