6'-Sialyllactose (sodium salt)

6'-Sialyllactose (sodium salt) (CAS No.: 157574-76-0) is a sialylated human milk oligosaccharide widely studied in glycobiology, microbiome research, and anti-infective drug discovery due to its role in modulating host–pathogen interactions and immune responses. As a naturally occurring lactose derivative capped with N-acetylneuraminic acid, it functions as a soluble decoy receptor that can bind microbial adhesins and viral proteins recognizing sialic acid-containing glycoconjugates, thereby interfering with pathogen attachment and entry into host cells. Experimental evidence indicates that it can inhibit the internalization of bacteria such as Pseudomonas aeruginosa into epithelial cells by disrupting receptor-mediated adhesion processes, highlighting its utility in studying early infection mechanisms. In parallel, it exhibits prebiotic activity by promoting the growth of beneficial gut microbiota, including Bifidobacterium and Lactobacillus species, while suppressing harmful bacterial proliferation, and it has been associated with anti-inflammatory and anti-angiogenic effects in cellular systems. Its ability to bind diverse viral strains, including influenza and HIV-related models, also supports its application in characterizing viral binding domains and screening antiviral strategies targeting sialic acid-recognizing pathways. In vitro studies typically employ concentrations in the micromolar to millimolar range depending on assay design, while in vivo or translational models explore its effects on microbiota composition, mucosal immunity, and tissue responses. Accordingly, 6'-Sialyllactose (sodium salt) serves as a versatile tool compound for investigating glycan-mediated signaling, host–microbe interactions, and the development of novel anti-infective or microbiome-modulating therapeutics.