木糖醇, Xylitol

Xylitol is a 5-carbon sugar alcohol with antibacterial activity, found in medicines and dental products.

Certified pharmaceutical secondary standards for application in quality control provide pharma laboratories and manufacturers with a convenient and cost-effective alternative to pharmacopeia primary standards. Xylitol is a naturally occurring polyhydric sugar alcohol with high sweetening power and anticariogenic properties.
Xylitol is a pentitol (five-carbon sugar alcohol) having meso-configuration, being derived from xylose by reduction of the carbonyl group. It has a role as a sweetening agent, an allergen, a hapten, a human metabolite, an algal metabolite, a Saccharomyces cerevisiae metabolite and a mouse metabolite.
D-Xylitol, also known as meso-xylitol or xylisorb, belongs to the class of organic compounds known as sugar alcohols. These are hydrogenated forms of carbohydrate in which the carbonyl group (aldehyde or ketone, reducing sugar) has been reduced to a primary or secondary hydroxyl group. D-Xylitol exists as a solid, soluble (in water), and a very weakly acidic compound (based on its pKa). D-Xylitol has been found in human prostate tissue, and has also been detected in most biofluids, including urine, blood, saliva, and feces. Within the cell, D-xylitol is primarily located in the cytoplasm. D-Xylitol has been linked to the inborn metabolic disorders including ribose-5-phosphate isomerase deficiency.
Xylitol is a naturally occurring five-carbon sugar alcohol found in most plant material, including many fruits and vegetables. Xylitol-rich plant materials include birch and beechwood. It is widely used as a sugar substitute and in "sugar-free" food products. The effects of xylitol on dental caries have been widely studied, and xylitol is added to some chewing gums and other oral care products to prevent tooth decay and dry mouth. Xylitol is a non-fermentable sugar alcohol by most plaque bacteria, indicating that it cannot be fermented into cariogenic acid end-products. It works by inhibiting the growth of the microorganisms present in plaque and saliva after it accummulates intracellularly into the microorganism. The recommended dose of xylitol for dental caries prevention is 6–10 g/day, and most adults can tolerate 40 g/day without adverse events.

Title: Xylitol

CAS Registry Number: 87-99-0

Additional Names: xylo-Pentane-1,2,3,4,5-pentol; xylite

Trademarks: Eutrit (Takeda); Kannit (Mect); Klinit (Eisai); Kylit (Taiho); Newtol (Mohan); Torch (Sanwa); Xyliton (Morishita)

Molecular Formula: C5H12O5

Molecular Weight: 152.15

Percent Composition: C 39.47%, H 7.95%, O 52.58%

Literature References: Intermediate in metabolism of D-glucose through glucuronate cycle in livers. Prepd by reduction of xylose: G. Bertrand, Bull. Soc. Chim. Fr. [3] 5, 555 (1891); E. Fischer, R. Stahel, Ber. 24, 538 (1891). Prepn of metastable crystals: M. L. Wolfrom, E. J. Kohn, J. Am. Chem. Soc. 64, 1739 (1942); of stable form: J. F. Carson et al., ibid. 65, 1777 (1943). Crystal structure: H. S. Kim, G. A. Jeffrey, Acta Crystallogr. 25B, 2607 (1969). Use in prevention of dental caries: E. Grunberg et al., Int. J. Vitam. Nutr. Res. 43, 227 (1973); A. Scheinin, K. K. Makinen, DE 2606533 (1976 to Hoffmann-La Roche), C.A. 85, 149140h (1976). Acute toxicity: S. Salminen et al., Toxicol. Lett. 18, Suppl. 1, 37 (1983). Reviews of toxicity, metabolism and use as dietary additive: International Symposium on Metabolism, Physiology and Clinical Uses of Pentoses and Pentitols, B. L. Horecker et al., Eds. (Springer-Verlag, New York, 1969) 408 pp; Sugars in Nutrition, H. L. Sipple, K. W. McNutt, Eds. (Academic Press, New York, 1974) passim; G. E. Demetrakopoulos, H. Amos, World Rev. Nutr. Diet 32, 96-122 (1978); R. Ylikahri, Adv. Food Res. 25, 159-180 (1979). Book: Xylitol, J. N. Counsel, Ed. (Applied Science, London, 1978) 191 pp.

Properties: Stable form: orthorhombic needles from THF, prisms from ethanol; mp 93-94.5°; d 1.52. Metastable form: colorless, monoclinic, lath-shaped crystals from anhydrous methanol; hygroscopic; mp 61-61.5°. Soly of stable form (g/100 g soln): abs methanol 6.0; abs ethanol 1.2; water 64.2. Relative sweetness equal to sucrose. LD50 orally in mice: approx 22 g/kg (Salminen).

Melting point: mp 93-94.5°; mp 61-61.5°

Density: d 1.52

Toxicity data: LD50 orally in mice: approx 22 g/kg (Salminen)

Use: As oral and intravenous nutrient; in anticaries preparations.