More than 70 bitter glycosides with cardiac activity, with five different aglyconees digitoxigenin, gitoxigenin, digoxigenin, diginatigenin and gitaloxigenin in the leaves act as a protection against herbivores. Yield and concentration of these cardiac glycosides are enhanced by greenhouse cultivation through enhanced temperature and enhanced carbon dioxide concentration.
The bitter glycosides in the leaves of plants are a defense mechanism against herbivores. Their production is enhanced by greenhouse cultivation through increased temperature and carbon dioxide levels.