Gallic acid
[CAS# 149-91-7]

Identification

• Classification: API >> Other chemicals >> Health and epidemic prevention drugs
• Name: Gallic acid
• Synonyms: 3,4,5-Trihydroxybenzoic acid; Pyrogallol-5-carboxylic acid
• Molecular Formula: C₇H₆O₅
• Molecular Weight: 170.12
• CAS Registry Number: 149-91-7
• EC Number: 205-749-9
• SMILES: C1=C(C=C(C(=C1O)O)O)C(=O)O

Properties

• Water solubility: 12 g/L cold water
• Density: 1.7±0.1 g/cm³, Calc.^*, 1.694 g/mL
• Melting point: 251 °C (dec.)
• Index of Refraction: 1.730, Calc.^*
• Boiling Point: 501.1±50.0 °C (760 mmHg), Calc.^*
• Flash Point: 271.0±26.6 °C, Calc.^*

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

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Risk Statements: H315-H318-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P305+P354+P338-P317-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Serious eye damage	Eye Dam.	1	H318
Specific target organ toxicity - single exposure	STOT SE	3	H336
Eye irritation	Eye Irrit.	2A	H319

Discovery and Applications

Gallic acid is a naturally occurring organic compound classified as a trihydroxybenzoic acid. It is widely distributed in various plant species, particularly in the leaves, fruits, and seeds of many flowering plants. The discovery of gallic acid dates back to the early 19th century when it was first isolated from gallnuts, which are abnormal growths on oak trees caused by insects. Its chemical structure consists of a benzene ring with three hydroxyl (−OH) groups and a carboxylic acid group (−COOH), giving it the systematic name 3,4,5-trihydroxybenzoic acid.

The applications of gallic acid are extensive and diverse, spanning multiple fields including food, pharmaceuticals, and cosmetics. In the food industry, gallic acid is recognized for its antioxidant properties, which help prevent oxidative damage to cells and maintain the quality and shelf-life of food products. It is often used as a natural preservative in various food formulations due to its ability to inhibit the growth of harmful bacteria and fungi.

In pharmaceuticals, gallic acid has garnered attention for its potential therapeutic effects. Research has shown that it possesses anti-inflammatory, antiviral, and anticancer properties, making it a subject of interest for drug development. Gallic acid has been found to induce apoptosis (programmed cell death) in cancer cells and to inhibit the proliferation of various tumor types. Its ability to scavenge free radicals and modulate various cellular pathways contributes to its therapeutic potential in the management of chronic diseases, including cancer and cardiovascular diseases.

Additionally, gallic acid is utilized in the cosmetic industry for its skin-protective effects. It is incorporated into formulations for its anti-aging and skin-brightening properties, as well as its ability to reduce skin irritation and redness. Its antioxidant activity helps protect the skin from environmental stressors and premature aging, making it a valuable ingredient in skincare products.

Gallic acid also plays a significant role in analytical chemistry, particularly in the field of food analysis and quality control. It is used as a standard reference compound in high-performance liquid chromatography (HPLC) and other analytical techniques for the quantification of phenolic compounds in various matrices, including food and plant extracts.

Safety considerations for gallic acid highlight its generally recognized as safe (GRAS) status when used in appropriate amounts. However, like any bioactive compound, excessive consumption may lead to adverse effects. Therefore, proper dosage and application are recommended in both food and cosmetic products.

In summary, gallic acid is a versatile compound with a rich history of discovery and numerous applications across various industries. Its antioxidant, anti-inflammatory, and therapeutic properties continue to drive research and innovation, reinforcing its significance in health and wellness.

References

2000. Effects of Acute and Chronic Coingestion of AlCl3 with Citrate or Polyphenolic Acids on Tissue Retention and Distribution of Aluminum in Rats. Biological Trace Element Research, 76(3).
DOI: 10.1385/bter:76:3:245

2000. Effect of black and green tea polyphenols on c-jun phosphorylation and H(2)O(2) production in transformed and non-transformed human bronchial cell lines: possible mechanisms of cell growth inhibition and apoptosis induction. Carcinogenesis, 21(11).
DOI: 10.1093/carcin/21.11.2035

2000. Antioxidative galloyl esters as enzyme inhibitors of p-hydroxybenzoate hydroxylase. FEBS Letters, 483(2-3).
DOI: 10.1016/s0014-5793(00)02100-1