Effects of soil pH on the growth, soil nutrient composition, and rhizosphere microbiome of Ageratina adenophora.

Ageratina adenophora is an invasive weed species found in many countries. Methods to control the spread of this weed have been largely unsuccessful. Soil pH is the most important soil factor affecting the availability of nutrients for plant and impacting its growth. Understanding the mechanisms of the influence of soil pH on the growth of A. adenophora may help to develop effective control measures. In this study, we artificially changed the soil pH in pot experiments for A. adenophora. We studied the effects of acidic (pH 5.5), weakly acidic (pH 6.5), neutral (pH 7.2), and alkaline (pH 9.0) soils on the growth, availability of soil nutrients, activity of antioxidant enzymes, levels of redox markers in the leaves, and the structure and diversity of the rhizosphere microbiome. Soil with a pH 7.2 had a higher (47.8%) below-ground height versus soils of pH 5.5 at day 10; plant had a higher (11.3%) above-ground height in pH 7.2 soils than pH 9.0 soils at day 90; no differences in the fresh and dry weights of its above- and belowground parts, plant heights, and root lengths were observed in plants growing in acid, alkaline, or neutral pH soil were observed at day 180. Correspondingly, the antioxidant enzymes SOD (superoxide dismutase), POD (peroxidase), CAT (catalase) and redox markers GSH (glutathione) and MDA (malondialdehyde) were measured in the leaves. Significant differences existed in the activities of CAT and the levels of GSH between those growing in acidic and alkaline soils and those in neutral pH soil at day 90; however, only lower (36.8%) CAT activities in those grown at pH 5.5 than those grown at pH 7.2 were found at day 180. Similarly, significant differences in available P (16.89 vs 3.04 mg Kg-1) and total K (3.67 vs 0.96 mg Kg-1), total P (0.37 vs 0.25 g Kg-1) and total N (0.45 vs 1.09 g Kg-1) concentrations were found between the rhizosphere soils of A. adenophora grown at pH 9.0 and 7.2 at day 90; no such differences were seen at day 180. High throughput analyses of the 16S rRNA and ITS fragments showed that the rhizosphere microbiome diversity and composition under different soil pH conditions changed over 180 days. The rhizosphere microbiomes differed in diversity, phylum, and generic composition and population interactions under acid and alkaline conditions versus those grown in neutral soils. Soil pH had a greater impact on the diversity and composition of the prokaryotic rhizosphere communities than those of the fungal communities. A. adenophora responded successfully to pH stress by changing the diversity and composition of the rhizosphere microbiome to maintain a balanced nutrient supply to support its normal growth. The unusual pH tolerance of A. adenophora may be one crucial reason for its successful invasion. Our results suggest that attempts use soil pH to control its invasion by changing the soil pH (for example, using lime) will fail.

Calmodulin-Targeting Molecules from Ageratina grandifolia.

Four new natural chemical entities, including 2-hydroxy-α-truxillic acid (2), (3R,4S)-2,2-dimethyl-3-hydroxy-4-(1-angeloyloxy)-6-acetyl-7-methoxychromane (3), N-tricosanoyltyramine (4), and grandifolamide (5), were isolated along with 11 known compounds (1, 6-15) from the aerial parts of Ageratina grandifolia. The chemical structures were elucidated using chemical derivatization and HR-MS, NMR, and DFT-calculated chemical shifts, combined with DP4+ statistical analysis. It was found that 2 decomposed into its biogenetic precursor, o-coumaric acid, upon standing at room temperature for a few weeks. 3,5-Diprenyl-4-hydroxyacetophenone (8), O-methylencecalinol (10), encecalin (11), and encecalinol (12) bound to calmodulin (CaM) with higher affinity than chlorpromazine, a well-known CaM inhibitor. Molecular dynamics studies revealed that the complexes of these compounds with CaM remained stable during the simulation. Altogether these results revealed the therapeutic and research tool potential of compounds 8, 10, 11, and 12.

Unusual 5/5 fused bicyclosesquiterpenoids from Eupatorium adenophorum.

The chemical analysis on the aerial sections of Eupatorium adenophorum Spreng. resulted in the identification of four unprecedented 5/5 fused bicyclosesquiterpenoids, eupatorid A (1), and its analogues named eupatorester A-C (2-4) using various chromatographic techniques. Their structures were unambiguously confirmed by detailed spectroscopic investigations (including 1D, 2D-NMR and HRMS), and single crystal X-ray diffraction. The anti-inflammatory activities, in vitro tumor growth inhibitory activities and antibacterial activities of these compounds were evaluated.

Adenophorone, An Unprecedented Sesquiterpene from Eupatorium adenophorum: Structural Elucidation, Bioinspired Total Synthesis and Neuroprotective Activity Evaluation.

(-)-Adenophorone (1), a caged polycyclic sesquiterpene featuring an unprecedented tricyclo[4.3.1.05,9 ]decane skeleton, was isolated from Eupatorium adenopharum Spreng. The structure of 1 was unambiguously established by a combination of spectroscopic analysis, X-ray crystallography, and bioinspired total synthesis. Key synthetic features include a sequential Reformatsky/oxidation/regio- and stereoselective hydrogenation, and subsequent merged MBH-Tsuji-Trost cyclization. The concise synthetic sequence efficiently constructs the bicyclic skeleton of cadinene sesquiterpene (+)-euptox A (2) in 8 steps from commercially available monoterpene (-)-carvone (6), with outstanding performance on diastereocontrol. The bioinspired synthesis of 1 was achieved from 2, a plausible biogenetic precursor, via transannular Michael addition. This work provides experimental evidence of our proposed biosynthetic hypothesis of 1. Additionally, compound 1 showed potent neuroprotective activity in H2 O2 -treated SH-SY5Y and PC12 cells.

Obtaining 2,3-Dihydrobenzofuran and 3-Epilupeol from Ageratina pichinchensis (Kunth) R.King & Ho.Rob. Cell Cultures Grown in Shake Flasks under Photoperiod and Darkness, and Its Scale-Up to an Airlift Bioreactor for Enhanced Production.

Ageratina pichinchensis (Kunth) R.King & Ho.Rob. is a plant used in traditional Mexican medicine, and some biotechnological studies have shown that its calluses and cell suspension cultures can produce important anti-inflammatory compounds. In this study, we established a cell culture of A. pichinchensis in a 2 L airlift bioreactor and evaluated the production of the anti-inflammatory compounds 2,3-dihydrobenzofuran (1) and 3-epilupeol (2). The maximum biomass production (11.90 ± 2.48 g/L) was reached at 11 days of culture and cell viability was between 80% and 90%. Among kinetic parameters, the specific growth rate (µ) was 0.2216 days-1 and doubling time (td) was 3.13 days. Gas chromatography coupled with mass spectrometry (GC-MS) analysis of extracts showed the maximum production of compound 1 (903.02 ± 41.06 µg/g extract) and compound 2 (561.63 ± 10.63 µg/g extract) at 7 and 14 days, respectively. This study stands out for the significant production of 2,3-dihydrobenzofuran and 3-epilupeol and by the significant reduction in production time compared to callus and cell suspension cultures, previously reported. To date, these compounds have not been found in the wild plant, i.e., its production has only been reported in cell cultures of A. pichinchensis. Therefore, plant cell cultured in an airlift reactor can be an alternative for the improved production of these anti-inflammatory compounds.

Anti-Inflammatory Activity of 3, 5-Diprenyl-4-hydroxyacetophenone Isolated from Ageratina pazcuarensis.

Inflammation is implicated in a wide variety of physiological and pathological processes. Plants are an important source of active anti-inflammatory compounds. The compound 3, 5-diprenyl-4-hydroxyacetophenone (DHAP) was isolated from the dichloromethane extract of the aerial parts of Ageratina pazcuarensis by chromatography and identified by spectroscopic (IR, NMR) and spectrometric (GC-MS) methods. Anti-inflammatory activity was evaluated on ear edema mouse induced with 12-O-tetradecanoylphorbol 13-acetate (TPA) at 2 mg/ear. The antioxidant activity of DHAP was determined using DPPH assay. Cell viability was tested in J774A.1 macrophages, the levels of NO, TNF-α, IL-1ß, IL-6, and IL-10 production in macrophages stimulated with lipopolysaccharide (LPS), and membrane lysis induced by hypotonic solution in erythrocytes were evaluated. DHAP diminished the ear edema mouse in 70.10%, and it had scavenger effect against the radical with IC50 of 26.00 ± 0.37 µg/mL. Likewise, 91.78 µM of this compound inhibited the production of NO (38.96%), IL-1ß (55.56%), IL-6 (51.62%), and TNF-α (59.14%) in macrophages and increased the levels of IL-10 (61.20%). Finally, 25 and 50 µg/mL DHAP provided the greatest protection against erythrocyte membrane lysis. These results demonstrate that DHAP has anti-inflammatory activity.

A new germacranolide from Ageratina vernalis.

The aerial parts of Ageratina vernalis provided the new germacranolide 1,10-epoxydeltoidin A (3), together with the known pentacyclic triterpenoid hopane-6α,22-diol (1), and the also known germacranolides deltoidin A (2) and 15-hydroxydeltoidin A (4). In addition, pTsOH catalyzed cyclization of 2 afforded the new guaianolide 5. The absolute configuration of 2, 4, and 5 was assigned by vibrational circular dichroism spectroscopy, while the complete 1H and 13C NMR data assignments of 2-5 followed from 1 D- and 2 D-NMR experiments.

Three new cadinane-type sesquiterpenes from Eupatorium adenophorum spreng.

Three new cadinane-type sesquiterpenes, eupatorinones A-C (1-3), along with seven known compounds (4-10), were obtained from the petroleum ether fraction of 95% ethanol extract of Eupatorium adenophorum Spreng. The structures of these new compounds were determined by NMR, MS, and ECD spectra analysis. The configuration of compound 3 was established by quantum chemical calculations of NMR chemical shifts and ECD spectra, that matched the experimental data. In addition, compounds 1, 3 and 5 increased the glucose uptake in L6 cells by 1.42, 1.21 and 1.60 times, respectively.[Formula: see text].

Ageratina adenophora Disrupts the Intestinal Structure and Immune Barrier Integrity in Rats.

The aim of this study was to investigate the effects of Ageratina adenophora on the intestines morphology and integrity in rat. Rats were randomly divided into two groups and were fed with 10 g/100 g body weight (BW) basal diet and 10 g/100 g BW experimental diet, which was a mixture of A. adenophora powder and basal diet in a 3:7 ratio. The feeding experiment lasted for 60 days. At days 28 and 60 of the experiment, eight rats/group/timepoint were randomly selected, weighed, and sacrificed, then blood and intestinal tissues were collected and stored for further analysis. The results showed that Ageratina adenophora caused pathological changes and injury in the intestine, elevated serum diamine oxidase (DAO), D-lactate (D-LA), and secretory immunoglobulin A (sIgA) levels, reduced occludin levels in intestinal tissues, as well as increased the count of intraepithelial leukocytes (IELs) and lamina propria leukocytes (LPLs) in the intestine (p < 0.05 or p < 0.01). In addition, the mRNA and protein (ELISA) expressions of pro-inflammation cytokines (IL-1ß, IL-2, TNF-α, and IFN-ϒ) were elevated in the Ageratina adenophora treatment groups, whereas anti-inflammatory cytokines such as IL-4 and IL-10 were reduced (p < 0.01 or p < 0.05). Therefore, the results obtained in this study indicated that Ageratina adenophora impaired intestinal function in rats by damaging the intestine structure and integrity, and also triggered an inflammation immune response that led to intestinal immune barrier dysfunction.

Computational Structural Revision of a 4-Hydroxy-3-(1'-angeloyloxy-2',3'-epoxy-3'-methyl)butylacetophenone Compound from Ageratina grandifolia.

The structure of the reported compound 4-hydroxy-3-((S)-1'-angeloyloxy-(R)-2',3'-epoxy-3'-methyl)butylacetophenone (1), isolated from Ageratina grandifolia, has been revised through the use of DFT computational predictions. Re-examination of the reported experimental and DFT computed chemical shifts has led to the proposal of a chromane skeleton rather than the original epoxide derivative. Empirical predictions of the 13C and 1H NMR shifts showed a much better fit for the chromane structure than for the epoxide. The relative configuration of the molecule was established using CASE-3D methodology on the basis of new DFT chemical shielding and J-coupling predictions, allowing the proposal of a new rel-2,2-dimethyl-3R-hydroxy-4S-(1-angeloyloxy)chromane structure (2) for the isolated compound. However, DFT prediction of the optical rotation for the CASE-3D selected configuration/conformations did not provide a conclusive answer for the absolute configuration.

α-Glucosidase Inhibitors from Ageratina grandifolia.

Fractionation of an aqueous extract from the aerial parts of Ageratina grandifolia yielded a new natural product, namely, 4-hydroxy-3-((S)-1'-angeloyloxy-(R)-2',3'-epoxy-3'-methyl)butylacetophenone (1), along with eight known compounds, including three flavonoids (2-4) and five chromenes (5-9). NMR data interpretation and DFT-calculated chemical shifts combined with DP4+ statistical and J-DP4 probability analyses allowed for the complete characterization of compound 1. The presence of compound 1 in a plant that biosynthesizes 2,2-dimethylchromenes is noteworthy, because an epoxy derivative has long been postulated as the reaction intermediate from the prenylated p-hydroxyacetophenones to cyclic dimethylchromenes. So far, this key intermediate has not been isolated, due to its purported chemical instability. Thus, this is the first report of a potential epoxide intermediate, leading to any of the chromene constituents of this plant. Compounds 1-9 inhibited yeast α-glucosidase with IC50 values ranging from 0.79 to 460 µM (acarbose, IC50 = 278.7 µM). The most active compounds were quercetagetin-7-O-(6-O-caffeoyl-ß-d-glucopyranoside (3) and 6-hydroxykaempferol-7-O-(6-O-caffeoyl-ß-d-glucopyranoside (4). Kinetic analysis of 3 revealed its mixed-type inhibitor nature. Docking studies into the crystallographic structure of yeast α-glucosidase (pdb 3A4A) predicted that 3 and 4 bind at the catalytic site of the enzyme.

Preliminary chemical characterization of ethanolic extracts from Colombian plants with promising anti - Trypanosoma cruzi activity.

Chagas disease is caused by Trypanosoma cruzi, and it is an important cause of morbidity and mortality in Latin America. There are no vaccines, and the chemotherapy available to treat this infection has serious side effects. In a search for alternative treatments, we determined the in vitro susceptibility of epimastigote and trypomastigote forms of T. cruzi and the cytotoxic effects on peripheral blood mononuclear cells (PBMCs) of ethanolic extracts obtained from six different plant species. The ethanolic extracts of Ageratina vacciniaefolia, Clethra fimbriata and Siparuna sessiliflora showed antiprotozoal activity against epimastigotes and low cytotoxicity in mammalian cells. However, only the ethanolic extract of C. fimbriata showed activity against T. cruzi trypomastigotes, and it had low cytotoxicity in PBMCs. An analysis on the phytochemical composition of C. fimbriata extract showed that its metabolites were primarily represented by two families of compounds: flavonoids and terpenoids. Lastly, we analyzed whether the A. vacciniaefolia, C. fimbriata, or S. sessiliflora ethanolic extracts induced IFN-γ or TNF-α production. Significantly, ethanolic extracts of C. fimbriata induced TNF-α production and S. sessiliflora induced both cytokines. In addition, C. fimbriata and S. sessiliflora induced the simultaneous secretion of IFN-γ and TNF-α in CD8+ T cells. The antiprotozoal and immunomodulatory activity of C. fimbriata may be related to the presence of flavonoid and triterpene compounds in the extract. Thus, these findings suggest that C. fimbriata may represent a valuable source of new bioactive compounds for the therapeutic treatment of Chagas disease that combines trypanocidal activity with the capacity to boost the immune response.

Influence of the Phenological State of in the Antioxidant Potential and Chemical Composition of Ageratina havanensis. Effects on the P-Glycoprotein Function.

Ageratina havanensis (Kunth) R. M. King & H. Robinson is a species of flowering shrub in the family Asteraceae, native to the Caribbean and Texas. The aim of this work was to compare the quantitative chemical composition of extracts obtained from Ageratina havanensis in its flowering and vegetative stages with the antioxidant potential and to determine the effects on P-glycoprotein (P-gp) function. The quantitative chemical composition of the extracts was determined quantifying their major flavonoids by UPLC-ESI-MS/MS and by PCA analysis. The effects of the extracts on P-gp activity was evaluated by Rhodamine 123 assay; antioxidant properties were determined by DPPH, FRAP and inhibition of lipid peroxidation methods. The obtained results show that major flavonoids were present in higher concentrations in vegetative stage than flowering stage. In particular, the extracts obtained in the flowering season showed a significantly higher ability to sequester free radicals compared to those of the vegetative season, meanwhile, the extracts obtained during the vegetative stage showed a significant inhibitory effect against brain lipid peroxidation and a strong reductive capacity. This study also showed the inhibitory effects of all ethanolic extracts on P-gp function in 4T1 cell line; these effects were unrelated to the phenological stage. This work shows, therefore, the first evidence on: the inhibition of P-gp function, the antioxidant effects and the content of major flavonoids of Ageratina havanensis. According to the obtained results, the species Ageratina havanensis (Kunth) R. M. King & H. Robinson could be a source of new potential inhibitors of drug efflux mediated by P-gp. A special focus on all these aspects must be taking into account for future studies.

An efficient, green, and easy-to-scale-up strategy for target-oriented isolating cadinene sesquiterpenoids from Eupatorium adenophorum Spreng.

A green and efficient strategy was established and optimized for target-oriented extraction, enrichment and separation of cadinene sesquiterpenoids from Eupatorium adenophorum Spreng., using the combination of supercritical fluid extraction, molecular distillation, and industrial preparative chromatography for the first time. The extraction conditions of supercritical fluid extraction were initially optimized by orthogonal experimental design. Under the optimum conditions, the contents of 9-oxo-10,11-dehydroageraphorone and 10Hß-9-oxo-ageraphorone, which were 55.00% and 6.01%, respectively, were much higher than conventional extraction methods. Then, the molecular distillation enrichment method was established and investigated by response surface methodology technology, which showed strong specificity for enriching target compounds and removing impurities from crude extracts. Under the optimum conditions of molecular distillation, total contents of cadinene sesquiterpenoids were increased to 89.19%. Finally, a total of 146 mg of 9-oxo-10,11-dehydroageraphorone and 29 mg of 10Hß-9-oxo-ageraphorone were easily obtained by industrial preparative chromatography, from 200 mg of distillation fraction, with purities over 99%. The contents of target components were analyzed by HPLC, and structures of them were identified by high-resolution MS, 1 H-NMR, and 13 C-NMR spectroscopy. These results indicate that it is a simple, effective, and eco-friendly strategy, which is easily converted into industrial scale.

Effectiveness of an encecalin standardized extract of Ageratina pichinchensis on the treatment of onychomycosis in patients with diabetes mellitus.

Ageratina pichinchensis is utilized in traditional medicine for the treatment of dermatomycosis and inflammation. The aim of this study was to evaluate the clinical and mycological effectiveness of the topical administration of an enecalin standardized extract of A. pichinchensis for treating onychomycosis in patients with type 2 diabetes mellitus (DM2). A double blind, randomized, and controlled clinical trial was carried out that included patients with DM2 and who had mild or moderate onychomycosis. Participants were administered topically, for 6 months, a lacquer containing the encecalin standardized extract of A. pichinchensis (experimental group) or 8% ciclopirox (control group). In a large percentage of both, the control group (77.2%) and the experimental group (78.5%), clinical efficacy was detected as a decrease in the number of affected nails and a reduction in the severity of nail involvement. Without exhibiting statistically significant differences between groups, the encecalin standardized extract of A. pichinchensis was clinically and mycologically effective in the treatment of mild and moderate onychomycosis in patients with DM2. The treatment of onychomycosis in patients with DM2 implies a greater challenge, while control of blood glucose levels in these patients, played a very important role in the response of patients to treatment.

[Chemical separation product of Ageratina adenophora essential oil (AAEO) inhibits the inflammation of RAW264.7 cells induced by lipopolysaccharide].

Objective To investigate the anti-inflammatory activity of Ageratina adenophora essential oil (AAEO-CP) and its effects on the expression of Toll-like receptor 4 (TLR4) protein in lipopolysaccharide (LPS)-induced RAW264.7 cells. Methods RAW264.7 cells were divided into control group, LPS group, and LPS combined with AAEO-CP group. The cytotoxicity of AAEO-CP was detected by CCK-8 assay. The mRNA and protein expression of interleukin-6 (IL-6) and IL-10 were detected by real-time PCR and ELISA, respectively, and the protein expression of TLR4 in RAW264.7 cells was measured by Western blotting. Results AAEO-CP below 20 mg/mL was not cytotoxic to RAW264.7 cells. LPS increased the protein expression of TLR4, also increased the protein and mRNA expression of IL-6, but decrease the protein and mRNA expression of IL-10 in RAW264.7 cells. And all of the above results were reversed by AAEO-CP. Conclusion AAEO-CP can play the anti-inflammatory effects by increasing the expression of IL-10 protein and decreasing the expression of IL-6 protein, and inhibiting TLR4 protein in LPS-induced RAW264.7 cells.

Ageratina adenophora induces mice hepatotoxicity via ROS-NLRP3-mediated pyroptosis.

Increasing evidences have demonstrated that Ageratina adenophora (A. adenophora) can cause hepatotoxicity of animals. Liver is an important site in immune regulation and inflammatory responses. However, the information about hepatotoxicity induced by A. adenophora in relation to inflammation is still finite. To investigate the underlying mechanism, we conducted animal experiments with different dosage of A. adenophora. Mice were randomly divided into 4 groups and administrated with 0%, 10%, 20% and 30% levels of A. adenophora pallet diet in control, group A, B and C, respectively. The results showed that A. adenophora caused hepatotoxicity as revealed by increasing alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase. Then, the reactive oxygen species (ROS) levels were shown to be elicited by A. adenophora through flow cytometry assay in a dose-dependent manner. Furthermore, pyroptosis was activated by A. adenophora, which was characterized by increasing protein and mRNA levels of caspase-1, gasdermin D and interleukin-1ß. Notably, ROS down-stream factors, including nod-like receptor inflammasome protein 3 and nuclear factor-κB, were also activated by A. adenophora. These data demonstrated that A. adenophora caused liver inflammatory injury and induced hepatocyte pyroptosis by activating NLRP3 inflammasome, which was triggered by elevating ROS production levels. This research might provide new insights into the mechanism of hepatotoxicity induced by A. adenophora.

Establishment and Phytochemical Analysis of a Callus Culture from Ageratina pichinchensis (Asteraceae) and Its Anti-Inflammatory Activity.

A protocol was established to produce bioactive compounds in a callus culture of Ageratina pichinchensis by using 1 mg L-1 NAA with 0.1 mg L-1 KIN. The phytochemical study of the EtOAc extract obtained from the callus biomass, allowed the isolation and characterization of eleven secondary metabolites, of which dihydrobenzofuran (5) and 3-epilupeol (7), showed important anti-inflammatory activity. Compound 5 inhibits in vitro the secretion of NO (IC50 = 36.96 ± 1.06 µM), IL-6 (IC50 = 73.71 ± 3.21 µM), and TNF-α (IC50 = 73.20 ± 5.99 µM) in RAW (Murine macrophage cells) 264.7 macrophages, as well as the activation of NF-κB (40% at 150 µM) in RAW-blue macrophages, while compound 7 has been described that inhibit the in vivo TPA-induced ear edema, and the in vitro production of NO, and the PLA2 enzyme activity. In addition, quantitative GC-MS analysis showed that the anti-inflammatory metabolites 5 and 7 were not detected in the wild plant. Overall, our results indicated that A. pichinchensis can be used as an alternative biotechnological resource for obtaining anti-inflammatory compounds. This is the first report of the anti-inflammatory activity of compound 5 and its production in a callus culture of A. pichinchensis.

[Exogenous NO application effectively alleviates the allelochemical stress on cucumber root border cells caused by Eupatorium adenophorum extracts.] / 外源NOç¼“è§£ç´«èŒŽæ³½å °æå–ç‰©å¯¹é»„ç“œæ ¹è¾¹ç¼˜ç»†èƒžçš„åŒ–æ„Ÿèƒè¿«.

Using suspension cultures of cucumber (Cucumis sativus) cultivar Jinyou 35, we investigated the effects of allelochemical stresses induced by Eupatorium adenophorum extracts on root border cells (RBC), and the role of exogenous NO application in alleviation of the damage of root tips exposed to E. adenophorum extracts. The results showed that, 1000 mg·L-1 E. adenophorum extracts had significant damage to the cucumber root tip, resulting in severe tissue damage, exfoliated surface cells and irregular arrangement of inner cells, while those damages could be effectively alleviated by spraying exogenous NO. Compared with the control, E. adenophorum extracts (ZL) markedly reduced RBC numbers and survival rates by 54.5% and 97.2%, respectively, the RBC apoptosis rates were 12.3 times higher, the thicknesses of RBC adhesive layers were increased by 31.4%, and the root cap PME activities were markedly increased. Compared with the ZL treatment, exogenous NO application (ZN) significantly increased RBC numbers and survival rates by 72.4% and 146.0%, respectively, reduced the corresponding RBC apoptosis rates and the thicknesses of RBC adhesive layers by 30.7% and 15.0%, respectively, and inhibited the PME activities by 14.3% upon treatment for 72 hours. Our findings revealed that E. adenophorum extracts showed toxic effects on the cucumber RBC, resulting in cell apoptosis, abolishment of the RBC protection on root tips, and the destruction of root tip structure. Exogenous NO application, to some extent, could prevent the root tip and RBC from cell damage caused by E. adenophorum extracts.

Chemical Composition and Antimicrobial Activity of Ageratina deltoidea.

The chemical study of Ageratina deltoidea afforded grandiflorenic acid (1), ent-kaurenoic acid (2), and eight benzylbenzoates (3 - 10), two of them, 3,5-dimethoxybenzyl 2,3,6-trimethoxybenzoate (5) and 4-(ß-d-glucopyranosyloxy)-3-hydroxybenzyl 2,6-dimethoxybenzoate (9), described for the first time. In addition, the new sesquiterpene lactone deltoidin C (13), together with the known 11 and 12, the phenolic compounds: ayanin, 2,6-dimethoxybenzoic acid, methyl 3,4-dihydroxycinnamate, chlorogenic acid, and 3,5-dicaffeoylquinic acid were also isolated. The structures of these compounds were determined by spectroscopic methods and chemical reactions. The antibacterial and antifungal activities of compounds 1 - 12 were evaluated on Staphylococcus aureus, Escherichia coli, and Candida albicans. Deltoidin A (11) was the most active antibacterial agent (MIC 16.0 µg ml-1 ) against E. coli, and the ent-kaurenoid derivatives (1 - 2) showed activity (MIC 31.0 µg ml-1 ) against S. aureus.