Biogeochemical aspects of selected elemental content in Ilex paraguayensis S.H from Eastern Paraguay
Abstract
Yerba mate, Ilex Paraguayensis, is a plant of Paraguayan origin used in infusions/macerations by the ancient inhabitants of Paraguay as a “reviver”/energy beverage and mineral supplier which consumption is lasting up today; furthermore, it is extended almost worldwide. In regard to its mineral content very few studies are known; moreover, none has been published related to the occurrence of REE (rare earth) and other refractory elements in the leaves. In this work, minor and trace elements composition have been investigated by XRF techniques to determine their correlation as well as provenance. The analysis of complex spectra was performed by the AXIL software and the quantitative analysis by the QAES software. Analyzed trace elements were the refractory Rb , Sr, Y, Zr, Nb, Ba, La, Ce, Nd , 3d as Ti, Cr, Ni, Cu, Zn. Minor elements were Mn, Fe which are often related to the above refractory together with Sand K.
Keywords
Download Options
Introduction
The role of mineral constituents and nutrients is of remarkable importance for Illex paraguayensis, according to its generally mentioned/accepted properties. Ilex paraguayensis or Ilex paraguariensis (Aquifoliaceae), is a small tree of Paraguayan origin called yerba mate in Spanish and Ka’a in Guaraní (Paraguay is a bilingual country. Official languages are Spanish and Guarani), and is used as infusions in hot water (mate) or as a maceration in cold water (terere) by the ancient inhabitants of Paraguay as a “reviver”/energy beverage (According the Paraguayan Codex Alimentarious the minimum caffeine content shall be no less than 1%) and mineral supplier whose consumption continues and is expanded to these days especially in Paraguay, Argentina, Brazil and Uruguay; furthermore, it is used almost worldwide as an infusion. When people, including those who are undernourished, drink inappropriate amounts any of these beverages, they gain/recover strength and their working yield improves. (Usually workers are entitled to a “mate break” or “tereré break” of about 30 min). In the Codex Alimentarius of Paraguay and elsewhere yerba mate is considered as a true foodstuff [1-2].
Mate tea, as it is cited in [3] has, due to some of its components, important pharmacological properties. Chlorogenic acid and caffeoyl derivatives, among others polyphenols such as tannins, rutin etc, contribute prominently for its antioxidant capacity. Xanthines, as theophilline, theobromine and caffeine (the latter present at higher concentration), account for diuretic, CNS stimulant, hepatoprotective as well as other biological/ pharmacological properties. Saponins (so called matesaponins) in addition to their role in the flavor, have hypocholesterolemic and antiinflamatory properties; some of them have antiparasitic effects, inter allia anti-trypanosomal, due to its content in tri-terpenoids (ICaround 4μM for Trypanosome brucei). An 50 excellent and comprehensive review in this regard is presented in [4& references therein].
The traditional way of manufacturing the yerba mate or yerba (as the product is called) is as follows: after raking leaves, twigs, and petioles, one proceeds to make bundles which are quickly passed over the flames of a bonfire, for achieving by fast evaporation a desiccation that prevents the decomposition of the yerba; the fire must be strong but without smoke; (a treatment called sapecado). Then comes the roasting, made over a framework of canes and sticks, done very carefully to avoid the loss of the green of the leaves. Afterwards, the material is submitted to milling [5]. The product consists of a powder-like mixture of tiny crushed leaves and small sticks.
Despite its wide use in Paraguay few papers & reports were produced in the country, such as those from the middle of the 20th century [6-8]; more recently, two interesting and recommended papers can be cited [9,10] & references therein, mainly related to minerals content, as well as others more recent in similar line [11,12]. Also some more can be cited from the neighboring countries of Brazil and Argentina, inter alia at the State do Parana [13,14] in the former at the Provinces of Misiones and Corrientes in the later, [15,16]) all of them bordering the East of Paraguay; just for expand the comparison, some other data[17] are also included.
They are mainly related to their multi-elemental contents; many of them, such as the essential microelements, are of utmost importance for living organisms.
An aspect very little considered is the geochemical approach, which represents a significant perspective on the ecology of plant nutrition [18-20], particularly in relation to their content of incompatible and refractory elements and their relationship in the Ilex Paraguayensis.
In this work, the composition of selected minor and trace elements have been investigated by EDXRF (Energy Dispersive X-Ray Fluorescence) techniques to determine their correlation as well as provenance. Analyzed elements were: K, Ti, Cr, Mn. Fe, Ni, Cu, Zn. Rb, Sr, Y, Zr, Nb, Ba, La, Ce, Nd .
Conclusion
The samples indicate that Ilex paraguayensis present in the aerial parts an important content of 3d elements, several of them considered essentials; besides K plays a prominent rol in the “reviver” property of mate beverages. On the other hand, results of the refractory are low, and except monovalent cations (K & Rb), well below the line of
