ICP-OES assessment of trace and toxic elements in Ziziphora clinopodioides Lam. from Iran by chemometric approaches.

The aim of the study was to evaluate the concentrations of some essential and toxic elements (including Ca, K, Mg, Na, Fe, Cu, Mn, Zn, Co, Mo, Pb, Ni, Cr, and Cd) in Ziziphora clinopodioides Lam. (endemic Iranian herb) from 14 different regions by ICP-OES (inductively coupled plasma-optical emission spectrometry) method followed by multivariate statistical analyses. The analytical performances were assessed as the limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy. Multivariate analysis (CA, PCA and HCA) showed the elemental distribution in the roots were higher than the shoots and significant element was Ca between regions. Three principal components (PCs) explained 77.94% of the total variance. They were as follows: PC1 with Cu, Zn, K, Cr, Ni, and Mn; PC2 with Na, Ca, Pb, and Fe; and PC3 with Mg. Hierarchical cluster analysis indicated four groups of Z. clinopodioides samples from the 14 regions based on their trace and toxic element levels. These chemometric approaches with multivariate analysis enable researchers to understand and quantify the relationship between the variables in a data set, and the analysis considers more than one factor. The concentrations of Cu, Na, Mn, Zn, and Pb in most Z. clinopodioides samples were below the WHO (world health organization) limit for herbal medicines (10, 51,340, 200, 50, and 10 µg g respectively), while Fe and Ca levels were higher than allowed (15 and 614 µg g respectively). However, the WHO limit for Mg, K, Co, and Mo in medicinal plants has not yet been determined. The results of this study confirmed that different parts of Z. clinopodioides can be used as an important source for human nutrition due to its essential mineral elements.