p-Toluic Acid belongs to the class of organic compounds known as benzoic acids. 4-Methylbenzoic acid has been primarily detected in saliva.

Propionic acid (PA) is widely used as an antifungal agent in food. It is present naturally at low levels in dairy products and occurs ubiquitously together with other short-chain fatty acids (SCFA) in the gastro-intestinal tract of humans and other mammals as an end-product of the microbial digestion of carbohydrates.

Diethyl oxalpropionate also known as methyloxalacetic acid diethyl ester or diethyl methyloxalacetate is a member of the class of compounds known as beta-keto acids and derivatives. These compounds are organic compounds containing an aldehyde substituted with a keto group on the C3 carbon atom.