Human milk oligosaccharides and their potential benefits for the breast-fed neonate.

Human milk oligosaccharides (HMO), unconjugated complex carbohydrates that are highly abundant in human milk but not in infant formula, have recently received much attention due to their potential benefits for the breast-fed neonate. While it is becoming evident that HMO structure determines their specific function, understanding the metabolic fate of ingested HMO is key in assessing their biological roles. Remarkably little is known about how, when and where they are metabolized. HMO have long been regarded as metabolically "inert" to the host, as significant amounts are excreted with the fe-ces. HMO reach the colon intact where their prebiotic effects promote healthy gut colonization. HMO can also function as soluble decoy receptors and block adhesion of microbial pathogens to epithelial surfaces. Local effects at the mucosal lining include differential cell responses or modulation of the innate immune system. A small percentage of HMO is believed to be absorbed intact in the small intestine and later excreted with the urine, which opens speculations on possible systemic effects, e.g. in the immune system or in the context of neuronal development. Oligosaccharides currently added to infant formula are structurally different from HMO and therefore most likely not functionally equivalent. Selected "authentic" HMO might soon become available for the supplementation of infant formula, but additional preclinical and clinical studies are required to demonstrate efficacy. This review provides an overview about the structural and functional properties of HMO with emphasis on recent findings in metabolism studies.

Therapeutically targeting protein-glycan interactions.

Glycosylation is the most common form of post-translational modifications by which oligosaccharide side chains are covalently attached to specific residues of the core protein. Especially O-linked glycan structures like the glycosaminoglycans were found to contribute significantly to many (patho-)biological processes like inflammation, coagulation, cancer and viral infections. Glycans exert their function by interacting with proteins thereby changing the structure of the interacting proteins and consequently modulating their function. Given the complex nature of cell-surface and extracellular matrix glycan structures, this therapeutic site has been neglected for a long time, the only exception being the antithrombin III-glycan interaction which has been successfully targeted by unfractionated and low-molecular weight heparins for many decades. Due to the recent breakthrough in the '-ome' sciences, among them proteomics and glycomics, protein-glycan interactions became more amenable for therapeutic approaches so that novel inhibitors of this interaction are currently in preclinical and clinical studies. An overview of current approaches, their advantages and disadvantages, is given and the promising potential of pharmacologically interfering with protein-glycan interactions is highlighted here.

The comparative effect of novel Pelargonium essential oils and their corresponding hydrosols as antimicrobial agents in a model food system.

Essential oils and their corresponding hydrosols, obtained after distillation of various scented Pelargonium (Geraniaceae) leaves were assessed for their antimicrobial activity in a model food system. Both the essential oils and hydrosols were used at 1000 ppm in broccoli soup, previously inoculated with Enterobacter aerogenes (at 10(5) cfu g(-1)) and Staphylococcus aureus (at 10(4) cfu g(-1)). The results showed a complete inhibition of S. aureus in the broccoli soup by the essential oils of 'Sweet Mimosa', 'Mabel Grey', P. graveolens, 'Atomic Snowflake', 'Royal Oak', 'Attar of Roses' and a lesser effect by 'Chocolate Peppermint' and 'Clorinda'; the hydrosols, however, had a potentiating effect on the bacterial population in the food. Both extracts showed a complete inhibition of S. aureus in the Maximum Recovery Diluent (MRD). Antibacterial activity against E. aerogenes in the broccoli soup was generally very much reduced: only the essential oil of 'Mabel Grey' showed complete inhibition and virtually no reductions in colonies were seen with the other essential oils; the hydrosols again caused an increase in bacterial colonies. All the essential oils, bar Chocolate Peppermint showed complete inhibition of E. aerogenes in MRD, but the hydrosols showed no effect. The results strongly suggest that the residual hydrosols from distillation of these plant essential oils have no potential as antibacterial agents in foods, in contrast to most of the essential oils, which show potential against some micro-organisms, but only in some food systems. The problem of food component interference and its possible management is discussed.