engleski

Identification and Determination of Methylxanthines in Erva Mate by Thin-Layer Chromatography

Mate tea (Port. erva mate, Sp. yerba mate) consists of well cut, dried parts of Ilex paraguariensis St.-Hil. (Aquifoliaceae) shrub. It contains methylxanthines, mainly caffeine, phenolic acids and saponins, and is used as everyday substitution for coffee (psycho stimulant) in the south of Brazil, north of Argentina and oriental Paraguay - the land of gaúchos. Manner of consumption depends of the origin area and in Rio Grande do Sul it is prepared in hollow piece of wood (cuia) well decorated outside in which erva is put. It is consumed using colander in the shape of straw (bomba), and cuia goes from hand to hand, each gaúcho putting hot water from thermos flask (térmica) and drinking bitter tea. In this work we were interested to identify and determine the content of caffeine and theobromine in water extract of erva mate. The method used was thin-layer chromatography in situ and it was compared to the total content of methylxanthines obtained using UV-Vis spectrophotometry. System used for development was ethyl acetate, methanol and water in volume ratio 40 : 5.4 : 4, and densitometry was done using CAMAG Scanner 3 (Basel, Switzerland). The results of TLC analysis were comparable to the total content of methylxanthines. Preliminary results suggest that TLC densitometry could be used for both, identification as well as determination of caffeine and theobromine in erva mate having in mind that most common method only for determination is time consuming titration.

TLC; xanthines; erva mate

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