Theophylline

A xanthine alkaloid present in small quantities in tea, more potent as a bronchodilator than theobromine. Theophylline was historically used as a pharmaceutical asthma treatment (brand name Theo-Dur). In tea, its concentration is low (1-4mg per cup), but it contributes to the overall stimulant and bronchodilatory effects. The compound relaxes smooth muscle and stimulates the heart, contributing to tea's traditional use for respiratory comfort.

Bronchodilation and respiratory support, smooth muscle relaxation, cardiac stimulation, diuretic effect, may support lung function in respiratory conditions.