Human Health Risk Assessment of Heavy Metals and Metalloids in Herbal Medicines Used to Treat Anxiety: Monitoring of Safety

The present study estimated the human health risk assessment and daily intake of heavy metals and metalloids in herbal medicines used to treat anxiety in Brazil. Six different brands of herbal medicines were purchased in the city of Campo Grande/MS, Brazil: Pasalix®, Calman®, Serenus®, Maracugina®, Prakalmar® and Calmasyn®. In total, eight elements including As, Ba, Cd, Co, Cr, Cu, Fe, and Pb were analyzed using optical emission spectrometry with inductively coupled plasma (ICP OES). Only the concentration of As in the herbal medicine Prakalmar® is above the values established by United States Pharmacopoeia Convention (USP) and Brazilian Pharmacopoeia (BF) for permitted concentration of elemental impurities in drugs substances. The concentration of Ba, Cd, Co, Cr and Cu in all herbal medicines are lower than the values set by USP and FB. The concentration of Pb in Calman® is lower than the limits established by BF, but higher than those established by USP. Pasalix, Serenus®, Calmasyn®, Prakalmar® and Marcacugina® have a higher Pb concentration than the values allowed by USP and BF. All herbal medications have concentrations within safe ranges for human consumption, with the exception of Calmasyn®, which has Pb over the value defined by USP for oral permissible daily exposure (PDE) for elemental impurities. The values of estimated daily intake (EDI) of metal (loid)s in adults and children obtained from the consumption of the herbal medicines are below the values stipulated by the minimal risk levels (MRLs). All the hazard index (HI) values recorded in this study were below 1. However, monitoring by regulatory agency is necessary, large doses of heavy metal may cause acute or chronic toxicities.

Remediation of Metal/Metalloid-Polluted Soils: A Short Review

The contamination of soil by heavy metals and metalloids is a worldwide problem due to the accumulation of these compounds in the environment, endangering human health, plants, and animals. Heavy metals and metalloids are normally present in nature, but the rise of industrialization has led to concentrations higher than the admissible ones. They are non-biodegradable and toxic, even at very low concentrations. Residues accumulate in living beings and become dangerous every time they are assimilated and stored faster than they are metabolized. Thus, the potentially harmful effects are due to persistence in the environment, bioaccumulation in the organisms, and toxicity. The severity of the effect depends on the type of heavy metal or metalloid. Indeed, some heavy metals (e.g., Mn, Fe, Co, Ni) at very low concentrations are essential for living organisms, while others (e.g., Cd, Pb, and Hg) are nonessential and are toxic even in trace amounts. It is important to monitor the concentration of heavy metals and metalloids in the environment and adopt methods to remove them. For this purpose, various techniques have been developed over the years: physical remediation (e.g., washing, thermal desorption, solidification), chemical remediation (e.g., adsorption, catalysis, precipitation/solubilization, electrokinetic methods), biological remediation (e.g., biodegradation, phytoremediation, bioventing), and combined remediation (e.g., electrokinetic–microbial remediation; washing–microbial degradation). Some of these are well known and used on a large scale, while others are still at the research level. The main evaluation factors for the choice are contaminated site geology, contamination characteristics, cost, feasibility, and sustainability of the applied process, as well as the technology readiness level. This review aims to give a picture of the main techniques of heavy metal removal, also giving elements to assess their potential hazardousness due to their concentrations.

Molecular Interaction and Evolution of Jasmonate Signaling With Transport and Detoxification of Heavy Metals and Metalloids in Plants

An increase in environmental pollution resulting from toxic heavy metals and metalloids [e.g., cadmium (Cd), arsenic (As), and lead (Pb)] causes serious health risks to humans and animals. Mitigation strategies need to be developed to reduce the accumulation of the toxic elements in plant-derived foods. Natural and genetically-engineered plants with hyper-tolerant and hyper-accumulating capacity of toxic minerals are valuable for phytoremediation. However, the molecular mechanisms of detoxification and accumulation in plants have only been demonstrated in very few plant species such as Arabidopsis and rice. Here, we review the physiological and molecular aspects of jasmonic acid and the jasmonate derivatives (JAs) in response to toxic heavy metals and metalloids. Jasmonates have been identified in, limiting the accumulation and enhancing the tolerance to the toxic elements, by coordinating the ion transport system, the activity of antioxidant enzymes, and the chelating capacity in plants. We also propose the potential involvement of Ca2+ signaling in the stress-induced production of jasmonates. Comparative transcriptomics analyses using the public datasets reveal the key gene families involved in the JA-responsive routes. Furthermore, we show that JAs may function as a fundamental phytohormone that protects plants from heavy metals and metalloids as demonstrated by the evolutionary conservation and diversity of these gene families in a large number of species of the major green plant lineages. Using ATP-Binding Cassette G (ABCG) transporter subfamily of six representative green plant species, we propose that JA transporters in Subgroup 4 of ABCGs may also have roles in heavy metal detoxification. Our paper may provide guidance toward the selection and development of suitable plant and crop species that are tolerant to toxic heavy metals and metalloids.