The role of stinging nettle (Urtica dioica L.) in the management of rotenone-induced Parkinson's disease in rats.

Parkinson's disease (PD) is one of the most common neurodegenerative conditions. Alpha-synuclein deposition, Lewy bodies (LBs) formation, disruption of the autophagic machinery, apoptosis of substantia nigra dopaminergic neurons, oxidative stress, and neuroinflammation are all pathologic hallmarks of PD. The leaves of the stinging Nettle (Urtica dioica L.) have a long history as an herbal cure with antioxidant, anti-inflammatory, anti-cancer, immunomodulatory, and neuroprotective properties. The current study aims for the first time to investigate the role of Nettle supplementation on Rotenone-induced PD. Rats were divided into five groups; a Saline control, Nettle control (100 mg/kg/day), Rotenone control (2 mg/kg/day), Rotenone + Nettle (50 mg /kg/day), and Rotenone + Nettle (100 mg/kg). After four weeks, the rats were examined for behavioral tests. The midbrains were investigated for histopathological alteration and immunohistochemical reaction for Tyrosine hydroxylase in the dopaminergic neurons, α-synuclein for Lewy bodies, caspase 3 for apoptotic neurons, LC3 and P62 for autophagic activity. Midbrain homogenates were examined for oxidative stress markers. mRNA expression of TNFα and Il6; inflammatory markers, Bcl-2, BAX and Caspase 3; apoptosis markers, were detected in midbrains. The results showed that Nettle caused recovery of midbrain dopaminergic neurons, by inhibiting apoptosis, inflammation, and oxidative stress and by restoring the autophagic machinery with clearance of α-synuclein deposits. We can conclude that Nettle is a potentially effective adjuvant in the treatment of Parkinson's disease.

Carbohydrate-binding protein from stinging nettle as fusion inhibitor for SARS-CoV-2 variants of concern.

Urtica dioica agglutinin (UDA) is a carbohydrate-binding small monomeric protein isolated from stinging nettle rhizomes. It inhibits replication of a broad range of viruses, including coronaviruses, in multiple cell types, with appealing selectivity. In this work, we investigated the potential of UDA as a broad-spectrum antiviral agent against SARS-CoV-2. UDA potently blocks transduction of pseudotyped SARS-CoV-2 in A549.ACE2+-TMPRSS2 cells, with IC50 values ranging from 0.32 to 1.22 µM. Furthermore, UDA prevents viral replication of the early Wuhan-Hu-1 strain in Vero E6 cells (IC50 = 225 nM), but also the replication of SARS-CoV-2 variants of concern, including Alpha, Beta and Gamma (IC50 ranging from 115 to 171 nM). In addition, UDA exerts antiviral activity against the latest circulating Delta and Omicron variant in U87.ACE2+ cells (IC50 values are 1.6 and 0.9 µM, respectively). Importantly, when tested in Air-Liquid Interface (ALI) primary lung epithelial cell cultures, UDA preserves antiviral activity against SARS-CoV-2 (20A.EU2 variant) in the nanomolar range. Surface plasmon resonance (SPR) studies demonstrated a concentration-dependent binding of UDA to the viral spike protein of SARS-CoV-2, suggesting interference of UDA with cell attachment or subsequent virus entry. Moreover, in additional mechanistic studies with cell-cell fusion assays, UDA inhibited SARS-CoV-2 spike protein-mediated membrane fusion. Finally, pseudotyped SARS-CoV-2 mutants with N-glycosylation deletions in the S2 subunit of the spike protein remained sensitive to the antiviral activity of UDA. In conclusion, our data establish UDA as a potent fusion inhibitor for the current variants of SARS-CoV-2.

Transcriptomic Changes in Internode Explants of Stinging Nettle during Callogenesis.

Callogenesis, the process during which explants derived from differentiated plant tissues are subjected to a trans-differentiation step characterized by the proliferation of a mass of cells, is fundamental to indirect organogenesis and the establishment of cell suspension cultures. Therefore, understanding how callogenesis takes place is helpful to plant tissue culture, as well as to plant biotechnology and bioprocess engineering. The common herbaceous plant stinging nettle (Urtica dioica L.) is a species producing cellulosic fibres (the bast fibres) and a whole array of phytochemicals for pharmacological, nutraceutical and cosmeceutical use. Thus, it is of interest as a potential multi-purpose plant. In this study, callogenesis in internode explants of a nettle fibre clone (clone 13) was studied using RNA-Seq to understand which gene ontologies predominate at different time points. Callogenesis was induced with the plant growth regulators α-napthaleneacetic acid (NAA) and 6-benzyl aminopurine (BAP) after having determined their optimal concentrations. The process was studied over a period of 34 days, a time point at which a well-visible callus mass developed on the explants. The bioinformatic analysis of the transcriptomic dataset revealed specific gene ontologies characterizing each of the four time points investigated (0, 1, 10 and 34 days). The results show that, while the advanced stage of callogenesis is characterized by the iron deficiency response triggered by the high levels of reactive oxygen species accumulated by the proliferating cell mass, the intermediate and early phases are dominated by ontologies related to the immune response and cell wall loosening, respectively.

Phenolic Profile, Antioxidant Capacity and Antimicrobial Activity of Nettle Leaves Extracts Obtained by Advanced Extraction Techniques.

Nettle is a widely known plant whose high biological activity and beneficial medicinal effects are attributed to various bioactive compounds, among which polyphenols play an important role. In order to isolate polyphenols and preserve their properties, advanced extraction techniques have been applied to overcome the drawbacks of conventional ones. Therefore, microwave-assisted extraction (MAE) has been optimized for the isolation of nettle leaves polyphenols and it was compared to pressurized liquid extraction (PLE) and conventional heat-reflux extraction (CE). The obtained extracts were analyzed for their individual phenolic profile by UPLC MS2 and for their antioxidant capacity by ORAC assay. MAE proved to be the more specific technique for the isolation of individual phenolic compounds, while PLE produced extracts with higher amount of total phenols and higher antioxidant capacity. Both techniques were more effective compared to CE. PLE nettle extract showed antimicrobial activity against bacteria, especially against Gram-negative Pseudomonas fragi ATCC 4973 and Campylobacter jejuni NCTC 11168 strains. This suggests that PLE is suitable for obtaining a nettle extract with antioxidant and antimicrobial potential, which as such has great potential for use as a value-added ingredient in the food and pharmaceutical industry.

The biological synthesis of gold/perlite nanocomposite using Urtica dioica extract and its chitosan-capped derivative for healing wounds infected with methicillin-resistant Staphylococcus aureus.

The preparation of ointments from natural compounds is essential for accelerating infected wounds. This study investigated the effects of topical uses of gold nanoparticles (Au)/perlite (Au/Perl) nanocomposites (NCs) by the help of Urtica dioica extract and its chitosan-capped derivative (Chit) on methicillin-resistant Staphylococcus aureus (MRSA)-infected wound healing in a mouse model. Furthermore, Au/Perl/Chit nanocomposite was prepared using protonated chitosan solution. The physicochemical properties of the as-synthesized nanocomposites were also investigated. The effects of Au/Perl/Chit NC were assessed by antibacterial, histopathological parameters as well as molecular evaluations. Then, they were compared with synthetic agent of mupirocin. The results revealed that Au/Perl NC was mesoporous and spherical in a range of 13-15 nm. Topical administration of Au/Perl/Chit ointment accelerated wound healing by reducing bacteria colonization and wound rate enhancing collagen biosynthesis and re-epithelialization, the expressions of IL-10, PI3K, AKT, bFGF, and COL1A genes, which is in agreement with the obtained results for mupirocin. In conclusion, the results strongly demonstrated that administration of ointments prepared from Au/Perl and Au/Perl/Chit nanocomposites stimulates MRSA-infected wound healing by decreasing the length of healing time and regulating PI3K/AKT/bFGF signaling pathway and is a promising candidate in stimulating MRSA-infected wound regeneration.

Metagenomic insights into the effects of Urtica dioica vegetable on the gut microbiota of C57BL/6J obese mice, particularly the composition of Clostridia.

Urtica dioica (UT) vegetable attenuates diet induced weight gain and insulin resistance. We hypothesized that UT imparts metabolic health by impacting the gut microbiota composition. We examined effects of UT on the cecal bacterial taxonomic signature of C57BL/6J mice fed isocaloric diets: a low-fat diet (LFD) with 10% fat, a high fat diet (HFD) with 45% fat or the HFD supplemented with 9% UT (HFUT). Among Firmicutes, the HFD had no significant impact on Clostridia, but increased Bacilli particularly genus Lactococcus and Lactobacillus. HFUT lowered Lactococcus but not Lactobacillus to levels of the LFD (P<.01; n=9). Further examination of Clostridia showed that HFUT increased genus Clostridium by over 2-fold particularly the species C. vincentii and C. disporicum and increased genus Turicibacter by three-fold (P<.05; n=9). Abundance of Clostridium and Turicibacter negatively correlated with body weight (P<.05; R2=0.42) and HOMA-IR (P<.05; R2=0.45). Turicibacter and Clostridium have been shown to be more abundant in lean phenotypes compared to obese. Clostridium impacts host phenotype by inducing intestinal T cell responses. The HFUT diet had no effect on members of Actinobacteria. Among Bacteroidetes, HFUT mainly increased proliferation of Bacteroides thetaiotaomicron (P<.05; n=9) with no significant impact on other groups. Functional analysis showed that HFUT enhanced bacterial beta-alanine and D-arginine metabolism both of which are associated with a lean phenotype and enhanced insulin sensitivity. We conclude that increasing the proliferation of Clostridium and Turicibacter and altering amino acid metabolism may be contributing mechanism(s) by which Urtica dioica impacts metabolic health.

Urtica dioica agglutinin (a plant lectin) has a caspase-dependent apoptosis induction effect on the acute lymphoblastic leukemia cell line.

Urtica dioica agglutinin (UDA) is a very small plant lectin with anti-prostatic activity. In this study, we investigated the effect of UDA on proliferation and apoptosis induction in human acute lymphoid leukemia (ALL) cell lines. The effect of UDA on Jurkat and Raji cell proliferation was examined by MTS assay. Distribution of cell cycle phases was determined by PI staining and apoptosis was examined with annexin V/PI and western blot. Results showed UDA treatment reduced cell proliferation in cells by inducing apoptosis. PI staining was associated with a higher percentage of the cell population in sub G1. Caspase-8 and caspase-9 dependent apoptosis occurred in Jurkat cells. Generally, UDA treatment resulted in cell death in ALL cell lines and induced apoptosis in the T-ALL cell line, Jurkat, through extrinsic and intrinsic pathways. These results may be considered as a guide to working on UDA as an anti-leukemic drug in the future.

Urtica Dioica Root Extract on Clinical and Biochemical Parameters in Patients with Benign Prostatic Hyperplasia, Randomized Controlled Trial.

BACKGROUND AND OBJECTIVES: Benign Prostatic Hyperplasia (BPH) is a common urological disorder as men get older. BPH can cause uncomfortable urinary tract symptoms. Given the high incidence of the disease, further research is an undeniable necessity for its better management. In this research, the efficacy of Urtica Dioica root extract (UDE) on clinical and biochemical parameters were evaluated in this type of patients. MATERIALS AND METHODS: Participants were 60 men with BPH that randomly allocated to two equal groups (Intervention = 30 and Comparison = 30). Block balanced Randomization method was performed using a computer by a trained nurse. Intervention and comparison groups received 450 mg day-1 UDE and placebo as tablets for 12 weeks, respectively. The main outcome was changes in International Prostate Symptoms Score (IPSS) from baseline to end of treatment. Data were collected by completing a standard questionnaire and performing relevant tests based on common laboratory methods. RESULTS: UDE had an intermediate effect on IPSS, a small effect on serum high-sensitivity C-reactive protein (hs-CRP), intermediate to large effect on malondialdehyde (MDA) levels and intermediate effect on superoxide dismutase (SOD) activity. The magnitude of the effects of UDE on other parameters was overall negligible compared to the comparison and not significant. No side effects were seen in these patients following tablet usage. CONCLUSION: UDE consumption for 12 weeks among BPH patients had clinically significant effects on IPSS, serum hs-CRP, MDA and SOD activity.

Impact of River Water and Bottom Sediment Pollution on Accumulation of Metal(loid)s and Arsenic Species in the Coastal Plants Stuckenia pectinata L., Galium aparine L., and Urtica dioica L.: A Chemometric and Environmental Study.

The role of water and bottom sediment pollution of a river subjected to a strong industrial anthropo-pressure in coastal plants was investigated. The work presented the influence of polluted environment on accumulation of metal(loid)s (including arsenic and its species) in Stuckenia pectinata L., Galium aparine L., and Urtica dioica L. The study provided important information on the contents of organic and inorganic arsenic species in selected plants and their response to heavy metal and arsenic contamination. The As(III), As(V), AB (arsenobetaine), MMA (monomethylarsonic acid), and DMA (dimethylarsinic acid) ions were successfully separated on the Hamilton PRP-X100 column with high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) techniques. The Pollution Load Index and geo-accumulation Index (Igeo) values clearly indicate significant pollution of the examined ecosystem with heavy metals. The chemometric analysis with the concepts of (Dis)similarity Analysis, Cluster Analysis, and Principal Component Analysis helped to visualize the variability of the As species concentrations and to analyse correlations between sampling point locations and analyte contents.

Metabolomics of the alimurgic plants Taraxacum officinale, Papaver rhoeas and Urtica dioica by combined NMR and GC-MS analysis.

INTRODUCTION: The phytoalimurgic plants, common dandelion (Taraxacum officinale), corn poppy (Papaver rhoeas) and stinging nettle (Urtica dioica) are a source of nutraceuticals. OBJECTIVES: To apply a combined metabolomic fingerprinting approach by nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS) to common dandelion, corn poppy and stinging nettles to obtain simultaneous identification and quantitation of the major classes of organic compounds. METHODOLOGY: The whole plants collected in the Cilento National Park were dried and then extracted to obtain non-polar and polar organic extracts. GC-MS was used for non-polar extracts while 1 H-NMR spectroscopy was used for polar extracts. In both cases, simultaneous identification and quantification of the bioactive metabolites was obtained. RESULTS: Non-polar organic extracts of all plants were mainly composed of palmitic, stearic and oleic acids. The two pentacyclic triterpenols α- and ß-amyrin were detected in nettle extract. The analysis of polar organic extracts allowed to detect and quantify organic acids and sugars as main metabolites along with amino acids, caffeoyl derivatives, flavonoids, and nucleotides. In particular, corn poppy leaves contained a huge amount of glyceric acid (55.7% of the total extract). Stinging nettles, instead, exhibited a large amount of choline (19.5%). CONCLUSION: Metabolomic approach coupling GC-MS with NMR spectroscopy allowed to provide a detailed metabolite profile of three alimurgic plants, common dandelion, corn poppy and stinging nettle, from both a qualitative and quantitative point of view.

Native Phytoremediation Potential of Urtica dioica for Removal of PCBs and Heavy Metals Can Be Improved by Genetic Manipulations Using Constitutive CaMV 35S Promoter.

Although stinging nettle (Urtica dioica) has been shown to reduce HM (heavy metal) content in soil, its wider phytoremediation potential has been neglected. Urtica dioica was cultivated in soils contaminated with HMs or polychlorinated biphenyls (PCBs). After four months, up to 33% of the less chlorinated biphenyls and 8% of HMs (Zn, Pb, Cd) had been removed. Bacteria were isolated from the plant tissue, with the endophytic bacteria Bacillus shackletonii and Streptomyces badius shown to have the most significant effect. These bacteria demonstrated not only benefits for plant growth, but also extreme tolerance to As, Zn and Pb. Despite these results, the native phytoremediation potential of nettles could be improved by biotechnologies. Transient expression was used to investigate the functionality of the most common constitutive promoter, CaMV 35S in Urtica dioica. This showed the expression of the CUP and bphC transgenes. Collectively, our findings suggest that remediation by stinging nettle could have a much wider range of applications than previously thought.

Cytotoxic effects of Urtica dioica radix on human colon (HT29) and gastric (MKN45) cancer cells mediated through oxidative and apoptotic mechanisms.

Defects in the apoptotic pathways are responsible for both the colorectal cancer pathogenesis and resistance to therapy. In this study, we examined the level of cellular oxidants, cytotoxicity and apoptosis induced by hydroalcoholic extract of U. dioica radix (0-2000 µg/mL) and oxaliplatin (0-1000 µg/mL, as positive control) in human gastric (MKN45) and colon (HT29) cancer, as well as normal human foreskin fibroblast (HFF) cells. Exposure to U. dioica or oxaliplatin showed a concentration dependent suppression in cell survival with IC50 values of 24.7, 249.9 and 857.5 µg/mL for HT29, MKN45 and HFF cells after 72 h treatment, respectively. ROS formation and lipid peroxidation were also concentration-dependently increased following treatment with U. dioica, similar to oxaliplatin. In addition, the number of apoptotic cells significantly increased concomitantly with concentration of U. dioica as compared with control cells, which is similar to oxaliplatin and serum-deprived cancer cells. In conclusion, the present study demonstrated that U. dioica inhibited proliferation of gastric and colorectal cancer cells while posing no significant toxic effect on normal cells. U. dioica not only increased levels of oxidants, but also induced concomitant increase of apoptosis. The precise signaling pathway by which U. dioica induce apoptosis needs further research.

Effect of Selected Pyrazine Derivatives on the Production of Phenolics and Rutin in Urtica dioica and Fagopyrum esculentum.

The effect of four pyrazine derivatives on the content of phenolic compounds in Urtica dioica L. and rutin in Fagopyrum esculentum Moench was studied. Pyrazine derivatives H1 and H2 were used on U. dioica, and derivatives S1 and S2 on F. esculentum, both separately and in combination with urea. The content of phenolic compounds in the stems of U. dioica after treatment with H2 at a concentration of 10(-3) M significantly increased compared with the control and to a lower concentration of the same pyrazine derivative. In the case of S1 and S2 for F. esculentum, rutin content also increased in stems, mainly after treatment together with urea. By contrast, rutin and phenolics contents in the leaves did not change in comparison with controls after application of H1, H2, S I and S2. Treatment with H1 and H2 in two chosen concentrations resulted in a significant increase in the net photosynthetic rate, transpiration rate and stomatal conductance. A slight increase in the rate of photosynthesis was observed also after application of variants of S1 and S1 with urea. Pyrazine derivatives did not show any effect on either the relative content of chlorophyll or chlorophyll fluorescence. A slight weight reduction of above ground biomass was shown only after application of Si and S2. Dark necrosis on the edges and center of the leaves was observed in all treated plants after pyrazine application. The results suggest that all the pyrazine derivatives possess herbicidal effects.

Effects of Urtica dioica dichloromethane extract on cell apoptosis and related gene expression in human breast cancer cell line (MDA-MB-468).

Breast cancer is the most common cancer among women in worldwide, especially in developing countries. Therefore, a large number of anticancer agents with herbal origins have been reported against this deadly disease. This study is the first to examine the cytotoxic and apoptotic effects of Urtica dioica in MDA-MB-468, human breast adenocarcinoma cells. The 3-(4,5-dimethylethiazol-2 yl)-2,5- diphenyltetrazolium (MTT) reduction and trypan-blue exclusion assay were performed in MDA-MB-468 cells as well as control cell line L929 to analyze the cytotoxic activity of the dichloromethane extract. In addition, Apoptosis induction of Urtica dioica on the MDA-MB-468 cells was assessed using TUNEL (terminal deoxy transferase (TdT)-mediated dUTP nick- end labeling) assay and DNA fragmentation analysis and real-time polymerase chain reaction (PCR). The results showed that the extract significantly inhibited cell growth and viability without inducing damage to normal control cells. Nuclei Staining in TUNEL and DNA fragments in DNA fragmentation assay and increase in the mRNA expression levels of caspase-3, caspase-9, decrease in the bcl2 and no significant change in the caspase-8 mRNA expression level, showed that the induction of apoptosis was the main mechanism of cell death that induce by Urtica dioica extract. Our results suggest that urtica dioica dichloromethane extract may contain potential bioactive compound(s) for the treatment of breast adenocarcinoma.

Sex-related differences in photoinhibition, photo-oxidative stress and photoprotection in stinging nettle (Urtica dioica L.) exposed to drought and nutrient deficiency.

Dimorphic plant species can show distinct nutrient needs due to sex-related differences in nutrient allocation to reproductive structures, which can potentially affect their sensitivity to photoinhibition and photo-oxidative stress. Here, we investigated sex-related differences in the extent of photo-oxidative stress in male and female individuals of U. dioica exposed to a combination of severe drought and nutrient starvation. Male and female individuals of U. dioica subject to severe drought stress were exposed to various levels of nutrient availability. First, a set of plants grown under field conditions and exposed to summer drought was used to test the effects of nutrient supply (given as NPK fertilizer). Secondly, the effects of various phosphate concentrations in the nutrient solution were tested in drought-stressed potted plants. The Fv/Fm ratio (maximum efficiency of PSII photochemistry), photoprotection capacity (levels of carotenoids, including the xanthophyll cycle, and vitamins C and E), and the extent of lipid peroxidation (hydroperoxide levels) were measured. Results showed that an application of the NPK fertilizer to the soil had a positive effect on drought-stressed plants, reducing the extent of lipid peroxidation in both males and females. P deficiency led to residual photoinhibition, as indicated by significant reductions in the Fv/Fm ratio, and enhanced lipid peroxidation in females, but not in males. We conclude that (i) increased nutrient availability in the soil can alleviate photo-oxidative stress in drought-stressed U. dioica plants, and (ii) U. dioica plants show sexual secondary dimorphism in terms of photoinhibition and photo-oxidative stress, but this is only apparent when stress infringed on plants is very severe.

The distribution of macronutrients, anti-nutrients and essential elements in nettles, Laportea peduncularis susp. peduncularis (River nettle) and Urtica dioica (Stinging nettle).

Laportea peduncularis and Urtica dioica, which are popularly known as "Nettles" belong to the plant family Urticaceae and are consumed as green vegetables or used for their medicinal benefit in many countries in Africa, Asia, Europe and America. This study aimed at investigating the effect of cooking on the macronutrient, anti-nutrient and elemental composition of L. peduncularis and U. dioica leaves. The results showed a decrease in the crude fat, ash, carbohydrate and vitamin C content with cooking, but an increase in the vitamin E content. The anti-nutrient content (cyanides, phytates and saponins) increased slightly with cooking, while the oxalate content has decreased. The concentration of essential elements in cooked L. peduncularis leaves were found to be in decreasing order of Ca > Mg > Fe > Mn > Zn > Cu > Cr > Ni > Co. Both raw and cooked leaves of nettles were found to be rich sources of macronutrients and essential elements and may be used as alternatives to commercially available nutrient supplements. Statistical analyses (principal component analysis and correlations) indicated that certain elements taken up by these plants were from common sources. Both positive and negative relationships between nutrients, anti-nutrients and elements were observed in the plant leaves.

Effects of dietary administration of stinging nettle (Urtica dioica) on the growth performance, biochemical, hematological and immunological parameters in juvenile and adult Victoria Labeo (Labeo victorianus) challenged with Aeromonas hydrophila.

We investigated effects of dietary administration of stinging nettle (Urtica dioica) on growth performance, biochemical, hematological and immunological parameters in juvenile and adult Victoria Labeo (Labeo victorianus) against Aeromonas hydrophila. Fish were divided into 4 groups and fed for 4 and 16 weeks with 0%, 1%, 2% and 5% of U. dioica incorporated into the diet. Use of U. dioica in the diet resulted in improved biochemical, hematological and immunological parameters. Among the biochemical parameters; plasma cortisol, glucose, triglyceride and cholesterol decreased while total protein and albumin in fish increased with increasing dietary inclusion of U. dioica. Among the haematology parameters: red blood cell (RBC), white blood cell (WBC) counts, haematocrit (Htc), mean cell haemoglobin (MCH), mean cell haemoglobin concentration (MCHC) and netrophiles increased with increasing dietary inclusion levels of U. dioica, some depending on the fish age. Serum immunoglobulins, lysozyme activity and respiratory burst were the main immunological parameters in the adult and juvenile L. victorianus measured and they all increased with increasing herbal inclusion of U. dioica in the diet. Dietary incorporation of U. dioica at 5% showed significantly higher relative percentage survival (up to 95%) against A. hydrophila. The current results demonstrate that using U. dioica can stimulate fish immunity and make L. victorianus more resistant to bacterial infection (A. hydrophila).

Influence of heavy metal stress on antioxidant status and DNA damage in Urtica dioica.

Heavy metals have the potential to interact and induce several stress responses in the plants; thus, effects of heavy metal stress on DNA damages and total antioxidants level in Urtica dioica leaves and stems were investigated. The samples are sampled from areas with different metal exposition. Metal content was analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), for total antioxidants level assessment the Ferric-Reducing Antioxidant Power (FRAP) assay was used, and genomic DNA isolation from frozen plant samples was performed to obtain DNA fingerprints of investigated plant. It was found that heavy metal contents in stems generally changed synchronously with those in leaves of the plant, and extraneous metals led to imbalance of mineral nutrient elements. DNA damages were investigated by Random Amplified Polymorphic DNA (RAPD) technique, and the results demonstrated that the samples exposed to metals yielded a large number of new fragments (total 12) in comparison with the control sample. This study showed that DNA stability is highly affected by metal pollution which was identified by RAPD markers. Results suggested that heavy metal stress influences antioxidant status and also induces DNA damages in U. dioica which may help to understand the mechanisms of metals genotoxicity.

Food-chain transfer of zinc from contaminated Urtica dioica and Acer pseudoplatanus L. to the aphids Microlophium carnosum and Drepanosiphum platanoidis Schrank.

This study examines the food-chain transfer of Zn from two plant species, Urtica dioica (stinging nettle) and Acer pseudoplatanus (sycamore maple), into their corresponding aphid species, Microlophium carnosum and Drepanosiphum platanoidis. The plants were grown in a hydroponic system using solutions with increasing concentrations of Zn from 0.02 to 41.9 mg Zn/l. Above-ground tissue concentrations in U. dioica and M. carnosum increased with increasing Zn exposure (p < 0.001). Zn concentrations in A. pseudoplatanus also increased with solution concentration from the control to the 9.8 mg Zn/l solution, above which concentrations remained constant. Zn concentrations in both D. platanoidis and the phloem tissue of A. pseudoplatanus were not affected by the Zn concentration in the watering solution. It appears that A. pseudoplatanus was able to limit Zn transport in the phloem, resulting in constant Zn exposure to the aphids. Zn concentrations in D. platanoidis were around three times those in M. carnosum.

Deposition and solubility of airborne metals to four plant species grown at varying distances from two heavily trafficked roads in London.

In urban areas, a highly variable mixture of pollutants is deposited as particulate matter. The concentration and bioavailability of individual pollutants within particles need to be characterised to ascertain the risks to ecological receptors. This study, carried out at two urban parks, measured the deposition and water-solubility of metals to four species common to UK urban areas. Foliar Cd, Cr, Cu, Fe, Ni, Pb and Zn concentrations were elevated in at least one species compared with those from a rural control site. Concentrations were, however, only affected by distance to road in nettle and, to a lesser extent, birch leaves. Greater concentrations of metal were observed in these species compared to cypress and maple possibly due to differences in plant morphology and leaf surfaces. Solubility appeared to be linked to the size fraction and, therefore, origin of the metal with those present predominantly in the coarse fraction exhibiting low solubility.