UK-1
Usnic acid
Usninic acid, Carbonusninic acid, Usno
Umirolimus
Biolimus, Biolimus A9, TRM 986
Unguinol
Yasimin, tris-dechloronidulin
Unguisin A
Unguisin B
Urocanic acid
Imidazole-4-acrylic acid, 4-Imidazolylacrylic acid, 5-Imidazoleacrylic acid, NSC 66357, Urocaninic acid
Ursolic acid
(+)-Ursolic acid, Bungeolic acid, Malol, Merotaine, NSC 167406, NSC 4060, Neoage UR, Prunol, Ursolisome, Urson, β-Ursolic acid
USF 2550A
Methyltriacetic lactone, USF 2550A, 4-Hydroxy-3,6-dimethyl-2-pyrone,