Composição fitoquímica de folhas de erva-mate (Ilex paraguariensis): influência das estações e da variabilidade clonal

Abstract

Yerba mate (Ilex paraguariensis A. St.-Hil.) is a species of high economic and cultural relevance in South America, widely recognized for its phytochemical composition, rich in methylxanthines, such as caffeine and theobromine, and in phenolic compounds, including flavonoids and chlorogenic acids, associated with stimulant and antioxidant properties. However, the concentration of these metabolites may vary significantly as a function of genetic and environmental factors, especially seasonality, directly impacting the quality of the raw material and derived products.This study aimed to quantify and compare the levels of total phenolic compounds, flavonoids, caffeine, theobromine, and chlorogenic acids in four yerba mate clones (C26, C27, C33, and Aupaba), evaluating the influence of clonal variability and seasons (winter, spring, summer, and autumn). Leaves and thin stems were collected in the four seasons, subjected to drying, grinding, and extraction with 70 % (v/v) ethanol. The quantification of total phenolic compounds and flavonoids was performed by UV-Vis spectrophotometry, while caffeine, theobromine, and six caffeoylquinic acid derivatives were identified and quantified by high-performance liquid chromatography with diode array detection (HPLC-DAD). The data were initially subjected to normality and homoscedasticity tests and subsequently statistically evaluated by factorial analysis of variance (ANOVA), followed by Tukey’s test.The results revealed significant variations among clones and seasons. For caffeine, summer was the season with the highest accumulation, with clone C27 standing out, reaching 2,41 g·100 g−1, whereas clone C33 showed low levels in all seasons (0,25 to 0,39 g·100 g−1), confirming a distinct metabolic profile. Theobromine showed higher concentrations in clone Aupaba, especially in winter (0,46 g·100 g−1), and a variable seasonal behavior in the other clones. Total phenolic compound levels ranged from 3,34 to 6,01 g·100 g−1, with higher accumulation in summer for clone C27, while flavonoids showed higher concentrations in winter and autumn, particularly in clone C26 (0,88 g·100 g−1). Regarding chlorogenic acids, a high contribution of 3-CQA and 3,5-di-CQA was observed, with emphasis on clone C27 in spring, which presented up to 4,81 g·100 g−1 of 3,5-di-CQA, evidencing metabolic sensitivity to seasonality.It is concluded that the phytochemical composition of yerba mate is strongly modulated by the interaction between genotype and season. Clone C27 proved to be promising for applications requiring high levels of caffeine and phenolic compounds, whereas clone C33 showed potential for products with low caffeine content. These results contribute to agronomic management, clonal selection, and the definition of strategic harvesting periods, aiming at standardizing raw material quality and adding value to the yerba mate production chain.