Study of the bioactive compounds variation during yerba mate (Ilex paraguariensis) processing

Ilex paraguariensis St. Hil. (Aquifoliaceae) (yerba mate) is one of the most used plant species in South America due to its nutritional and medicinal properties. The industrial processing involves different stages (green leaves, zapecado, drying, forced or natural aging) which can modify the qualitative and quantitative composition and the pharmacological activities. In this work, the main compounds, caffeoyl derivatives (caffeic acid, mono- and dicaffeoylquinic acids), methylxanthines (caffeine and theobromine) and flavonoids (rutin, quercetin and kaempferol) were studied by HPLC in extracts obtained by decoction of samples of a large amount of I. paraguariensis during its industrial process stages. The comparative quantitative analysis of all the samples indicated that those obtained after the zapecado, drying and aging stages possess higher content of biologically active principles when compared with green leaves. No differences were found between the natural and forced aging processes. This is the first complete report on the quantitative variation of the bioactive compounds of I. paraguariensis during each step of the industrial processing. The results obtained in this work provide a guideline for the obtention of extracts enriched in biological principles for the pharmaceutical, food and cosmeceutical industry.