D(-)Mannitol

D(-)Mannitol is a sugar alcohol that can be used as an inert osmotic control substance. The uptake and phosphorylation of d-mannitol is catalyzed by the mannitol-specific phosphoenolpyruvate-dependent phosphotransferase systems (PTS). Mannitol can interact with neutrophils and monocytes. Experiments have shown that it is able to decrease neutrophil apoptosis in vitro. The compound has been used in studies as a stimulator of cecal microbial growth and cellulolytic activity in rabbits. It has been observed that mannitol can lower the fat digestibility and body fat accumulation in both normal and cecectomized rats, as well as upregulate monocyte HLA-DR, monocyte and neutrophil CD11b. Studies show that the mannitol operon is repressed by the transcription factor, mannitol operon repressor (MtlR) in Escherichia coli.