Binding Studies of ¹⁴C-Caffeine to Artificial Receptors

Caffeine is among the most frequently consumed alkaloidal compounds and is omnipresent in many plants. The traditional significant sources of caffeine in daily life are coffee, black tea and cocoa. Actually, the alkaloid is an ingredient of Cola beverages and energy drinks. Many analgesics sold-over-the-counter contain also caffeine. Because of the wide range of applications and the potential of new analytical tools caffeine is currently gathering an increasing attention. Recently, we reported the synthesis of functionalized triphenylene ketals which represent the rigid C3v symmetric scaffold of our novel receptors (1). The cleft like structure exhibits a high affinity to caffeine and does not interfere with the alkyl groups of the oxopurine system leading to a novel concept for the molecular recognition of caffeine and related compounds. Based on this concept several methods for the detection of caffeine in real life samples have been established. With extraction studies using ¹⁴C-labelled caffeine the potential of this receptor systems and their binding action could be elucidated. This is a key prerequisite for the further development of caffeine detection systems on a dip-stick model. Furthermore, first experiments were done in view of the development of controlled release systems for caffeine in aqueous media.