What molecule am I?
Ellagic acid is a natural fused-ring polyphenol with a pKa of 5.5. It is found in fruits, nuts, the galls of oak trees, and the kino (gum) of eucalyptus trees. Its name comes from the French acide ellagique, coined from the word galle (gall) spelled backward.
Ellagic acid has been known since the first half of the 19th century as a component of tanning materials. It was mentioned in the chemical literature as early as 1868, when German chemist and industrialist Julius Löwe synthesized it by oxidizing gallic acid1 with arsenic acid or silver oxide. In 1905, Arthur George Perkin2* and Maximilian Nierenstein at the University of Leeds (UK) refined the process by using sodium persulfate as the oxidant.
Ellagic acid has been touted as a natural antioxidant and marketed as a dietary supplement with claims that it can prevent or treat cancer and heart disease. From 2008 to 2021, the US Food and Drug Administration issued warnings to drug companies and the public about false health claims about the molecule.
But ellagic acid may have some health benefits. In 2006, Juan Carlos Espin and colleagues at CEBAS−CSIC3 (Murcia, Spain) found that two colonic microflora ellagic acid metabolites (urolithins A4 and B5) have, oddly, both estrogenic and antiestrogenic activity. The authors suggested that the urolithins may have implications for treating breast cancer. Espin and his group subsequently investigated several aspects of urolithin activity, including its anti-inflammatory properties.
Fast forward to September 2022: Building on Espin’s work, Jian Zhao and co-workers at Sichuan University (Chengdu, China), used mouse studies to determine that urolithin A attenuates Helicobacter pylori-induced damage in vivo. Urolithin A not only decreased inflammation in the gut, but it also reduced H. pylori virulence factor secretion, tissue injuries, and the relative abundance of Helicobacter spp. In feces of H. pylori-infected mice.
For other findings on ellagic acid, see ScienceDirect’s information page.
1. CAS Reg. No. 149-91-7.
2. For whom the Perkin Transactions journals were named.
3. Center for Edaphology and Applied Biology of Segura, Spanish National Research Council. Edaphology is a type of soil science.
4. CAS Reg. No. 1143-70-0.
5. CAS Reg. No. 1139-83-9.
Ellagic acid hazard information
|Hazard class**||GHS code and hazard statement|
|Acute toxicity, oral, category 4||H302—Harmful if swallowed|
|Skin corrosion/irritation, category 2||H315—Causes skin irritation|
|Serious eye damage/eye irritation, category 2A||H319—Causes serious eye irritation|
|Specific target organ toxicity, single exposure, respiratory tract irritation, category 3||H335—May cause respiratory irritation|
*Compilation of multiple safety data sheets.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. Explanation of pictograms
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Ellagic acid fast facts
|CAS Reg. No.||476-66-4|
|SciFinder nomenclature||Benzopyrano[5,4,3-cde]benzopyran-5,10-dione, 2,3,7,8-tetrahydroxy-|
|Molar mass||302.19 g/mol|
|Appearance||Cream-colored to yellow crystals or powder|
|Melting point||>360 °C|
|Water solubility||0.82 g/L|
Nitric oxide1 (NO) was the Molecule of the Week for February 4, 2013. It is a colorless, toxic gas that is a stable free radical and a physiological signaling molecule. This month, Ke Chu and coauthors at Lanzhou Jiaotong University (Lanzhou) and Henan University (Kaifeng, both in China) reported that NO can be electrolytically hydrogenated to ammonia on molybdenum carbide (Mo2C) nanosheets, a catalyst that selectively activates NO.
Aspartame2 was the Molecule of the Week for November 4, 2019. It is a widely used dipeptide artificial sweetener that has come under scrutiny because consuming it has been linked to increased appetite and weight gain. It may also be a public health hazard: This month, Xing-Fang Li and co-workers at the University of Alberta (Edmonton) described reactions of aspartame with residual chlorine in tap water to form chlorinated disinfection byproducts—in particular, significant amounts of potentially toxic 2,6-dichloro-1,4-benzoquinone3.
1. CAS Reg. No. 10102-43-9.
2. CAS Reg. No. 22839-47-0.
3. CAS Reg. No. 697-91-6.
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