Alkaloids in tea

Alkaloids are small organic molecules, secondary metabolites of plants, containing nitrogen usually in a ring; about 20% of plant species consist of alkaloids. They usually have remarkable biological activity and pharmacological effects, and are widely distributed in more than 2,000 kinds of plants in more than 100 families.

Plants normally produce highly complex mixtures of alkaloids with the desirable types often at low levels, with the result that commercially produced specific alkaloids are very expensive.

Fresh leaves tea contains, on average, 3-4% of alkaloids known as methylxanthines, such as caffeine, theobromine, and theophylline.

Caffeine is the highest alkaloid in both green and black teas, generally accounting for 2%−5% of the dry matter content. It is one of the most important quality and functional components in tea. Caffeine treatment prevented the onset of colitis with reduced chitinase 3-like 1 expression in intestinal epithelial cells.

Theophylline (1,3-dimethylxanthine) , which is the isomer of theobromine, and the content in tea is much lower, generally about 0.05%. Theophylline acts as a breathing dilator, being one of the reasons people find it easier to breathe after drinking tea. It does this mainly through increasing the amount of oxygen taken in through the lungs.
Alkaloids in tea