Heavy metals contamination in two species of medicinal plants in the Iranian market

ABSTRACT

Global threat resulting in heavy metal contamination of medicinal plants is considered a serious concern. The quantitative evaluation of four heavy metals, lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu), was investigated frequently sold medicinal plants in the markets of Iran. Two medicinal plants, Mentha piperita L., and Zataria multiflora Boiss. were selected from six different herbalists of six districts of Shiraz, Iran. The dissolution of the sample was performed by a conventional wet acid digestion method, and heavy metal levels were determined using Polarograph. Statistical Analysis was used by SPSS.21. According to the achieved results in M.piperita the levels of Zn, Cd, Pb, and Cu were in the range of 2.66 ± 0.76 mg/kg, 0.017 ± 0.009 mg/kg, 0.092 ± 0.069 mg/kg, and 0.237 ± 0.080 mg/kg, respectively. The concentrations of Zn, Cd, Pb, and Cu in Z. multiflora samples were 1.46 ± 0.74 mg/kg, 0.019 ± 0.004 mg/kg, 0.11 ± 0.05 mg/kg, and 0.41 ± 0.17 mg/kg, respectively. There was a correlation between Zn with Cu in our finding (r = 0.9). Based on these results, we found that the concentration of heavy metals in these two medicinal plants was not more than the standard concentration reported for similar plants. It appears that these plants are generally safe in usual doses. The finding of this study can be used to determine standard heavy metals limits in M.piperita and Z.multiflora in future studies.

KEYWORDS:

• Heavy metal
• Mentha piperita
• Zataria multiflora
• medicinal plants

Acknowledgments

The study is a part of the master’s student thesis. The authors would like to appreciate all the subjects who participated in the study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Publication ethics

The authors declare that the investigations were carried out following the rules of the Declaration of Helsinki of 1975.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This research received no external funding.