Description:
D-mannitol is the D-enantiomer of mannitol. It has a role as an osmotic diuretic, a sweetening agent, an antiglaucoma drug, a metabolite, an allergen, a hapten, a food bulking agent, a food anticak... ing agent, a food humectant, a food stabiliser, a food thickening agent, a member of compatible osmolytes, a weak renal vasodilator and a renal function diagnostic aid. Chemically, mannitol is a sugar alcohol, or a polyol, and occurs naturally in fruits and vegetables; it is similar to xylitol or sorbitol. However, mannitol has a tendency to lose a hydrogen ion in aqueous solutions, which causes the solution to become acidic. For this, it is not uncommon to add a substance to adjust its pH, such as sodium bicarbonate. Mannitol is a non-permeating molecule i.e. it cannot cross biological membranes. It is found to be associated with cytochrome c oxidase deficiency and ribose-5-phosphate isomerase deficiency, which are inborn errors of metabolism. Mannitol is also a microbial metabolite found in Aspergillus, Candida, Clostridium, Gluconobacter, Lactobacillus, Lactococcus, Leuconostoc, Pseudomonas, Rhodobacteraceae, Saccharomyces, Streptococcus, Torulaspora and Zymomonas (PMID:15240312; PMID:29480337). It has little significant energy value as it is largely eliminated from the body before any metabolism can take place (is metabolically inert in humans). It can be used to treat oliguria associated with kidney failure or other manifestations of inadequate renal function and has been used for determination of glomerular filtration rate. Mannitol is freely filtered by the glomerulus and poorly reabsorbed from the renal tubule, thereby causing an increase in osmolarity of the glomerular filtrate. An increase in osmolarity limits tubular reabsorption of water and inhibits the renal tubular reabsorption of sodium, chloride, and other solutes, thereby promoting diuresis, before irreversible renal failure becomes established. It may also be used for the promotion of urinary excretion of toxic substances or as a research tool in cell biological studies, usually to control osmolarity. Mannitol elevates blood plasma osmolality, resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma. As a result, cerebral edema, elevated intracranial pressure, and cerebrospinal fluid volume and pressure may be reduced. (CHEBI:16899)