Natural Lead Levels in Dandelions ( Taraxacum officinale): A Weed, Folk Medicine, and Biomonitor

Effects of polyethylene and biodegradable microplastics on the physiology and metabolic profiles of dandelion

Biodegradable plastics, such as poly(butylene adipate terephthalate) (PBAT) and polylactic acid (PLA), are potential alternatives to conventional polyethylene (PE), both of which are associated with the production of microplastics (MPs). However, the toxicity of these compounds on medicinal plants and their differential effects on plant morphophysiology remain unclear. This study supplemented soils with MPs sized at 200 μm at a rate of 1% w/w and incubated them for 50 days to investigate the impact of MPs on the growth and metabolites of dandelion (Taraxacum mongolicum Hand.-Mazz.). The results demonstrated that the investigated MPs decreased the growth of dandelion seedlings, induced oxidative stress, and altered the activity of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase). Based on the comprehensive toxicity assessment results, the ecological toxicity was in the following order: PE MPs > PBAT MPs > PLA MPs. Metabolomics analyses revealed metabolic reprogramming in dandelion plants, leading to the enrichment of numerous differentially accumulated metabolites (DAMs) in the leaves. These pathways include carbohydrate metabolism, energy metabolism, and biosynthesis of secondary metabolites, suggesting that dandelions respond to MP stress by enhancing the activity of sugar, organic acid, and amino acid metabolic pathways. In addition, phenolic acids and flavonoids are critical for maintaining the balance in the antioxidant defense system. Our results provide substantial insights into the toxicity of biodegradable MPs to plants and shed light on plant defense and adaptation strategies. Further assessment of the safety of biodegradable MPs in terrestrial ecosystems is essential to provide guidance for environmentally friendly management.

Biomonitoring with the Use of the Herbal Plant Taraxacum officinale as a Source of Information on Environmental Contamination

The aim of this study was to assess the level of contamination of the common dandelion-Taraxacum officinale-with selected metals (Mn, Fe, Ni, Cu, Zn, Cd, and Pb) and to demonstrate that this plant can be used in passive biomonitoring of industrial sites. Two sample transects (the first was near a forest, an area potentially uncontaminated by analytes [A], while the second ran near a steel mill, a contaminated area [B]), each about 1.5 km long, located in Ozimek, Opole Province, Poland, were used in this study. Metals in plant and soil samples were determined by atomic absorption spectroscopy (AAS). Based on the analysis of the obtained results to determine the concentration of metals, plants at site A were more contaminated with Mn (240 mg/kg d.m.) and those at site B with Fe (635 mg/kg d.m.). Mean Pb values (8.39 mg/kg d.m.) were higher at the industrial site (B) and statistically significant at the forest site (A), together with Mn and Fe at the p < 0.001 level. The BCF values for T. officinale showed that Cu (0.473) and Zn (0.785) accumulated to an average degree on both transects. This shows that dandelion is heavily loaded with these metals. Both dandelion and soil samples showed the highest concentrations of Mn, Fe, and Zn, especially in the polluted area B, which is the result of pollution not only from the smelter (dust from electric arc furnaces in steel smelting, extraction installations in production halls transmitting pollutants into the air from molding sand, or waste from molding and core masses dumped on the heap and blown by the wind from the landfill) but also from the high anthropopressure caused by human activity-for example, heating processes or road transport. Our results confirmed that Taraxacum officinale can be successfully used as a herbal plant in passive biomonitoring to assess the quality of the environment, but it must be collected from uncontaminated areas if we want to use it like a medicinal plant.

External application of dandelion combined with borneol effectively reduced pain and facial swelling after jaw surgery

BACKGROUND

To explore the effects of the combination of dandelion with borneol on the maxillofacial region of patients after jaw surgery in reducing the acute inflammatory reaction after surgery, the degree of facial swelling, pain, and limitation of mouth opening, and increasing patient satisfaction.

METHODS

A total of 120 patients who met the inclusion criteria were randomly divided into 4 groups: group A: ice compress; Group B: dandelion; Group C: borneol; Group D: dandelion combined with borneol. Patients were evaluated on the day of the operation, the first day, and the second day after the operation.

RESULTS

External application of dandelion combined with borneol had a better controlling effect on facial swelling and limited mouth opening compared with the single treatment groups, and the satisfaction score was higher ( P  < .05).

CONCLUSION

External application of dandelion combined with borneol was effective in the treatment of maxillofacial swelling and pain. This approach quickly relieved swelling, restored the limitation of mouth opening, and improved patient satisfaction.

Phytotoxicity assessment of dandelion exposed to microplastics using membership function value and integrated biological response index

Microplastic (MP) pollution is a critical environmental issue. Dandelions could be used as a biomonitor of environmental pollution. However, the ecotoxicology of MPs in dandelions remains unclear. Therefore, the toxic effects of polyethylene (PE), polystyrene (PS), and polypropylene (PP) at concentrations of 0, 10, 100, and 1000 mg L-1 on the germination and early seedling growth of dandelion were investigated. PS and PP inhibited seed germination and decreased root length and biomass while promoting membrane lipid peroxidation, increasing O2•-, H2O2, SP, and proline contents, and enhancing the activities of SOD, POD, and CAT. Principal component analysis (PCA) and membership function value (MFV) analysis indicated that PS and PP could be more harmful than PE in dandelion, especially at 1000 mg L-1. In addition, according to the integrated biological response (IBRv2) index analysis, O2•-, CAT, and proline were sensitive biomarkers of dandelion contamination by MPs. Here we provide evidence that dandelion has the potential to be a biomonitor to assess the phytotoxicity of MPs pollution, especially PS with high toxicity. Meanwhile, we believe that if dandelion is to be used as a biomonitor for MPs, attention should also be paid to the practical safety of dandelion.

Novel metallomic profiling and non-carcinogenic risk assessment of botanical ingredients for use in herbal, phytopharmaceutical and dietary products using HR-ICP-SFMS

Knowledge of element concentrations in botanical extracts is relevant to assure consumer protection given the increased interest in plant-based ingredients. This study demonstrates successful multi-element investigations in order to address the lack of comprehensive profiling data for botanical extracts, while reporting for the first time the metallomic profile(s) of arnica, bush vetch, sweet cicely, yellow rattle, bogbean, rock-tea and tufted catchfly. Key element compositions were quantified using a validated HR-ICP-SFMS method (µg kg-1) and were found highly variable between the different plants: Lithium (18-3964); Beryllium (3-121); Molybdenum (75-4505); Cadmium (5-325); Tin (6-165); Barium (747-4646); Platinum (2-33); Mercury (5-30); Thallium (3-91); Lead (12-4248); Bismuth (2-30); Titanium (131-5827); Vanadium (15-1758); Chromium (100-4534); Cobalt (21-652); Nickel (230-6060) and Copper (1910-6340). Compendial permissible limits were not exceeded. Overall, no evidence of a health risk to consumers could be determined from consumption of the investigated plants at reasonable intake rates. Mathematical risk modelling (EDI, CDI, HQ, HI) estimated levels above safe oral thresholds only for Cd (16%) and Pb (8%) from higher intakes of the respective plant-derived material. Following high consumption of certain plants, 42% of the samples were categorised as potentially unsafe due to cumulative exposure to Cu, Cd, Hg and Pb. PCA suggested a potential influence of post-harvest processing on Cr, Ti and V levels in commercially-acquired plant material compared to wild-collected and farm-grown plants. Moreover, a strong correlation was observed between Pb-Bi, Be-V, Bi-Sn, and Tl-Mo occurrence. This study may support future research by providing both robust methodology and accompanying reference profile(s) suitable for the quality evaluation of essential elements and/or metal contaminants in botanical ingredients.

Morphological, physiological, and secondary metabolic responses of Taraxacum officinale to salt stress

Salt stress has a major effect on growth and secondary metabolism in medicinal plants, however, the effect of salt stress on Taraxacum officinale F. H. Wigg. is still scarce. In this study, we evaluated the effects of salt stress on the physiology, morphology, phenolic acid accumulation, and expression of genes involved in phenolic acid biosynthesis in T. officinale. We found that plants grew well at 1 g kg^-1 NaCl, and the state of photosystem Ⅱ (PSⅡ) and the organization of the chloroplasts at 0.5 g kg^-1 NaCl showed no significant differences compared with the control. However, 2 g kg^-1 and 4 g kg^-1 NaCl inhibited growth and accelerated leaf senescence. At 4 g kg^-1 NaCl, the fresh and dry weights decreased to 28% and 42% of the control, while chlorosis and necrosis were observed on the leaves. Furthermore, up-regulation of the expression of ToC3'H corresponded with an increase in the levels of caffeoylquinic acids (chlorogenic acid and isochlorogenic acid A) at NaCl concentration ≤ 1 g kg^-1. Expressions of four phenolic acid biosynthesis genes, ToC4H, To4CL, ToHCT, and ToHQT, were down-regulated with increasing NaCl concentrations, consistent with the observed decreases in caftaric and cichoric acids. In summary, cultivation of T. officinale under mild salt stress (NaCl ≤ 1 g kg^-1) is feasible and facilitates the accumulation of caffeoylquinic acids; thus this species may be recommended for saline soils.

Effects of polystyrene nanoplastics on lead toxicity in dandelion seedlings

Increasing rates of commercialization and industrialization have led to the comprehensive evaluation of toxic effects of microplastics on crop plants. However, research on the impact of functionalized polystyrene nanoplastics on the toxicity of heavy metals remains limited. This study investigated the effects of polystyrene, carboxy-modified polystyrene, and amino-modified polystyrene on lead (Pb) toxicity in dandelion seedlings. The results showed that carboxy -modified polystyrene with a negative charge absorbed more Pb²⁺ than polystyrene and amino-modified polystyrene, and their maximum adsorption amounts were 5.328, 0.247, and 0.153 μg g^-1, respectively. The hydroponic experiment demonstrated that single amino-modified polystyrene was more toxic to dandelion seedlings than polystyrene and carboxy-modified polystyrene. The presence of Pb²⁺ was found to increase antioxidant enzymes (superoxide dismutase and catalase) and non-antioxidant enzymes (glutathione and ascorbic acid) activities in response to excessive reactive oxygen species in dandelion leaves and roots treated with polystyrene and carboxy-modified polystyrene, while it did not change much when amino-modified polystyrene was added. Interestingly, compared with single Pb²⁺, the addition of amino-modified polystyrene with positive charges induced an obvious decrease in the above parameters; however, they declined slightly in the treatments with polystyrene and carboxy-modified polystyrene despite a stronger adsorption capacity for Pb²⁺. Similarly, the bioactive compounds, including flavonoids, polyphenols, and polysaccharides in dandelion, showed a scavenging effect on O₂^- and H₂O₂, thereby inhibiting the accumulation and reducing medicinal properties. This study found that the effects of microplastics on the uptake, distribution, and toxicity of heavy metals depended on the nanoparticle surface charge.

A Circular Economy Approach to Restoring Soil Substrate Ameliorated by Sewage Sludge with Amendments

This study examined the use of an artificial soil substrate in a mine waste reclamation area and its effect on plant metabolic functions. Research was conducted by determining the relationship between the plants’ biochemical features and the properties of plant growth medium derived from post-flotation coal waste, sewage sludge, crushed stone and fly ash on the surface of the mine waste disposal area. Trees and shrubs were established on the material and allowed to grow for eight years. The study determined that the applied plants and the naturally occurring Taraxacum officinale were suitable for physio-biochemical assessment, identification of derelict areas and reclamation purposes. An evaluation of a soil substrate applied to post-mining areas indicated that it was beneficial for plant growth since it activated the metabolic functions of herbaceous plants, shrubs, and trees. The study showed that soil substrate can be targeted to improve plant stress tolerance to potentially toxic elements (PTEs). These data suggest the potential for growth and slower susceptible response to Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. It is possible that the constructed soil-substitute substrate (biosolid material) would be an effective reclamation treatment in areas where natural soil materials are polluted by PTEs. This observation may reflect a more efficient use of soil substrate released from the cycling of organic biogene pools, in accordance with the circular economy approach. In further studies related to land reclamation using sewage sludge amendments, it would be necessary to extend the research to other stress factors, such as salinity or water deficiency.

Distinguishing between Natural and Industrial Lead in Consumer Products and Other Environmental Matrices

California's Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65) was designed to protect the state's populace from exposures to toxic levels of chemicals in consumer products, including foods, by requiring businesses to warn the public about any of those hazards. There is, however, one qualification in the legislation, which is that warnings are not required if the source of that contamination is natural, as opposed to industrial. That qualification is especially problematic for lead because "natural" and "industrial" lead have a common origin and behave the same in the environment and industrial lead contamination has been pandemic for millennia. As a result of that historic and ongoing contamination, ambient lead levels in the biosphere may be orders of magnitude above natural levels, limiting comparisons of "natural" versus "industrial" lead concentrations in products. Further complicating those comparisons are reports of erroneously high measurements of lead concentrations in the biosphere as a result of sample contamination during collection, storage, and analysis. Some of those problems may be addressed with measurements of lead concentrations using rigorous trace metal clean techniques. These techniques often yield lead concentrations that are below the Act's maximum exposure in foods and non-foods of 0.5 μg/day, eliminating the need for a public alert. Those techniques have also been used to derive natural lead concentrations in a few organisms (marine fish, humans, rats, and dandelions), which range from 2- to 100-fold below ambient levels. However, extrapolating from those few determinations to establish natural lead levels in other organisms is complicated and often inappropriate. Complementary stable lead isotopic composition measurements have also been used to estimate the percent of natural and industrial lead in some consumer products, including foods, wine, and dietary supplements. These measurements, however, require the isotopic compositions of both the "natural" and "industrial" lead end members, which may be poorly defined. In addition, the global market has further complicated identification of the "industrial" lead end member, because lead contamination of foods can occur during production, harvesting, storage, shipping, processing, and packaging, which can happen in different locales within a country, different countries, and even different continents.