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a b s t r a c tKefiran, an exopolysaccharide isolated from kefir d'acqua grains, has anti-inflammatory and antimicrobial activities, however, a mechanism of action directly associated with biomembranes is not yet understood. The influence of kefiran on a L-a-Phosphatidylcholine/cholesterol supported bilayer lipid membrane using a Pt electrode was studied by voltammetry and electrochemical impedance spectroscopy. The interaction of the oligosaccharide with s-BLMs promoted the access of FeðCNÞ 3À=4À 6 probe ions to the electrode surface. Kefiran was found to induce molecular pores at the s-BLM surface within 5 min at 11.4 lmol/L. The suggested mechanism seems to involve hydrogen bonding between the carbohydrate and the phosphate head group of the phospholipid with a carpet-like model of interaction. The overall results can be contributed to direct molecular interactions between the prebiotic oligosaccharides and the cell surfaces, which can be related to the biological activity of kefiran in several experimental models.

Fructooligosaccharides from chicory (FOSC) are functional prebiotic foods recognized to exert several well-being effects in human health and animal production, as decreasing blood lipids, modulating the gut immune system, enhancing mineral bioavailability, and inhibiting microbial growth, among others. Mechanisms of actions directly on cell metabolism and structure are however little known. In this sense this work was targeted to investigate the interaction of FOSC with biomimetic membranes (liposomes and supported bilayer membrane; s-BLM) through cyclic voltammetry, impedance spectroscopy, spectrofluorimetry, and microscopy. FOSC was able to disrupt the membrane structure of liposomes and s-BLM from the onset of molecular pores induced on it. The mechanism of interaction of fructans with biomimetic membranes suggests hydrogen bonding between the polyhydroxylated structure of the oligosaccharides and the negative polar group of L-α-phosphatidylcholine (PC) present in both liposomes and s-BLM.