Elemental composition of Marrubium astracanicum Jacq. growing in tungsten-contaminated sites

Chelate facilitated phytoextraction of Pb, Cd, and Zn from a lead-zinc mine contaminated soil by three accumulator plants

This study aims to evaluate the enhancement of phytoextraction of heavy metals (Pb, Cd, and Zn) by species Marrubium cuneatum, Stipa arabica, and Verbascum speciosum, through EDTA amendment. Assisted phytoextraction pot experiments were performed at different EDTA dosages (0, 1, 3, and 5 mmol kg-1 soil). The DTPA-extractable metal content increased in the presence of EDTA, followed by their contents in the tissues of all three studied species. Resulting from oxidative stress, the activity of antioxidant enzymes such as glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT) increased when the chelating agent was added. EDTA in higher doses partially decreased chlorophyll concentration, and 5 mmol kg-1 of that reduced the biomass of the studied species. The bioconcentration factor (BCF) for Cd was notably high in all studied plants and considerably elevated for Zn and Pb with the addition of EDTA in M. cuneatum and S. arabica (BCF > 1), whilst an accumulation factor greater than one (AF > 1) was found for Cd in all species and for Pb in the case of S. arabica. In general, the results demonstrated that EDTA can be an effective amendment for phytoextraction of Cd, Zn, and Pb by M. cuneatum, V. speciosum and S. arabica in contaminated soils.

Metabolome Profiling of Marrubium peregrinum L. and Marrubium friwaldskyanum Boiss Reveals Their Potential as Sources of Plant-Based Pharmaceuticals

Marrubium species have been used since ancient times as food additives and curative treatments. Their phytochemical composition and various pharmacological activities were the focus of a number of scientific investigations but no comprehensive metabolome profiling to identify the numerous primary and secondary metabolites has been performed so far. This study aimed to generate a comprehensive picture of the total metabolite content of two Marrubium species-M. peregrinum and M. friwaldskyanum-to provide detailed information about the main primary and secondary metabolites. In addition, the elemental composition was also evaluated. For this purpose, non-targeted metabolomic analyses were conducted using GC-MS, UPLC-MS/MS and ICP-MS approaches. Nearly 500 compounds and 12 elements were detected and described. The results showed a strong presence of phenolic acids, flavonoids and their glucosides, which are generally of great interest due to their various pharmacological activities. Furthermore, tissue-specific analyses for M. friwaldskyanum stem, leaves and flowers were carried out in order to outline the sources of potentially important bioactive molecules. The results generated from this study depict the Marrubium metabolome and reveal its dual scientific importance-from one side, providing information about the metabolites that is fundamental and vital for the survival of these species, and from the other side, defining the large diversity of secondary substances that are a potential source of phytotherapeutic agents.

Effect of planting density and harvest protocol on field-scale phytoremediation efficiency by Eucalyptus globulus

The phytoremediation efficiency of multi-metal-polluted sites in an electronic waste recycling town by Eucalyptus globulus was evaluated through a series of 2-year field experiments. Different initial planting densities (2500, 5000, and 10,000 plants per ha), coppice rotations, and harvesting position (5 or 30 cm above the ground) protocols were designed to improve the remediation potential of the species. There were unnoticeable variations in metal concentrations and distribution characteristics in plant tissues in a low and medium planting-density field during the experimental period. At the end of the experiment, total biomass production per hectare in different protocols displayed a wide range with maximum yield produced in high density, moderate harvesting, and coppice rotation protocol being 2.9 times higher than the minimum yield. The moderate harvest protocol performed with medium planting density was the optimal Cd and Cu decontamination technique. Although the high planting-density field without coppice rotation had the strongest potential for Pb decontamination, it would take more time to remove other metals for the multi-metal-polluted soil decontamination. Considering the remediation efficiency and maintainability of the cultivation system, the moderate harvest protocol performed with the medium planting density was commended for phytoremediation of e-waste recycling impacted area.