New sialic acid-containing sulfolipid: “ungulic acid”.

This research article discusses the identification and analysis of a new type of lipid, called “ungulic acid”, found in human and animal tissues, including human epidermis, hair, nails, kidneys and in hooves of bovines and horses. The article further elaborates on the chemical composition and properties of this new lipid.

Discovery of Ungulic Acid

• The research began with the detection of a lipid fraction in several human and animal tissues. This fraction was not just specific to humans but also found in certain types of animals. Specifically, the lipid was identified in human epidermis, hair, nails, and kidney, along with bovine and horses’ hooves.
• Upon screening these substances using thin-layer chromatography, the researchers found that this lipid fraction migrated slightly ahead of cerebroside sulfate esters, i.e., it appeared before this known lipid on the chromatograph. It was also noted to produce a color reaction characteristic of the presence of sialic acid.
• The researchers isolated this lipid fraction from horse hooves since its concentration was exceptionally high, nearly half of the total lipids present in the hoof. This indicated the significance of this lipid in horses specifically.

Chemical Composition and Properties of Ungulic Acid

• The isolation and subsequent analysis of the lipid revealed several distinct features. Firstly, the lipid contained sulfur but no phosphorus, and analysis of the IR spectrum showed the presence of a sulfate group, confirmed further by the benzidine method.
• The analysis of the products of acid hydrolysis, using thin-layer and gas-liquid chromatography, indicated the presence of various chemicals including sphingosine, galactose, galactosamine, and sialic acid.
• The fatty acid analysis showed that stearic acid was the major component of this lipid, with minor amounts of palmitic and arachidic acids also being present.
• Further, the fraction isolated from the hoof was found to contain ceramide, sialic acid, galactose, galactosamine, and sulfate in equal amounts. This highlights the varied composition of the identified lipid fraction and its potential biochemical significance.

Conclusion

• Based on all these observations and analyses, the researchers concluded that this new lipid is essentially a ganglioside sulfate. This term refers to a group of complex lipids that are part of nerve tissue cells in the body.
• Since this new lipid was first isolated and identified from a horse’s hoof, the researchers named it “ungulic acid”, deriving from the Latin word for hoof, ‘ungula’.