Inositol
[CAS 87-89-8]

Identification

• Classification: Organic raw materials >> Aldehyde
• Name: Inositol
• Synonyms: Myo-Inositol; 1,2,3,4,5,6-Cyclohexanehexol; Hexahydroxycyclohexane
• Molecular Formula: C₆H₁₂O₆
• Molecular Weight: 180.16
• CAS Registry Number: 87-89-8
• EC Number: 201-781-2
• SMILES: C1(C(C(C(C(C1O)O)O)O)O)O

Properties

• Density: 2.0±0.1 g/cm³ Calc.^*, 1.75 g/mL (Expl.)
• Melting point: 222 - 227 °C (Expl.)
• Boiling point: 291.3±40.0 °C 760 mmHg (Calc.)^*
• Flash point: 143.4±21.9 °C (Calc.)^*
• Solubility: H2O: 0.5 M (20 °C) (Expl.)
• Index of refraction: 1.784 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2A	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315

chemBlink Chemical Story

Inositol is a naturally occurring cyclitol with the molecular formula C₆H₁₂O₆. Although it has the same empirical formula as glucose, its six carbon atoms form a saturated cyclohexane ring bearing six hydroxyl groups rather than an open-chain or pyranose structure. Nine stereoisomers of inositol are known, of which **myo-inositol** is by far the most abundant in nature and is generally referred to simply as "inositol." It is widely distributed in plants, animals, and microorganisms, where it serves as both a structural component and a precursor of numerous biologically important molecules.

Inositol was first isolated in the nineteenth century during investigations of natural products from animal tissues and plants. Early chemists recognized that it resembled a sugar in composition but exhibited unusual chemical properties because it lacked a carbonyl group. This discovery contributed to the establishment of the cyclitol family and broadened the understanding of naturally occurring carbohydrates beyond conventional sugars.

For many years, inositol was regarded primarily as a nutritional factor. Because it was frequently found together with members of the vitamin B complex and deficiency symptoms could be demonstrated in certain experimental animals, it was once described as "vitamin B₈." Subsequent research, however, showed that humans and many other animals can synthesize sufficient amounts of myo-inositol from glucose, and it is therefore no longer classified as an essential vitamin. Nevertheless, its widespread occurrence in foods and tissues continued to attract scientific interest.

The importance of inositol increased dramatically during the second half of the twentieth century with the discovery of phosphatidylinositol and its phosphorylated derivatives as key components of cell membranes. These phosphoinositides participate in one of the most fundamental signaling systems in biology. Activation of membrane receptors stimulates phospholipase C to cleave phosphatidylinositol 4,5-bisphosphate, generating two intracellular messengers—inositol 1,4,5-trisphosphate (IP₃) and diacylglycerol (DAG). IP₃ triggers the release of calcium ions from intracellular stores, while DAG activates protein kinase C. This signaling pathway has become one of the cornerstones of modern cell biology and molecular pharmacology.

Beyond signal transduction, inositol derivatives regulate membrane trafficking, cytoskeletal organization, ion channel activity, gene expression, and intracellular metabolism. Inositol phosphates containing additional phosphate groups, including highly phosphorylated species such as IP₆, have been shown to participate in numerous regulatory processes. The study of these molecules has greatly expanded our understanding of how cells coordinate responses to hormones, neurotransmitters, and environmental stimuli.

Interest in inositol has also grown in nutritional science and medicine. Myo-inositol and D-chiro-inositol have been investigated for their roles in insulin signaling, metabolic regulation, polycystic ovary syndrome (PCOS), reproductive medicine, and neurological disorders. While clinical applications continue to be evaluated and recommendations depend on the specific condition and available evidence, these studies illustrate the broad physiological importance of inositol metabolism.

Commercially, inositol is produced from naturally occurring phytate or by other industrial processes and is widely used in nutritional products, pharmaceutical formulations, infant nutrition, fermentation media, and biochemical research. Its derivatives have become indispensable tools in cell biology, analytical chemistry, and drug discovery.

The scientific history of inositol demonstrates how a seemingly simple naturally occurring molecule can transform an entire field of biology. From an unusual sugar alcohol identified in the nineteenth century to the central scaffold of one of the most important intracellular signaling pathways, inositol has profoundly influenced modern biochemistry, cell biology, and medicine. Few naturally occurring compounds illustrate the evolution of biological chemistry as clearly as this remarkable cyclitol.

**References**

1. Michell, R.H. (1975) 'Inositol phospholipids and cell surface receptor function', *Biochimica et Biophysica Acta*, 415, pp. 81–147.

2. Berridge, M.J. and Irvine, R.F. (1984) 'Inositol trisphosphate, a novel second messenger in cellular signal transduction', *Nature*, 312, pp. 315–321.

3. Majerus, P.W. (1992) 'Inositol phosphate biochemistry', *Annual Review of Biochemistry*, 61, pp. 225–250.