| Member | Definition | Role |
|---|
| 1,7-dimethylxanthine | A dimethylxanthine having the two methyl groups located at positions 1 and 7. It is a metabolite of caffeine and theobromine in animals. | 1,7-dimethylxanthine |
| lisofylline | A dimethylxanthine that is 3,7-dihydro-1H-purine-2,6-dione which is substituted at positions 1,3 and 7 by a 5-hydroxyhexyl group, methyl group and methyl group, respectively. | 1-(5-hydroxyhexyl)-3,7-dimethyl-3,7-dihydro-1H-purine-2,6-dione |
| theobromine | A dimethylxanthine having the two methyl groups located at positions 3 and 7. A purine alkaloid derived from the cacao plant, it is found in chocolate, as well as in a number of other foods, and is a vasodilator, diuretic and heart stimulator. | theobromine |
| theophylline | A dimethylxanthine having the two methyl groups located at positions 1 and 3. It is structurally similar to caffeine and is found in green and black tea. | theophylline |