Interrelationships among selected essential elements in medicinal plant raw materials and their water-extractable forms
In the study, the relationships were investigated among N, P, Fe, Zn, Mn and Cu, in medicinal plant raw materials (herbal bags) and their water-soluble chemical forms in infuses. 42 independent samples of plant materials were chosen, represented by different morphological plant parts as herbs, leaves, flowers and fruits. The elements were determined by UV/Vis spectrometry (non-metals), and FAAS (metallic elements) after previous mineralization of plant samples (total concentrations), and directly in herbal teas (water-extractable forms). Most frequently the correlations between non-metals and Zn and Mn occurred, both between their total contents the water-extractable forms. Statistically significant correlations were also found in pairs: Zn-Mn, Fe-Zn, Mn-Fe, and Cu-Zn. Application of multivariate analysis revealed that cluster analysis grouped the studied samples into clusters with similar levels of the analyzed elements, and principal component analysis allowed the identification of water-extractable Zn, P-PO4 and water-extractable Cu as the most crucial factors determining the differentiation of the studied plant samples.