Teores de cafeína, teobromina e compostos fenólicos totais em amostras de folhas de Ilex paraguariensis

Abstract

Currently Brazil is one of the largest producers of yerba mate (Ilex paraguariensis St. Hill) with most of the commercial production in plantations without genetic improvement or extraction into areas of natural occurrence. The production and accumulation of compounds of interest such as methylxanthines (i.e. caffeine and theobromine) and phenolic compounds (i.e. flavonoids) can vary by genetic factors as by environmental factors. Thus, a high level of these compounds can enrich the commercial yerba mate and are indicative of quality of the product consumed. This study aimed to quantify the levels of caffeine and theobromine by high-performance liquid chromatography with diode array detector and total phenolic compounds by UV-Visible, Folin Ciocalteu method, in extracts prepared by the infusion of dried and crushed leaves in boiling water from the 52 yerba mate progenies, 49 coming from Ivaí / PR and 3 grown at Embrapa Forests. This quantification will help to select individuals who will be cloned and evaluated in future genetic improvement experiments carried out in partnership with Embrapa Forests. Spectra of near infrared were obtained from the dried and ground material in the attempt to create an estimation model of the levels assessed by multivariate calibration. A wide range in the methylxantines levels found in the extracts evaluated was observed, the maximum level of caffeine found 2.39 g/100 g of dry leaf, theobromine 1.56 g / 100 g and phenolic compounds 13.38 g/100g. In 4 samples evaluated the concentration of the methylxantine theobromine was below the limit of quantification, the minimum content of caffeine was found to be 0.01 g/100g and a minimum amount of phenolic compounds was 6.65 g /100g. The model obtained by partial least squares regression (PLS) allowed the screening of samples with caffeine levels above 1.5 g /100 g of dry leaves.