Arabitol (Ara)

Arabitol or arabinitol is a sugar alcohol. It can be formed by the reduction of either arabinose or lyxose. Some organic acid tests check for the presence of D-arabitol, which may indicate overgrowth of intestinal microbes such as Candida albicans or other yeast/fungus species. Candida albicans produces large amounts of the acyclic pentitol D-arabitol in culture and in infected animals and humans, and most strains also grow on minimal D-arabitol medium. An earlier study showed that the major metabolic precursor of D-arabitol in C. albicans was D-ribulose-5-PO4 from the pentose pathway, that C. albicans contained an NAD-dependent D-arabitol dehydrogenase (ArDH), and that the ArDH structural gene (ARD) encoded a 31-kDa short-chain dehydrogenase that catalyzed the reaction D-arabitol + NAD <=> D-ribulose + NADH. C. albicans synthesizes and utilizes D-arabitol via separate metabolic pathways, which was not previously suspected for fungi.