What is "inositol"

inositol \i*no"si*tol\ ([i^]*n[o^]s"[i^]*t[o^]l), n. [Gr. 'i`s, 'ino`s, strength, muscle.] (Physiol. Chem.) A white crystalline substance ( C6H12O6) with a sweet taste, widely distributed in certain animal tissues and fluids, particularly in the muscles of the heart and lungs, and also in some plants, as in unripe pease, beans, potato sprouts, etc. Although isomeric with dextrose, it has no carbonyl (aldehyde or ketone) group, and is therefore not a carbohydrate, but a derivative of cyclohexane. Called also inosite, cyclohexitol, cyclohexanehexol, hexahydroxycyclohexane and phaseomannite. There are nine possible steroisomers, not all of which are found naturally. The predominate natural form is cis-1,2,3,5-trans-4,6-cyclohexanehexol, also called myo-inositol. The naturally occurring phytic acid in plants is the hexaphosphate of inositol, from which inositol may be manufactured; phytin is the calcium-magnesium salt of phytic acid. It is also a component of phosphatidylinositol.
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n. (context biochemistry English) any of several isomeric cyclic polyhydric alcohols, C₆H₁₂O₆, found in both plant and animal tissue.

n. an optically inactive alcohol that is a component of the vitamin B complex

Inositol or cyclohexane-1,2,3,4,5,6-hexol is a chemical compound with formula or (-CHOH-), a six-fold alcohol ( polyol) of cyclohexane. It exists in nine possible stereoisomers, of which the most prominent form, widely occurring in nature, is cis-1,2,3,5-trans-4,6-cyclohexanehexol, or myo-inositol (former names meso-inositol or i-inositol). Inositol is a sugar alcohol. Its taste has been assayed at half the sweetness of table sugar ( sucrose).

myo-Inositol plays an important role as the structural basis for a number of secondary messengers in eukaryotic cells, the various inositol phosphates. In addition, inositol serves as an important component of the structural lipids phosphatidylinositol (PI) and its various phosphates, the phosphatidylinositol phosphate (PIP) lipids.

Inositol or its phosphates and associated lipids are found in many foods, in particular fruit, especially cantaloupe and oranges. In plants, the hexaphosphate of inositol, phytic acid or its salts, the phytates, are found. These serve as phosphate stores in the seed. Phytic acid occurs also in cereals with high bran content and also nuts and beans. Yet, inositol, when present as phytate, is not directly bioavailable to humans in the diet, since it is not digestible. Some food preparation techniques partly break down phytates to change this. Inositol as it occurs in certain plant-derived substances such as lecithins, however, is well-absorbed and relatively bioavailable.

myo-Inositol (free of phosphate) was once considered a member of the vitamin B complex (formerly Vitamin B); however, because it is produced by the human body from glucose, it is not an essential nutrient. Some substances such as niacin can also be synthesized in the body, but are not made in amounts considered adequate for good health, thus are still classified as essential nutrients. However, no convincing evidence indicates this is the case for myo-inositol.