3-Methylxanthine, a xanthine derivative, is a cyclic guanosine monophosphate (GMP) inhibitor.

3-Methylhistidine belongs to the class of organic compounds known as histidine and derivatives. Histidine and derivatives are compounds containing cysteine or a derivative thereof resulting from reaction of cysteine at the amino group or the carboxy group or from the replacement of any hydrogen of glycine by a heteroatom.

3-Methyl-2-cyclopenten-1-one, used as a food additive to enhance the flavor of meat and meat products at 2-5 ppm, demonstrated gastric cytoprotective activity when administered orally to male Wistar rats.