foliage phenolics, in-vitro antioxidant activities, and in-vivo anti-diabetic potential

Introduction: The present research aimed to fractionate Xanthium strumarium L. (XSL) foliage phenolics into a set of solvents and evaluate their antioxidant potential and in-vivo anti-diabetic activity against Alloxan monohydrate-induced diabetic mice. Methodology: For this purpose, XSL foliage was fractionated into petroleum ether, ethyl acetate, ethanol, and water via orbital type shaking and tested for the presence of phenolics, and their antioxidant and antidiabetic potential. Results and discussion: The results revealed that the ethyl acetate fraction of XSL foliage contained the highest amount of total phenolics 95.25 mg GAE/g of extract, followed by ethanol (65.14 mg GAE/g), petroleum ether (25.12 mg GAE/g), water (12.20 mg GAE/g), and XSL powder (69.13 mg GAE/g). At the end of treatment time (day 18 of oral administration of 400 mg/kg body weight of mice), the ethyl acetate fraction significantly (p ≤ 0.05) lowered blood glucose level (353 ± 10.6 to 220 ± 25.5 mg/dL) which might due to the elevated level of phenolic compounds in this fraction. Conclusion: Overall, it can be speculated that ethyl acetate and ethanol may work efficiently for the enrichment of XSL phenolic without compromising their antidiabetic potential.

sibiricum to cadmium/copper/nickel tailings

Invasive plants could play an important role in the restoration of tailings, but their invasiveness limits their practical application. In this study, the phytoremediation potentials and invasive risks of an exotic invasive plant (Xanthium strumarium, LT), a native plant (X. sibiricum, CR), and combinations of inoculations (EG, with CR as the scion and LT as the rootstock; SG, with CR as both the scion and rootstock) were evaluated on Cd/Cu/Ni tailings. LT rootstock has a stronger nutrient and metal transport capacity, compared with CR. EG not only had higher biomass and Cd/Cu/Ni accumulation, but also abundant rhizosphere microbial communities. Hydroponic and common garden experiments showed that the growth and metal enrichment characteristics of EG are not inherited by plant offspring, which reduces the risk of the biological diffusion in the process of using exotic species. Transcriptome analysis shows that a large number of differentially-expressed genes in EG leaves and roots are involved in phenylpropanoid biosynthesis, secondary metabolite generation, and signal transduction. The genes induced in EG leaves, including cyclic nucleotide-gated ion channel, calcium-binding protein, and WRKY transcription factor, were found to be differentially expressed compared to CR. The genes induced in EG roots, included phenylalanine ammonia-lyase, cinnamoyl-CoA reductase, caffeoyl-CoA O-methyltransferase, and beta-glucosidase. We speculate that lignin and glucosinolates play an important role in the metal accumulation and transportation of EG. The results demonstrate that grafting with LT not only improved CR tolerance and accumulation of Cd, Cu, and Ni, but also created a beneficial microbial environment for plants in tailings. More importantly, grafting with LT did not enhance the invasiveness of CR. Our results provide an example of the safe use of invasive plants in the restoration of Cd/Cu/Ni tailings.

sibiricum

Few studies explore the effects of nitrogen forms on exotic plant invasions, and all of them are conducted from the perspective of nitrogen form utilization without considering the effects of ammonium toxicity. The invasive plant Xanthium strumarium prefers to use nitrate, while its native congener X. sibiricum prefers to use ammonium, and the invader is more sensitive to high ammonium based on our preliminary observations. To further reveal the effects of nitrogen forms on invasiveness of X. strumarium, we studied the difference and related physiological mechanisms in sensitivity to ammonium between these species. With increasing ammonium, total biomass, root to shoot ratio and leaf chlorophyll content of X. strumarium decreased, showing ammonium toxicity. For X. sibiricum, however, ammonium toxicity did not occurr. With increasing ammonium, ammonium concentration increased in leaves and roots of X. strumarium, which is associated with the decreased activities of glutamine synthetase and glutamate synthase and the increased ammonium uptake; and consequently the contents of hydrogen peroxide and malondialdehyde also increased, which is associated with the decreased contents of reduced glutathione and ascorbic acid. By contrast, the abilities of ammonium assimilation and antioxidation of X. sibiricum were less affected by the increase of ammonium, and the contents of ammonium nitrogen, hydrogen peroxide and malondialdehyde in leaves and roots were significantly lower than those in X. strumarium. Our results indicate that ammonium accumulation and oxidative damage may be the physiological mechanisms for the ammonium toxicity of X. strumarium, providing a possible explanation that it generally invades nitrate-dominated and disturbed habitats and a theoretical basis for future studies on the control of invasive plants by regulating soil nitrogen.

Puerarin mitigates oxidative injuries, opening of mitochondrial permeability transition pores and pathological damage associated with liver and kidney in Xanthium strumarium-intoxicated rats

In this study, the therapeutic effects of puerarin on Xanthium strumarium toxicity, which can develop in many species and does not have a specific antidote, were investigated. A single dose of 100 g/kg X. strumarium seeds was administered by gavage to female Sprague-Dawley rats, 6 h following which 200 mg/kg puerarin was administered by the same route, with puerarin administration being repeated daily at the same time. After completing the application, the blood, liver and kidney tissues of the rats were examined. Further, the biochemical parameters, glucose, MDA, GSH, SOD, mitochondrial Ca²⁺ and mitochondrial permeability transition pore (mPTP) opening levels, apoptotic factors (TUNEL, Bax and Bcl-2), ATP synthase and histopathological changes of the experimental rats were examined. The results revealed that while the administration of X. strumarium resulted in increased blood AST, ALT, ALP, LDH, CK, BUN and creatinine levels, it decreased glucose levels. In addition, it increased the MDA levels in the tissues and significantly increased the oxidative stress levels by decreasing the GSH levels and SOD activity. X. strumarium caused an increase in the mitochondrial Ca²⁺ and mPTP opening levels. Moreover, it increased the immunohistochemically determined ATP synthase expression and histopathologically identified necrotic liver cell death rates. Owing to its antioxidant properties and inhibitory effects on mPTP opening, puerarin administered for therapeutic purposes decreased the oxidative damage caused by X. strumarium toxicity, blood biochemical parameter levels, mitochondrial Ca²⁺ levels, mPTP opening, ATP synthase expression and the percentage of necrotic cells. Hence, the reduction in the liver and kidney damage in X. strumarium toxicity by puerarin indicates its potential use as an antidote for X. strumarium poisoning.

Phytoremediation potential of hybrids of the exotic plant Xanthium strumarium and its native congener Xanthium sibiricum for cadmium-contaminated soils

Exotic plants could play an essential role in the restoration of heavy metal-contaminated soil. This study evaluated the tolerance of and extraction of cadmium (Cd) by ZCR (CR♀ × LT♂), hybrids of Xanthium strumarium (LT, exotic species) and X. sibiricum (CR, indigenous congener), and their parental species under different Cd treatments (0, 10, 40, and 80 mg·kg^-1). The results showed that the hybrids had significantly improved tolerance to Cd. Under Cd stress, the biomass of ZCR increased by more than 50% on average compared with that of CR. Moreover, the hybrids showed a more remarkable ability to transport Cd from the root to the shoot. The Cd content of the shoots of ZCR increased by 128.33, 147.22, and 252.63% when treated with 10, 40, and 80 mg·kg^-1 Cd, respectively. ZCR stored more than 70% of Cd in litter leaves, thereby reducing the toxic effects of Cd on photosynthesis and growth. The results showed that ZCR showed excellent Cd tolerance and enrichment in the presence of Cd. The hybrids of Xanthium strumarium and its native congener X. sibiricum may remediate soil Cd pollution.Novelty statementWith the changing world economy and increasing human activities, exotic plants have become a global issue of common concern to the international community. This study describes new findings on using hybrids of the exotic plant of Xanthium strumarium and its native congener Xanthium sibiricum for the restoration of cadmium-contaminated soils. Under Cd stress, the hybrids' biomass, tolerance, and ability to accumulate Cd were significantly higher than that of X. sibiricum, indicating that hybrids gained useful heavy metal extraction traits from X. strumarium.

Phytochemical investigation of the fruits of Xanthium strumarium and their cytotoxic activity

Eight pentacyclic triterpenoids including two new ones (1, 2) were isolated from the fruits of Xanthium strumarium. Their structures were elucidated by extensive spectroscopic analysis. All isolates were evaluated for in vitro cytotoxic activity on HepG2, A549, HCT116 and SW480 cancer cells. Among them, the new compound 2 was found to exhibit significant cytotoxic activity on A549, HCT116 and SW480 cancer cells with IC₅₀ values of 9.68, 4.27 and 7.58 μM, respectively. Further, 2 was selected for cell cycle analysis and results revealed that 2 could cause HCT116 cell cycle arrest in G1 phase. In addition, Annexin V-FITC/PI staining assay showed that 2 could induce the death of HCT116 cells.

New flavonoid glycosides from Xanthium strumarium with their protein tyrosine phosphatase 1B inhibitory activity

Two new flavonoid glycosides named 6-hydroxy-3-methoxy-apigenin 7-O-α-ʟ-rhamnopyranoside (1) and 3-hydroxyl-apigenin 8-C-β-ᴅ-xylopyranoside (2), along with five known compounds (3-7), were isolated from Xanthium strumarium. Their structures were elucidated on the basis of spectroscopic and physicochemical analyses. All compounds were evaluated for in vitro inhibitory activity against PTP1B. Among them, compounds 1 and 5 showed significant inhibitory activity on PTP1B with IC₅₀ values of 11.3 ± 1.7 and 8.9 ± 0.7 μM, respectively.

sibiricum to Cadmium

Hybridization is one of the important factors influencing the adaptive evolution of invasive plants. According to previous studies, hybridization with an invasive plant reduces the adaptability of its native congener to environment. However, in this study, the hybridization with an invasive plant of Xanthium strumarium (LT) improves the tolerance and accumulation of its native congener Xanthium sibiricum (CR) to cadmium (Cd). Under Cd stress, X. sibiricum♀ × X. strumarium♂ (ZCR) showed higher biomass and Cd accumulation. Compared with CR, ZCR has longer vegetative and reproductive growth time. Moreover, ZCR adopted more reasonable biomass allocation strategy. ZCR increased the proportion of reproductive allocation and ensured its own survival with the increase of Cd stress. Furthermore, ZCR increased the translocation of Cd to aboveground parts and changed the distribution of Cd. A large amount of Cd is stored in senescent leaves and eliminated from the plant when the leaves fall off, which not only reduces the Cd content in the plant, but also reduces the toxicity of Cd in the normal leaves. Transcriptome analysis shows a total of 2055 (1060 up and 995 down) differentially expressed genes (DEGs) were detected in the leaves of Cd-stressed ZCR compared with CR, while only 792 (521 up and 271 down) were detected in X. strumarium♀ × X. sibiricum♂ (ZLT) compared with LT. A large number of DGEs in ZCR and ZLT are involved in abscisic acid (ABA) synthesis and signal transduction. The genes induced by ABA in ZCR, including CNGC5/20, CPK1/28, CML, PTI1-like tyrosine-protein kinase 3, respiratory burst oxidase homolog protein C, and WRKY transcription factor 33 were found differentially expressed compared CR. carotenoid cleavage dioxygenase 4, NCED1/2, phytoene synthase 2, and CYP707A involved in ABA synthesis and decomposition in ZLT were found differentially expressed compared LT. We speculated that ABA played an important role in Cd transportation of hybrids and Cd distribution in senescent and normal leaves. The results demonstrate that hybridization with an invasive plant improves the adaptability of the hybrid to Cd stress and may enhance the extinction risk of native congener in pollution environment.

Endemic Xanthium strumarium poisoning in cattle in flooded areas of the Araguari River, Minas Gerais, Brazil

In this paper, we describe poisoning outbreaks of Xanthium strumarium in cattle on the borders of the Araguari River, Southeastern Brazil. In this region, several hydroelectric plants promote transient flooding, which creates a favorable environment for the invasion of X. strumarium in extensive areas, often as the predominant species in those areas. The outbreaks occurred between July and September (dry season). Bovines of all ages were affected, including suckling animals. Mortality varied from 2% to 5.5%. The animals exhibited ataxia, weakness, loss of balance, recumbency, and the majority were found dead. Laboratory results showed a marked increase in the serum activities of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and gamma-glutamyltransferase. Histological and ultrastructural changes in the liver consisted of centrilobular necrosis and hemorrhage. On toxicological evaluation, the dicotyledons contained 0.30 μg/mg of atractyloside and 0.37 μg/mg of carboxyatractyloside. Considerable economic loss has occurred in this region due to the lack of knowledge regarding X. strumarium as a toxic plant and its adaptation to the environmental and climatic conditions of the region, which have made the condition endemic.

sibiricum

The chemical investigation of the fruits of Xanthium strumarium (Asteraceae) led to the isolation of two new ent-kauranoid glucosides named 2-O-(6-O-isocaleryl-β-D-glucopyranosyl) atractyligenin (1) and 2-O-(2-O-isovaleryl-β-D-glucopyranosyl) atractyligenin (2), together with one known compound. Their structures were established by comprehensive spectroscopic analysis coupled with single-crystal X-ray diffraction and electronic circular dichroism data. All compounds and their aglycone were evaluated for their anti-proliferative activities in vitro against three human cancer cell lines.

Turning Meadow Weeds Into Valuable Species for the Romanian Ethnomedicine While Complying With the Environmentally Friendly Farming Requirements of the European Union's Common Agricultural Policy

The cross-compliance mechanism of the European Union (EU)'s common agricultural policy (CAP) makes the approval of the direct payments to the European farmers subject to compliance with the requirement to maintain the land in good agricultural and environmental condition. One of the obligations of the Romanian land owners and farmers is to avoid the installation of unwanted vegetation on their land plots. This vegetation is represented by some species of herbaceous or woody plants, annual or perennial, that spontaneously invade the agricultural lands, diminishing the production capacity of the cultivated plants. Included in this category are 10 meadow weeds, without fodder value or even toxic to animals: Arctium lappa L., Carduus nutans L., Conium maculatum L., Eryngium campestre L., Euphorbia cyparissias L., Pteridium aquilinum (L.) Kuhn, Rumex acetosella L., Veratrum album L., Xanthium spinosum L., and Xanthium strumarium L. Various and multiple uses in traditional medicine of these meadow weed species have been reported for Romania and other nine neighboring East European countries, i.e. Bosnia and Herzegovina, Bulgaria, Czech Republic, Estonia, Kosovo, Russia, Turkey, Serbia, and Ukraine. For A. lappa were recorded the highest number of ethnomedicinal uses, in the largest number of East European countries, including Romania. C. maculatum and V. album are not recommended for human consumption but can be further investigated as potential sources of pharmaceutically active compounds. Once removed by landowners and farmers from their land, the raw plant material of these 10 species become readily and easily available to the Romanian local communities and the industry of herbal food supplements, while the biodiversity of the agro-ecosystems is maintained.

Natural product-based semisynthesis and biological evaluation of thiol/amino-Michael adducts of xanthatin derived from Xanthium strumarium as potential pesticidal agents

Xanthatin, a natural sesquiterpene lactone, occurs as one of the major constituents of Xanthium plants (Compositae) and exhibits many important biological properties. To discover natural products-based pesticides, forty-nine Michael-type thiol/amino adducts of xanthatin were synthesized and characterized, while their pesticidal activities were investigated. Among them, compounds 2c, 2h, 2i, and 2t exhibited more potent antifungal activity against Botrytis cinerea (IC₅₀ = 0.96, 0.38, 6.33, and 7.21 µg/mL, respectively) than xanthatin and the two commercial fungicides. Compounds 2t and 2u displayed broad-spectrum and excellent antifungal effects against all tested phytopathogenic fungi, while their IC₅₀ values ranged from 7.21 to 75.88 µg/mL. Compounds 2a, 2f, 2l, 2m, 2v, 7c, 7e, 7h, 7i, and 7j showed moderate larvicidal activity against Plutella xylostella Linnaeus. Furthermore, compounds 2b, 7g, and 7h demonstrated significant ovicidal activity against P. xylostella with the LC₅₀ values of 14.04, 10.00, and 11.95 mg/L, respectively. These findings suggest that thiol/amino appended in the C-13 position of xanthatin may improve antifungal and ovicidal activities for the derivatives. It was also noticed that the exocyclic double bond of xanthatin is crucial for its larvicidal activity. This work also provides some important hints for further design, synthesis, and structural modification of the xanthanolides sesquiterpene lactones toward development of the new environmentally friendly pesticides for sustainable agricultural production.

germination and growth

In this study, the effects of diesel fuel contamination on common cocklebur (Xanthium strumarium L.) seeds have been investigated. Five levels of contamination were used (0 g, 2.5 g, 5 g, 7.5 g, and 10 g diesel per 100 g of substrate). Germination was significantly reduced only at 7.5 g and 10 g diesel and the highest percentage germination (97%) was recorded at 5 g diesel. Diesel contamination caused a significant reduction in shoot length, but the decline began to be important at 7.5 g diesel. The root length was positively influenced by diesel fuel contamination, the shortest root (12.89 cm) was observed in the control and the longest (19.92 cm) at 5 g diesel. Xanthium strumarium seeds germinated successfully at different levels of contamination, its root length seemed to take advantage of the diesel fuel contamination and its shoot length was mostly affected by the high contamination levels. Therefore, we can propose this plant species as a potential candidate for the phytoremediation of sites contaminated with diesel. Furthermore, the results could help improve our understanding of the behavior of X. strumarium, and its ability to germinate and grow in different soil conditions.

Effects of manganese stress on phenology and biomass allocation in Xanthium strumarium from metalliferous and non-metalliferous sites

Xanthium strumarium is an annual pseudometallophyte. To reveal the mechanisms of this species to adapt to metallicolous environmental conditions, phenological traits and biomass allocation of metallicolous and non-metallicolous populations of X. strumarium under six Mn²⁺ concentrations by pot culture experiments were performed. The results showed that both time to bolting and time to fruit setting in the metallicolous population were earlier than those in the non-metallicolous population. The number of flowers, fruits, seeds and 1000-seed weight in the metallicolous population were higher than those in the non-metallicolous population under Mn stress. Reproductive allocation and harvest index in the metallicolous population were higher than those in the non-metallicolous population. Furthermore, all the Mn concentrations in leaves, stems, roots, and fruits of the metallicolous population were higher than the counterparts of non-metallicolous population. These results suggested that metallicolous population had higher tolerance to Mn stress than non-metallicolous population, the earlier flowering and fruiting, and the enhancement in reproductive allocation may contribute to plant tolerance to Mn toxicity for X. strumarium.

Xanthium strumarium´s xanthatins induces mitotic arrest and apoptosis in CT26WT colon carcinoma cells

BACKGROUND

Colorectal cancer is one of the most common malignancies worldwide and is associated with high mortality rates. We previously reported that Xanthium strumarium L. induces mitotic arrest in proliferating cells, a process mediated by xanthatins.

HYPOTHESIS/AIM

The aim of this work is to study if xanthatins, isolated from X. strumarium total extract, affect the proliferative capacity of CT26WT colon cancer cells and, in consequence, if tumor growth and proliferation of (lung) metastatic sites can also be arrested in vivo.

STUDY DESIGN

This study consisted of both in vitro and in vivo experiments involving the CT26WT cell line and a subcutaneous mouse model of colon cancer. In vitro cell cycle progression, in vivo tumoral growth and anti-metastatic activity were analyzed to investigate whether xanthatins of X. strumarium induce mitotic arrest in proliferating colorectal carcinoma.

RESULTS

Our in vitro results show that X. strumarium, mediated by xanthatins, induces G₂/M arrest and impair anaphase entrance. This leads to a significant induction of apoptotic and necrotic in CT26WT cells, demonstrating their significant anti-proliferative activity through interfering with the mitotic apparatus. Furthermore, our in vivoresults reveal that X. strumarium inhibits both tumor growth and metastasis progression.

CONCLUSION

X. strumarium antitumor activities are mainly mediated by xanthatins through inhibition of tumor growth and metastasis, inducing mitotic arrest and apoptosis in colon carcinoma cells. These findings further confirm the therapeutic potential of X. strumarium in colorectal cancer.

Volatiles Profiling, Allelopathic Activity, and Antioxidant Potentiality of Xanthium Strumarium Leaves Essential Oil from Egypt: Evidence from Chemometrics Analysis

The essential oil (EO) of Xanthium strumarium L. leaves (family: Asteraceae) was extracted by hydrodistillation, and then analyzed by gas chromatography-mass spectrometry (GC-MS). Forty-three essential compounds were identified. The sesquiterpenoids represented the major constituents (72.4%), including oxygenated (61.78%) and non-oxygenated (10.62%) sesquiterpenes, followed by monoterpenes (25.19%). The diterpenoids and oxygenated hydrocarbons were determined as minor compounds. The main constituents of the EO were 1,5-dimethyltetralin (14.27%), eudesmol (10.60%), l-borneol (6.59%), ledene alcohol (6.46%), (-)-caryophyllene oxide (5.36%), isolongifolene, 7,8-dehydro-8a-hydroxy (5.06%), L-bornyl acetate (3.77%), and aristolene epoxide (3.58%). A comparative analysis was stated here between the EO of Egyptian X. strumarium and those previously reported from Pakistan, Iran, and Brazil based on chemometic tools such as principal components analysis (PCA) and agglomerative hierarchical clustering (AHC). The EO of X. strumarium showed weak 1, 1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity with IC₅₀ 321.93 µL/L⁻¹, which was comparable to ascorbic acid as a reference. However, the EO exhibited significant allelopathic potential regarding the germination and growth of the noxious weed Bidens pilosa in a concentration-dependent manner. Therefore, further study is recommended to characterize the EO from X. strumarium as an eco-friendly green bioherbicide against weeds, as well as determine their mode of actions.

Morphophysiological responses and tolerance mechanisms of Xanthium strumarium to manganese stress

Effective phytoremediation of manganese (Mn) requires the careful selection of a species that has a relatively high manganese tolerance. Exploring the physiological mechanisms related to Mn stress responses is crucial for identifying and employing species for Mn phytoremediation. Xanthium strumarium is a species that can accumulate high levels of Mn, thus it is a candidate species for Mn-phytoremediation. To reveal the tolerance mechanisms of this species to manage Mn stress, the morphological, physiological, and biochemical responses of seedlings grown in water cultures under six different Mn concentrations were analyzed. The results showed that X. strumarium can accumulate high levels of Mn, even as plant growth was inhibited by rising Mn concentrations. Malondialdehyde (MDA) content increased and catalase (CAT) activity decreased along with the increased Mn concentrations, while soluble protein and proline content, as well as the superoxide dismutase (SOD) and peroxidase (POD) enzymes, all increased initially and then declined. The highest value of POD, SOD, soluble protein and proline all occurred at 5000 µM of Mn stress, which means that X. strumarium can adapt to low concentration of Mn stress. The net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO₂ concentration (Ci) and transpiration rate (Tr) decreased, and the stomatal limitation (Ls) increased in response to Mn stress. Furthermore, water use efficiency (WUE) and intrinsic water use efficiency (WUEi) increased first under low concentration of Mn, and then reduced as the concentration of Mn increased. The maximum quantum efficiency of PSII photochemistry (Fv/Fm), efficiency of excitation capture by open PSII reaction centers (Fv'/Fm'), electron transport rate (ETR) declined as Mn concentration increased. In conclusion, the above results showed that X. strumarium can be effectively used for phytoremediation of Mn-contaminated soils.

Alteration in Oxidative/nitrosative imbalance, histochemical expression of osteopontin and antiurolithiatic efficacy of Xanthium strumarium (L.) in ethylene glycol induced urolithiasis

Xanthium strumarium has traditionally been used in the treatment of urolitiasis especially by the rural people in India, but its antiurolithiatic efficacy was not explored scientifically till now. Therefore, the present study was designed to validate the ethnic practice scientifically, and explore the possible antiurolithiatic effect to rationalize its medicinal use. Urolitiasis was induced in hyperoxaluric rat model by giving 0.75% ethylene glycol (EG) for 28days along with 1% ammonium chloride (AC) for first 14days. Antiurolithiatic effect of aqueous-ethanol extract of Xanthium strumarium bur (xanthium) was evaluated based on urine and serum biochemistry, oxidative/nitrosative stress indices, histopathology, kidney calcium and calcium oxalate content and immunohistochemical expression of matrix glycoprotein, osteopontin (OPN). Administration of EG and AC resulted in hyperoxaluria, crystalluria, hypocalciuria, polyurea, raised serum urea, creatinine, erythrocytic lipid peroxidise and nitric oxide, kidney calcium content as well as crystal deposition in kidney section in lithiatic group rats. However, xanthium treatment significantly restored the impairment in above kidney function test as that of standard treatment, cystone. The up-regulation of OPN was also significantly decreased after xanthium treatment. The present findings demonstrate the curative efficacy of xanthium in ethylene glycol induced urolithiasis, possibly mediated through inhibition of various pathways involved in renal calcium oxalate formation, antioxidant property and down regulation of matrix glycoprotein, OPN. Therefore, future studies may be established to evaluate its efficacy and safety for clinical use.

Xanthium strumarium as an Inhibitor of α-Glucosidase, Protein Tyrosine Phosphatase 1β, Protein Glycation and ABTS⁺ for Diabetic and Its Complication

Phytochemical investigation of the natural products from Xanthium strumarium led to the isolation of fourteen compounds including seven caffeoylquinic acid (CQA) derivatives. The individual compounds were screened for inhibition of α-glucosidase, protein tyrosine phosphatase 1β (PTP1β), advanced glycation end products (AGEs), and ABTS⁺ radical scavenging activity using in vitro assays. Among the isolated compounds, methyl-3,5-di-caffeoyquinic acid exhibited significant inhibitory activity against α-glucosidase (18.42 μM), PTP1β (1.88 μM), AGEs (82.79 μM), and ABTS⁺ (6.03 μM). This effect was marked compared to that of the positive controls (acarbose 584.79 μM, sumarin 5.51 μM, aminoguanidine 1410.00 μM, and trolox 29.72 μM respectively). In addition, 3,5-di-O-CQA (88.14 μM) and protocatechuic acid (32.93 μM) had a considerable inhibitory effect against α-glucosidase and ABTS⁺. Based on these findings, methyl-3,5-di-caffeoyquinic acid was assumed to be potentially responsible for the anti-diabetic actions of X. strumarium.

PDK1 in NF-κB signaling is a target of Xanthium strumarium methanolic extract-mediated anti-inflammatory activities

ETHNOPHARMACOLOGICAL RELEVANCE

Xanthium strumarium L. (Asteraceae) has traditionally been used to treat bacterial infections, nasal sinusitis, urticaria, arthritis, chronic bronchitis and rhinitis, allergic rhinitis, edema, lumbago, and other ailments. However, the molecular mechanisms by which this plant exerts its anti-inflammatory effects are poorly characterized. Here we studied the immunopharmacological activities of the methanolic extract of the aerial parts of this plant (Xs-ME) and validated its pharmacological targets.

MATERIALS AND METHODS

To evaluate the anti-inflammatory activity of Xs-ME, we employed lipopolysaccharide (LPS)-treated macrophages and an HCl/EtOH-induced mouse model of gastritis. We also used HPLC to identify the potentially active anti-inflammatory components of this extract. The molecular mechanisms of its anti-inflammatory activity were studied by kinase assays, reporter gene assays, immunoprecipitation analysis, and overexpression of target enzymes.

RESULTS

The production of nitric oxide (NO) and prostaglandin E2 (PGE2) were both suppressed by Xs-ME. Moreover, orally administered Xs-ME ameliorated HCl/EtOH-induced gastric lesions. Furthermore, this extract downregulated the expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 and reduced the nuclear levels of NF-κB. Signaling events upstream of NF-κB translocation, such as phosphorylation of AKT and the formation of PDK1-AKT signaling complexes, were also inhibited by Xs-ME. Moreover, Xs-ME suppressed the enzymatic activity of PDK1. Additionally, PDK1-induced luciferase activity and Akt phosphorylation were both inhibited by Xs-ME. We also identified the polyphenol resveratrol as a likely active anti-inflammatory component in Xs-ME that targets PDK1.

CONCLUSION

Xs-ME exerts anti-inflammatory activity in vitro and in vivo by inhibiting PDK1 kinase activity and blocking signaling to its downstream transcription factor, NF-κB.

Biological activity of Xanthium strumarium seed extracts on different cancer cell lines and Aedes caspius, Culex pipiens (Diptera: Culicidae)

Effects of methanol extracts of Xanthium strumarium on different cancer cell lines and on the mortality rates of Aedes caspius, Culex pipiens (Diptera: Culicidae) were investigated. Among the cell lines tested, the Jurkat cell line was the most sensitive to the methanol extract and ethyl acetate fraction, with reported LC₅₀ values of 50.18 and 48.73 μg/ml respectively. Conversely, methanol extracts were not that toxic to the A549 cell line though the toxicity increased on further purification. The percentage of growth inhibition was dose dependent for the methanol extract and ethyl acetate fraction. The ethyl acetate fraction showed higher toxicity to all cell lines tested when compared to the methanol extract. The results showed that methanol extracts of plant seeds caused 100% mortality of mosquito larvae at a concentration of 1000 μg/ml after 24 h of treatment. The LC₅₀ and LC₉₀ values of X. strumarium were found to be 531.07 and 905.95 μg/ml against Ae. caspius and 502.32 and 867.63 μg/ml against Cx. Pipiens, respectively. From the investigations, it was concluded that the crude extract of X. strumarium showed a weak potential for controlling the larval instars of Ae. caspius and Cx. pipiens. However, on further purification the extract lost the larvicidal activity. The ethyl acetate fraction showed higher toxicity to all cell lines tested when compared to the methanol extract. The ethyl acetate fraction investigated in this study appears to have a weak larvicidal activity but a promising cytotoxic activity. Future studies will include purification and investigation in further detail of the action of X. strumarium on Cancer Cell Lines and mosquitoes.

Identification and Functional Characterization of Sesquiterpene Synthases from Xanthium strumarium

Xanthium strumarium synthesizes various pharmacologically active sesquiterpenes. The molecular characterization of sesquiterpene biosynthesis in X. strumarium has not been reported so far. In this study, the cDNAs coding for three sesquiterpene synthases (designated as XsTPS1, XsTPS2 and XsTPS3) were isolated using the X. strumarium transcriptome that we recently constructed. XsTPS1, XsTPS2 and XsTPS3 were revealed to have primary activities forming germacrene D, guaia-4,6-diene and germacrene A, respectively, by either ectopic expression in yeast cells or purified recombinant protein-based in vitro assays. Quantitative real-time PCRs and metabolite analysis for the different plant parts showed that the transcript abundance of XsTPS1-XsTPS3 is consistent with the accumulation pattern of their enzymatic products, supporting their biochemical functions in vivo. In particular, we discovered that none of the XsTPS2 product, guaia-4,6-diene, can be detected in one of the X. strumarium cultivars used in this study (it was named the Hubei-cultivar), in which a natural deletion of two A bases in the XsTPS2 cDNA disrupts its activity, which further confirmed the proposed biochemical role of XsTPS2 in X. strumarium in vivo.

Comparative Transcriptome Analysis Identifies Putative Genes Involved in the Biosynthesis of Xanthanolides in Xanthium strumarium L

Xanthium strumarium L. is a traditional Chinese herb belonging to the Asteraceae family. The major bioactive components of this plant are sesquiterpene lactones (STLs), which include the xanthanolides. To date, the biogenesis of xanthanolides, especially their downstream pathway, remains largely unknown. In X. strumarium, xanthanolides primarily accumulate in its glandular trichomes. To identify putative gene candidates involved in the biosynthesis of xanthanolides, three X. strumarium transcriptomes, which were derived from the young leaves of two different cultivars and the purified glandular trichomes from one of the cultivars, were constructed in this study. In total, 157 million clean reads were generated and assembled into 91,861 unigenes, of which 59,858 unigenes were successfully annotated. All the genes coding for known enzymes in the upstream pathway to the biosynthesis of xanthanolides were present in the X. strumarium transcriptomes. From a comparative analysis of the X. strumarium transcriptomes, this study identified a number of gene candidates that are putatively involved in the downstream pathway to the synthesis of xanthanolides, such as four unigenes encoding CYP71 P450s, 50 unigenes for dehydrogenases, and 27 genes for acetyltransferases. The possible functions of these four CYP71 candidates are extensively discussed. In addition, 116 transcription factors that are highly expressed in X. strumarium glandular trichomes were also identified. Their possible regulatory roles in the biosynthesis of STLs are discussed. The global transcriptomic data for X. strumarium should provide a valuable resource for further research into the biosynthesis of xanthanolides.

Two new compounds from Xanthium strumarium

One new lignan, fructusol A (1), and one new thiazine derivative, 2-hydroxy-xanthiazone (2), along with eight known ones, were isolated from the seeds of Xanthium strumarium. The structures of new compounds were elucidated on the basis of extensive spectroscopic methods. Meanwhile, compounds 1-3 were tested for their antifungal activities against Candida albicans (ATCC 10231) in vitro. No one showed obvious inhibitions (MIC90 > 128 μg/ml).

Identification of tyrosinase specific inhibitors from Xanthium strumarium fruit extract using ultrafiltration-high performance liquid chromatography

In this study, a strategy based on ultrafiltration-high performance liquid chromatography coupled with diode array detection (UF-HPLC-DAD) was proposed for screening tyrosinase specific inhibitors in Xanthii fructus. The false negatives were distinguished by optimizing the UF-HPLC-DAD parameters to reduce the background noise; the false positives were distinguished by introducing a blocked tyrosinase in the control group for comparison. To obtain the best blocker, the competitive experiments were performed using various known ligands. Using this strategy, three competitive inhibitors (protocatechuic acid; 3,5-di-O-caffeoylquinic acid; and 1,5-di-O-caffeoylquinic acid) and one mixed-type inhibitor (chlorogenic acid) were identified. These results were verified using tyrosinase inhibition assay, kinetic analysis, and structural simulation of the complex. Our experimental results suggest that the proposed strategy could be useful for high-throughput identification of tyrosinase specific inhibitors in natural products.

Sesquiterpenes with TRAIL-resistance overcoming activity from Xanthium strumarium

The ability of TRAIL to selectively induce apoptosis in cancer cells while sparing normal cells makes it an attractive target for the development of new cancer therapy. In search of bioactive natural products for overcoming TRAIL-resistance from natural resources, we previously reported a number of active compounds. In our screening program on natural resources targeting overcoming TRAIL-resistance, activity-guided fractionations of the extract of Xanthium strumarium led to the isolation of five sesquiterpene compounds (1-5). 11α,13-dihydroxanthinin (2) and 11α,13-dihydroxanthuminol (3) were first isolated from natural resources and xanthinosin (1), desacetylxanthanol (4), and lasidiol p-methoxybenzoate (5) were known compounds. All compounds (1-5) showed potent TRAIL-resistance overcoming activity at 8, 20, 20, 16, and 16 μM, respectively, in TRAIL-resistant AGS cells. Compounds 1 and 5 enhanced the levels of apoptosis inducing proteins DR4, DR5, p53, CHOP, Bax, cleaved caspase-3, cleaved caspase-8, and cleaved caspase-9 and also decreased the levels of cell survival protein Bcl-2 in TRAIL-resistant AGS cells in a dose-dependent manner. Compound 1 also enhanced the levels of DR4 and DR5 proteins in a time-dependent manner. Thus, compounds 1 and 5 were found to induce both extrinsic and intrinsic apoptotic cell death. Compound 1 also exhibit TRAIL-resistance overcoming activity in DLD1, DU145, HeLa, and MCF7 cells but did not decrease viability in non-cancer HEK293 cells up to 8 μM.

Sesquiterpene lactone stereochemistry influences herbivore resistance and plant fitness in the field

BACKGROUND AND AIMS

Stereochemical variation is widely known to influence the bioactivity of compounds in the context of pharmacology and pesticide science, but our understanding of its importance in mediating plant-herbivore interactions is limited, particularly in field settings. Similarly, sesquiterpene lactones are a broadly distributed class of putative defensive compounds, but little is known about their activities in the field.

METHODS

Natural variation in sesquiterpene lactones of the common cocklebur, Xanthium strumarium (Asteraceae), was used in conjunction with a series of common garden experiments to examine relationships between stereochemical variation, herbivore damage and plant fitness.

KEY RESULTS

The stereochemistry of sesquiterpene lactone ring junctions helped to explain variation in plant herbivore resistance. Plants producing cis-fused sesquiterpene lactones experienced significantly higher damage than plants producing trans-fused sesquiterpene lactones. Experiments manipulating herbivore damage above and below ambient levels found that herbivore damage was negatively correlated with plant fitness. This pattern translated into significant fitness differences between chemotypes under ambient levels of herbivore attack, but not when attack was experimentally reduced via pesticide.

CONCLUSIONS

To our knowledge, this work represents only the second study to examine sesquiterpene lactones as defensive compounds in the field, the first to document herbivore-mediated natural selection on sesquiterpene lactone variation and the first to investigate the ecological significance of the stereochemistry of the lactone ring junction. The results indicate that subtle differences in stereochemistry may be a major determinant of the protective role of secondary metabolites and thus of plant fitness. As stereochemical variation is widespread in many groups of secondary metabolites, these findings suggest the possibility of dynamic evolutionary histories within the Asteraceae and other plant families showing extensive stereochemical variation.

Interaction Among a Nematode (Heterodera glycines), an Insect, and Three Weeds in Soybean

A 2 x 3 x 4 factorial field experiment was established to determine the interaction among a nematode, an insect, and three weed species on soybean in 1983-86. Low (nematicide treated) or high (untreated) population densities of the soybean cyst nematode (SCN), Heterodera glycines, and 0, 30, or 70% main stem girdling by the threecornered alfalfa hopper (TCAH), Spissistilus festinus, were combined with no weeds, one common cocklebur (CC), Xanthium strumarium, one sicklepod (SP), Cassia obtusifolia, or one pitted morningglory (PMG), Ipomoea lacunosa, per meter of row in all possible combinations. Most of the losses from the pests were significant (P </= 0.05) and additive. The high population density of SCN suppressed soybean seed yield by 14%. Girdling of 30 and 70% by TCAH suppressed yields by 10 and 25%, respectively. One CC, SP, or PMG per meter of row suppressed yield by 22, 14, and 12%, respectively. The addition of loss predictions for each pest was approximately the actual treatment losses recorded. The pests did not have an evident interactive effect on yield losses; however, the losses attributed to each pest were additive.

Host Status of Seven Weed Species and Their Effects on Ditylenchus destructor Infestation of Peanut

The host suitability to Ditylenchus destructor of seven common weed species in peanut (Arachis hypogaea) fields in South Africa was determined. Based on the number of nematodes per root unit, white goosefoot (Chenopodium album), feathertop chloris (Chloris virgata), purple nutsedge (Cyperus rotundus), jimson weed (Datura stramonium), goose grass (Eleusine indica), khaki weed (Tagetes minuta), and cocklebur (Xanthium strumarium) were poor hosts. Ditylenchus destructor survived on all weed species; population densities increased in peanut hulls and caused severe damage to seeds of peanut grown after weeds. Roots of purple nutsedge left in the soil suppressed populations of D. destructor and root and pod development in peanut grown after the weed. However, nematode populations in peanut hulls and seeds were not suppressed. Some weed species, especially purple nutsedge which is common in peanut fields, can be used to indicate the presence of D. destructor in the absence of peanut.