Short communication
Trace elements analysis of Echinacea purpurea—herbal medicinal

https://doi.org/10.1016/S0731-7085(03)00338-8Get rights and content

Abstract

Elemental composition of Echinacea purpurea (Asteracae), grown in Serbia under strongly controlled conditions, has been studied. To distinguish elemental patterns of different parts of the plant, the content of Zn, Fe, Cu, Mn, Ca, Mg, Sr, Ni, and Li in root versus upper plant parts were determined, by flame atomic absorption and flame atomic emission spectrometry. Analyses of the mentioned elements in soil and in an ethanolic extract of E. purpurea were made, too. The trace element data were evaluated by multivariate methods, i.e. principal component analysis and hierarchical cluster analysis. This revealed two groups of elements (I: Fe, Cu, Mn, Li; II: Ca, Mg, Zn, Ni), while trace element profiles of root, stem, leaves, and flowers of this plant differed significantly. However, no significant difference in the trace element patterns between the summer and the autumn harvest samples was found.

Introduction

Echinacea purpurea (Asteraceae), also known as the purple coneflower, is an herbal medicine with positive effects on various immune parameters [1]. It is usually used in supportive therapy of colds and chronic infections of the respiratory and the lower urinary tract. Although many of the active compounds of E. purpurea have been identified, the mechanism of its action remained unknown [2]. Specifically, there are some recent literature data on the determination of numerous molecular constituents of this plant [3], [4], [5], [6], [7], [8], [9], [10], [11] and also on the Echinacea products activity [12]. But, as far as trace and minor elements determination in this medicinal plant is concerned, the data are still missing. These elements are essential for normal growth of plants, their protection against plant viruses, immunity and the completion of the life cycle [13], [14].

The objective of this study was to quantify the content of various elements that might be responsible for some properties of Echinacea, such as its immunostimulatory and anti-inflammatory activities. Investigated elements were chosen (Zn, Fe, Cu, Mn, Ca, Mg, Sr, Ni and Li) according to their role and importance in many biological mechanisms.

Quantitative determination of the mentioned elements in different parts of E. purpurea, grown in the eastern part of Serbia (samples from the summer and autumn harvests of 2001), as well as within the soil itself, was performed. In addition, an evaluation of their distribution in plant tissues was discussed.

In order to provide a better insight into the elemental pattern, a common chemometrics approach to data analysis was used. Several multivariate methods have been used to analyze the data sets obtained by chemical measurement of trace elements in various plants [15], [16]. However, except one article [6] dealing with multivariate analysis of organic compounds data set, there are no data on trace elements in E. purpurea analyzed by means of chemometrics. Principal component analysis and cluster analysis were used in this work to study the association of nine trace elements in E. purpurea and to evaluate their distribution between different parts of this plant.

Section snippets

Solutions and reagents

Standard solutions were prepared by dilution of single-element standards (1000 μg/ml) obtained from Merck (Darmstadt, Germany) with 1 M HCl. Concentrations of these working standard solutions (five standards for each element) were in the linear calibration range of each element. All acids (HCl, HNO3, HClO4 and HF) used in this work were purchased from Merck and were of reagent grade quality. All aqueous solutions and dilutions were prepared with bidistilled water.

Sample preparation

E. purpurea cultivated in

Results and discussion

The biological effects of estimated elements (Zn, Fe, Cu, Mn, Ca, Mg, Sr, Ni and Li) in living systems strongly depend on their concentration [14], [19] and thus should be carefully controlled [20], especially when herbs and their products are used in human medicine as it is the case with Echinacea. Trace element concentrations in plants vary widely with the soil type, pH, fertilizer and organic content, climate, species, etc. To distinguish the elemental pattern of different parts of this

Conclusion

E. purpurea from eastern Serbia exhibits two different elemental distribution patterns within the plant. Flowers contain the highest concentration of Cu, Zn and Ni, while the concentration of Mg, Ca, Fe, Mn, Li and Sr is the highest in leaves. In order to develop a stronger basis to estimated the curative effects of E. purpurea, the extract has to be investigated both in terms of elemental composition and biochemical make-up.

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