5-Aminolevulinic acid (ALA; Levulan) is a novel and potent drug approved for treating actinic keratosis.

5,6-Dihydrouracil is a novel and potent intermediate product from the breakdown of uracil.

N-Acetyl-D-mannosamine (also known as ManNAc) is the direct precursor of all physiological sialic acids.

Ursocholic acid (UCA), a bile acid and the 7β-hydroxyepimer of cholic acid, is found predominantly in bile of mammals, and can be transformed into deoxycholic acid by the intestinal microflora in mice.

2-Methoxybenzoic acid (O-Methylsalicylic acid; NSC 3778) is a novel antiemetic that is also widely used as an internal standard of salicylic acid and its putative biosynthetic precursors in cucumber leaves.

Phenylacetylglutamine (NSC-203800; Phenylacetyl-L-glutamine) is a product formed by the conjugation of phenylacetate and glutamine.

Glycocholic acid (cholylglycine; glycocholate) is a bile acid derivative formed by conjugate of cholic acid with glycine.

All-trans-retinal (Retinaldehyde; NSC-626581; Retinal A; NSC-122757; Vitamin A aldehyde) is one of the major vitamin A metabolites in the retina.

Umbelliferone (also known as 7-Hydroxycoumarin, Hydrangin or Skimmetin) is a natural product of the coumarin class, it is a fluorescing compound which can be used as a sunscreen agent.

5α-Cholestan-3β-ol (5α-Cholestanol; Cholestanol; Dihydrocholesterol; NSC 18188), a reduced form of cholesterol at the 5,10-ene position, is derived from cholesterol by the action of intestinal microorganisms and can also be isolated from the testes of White Carneau pigeons.