Impact of abiotic stressors on nutrient removal and rhizomicrobiome composition in floating treatment wetland with Equisetum hyemale.

Floating treatment wetlands (FTW) are receiving growing interest as a phyto-technology. However, there are significant research gaps regarding the actual role of plant species and plant-microbiome interactions. In this study, the nutrient uptake of Equisetum hyemale was examined in FTW microcosms under the influence of abiotic stressors: As (3 mg/L) and Pb (3 mg/L) as well as Cl- (300 and 800 mg/L) in reference to a control during a short screening experiment. High removal efficiency of nutrients in water solutions, up to 88 % for TN and 93 % for PO4-P, was observed. However, PO4-P removal was inhibited in the As reactor, with a maximum efficiency of only 11 %. Lead and As were removed with high efficiency, reaching 98 % and 79 % respectively. At the same time only Pb was effectively bound to root biomass, reaching up to 51 %. Limited As accumulation of 0.5 % in plant roots suggests that microbial processes play a major role in its reduction. The development and structure of microbiome in the microcosms was analysed by means of 16S rRNA gene amplicon sequencing, proving that Pb was the most influential factor in terms of selection pressure on specified bacterial groups. In the As treatment, the emergence of a Serratia subpopulation was observed, while the Cl- treatment preserved a rhizobiome composition most closely resembling the control. This study indicates that E. hyemale is a suitable species for use in FTWs treating Pb polluted water that at the same time is capable to withstand periodic increases in salinity. E. hyemale exhibits low As binding in biomass; however, extended exposure might amplify this effect because of the slow-acting, but beneficial, mechanism of As uptake by roots and shoots. Microbiome analysis complements insights into mechanisms of FTW performance and impact of stress factors on bacterial structure and functions.

From Stem to Spectrum: Phytochemical Characterization of Five Equisetum Species and Evaluation of Their Antioxidant Potential.

The Equisetaceae family, commonly known as horsetails, has been of scientific interest for decades due to its status as one of the most ancient extant vascular plant families. Notably, the corresponding species have found their place in traditional medicine, offering a wide array of applications. This study presents a comprehensive phytochemical analysis of polar secondary metabolites within the sterile stems of five distinct Equisetum species using HPLC-DAD-ESI-MSn. For this purpose, fresh plant material was extracted with acetone/water, and the resulting crude extracts were fractionated using dichloromethane, ethyl acetate, and n-butanol, respectively. The results reveal a complex array of compounds, including hydroxycinnamic acids, hydroxybenzoic acids, flavonoids, and other phenolic compounds. In addition, total phenolic contents (Folin-Ciocalteu assay) and antioxidant activities (DPPH assay) of the plant extracts were evaluated using spectrophotometric methods. The present comparative analysis across the five species highlights both shared and species-specific metabolites, providing valuable insights into their chemical diversity and potential pharmacological properties.

Equisetum arvense as a silica fertilizer.

The aim was to use the agricultural weed and silica (Si) hyperaccumulator Equisetum arvense as Si fertilizer in plant cultivation. We investigated (1) the Si uptake in various Equisetum species, (2) where Si accumulates in the Equisetum plant, (3) processing methods to release as much Si as possible from dried, ground E. arvense plants and (4) which treatment yields gives the highest uptake of Si in young wheat plants cultivated in soil containing ground E. arvense. The results showed that E. arvense containes 22% Si and was among the best Si accumulators. Equisetum arvense accumulates Si as both soluble and firmly bound fractions. Amorphous silica (SiO2) accumulates in the outer cell walls of epidermis of the entire plant. Regarding the processing method, a longer treatment time, greater concentration of Equisetum, boiling, and the addition of sodium bicarbonate increased the Si availability in ground, dried E. arvense. The addition of untreated, ground, dried E. arvense to the soil, corresponding to 160 kg Si ha-1, increased the available Si in the soil and the Si uptake in wheat plants by five-fold, compared with the control. Boiling the ground E. arvense increased the Si uptake by 10 times, and the of sodium bicarbonate increased the availability and uptake by 40 times, compared with the control. In conclusion, dried, ground E. arvense can be used as a Si fertilizer as is, after boiling for a slightly better effect, or with sodium bicarbonate (up to a similar amount as the ground material) for best effect.

Equisetum arvense standardized dried extract hinders age-related osteosarcopenia.

Age-associated osteosarcopenia is an unresolved syndrome characterized by the concomitant loss of bone (osteopenia) and skeletal muscle (sarcopenia) tissues increasing falls, immobility, morbidity, and mortality. Unbalanced resorption of bone in the remodeling process and excessive protein breakdown, especially fast type II myosin heavy chain (MyHC-II) isoform and myofiber metabolic shift, are the leading causes of bone and muscle deterioration in the elderly, respectively. Equisetum arvense (EQ) is a plant traditionally recommended for many pathological conditions due to its anti-inflammatory properties. Thus, considering that a chronic low-grade inflammatory state predisposes to both osteoporosis and sarcopenia, we tested a standardized hydroalcoholic extract of EQ in in vitro models of muscle atrophy [C2C12 myotubes treated with proinflammatory cytokines (TNFα/IFNγ), excess glucocorticoids (dexamethasone), or the osteokine, receptor activator of nuclear factor kappa-B ligand (RANKL)] and osteoclastogenesis (RAW 264.7 cells treated with RANKL). We found that EQ counteracted myotube atrophy, blunting the activity of several pathways depending on the applied stimulus, and reduced osteoclast formation and activity. By in silico target fishing, IKKB-dependent nuclear factor kappa-B (NF-κB) inhibition emerges as a potential common mechanism underlying EQ's anti-atrophic effects. Consumption of EQ (500 mg/kg/day) by pre-geriatric C57BL/6 mice for 3 months translated into: i) maintenance of muscle mass and performance; ii) restrained myofiber oxidative shift; iii) slowed down age-related modifications in osteoporotic bone, significantly preserving trabecular connectivity density; iv) reduced muscle- and spleen-related inflammation. EQ can preserve muscle functionality and bone remodeling during aging, potentially valuable as a natural treatment for osteosarcopenia.

Determination of the Cytotoxicity and Antibiofilm Potential Effect of Equisetum arvense Silver Nanoparticles.

This study aimed to synthesize and characterize silver nanoparticles (AgNPs) by green synthesis from Equisetum arvense (Ea) extracts and to investigate their cytotoxicity, antibiofilm activity, and α-glucosidase enzyme inhibition. Diverse characterization techniques were applied to verify the production of nanoparticles. SEM examination confirmed that the size of nanoparticles is in the range of 40-60 nm. Also, interactions between silver and natural compounds of plant extract were confirmed through FT-IR and EDX analyses. It was determined that Equisetum arvense silver nanoparticles had antibiofilm activity against three different clinical strains with high biofilm-forming ability. AgNPs reduced the biofilm-forming capacity of clinical A. baumannii isolate with strong biofilm-forming capacity by approximately twofold, while the capacity of clinical K.pneumonaie and E.coli isolates decreased by 1.5 and 1.2 fold, respectively. The α-glucosidase enzyme inhibition potential of the AgNPs, which is determined as 93.50%, was higher than the plant extract with, and the α- 30.37%. MTT was performed to assess whether incubation of nanoparticles with A549 and ARPE-19 cell lines affected their viability, and a dramatic reduction in cell growth inhibition of both A549 and ARPE-19 cells was observed. It has been shown that A549 cells treated with 200 and 150 µg/mL nanoparticles had less cell proliferation compared to control cells at 24-h and 48-h incubation time. According to these results, Ea-derived AgNPs appear to have potential anticancer activity against A549 cancer cells. Investigating the effects of green synthesis nanoparticles on microbial biofilm and various tumors may be important for developing new therapies. The outcomes of this study have showed that Ea-AgNPsmay have a high potential both in the treatment of pathogenic strains that form biofilms, as well as in anticancer therapy use.

Equisetum praealtum and E. hyemale have abundant Rubisco with a high catalytic turnover rate and low CO2 affinity.

The kinetic properties of Rubisco, a key enzyme for photosynthesis, have been examined in numerous plant species. However, this information on some plant groups, such as ferns, is scarce. This study examined Rubisco carboxylase activity and leaf Rubisco levels in seven ferns, including four Equisetum plants (E. arvense, E. hyemale, E. praealtum, and E. variegatum), considered living fossils. The turnover rates of Rubisco carboxylation (kcatc) in E. praealtum and E. hyemale were comparable to those in the C4 plants maize (Zea mays) and sorghum (Sorghum bicolor), whose kcatc values are high. Rubisco CO2 affinity, estimated from the percentage of Rubisco carboxylase activity under CO2 unsaturated conditions in kcatc in these Equisetum plants, was low and also comparable to that in maize and sorghum. In contrast, kcatc and CO2 affinities of Rubisco in other ferns, including E. arvense and E. variegatum were comparable with those in C3 plants. The N allocation to Rubisco in the ferns examined was comparable to that in the C3 plants. These results indicate that E. praealtum and E. hyemale have abundant Rubisco with high kcatc and low CO2 affinity, whereas the carboxylase activity and abundance of Rubisco in other ferns were similar to those in C3 plants. Herein, the Rubisco properties of E. praealtum and E. hyemale were discussed regarding their evolution and physiological implications.

In Vitro Insight on Antifungal-Specific Potentiality of Ni(II) Complex against Colletotrichum siamense and Fusarium equisetum Phytopathogens.

In an initiation to investigate a prospective bioactive compound, a mononuclear Ni(II) complex with N, N, and O donor Schiff base ligand was synthesized and characterized in the present study through FTIR, ESI-mass, and X-ray crystallographic diffraction studies. A slightly distorted octahedral geometry has been obtained for the Ni(II) complex from X-ray crystallographic diffraction studies. In vitro comprehensive biological studies show the antifungal specific efficiency of the complex against Colletotrichum siamense (AP1) and Fusarium equisetum (F.E.) pathogens, which are responsible for anthracnose and wilt disease, respectively, but no inhibitory effect on both Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration (MIC) for these pathogens was observed to be 0.25 and 0.5 mM, respectively. The experiment also reveals that significant damage of mycelia and enlarged, misshaped damaged spores are noticed in comparison to hexaconazole, used as a positive control under a light microscope post 48 h treatment of AP1 and F.E. with the MIC of the complex. The binding interaction studies of the complex with DNA and BSA performed through a variety of spectroscopic techniques demonstrate a strong binding behavior of the complex for both the binding systems. The observed negative ΔH° and ΔS° values for DNA reveal the existence of hydrogen-bonding/van der Waals interactions for DNA which was also exemplified from the molecular docking and self-assembly studies of the complex. The positive ΔH° and ΔS° values for BSA demonstrate the hydrophobic interactions of the complex with BSA. However, cytotoxicity studies against the MDA-MB-231 breast cancer cell line did not demonstrate any significant potentiality of the complex as an anticancer agent. All the bio-experimental studies provide clear evidence that the synthesized Ni(II) complex exhibits potential antifungal activity and could be used as a therapeutic fungicide agent in comparison to hexaconazole in agricultural practices.

Apocarotenoids from Equisetum debile Roxb. ex Vaucher regulate the lipid metabolism via the activation of the AMPK/ACC/SREBP-1c signaling pathway.

Sixteen undescribed apocarotenoids (1-16), along with 22 known analogues, were isolated from the aerial parts of Equisetum debile. Their structures, including absolute configurations, were elucidated by NMR, HRESIMS, X-ray diffraction analysis, the modified Mosher's method and the quantum-chemical calculation of electronic circular dichroism (ECD) spectra. Compounds 1-9, 11-12 are the first example of C16-apocarotenoids appeared in nature. The plausible biosynthetic pathway of 1-16 was proposed. Moreover, the isolates were evaluated for their lipid-lowering activity, and the results showed that 13, 14, 15, 22, 31, 32 and 33 could remarkably decrease the levels of both TC and TG in FFA induced HepG2 cells at 20 µM. The oil red staining assay further demonstrated the lipid-lowering effects of 13, 14 and 15. The western blot results indicated that compounds 13, 14 and 15 could regulate the lipid metabolism via the activation of the AMPK/ACC/SREBP-1c signaling pathway. A preliminary structure-activity relationship (SAR) study of the isolates indicated that the apocarotenoids with 6/5 ring system displayed more potent lipid-lowering effects.

Subcritical water extraction of Equisetum arvense biomass withdraws cell wall fractions that trigger plant immune responses and disease resistance.

Plant cell walls are complex structures mainly made up of carbohydrate and phenolic polymers. In addition to their structural roles, cell walls function as external barriers against pathogens and are also reservoirs of glycan structures that can be perceived by plant receptors, activating Pattern-Triggered Immunity (PTI). Since these PTI-active glycans are usually released upon plant cell wall degradation, they are classified as Damage Associated Molecular Patterns (DAMPs). Identification of DAMPs imply their extraction from plant cell walls by using multistep methodologies and hazardous chemicals. Subcritical water extraction (SWE) has been shown to be an environmentally sustainable alternative and a simplified methodology for the generation of glycan-enriched fractions from different cell wall sources, since it only involves the use of water. Starting from Equisetum arvense cell walls, we have explored two different SWE sequential extractions (isothermal at 160 ºC and using a ramp of temperature from 100 to 160 ºC) to obtain glycans-enriched fractions, and we have compared them with those generated with a standard chemical-based wall extraction. We obtained SWE fractions enriched in pectins that triggered PTI hallmarks in Arabidopsis thaliana such as calcium influxes, reactive oxygen species production, phosphorylation of mitogen activated protein kinases and overexpression of immune-related genes. Notably, application of selected SWE fractions to pepper plants enhanced their disease resistance against the fungal pathogen Sclerotinia sclerotiorum. These data support the potential of SWE technology in extracting PTI-active fractions from plant cell wall biomass containing DAMPs and the use of SWE fractions in sustainable crop production.

Genus Equisetum L: Taxonomy, toxicology, phytochemistry and pharmacology.

INTRODUCTION: The genus Equisetum (Equisetaceae) is cosmopolitan in distribution, with 41 recognized species. Several species of Equisetum are widely used in treating genitourinary and related diseases, inflammatory and rheumatic problems, hypertension, and wound healing in traditional medicine practices worldwide. This review intends to present information on the traditional uses, phytochemical components, pharmacological activities, and toxicity of Equisetum spp. and to analyze the new insights for further study. METHODS: Relevant literature has been scanned and collected via various electronic repositories, including PubMed, Science Direct, Google Scholar, Springer Connect, and Science Online, from 1960 to 2022. RESULTS: Sixteen Equisetum spp. were documented as widely used in traditional medicine practices by different ethnic groups throughout the world. A total of 229 chemical compounds were identified from Equisetum spp. with the major group of constituents being flavonol glycosides and flavonoids. The crude extracts and phytochemicals of Equisetum spp. exhibited significant antioxidant, antimicrobial, anti-inflammatory, antiulcerogenic, antidiabetic, hepatoprotective, and diuretic properties. A wide range of studies have also demonstrated the safety of Equisetum spp. CONCLUSION: The reported pharmacological properties of Equisetum spp. support its use in traditional medicine, though there are gaps in understanding the traditional usage of these plants for clinical experiments. The documented information revealed that the genus is not only a great herbal remedy but also has several bioactives with the potential to be discovered as novel drugs. Detailed scientific investigation is still needed to fully understand the efficacy of this genus; hence, very few Equisetum spp. were studied in detail for phytochemical and pharmacological investigation. Moreover, its bioactives, structure-activity connection, in vivo activity, and associated mechanism of action ought to be explored further.

Novel Approach to the Treatment of Neuropathic Pain Using a Combination with Palmitoylethanolamide and Equisetum arvense L. in an In Vitro Study.

Neuropathic pain is a typical patient disorder resulting from damage and dysfunction of the peripheral neuraxis. Injury to peripheral nerves in the upper extremities can result in a lifelong reduction in quality of life and a devastating loss of sensory and motor function. Since some standard pharmaceutical therapies can cause dependence or intolerance, nonpharmacological treatments have gained great interest in recent years. In this context, the beneficial effects of a new combination of palmitoylethanolamide and Equisetum arvense L. are evaluated in the present study. The bioavailability of the combination was initially analyzed in a 3D intestinal barrier simulating oral intake to analyze its absorption/biodistribution and exclude cytotoxicity. In a further step, a 3D nerve tissue model was performed to study the biological effects of the combination during the key mechanisms leading to peripheral neuropathy. Our results demonstrate that the combination successfully crossed the intestinal barrier and reached the target site, modulating the nerve recovery mechanism after Schwann cell injury and offering the initial response of relieving pain. This work supported the efficacy of palmitoylethanolamide and Equisetum arvense L. in reducing neuropathy and modifying the major pain mechanisms, outlining a possible alternative nutraceutical approach.

New substances of Equisetum hyemale L. extracts and their in vivo antitumoral effect against oral squamous cell carcinoma.

ETHNOBOTANICAL RELEVANCE: Equisetum hyemale is used in traditional medicine as an anti-inflammatory, antioxidant, diuretic and anticancer agent. Recent studies have observed antiproliferative activity of this species in some tumor cell lines. AIM OF THE STUDY: The aim of this study was to evaluate the antiproliferative activity of the ethanol extract of E. hyemale and its partitions in oral squamous carcinoma cell lines, the death pathways induced by the most active partition, the acute toxicity and therapeutic activity, and the identification of the main compounds. MATERIALS AND METHODS: The ethanol crude extract was prepared from the stems of E. hyemale and partitions were obtained from this extract with n-hexane, dichloromethane and ethyl acetate. Cytotoxicity assays were performed using MTT on human oral tumor lines SCC-9, SCC4 and SCC-25, and normal primary fibroblasts. The main pathways of programmed cell death were analyzed. Acute toxicity in mice was performed using the most active partition, ethyl acetate. Antitumor activity was accessed in xenotransplants grafts of SCC-9 cells in Balb/nude mice. Phytochemical analysis was performed using UHPLC-MS/MS and dereplication was done using Global Natural Product Social Molecular Networking (GNPS) analysis. RESULTS: Ethanol extract, n-hexane and ethyl acetate partitions showed dose-dependent activity and selectivity towards oral tumor cells, with the ethyl acetate being the most bioactive. This medium polarity partition was shown to induce tumor cell death through apoptosis due to the presence of activated caspase 3/7, DNA fragmentation, chromatin condensation and phosphatidylserine exposure. The ethyl acetate partition also produced low toxicity in mice, provoking mild hepatic changes, but without causing necrosis and significantly reduced tumors volume and weight in xenotransplants of SCC-9 cells. Phytochemical analysis allowed identification of kaempferol glycosides and cinnamic acid derivatives previously described for E. hyemale. In addition it was possible to identify 6 new non-glycolyzed flavonoids 5-Hydroxy-3',4',7,8-tetramethoxyflavone (14), 5,4'-Dihydroxy-7,8,3'-trimethoxyflavone (15), 5,7-Dihydroxy-3',4'-dimethoxyflavone (16), 3',4,5,7-Tretramethoxyflavone (17), 5-Hydroxy-3'4',7-trimethoxyflavone (18), and 5,4'-Dihydroxy-3'-7'-dimethoxyflavone (19); besides 5 compounds already determined to be cytotoxic in other species, Isoferulic acid (1), Ferulic acid (2), Atractylenolide III (6), Dihydroxy-3',4'-dimethoxyflavone (16), and 5-Hydroxy-3'4 ',7-trimethoxyflavone (18). CONCLUSION: The results indicate that the E. hyemale extract and partitions inhibited 3 different cell lines of OSCC in a highly selective nontoxic way by inducing apoptosis of the cells. We identified 6 new non-glycosylated flavonoids and 5 other substances in this species.

Heavy metal accumulation efficiency and subsequent of cytogenotoxicity evaluation in the medicinal plant Equisetum hyemale.

Heavy metals in soils represent a threat to the environment, food safety, as well as human and animal health. The bioaccumulation of these elements in plants might enhance medium- and long-term adverse health risk promoting genetic alterations that lead to dermal, gastrointestinal, circulatory, renal, and brain disorders. The present study aimed to determine the bioaccumulation potential and cytogenotoxic effect of Equisetum hyemale extracts. E. hyemale seedlings were divided into two groups: exposed group (plants cultivated in soil with heavy metals solution) and control (plants cultivated in soil with distilled water). Heavy metals were quantified in the cultivation soils (control and exposed) and extracts (ethanolic and infusion) of vegetative parts from E. hyemale cultivated in both soils. Root length and cytogenotoxic effect were determined utilizing Allium cepa bioassay. Data demonstrated that Equisetum hyemale present the ability to absorb and bioaccumulate different heavy metals including lead, copper, cobalt manganese, zinc, iron and chromium. Given this property E. hyemale may be considered a reliable bioindicator to assess cytogenotoxicity of certain substances that exert adverse risks to environment and human and animal health.

Equisetum hyemale-derived unprecedented bioactive composite for hard and soft tissues engineering.

Although Bioactive Glasses (BGs) have been progressively optimized, their preparation often still involves the use of toxic reagents and high calcination temperatures to remove organic solvents. In the present work, these synthesis related drawbacks were overcome by treating the ashes from the Equisetum hyemale plant in an ethanol/water solution to develop a bioactive composite [glass/carbon (BG-Carb)]. The BG-Carb was characterized by scanning electron microscopy, and transmission electron microscopy; and its chemical composition was assessed by inductively coupled plasma-optical emission spectroscopy. Brunauer-Emmett-Teller gas adsorption analysis showed a specific surface area of 121 m2 g-1. The formation of hydroxyapatite (HA) surface layer in vitro was confirmed by Fourier-transform infrared spectroscopy analysis before and after immersion in simulated body fluid (SBF) solution. The Rietveld refinement of the XRD patterns and selected area electron diffraction analyses confirmed HA in the sample even before immersing it in SBF solution. However, stronger evidences of the presence of HA were observed after immersion in SBF solution due to the surface mineralization. The BG-Carb samples showed no cytotoxicity on MC3T3-E1 cells and osteo-differentiation capacity similar to the positive control. Altogether, the BG-Carb material data reveals a promising plant waste-based candidate for hard and soft tissue engineering.

Four new glucosides from the aerial parts of Equisetum sylvaticum.

Two previously undescribed megastigmane glucosides, (3S)-3-hydroxy-4-oxo-7,8-dihydro-ß-ionone-3-O-ß-D-glucopyranoside (1), (3S)-3-hydroxy-4-oxo-ß-ionone-3-O-ß-D-glucopyranoside (2), an apocarotenoid glucoside named equiseoside A (3) and an unusual aromatic compound with a glucose-fused skeleton named equiseoside B (4), together with 35 known compounds (5-39) were isolated from the aerial parts of Equisetum sylvaticum. The structures of these compounds were elucidated by spectroscopic methods, including 1D and 2D NMR, IR, CD, and HR-MS.

Aqueous extract from Equisetum arvense stimulates the secretion of Tamm-Horsfall protein in human urine after oral intake.

BACKGROUND: Within European traditional phytotherapy, extracts from different herbal plants are used for prevention and therapy of uncomplicated urinary tract infections and for flushing out of kidney grits. Besides increased urine flow by slight diuretic effects, also stimulation of Tamm-Horsfall protein (syn. THP, uromodulin) in the distal part of the kidney could explain reduced kidney gravel and anti-virulent activity against uropathogenic E. coli. PURPOSES: Evaluation of THP-inducing activity of extracts from Equisetum arvense, Levisticum officinalis, Ilex paraguariensis, Juniperus communis, Urtica dioica, and Taraxacum officinale by quantification of THP in urine samples after oral application to humans. STUDY DESIGN: 7 days p.o. application of the test intervention to healthy volunteers (n = 10 per intervention group) and analysis of urine samples at day 1 (untreated control values), and days 3, 6 and 8 on THP content by validated ELISA. Antiadhesive activity of urine samples was monitored by flow cytometry using UPEC strain NU14 against human T24 bladder cells. RESULTS: An aqueous extract from E. arvense, fully characterized by a specific LC-MS method, induced THP concentration in urine samples significantly during a 7-day p.o. application up to 300%, related to the untreated controls. Ex vivo investigation of the individual and pooled urine samples with elevated THP concentrations showed good correlation to antiadhesive effects against UPEC NU14 to T24 cells. Urine samples of the Equisetum treated volunteers had no effect on the proliferation and on biofilm formation of UPEC NU14. Silica excretion in the urine samples had no correlation to the respective THP levels. Monitoring of electrolyte content in the urine samples indicat ed diuretic effects of the intervention with Equisetum extract. Detailed phytochemical analysis of the Equisetum extract by LC-MS and LC-UV revealed an analytical protocol, which identified > 80 compounds from the extract by MS evaluations and 18 compounds by UV detection. This protocol will provide a valuable tool for future quality control of Equisetum extract. CONCLUSION: Aqueous extract from E. arvense significantly stimulates THP secretion in urine samples after 7 days of oral intake and inhibits the interplay between UPEC and bladder host cells. This could explain the therapeutic use of this herbal material for urinary tract infections and kidney gravel. Detailed phytochemical analysis of the Equisetum extract by LC-MS and LC-UV revealed an analytical protocol, which identified > 82% of all eluted compounds. This protocol will provide a valuable tool for future quality control of Equisetum extract.

Comparison of Biogenic Amorphous Silicas Found in Common Horsetail and Oat Husk With Synthetic Amorphous Silicas.

The present study summarizes the current literature on the presence and the structure of biogenic amorphous silica (BAS) in nature. Based on this review, it is shown that BAS is ubiquitous in nature and exhibits a structure that cannot be differentiated from the structure of synthetic amorphous silica (SAS). The structural similarity of BAS and SAS is further supported by our investigations-in particular, specific surface area (BET) and electron microscope techniques-on oat husk and common horsetail. Many food products containing BAS are considered to be beneficial to health. In the context of the use of SAS in specific applications (e.g., food, feed, and cosmetics), this is of particular interest for discussions of the safety of these uses.

Dose-Dependent Variation in Anticancer Activity of Hexane and Chloroform Extracts of Field Horsetail Plant on Human Hepatocarcinoma Cells.

Horsetail fern plant is botanically known as Equisetum arvense L., and it is a good source of phenolic flavonoids, phenolic acids, and compounds. Anticancer properties of hexane and chloroform extracts of the horsetail fern plant and their mechanisms involved in the anticancer activity on human hepatocarcinoma (HuH-7) cells were examined. Cytotoxicity was evaluated by using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and NRU (neutral red uptake) assays. Other parameters such as oxidative stress and apoptosis in pretreated hexane and chloroform extracts of the horsetail fern plant were examined in HuH-7 cells. The observation showed that hexane and chloroform extract of the horsetail fern plant exhibited cytotoxicity against HuH-7 cells. The value of IC50-24 h of hexane and chloroform extract of the horsetail fern plant was determined as 199.0 µg/ml and 161.90 0 µg/ml for HuH-7 cells, respectively, and on the basis of IC50 value, three acute concentrations, viz., 75% of IC50, 50% of IC50, and 25% of IC50, were determined for further study. The lower dose of extracts hexane and chloroform extract of the horsetail fern plant did not show significant toxicity. Higher concentrations of extract induced significant antioxidant effects as well as apoptosis effects. However, exposure to hexane and chloroform extract of the horsetail fern plant upregulated the expression of Bax and p53 in HuH-7 cells. These data suggest that hexane and chloroform extract of the horsetail fern plant plays a significant role in the induction of toxicity via the regulation of oxidative stress in HuH-7 cells. This work may be useful for cancer chemotherapy.

Nitrogen fixation and other biogeochemically important features of Atacama Desert giant horsetail plant microbiomes inferred from metagenomic contig analysis.

BACKGROUND AND AIMS: Canyon stream beds in the hyperarid Atacama Desert surprisingly harbour magnificent groves of endemic giant horsetail wetland plants, Equisetum xylochaetum. Our previous metagenomic study of eukaryotes closely associated with this plant indicated that the microbiome included prokaryotes that might likewise influence host success and environment. We explored this possibility by using the metagenomic sequence to characterize prokaryote taxa and functional genes present in the microbiome of E. xylochaetum sampled from remote sites differing in the degree of anthropogenic disturbance. We focused on biogeochemical functions known to be important in wetland ecosystems. METHODS: To ensure that analyses were conducted on microbes most closely associated with plants, we extracted DNA from well-washed plant organs whose microbial biofilms were revealed with scanning electron microscopy. To assess the benefits of longer sequences for taxonomic and gene classifications, results of analyses performed using contigs were compared with those obtained with unassembled reads. We employed methods widely used to estimate genomic coverage of single taxa for genomic analysis to infer relative abundances of taxa and functional genes. KEY RESULTS: Key functional bacterial genera (e.g. Hydrogenophaga, Sulfuritalea and Rhodoferax) inferred from taxonomic and functional gene analysis of contigs - but not unassembled reads - to occur on surfaces of (or within) plants at relatively high abundance (>50× genomic coverage) indicated roles in nitrogen, sulfur and other mineral cycling processes. Comparison between sites revealed impacts on biogeochemical functions, e.g. reduced levels of the nifH gene marker under disturbance. Vanadium nitrogenases were more important than molybdenum nitrogenases, indicated by both functional genes and taxa such as Rhodomicrobium and Phaeospirillum inferred from contigs but not unassembled reads. CONCLUSIONS: Our contig-based metagenomic analyses revealed that microbes performing key wetland biogeochemical functions occur as tightly adherent biofilms on the plant body, not just in water or sediments, and that disturbance reduces such functions, providing arguments for conservation efforts.