Caffeine, theophylline, and theobromine are not found in animal tissues, but are fairly widely distributed in plants.
theophylline the·oph·yl·line (thē-ŏf'ə-lĭn, thē'ō-fĭl'ēn')
A colorless crystalline alkaloid derived from tea leaves or made synthetically, used as a cardiac stimulant and diuretic.
A colorless, crystalline alkaloid derived from tea leaves or made synthetically. It is used in medicine especially as a bronchial dilator. Theophylline is a xanthine that is similar in structure to caffeine and is a structural isomer of theobromine. Chemical formula: C7H8N4O2.