Phytotoxic Potential Research Articles

Synergism and phytotoxicity: The effects of tank‐mix additives on the biological efficacy of Cu2+ against Venturia inaequalis and Podosphaera leucotricha

AbstractThe wetting behaviour of the spray and the biological efficacy of Cu2+ active ingredients in agrochemical formulations may be enhanced by tank‐mix additives. We investigated how three BREAK‐THRU® additives (BT301: biodegradable, BT133 and BT420: bio‐based and biodegradable) tank‐mixed with commercial copper preparations influenced the spray distribution, leaf uptake and biological efficacy of copper additive mixtures against apple scab and apple powdery mildew under controlled conditions. We quantified the synergetic effects of these additives in foliar applications. In addition, we determined the phytotoxic potential and evaluated their impacts on photosynthetic activity, non‐photochemical quenching and ROS activity. The additives BT301 and BT420 strongly reduced surface tension and contact angle of copper treatments. The fluorescence observations revealed that BT301 achieved better spreading of copper formulation with more complete coverage of the leaf surface than BT420 and BT133, whereas ‘coffee‐ring’ spreading was observed with BT133. The additive BT301 showed an increase in relative fluorescence area, indicating higher ROS production as a signal of intra‐cellular tissue activity. The photochemical efficiency of photosystem II (Fv/Fm) was not negatively influenced by copper or additive treatment. Thus, we observed no phytotoxic effects of copper‐additive mixtures on apple leaves at treatment doses of 4 g Cu2+ L−1. All copper treatments reduced apple scab infections significantly, by 53%–76%. Interestingly, addition of BT301 to copper preparations showed the strongest biological efficacy (83% reduction) against Venturia inaequalis, whereas addition of BT420 showed the strongest effect against Podosphaera leucotricha (89% infection reduction). The synergetic effects of additives on the biological efficacy without phytotoxic effects on plants may have potential for reducing copper loads in horticultural production systems.

Phytotoxic Interference of Culture Filtrates of Endophytic Bacteria Associated with Nerium oleander Leaf Against Seed Germination of the Invasive Noxious Weed Cenchrus echinatus

Weeds cause destructive agricultural losses, so weed control is an urgent challenge facing agriculture. The extensive use of synthetic chemical herbicides has detrimental environmental impacts and promotes the emergence of resistant species. Therefore, in this study we tried to find a new natural weed control that can ensure biosafety and eco-sustainability. The phytotoxic potential of culture filtrates of the endophytes Bacillus inaquosorum NL1 and Bacillus safensis NL2 isolated from Nerium oleander leaf against the invasive harmful weed species Cenchrus echinatus was evaluated. Culture filtrates of both bacterial species exhibited potent phytotoxic activity, which resulted in 100% germination inhibition of C. echinatus. The chemical analysis of culture filtrates revealed high contents of total phenolics and n-alkanes that have phytotoxic effects against seed germination. According to the findings of this study the endophytic bacteria associated with N. oleander leaf can be used in the future to develop a sustainable bio-herbicide formulation.

Antioxidant activity, phytotoxicity and allelopathic potential of green walnut (Juglans regia L.) fruit extract

The potential allelopathic effect of a green walnut fruit extract on seed germination and early growth of three weed species (Chenopodium album, Amaranthus retroflexus, Daucus carota) was tested, as well as its phytotoxic effect on seed germination and early growth of maize (Zea mays). Another objective was to analyze the plant extract and assess its antioxidative activity. Antioxidative activity of the plant extract was evaluated based on its ability to neutralize DPPH (2,2-diphenyl-1-picrylhydrazyl) radical and capacity for iron reduction using the FRAP method. Inhibition of the evaluated parameters (total germination and seedling length) decreased proportionally with decreasing concentrations of extract solution of green walnut fruit. The parameters of seedling growth were also found to show greater susceptibility than total seed germination of all three of the tested weed species. Although the seed bioassay results indicated a high inhibitory effect on germination and early growth of the tested weeds, they also revealed phytotoxic activity during early growth of the cultivated Z. mays.

Óleos essenciais de plantas condimentares e medicinais no controle de contaminantes da micropropagação de Myrciaria dubia

Abstract The main limitation of the micropropagation of camu-camu (Myrciaria dubia) is related to in vitro contamination. In order to overcome contamination, the effect of essential oils was studied as an alternative to conventional chemical treatments. This study aimed to analyze the action of essential oils from four condiment and medicinal plants (Oregano, Origanum vulgare L.; Garlic, Allium sativum L.; Citronella, Cymbopogon nardus L.;and Ginger, Zingiber officinale Rosc.) in reducing microbial contamination growth and on the survival rate of explants in the micropropagation of camu-camu. The antimicrobial activity of essential oils was analyzed on the in vitro contamination of tissue culture from camu-camu at concentrations of 0.5, 1, 2, 3 and 4 µL mL-1 in woody plant medium (WPM), emulsified with 1% Polysorbate 80 (Tween 80). The antibacterial activity of essential oils on strains isolated from camu-camu tissue culture was also analyzed using agar diffusion and broth microdilution methods. The use of essential oils allowed a reduction in the rate of in vitro contamination in tissue culture, it being observed that, from the concentration of 2 µL mL-1, there was no manifestation of fungal contaminants, with a significant reduction in the rate of bacterial contamination, with the exception of ginger essential oil that showed significant contamination in all analyzed concentrations. Inversely in relation to the reduction in microbial growth in vitro, there is an increase in explant oxidation as concentrations increase, with citronella and oregano oils showing phytotoxic potential from the lowest concentrations. Garlic essential oil showed better balance, with lower oxidation rates and greater control of microorganisms in tissue culture at concentrations of 0.5 and 1 µL mL-1. Oregano and citronella essential oils showed better antibacterial activity in the agar diffusion test.

A Serbian endemic plant „Nepeta rtanjensis“ Diklić et Milojević – chemical composition and biological activity

Nepeta rtanjensis Diklić et Milojević as an endemic and critically endangered plant in Serbia is the object of great scientific interest. N. rtanjensis is a rare plant of a limited distribution its application in traditional medicine is practically unknown. However, bioactive potential of 4aα,7α,7aβ-nepetalactone, the main compound from volatile fraction, as well as rosmarinic and 3-O-caffeoylquinic acid from non-volatile fraction is great. Scientists found that this plant possesses good antimicrobial activities against Aspergillus sp., Bacillus cereus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Listeria monocytogenes, Micrococcus flavus, Penicillium sp., Pseudomonas aeruginosa, Salmonella sp. and Staphylococcus aureus. N. rtanjensis can be used preserving foods and beverages as well as for prevention and treatment of diseases caused by common and emerging food borne pathogens. Furthermore, antioxidant, anticancer (cervix, breast and colon carcinoma, lung adenocarcinoma and myelogenous leukemia cells) and immunomodulating activity are also noted. However, toxicity in zebrafish model was not observed, so N. rtanjensis can be classified as safe for human health. Furthermore, phytotoxic potential against Ambrosia artemisiifolia as well as activity against plant pathogens (Alternaria sp., Cladosporium cladosporoides, Bipolaris spicifera and Trichoderma viridae) are also noted. There is potential fordeveloping novel biopesticide formulations.

Assessment of the Phytotoxic Potential of Dregea volubilis (L.f.) Benth. ex Hook.f. and Identification of its Phytotoxic Substances for Weed Control

The phytotoxic potential of plants and the effect of their active components on another plant species is being explored as a potential alternative to synthetic herbicides for weed control. In the current study, we investigated the phytotoxic potential of the leaves of Dregea volubilis (L.f.) Benth. ex Hook.f. against four test plants [timothy (Phleum pratense L.), barnyard grass (Echinochloa crus-galli (L.) P. Beauv), lettuce (Lactuca sativa L.), and alfalfa (Medicago sativa L.)] and observed significant growth inhibition on those plants at concentrations >3 mg D.W. equivalent extract mL−1. A bioassay-governed purification of the D. volubilis extracts using different chromatography phases produced two growth inhibitory compounds, 3-hydroxy-α-ionone (compound 1) and 5-hydroxy-3,4-dimethyl-5-pentylfuran-2(5H)-one (compound 2). The compounds retarded the growth of barnyard grass and cress (Lepidium sativum L.) with I50 (concentration required for 50% growth suppression) values ranging from 0.098 to 0.450 mM for 3-hydroxy-α-ionone and 0.029 to 0.420 mM for 5-hydroxy-3,4-dimethyl-5-pentylfuran-2(5H)-one. Thus, the extracts and identified compounds may have the possibility to be utilized as bioagents for weed control.

Environmental conditions and plant physiology modulate Cu phytotoxicity in field-contaminated soils

Foliar Cu concentration has been widely used as a biomarker of plant growth in phytotoxicity bioassays. This relation has helped find plant processes altered by Cu in dose-response experiments (a bivariate approach). However, when plants are grown in field conditions, their responses can vary in function of multiple variables, such as the environment, plant physiology, and other elements in plant (plant ionome). These sources of variability are commonly unreported, which could limit bioassays’ utility. Thus, the present study aimed to assess and integrate the mentioned sources of variability on Cu phytotoxicity. Lettuce was used as plant model. Lettuces were grown in growth chambers with contrasting light and air humidity conditions and on two different field-contaminated soils (sandy and loamy soils). Results showed that environmental conditions significantly affected foliar Cu and plant growth, but this effect differed in the two studied soils. Foliar Cu was not a good biomarker of plant growth. In contrast, integrating the potential phytotoxicity effect with the plant's nutritional status allowed a better understanding of plant growth. We remarked on using a structural equation modeling approach (SEM) to integrate plant physiology and plant ionome as moderators of plant growth. Results showed that plant growth was primarily related to plant nutritional status rather than Cu phytotoxicity. Also, the foliar Cu concentration would affect plant nutritional status due to photosynthesis-related plant processes and cation balance. Finally, this research invites to state and include sources of variability when assessing phytotoxicity. This way, it is possible to advance toward understanding complex linked processes occurring in field conditions.

Impact of physical factors on bio-control potential of Lawsonia inermis leaf extract and bio-formulations as fungicides

The present study is carried out to ascertain the effect of different physical factors (sunlight, temperature, pH) and storage conditions on the antimicrobial efficacy of Lawsonia inermis leaf extracts and bio-formulation against the Alternaria alternata. In addition, the phytotoxic potential of 100% alcoholic crude extract as well as the acetone fraction of young leaves of Lawsonia inermis was also checked on seed germination of chilli (Capsicum annuum). Results showed that there was no adverse effect of wet heat (50–100 °C) and dry heat (40–90 °C) on extract and bio-formulation efficacy. Storage for 6 and 12 months had no adverse effect on extract and bio-formulation efficacy and the antifungal activity was observed similar to freshly prepared extract. We have used concentrations of 5,10, 15, 20 and 25 mg/ml to perform a phytotoxicity assay. The measurement of phytotoxicity was done by using the Standard blotter method and the result revealed that 5, 10 and 15 mg/ml concentration of the extract was non phytotoxic and were further used for in vivo experiments. These plant extracts and bio-formulations have extensive antimicrobial potential to be explored for application in sustainable agriculture.

Evaluation of herbicidal and fungicidal activities of six natural components and their phenoxyacetic acids derivatives and assessment of human health risk posed by oral exposure to them

ABSTRACT In the present study, we isolated linalool, geraniol, carvacrol, thymol, menthol and eugenol; synthesised their phenoxyacetic acid derivatives; and assessed their phytotoxic and genotoxic potentials against weeds and agricultural crops. Moreover, the fungicidal activity of both categories of compounds against 12 fungi was examined. Finally, using probabilistic assessment based on Risk Quotient (RQ) by the Monte Carlo simulation (MCS) method, we examined human health risks via oral exposure to these compounds. Toxic potencies to plants demonstrated that all parameters and related indices including germination percentage, mean germination time, germination rate, root length, shoot length, seedling length and vigour index dose-dependently decreased in both weeds and agricultural crops. Based on the comet assay, DNA damage was observed in the root meristems of the plants. Consequently, a significant decrease was observed in head DNA, whereas a significant increase in tail DNA was observed in response to treatments. Besides, the natural components and semisynthetic molecules showed a broad spectrum of fungicidal traits. However, eugenol and eugenoxyacetic acid inhibitory effects on the growth of the tested fungi were similar to that of benomyl. Our probabilistic health risk assessment indicated di minimis risk for natural components and their phenoxyacetic acid derivatives. Sensitivity analysis showed that concentrations of residues of the compounds had the most significant effect on risk. Current findings could offer a platform for developing sustainable approaches to reduce chemical residues and their consequent risks to the environment and human health.

Phytochemical Profile, In Vitro Bioactivity Evaluation, In Silico Molecular Docking and ADMET Study of Essential Oils of Three Vitex Species Grown in Tarai Region of Uttarakhand.

A comparative study of volatiles, antioxidant activity, phytotoxic activity, as well as in silico molecular docking and ADMET study, was conducted for essential oils from three Vitex species, viz., V. agnus-castus, V. negundo, and V. trifolia. Essential oils (OEs) extracted by hydrodistillation were subjected to compositional analysis using GC-MS. A total number of 37, 45, and 43 components were identified in V. agnus-castus, V. negundo, and V. trifolia, respectively. The antioxidant activity of EOs, assessed using different radical-scavenging (DPPH, H2O2 and NO), reducing power, and metal chelating assays, were found to be significant as compared with those of the standards. The phytotoxic potential of the EOs was performed in the receptor species Raphanus raphanistrum (wild radish) and the EOs showed different levels of intensity of seed germination inhibition and root and shoot length inhibition. The molecular docking study was conducted to screen the antioxidant and phytotoxic activity of the major and potent compounds against human protein target, peroxiredoxin 5, and 4-hydroxyphenylpyruvate dioxygenase protein (HPPD). Results showed good binding affinities and attributed the strongest inhibitory activity to 13-epi-manoyl oxide for both the target proteins.

Recycling Electric Arc Furnace Slag into Fertilizer: Effects of “Waste Product” on Growth and Physiology of the Common Bean (Phaseolus vulgaris L.)

The aim of this study was to investigate if electric arc furnace (EAF) slag generated during steel production could have an application as a soil enhancer in agriculture. For that purpose, a greenhouse experiment was conducted on common beans (Phaseolus vulgaris) cultivated in soil enriched with EAF slag (at 1% and 2% level), synthetic fertilizer (NPK), combined EAF slag and synthetic fertilizer, or in control (untreated) soil. The beans were exposed to test soils until maturity (for 8 weeks). Following that period, physico-chemical properties of the soils, as well as nutrient status, growth, photosynthetic and oxidative stress parameters of bean plants were determined. EAF slag improved the mineral status of the soil and significantly increased Fe, Mg, N, P and K in different bean plant organs. EAF slag and/or NPK increased plant height. EAF slag, especially at lower levels, positively affected dry weight of leaf and seed. Soil supplementation with a lower level of EAF slag, as well as with a combination of EAF slag and NPK, led to significant improvement in gas exchange parameters (net photosynthetic rate, intercellular CO2 concentration and stomatal conductance) and nitrate reductase activity, indicating a positive influence on bean plants. Potential phytotoxicity of EAF slag was not detected, as evidenced by the oxidative stress parameters. Thus, EAF slag applied at a low level shows promising potential as an efficient soil enhancer, and as a valuable source of nutrients essential to plants, with an equal or even better performance compared to synthetic fertilizer.

Phytotoxicity of Chemical Compounds from Cinnamomum camphora Pruning Waste in Germination and Plant Cultivation.

Much previous research has indicated most composts of pruning waste are characterized by potential phytotoxicity, it is highly correlated with the chemical compounds of raw materials. Cinnamomum camphora, a common kind of pruning waste in Southeast Asia and East Asia, is characterized by intense bioactivities due to complex chemical components. This study investigated the potential phytotoxicity of C. camphora pruning waste in light of germination and higher plant growth. C. camphora extracted from leaves completely inhibited seed germination and still showed suppression of root elongation at an extremely low dosage. C. camphora extract also displayed significant inhibition of nutrient absorption in tomato seedlings, including moisture, available nutrients (N, P and K) and key microelements (Fe, Mn, Zn and S). The gene expression of aquaporins and transporters of nitrate and phosphate was significantly up-regulated in roots. This could be regarded as a positive response to C. camphora extract for enhancing nutrient absorption. Moreover, the severe damage to the plasma membrane in roots caused by C. camphora extract might seriously affect nutrient absorption. Camphor is the main component of the C. camphora extract that may induce the phytotoxicity of plasma membrane damage, resulting in the inhibition of nutrient absorption and low biomass accumulation. This study provided a new understanding of the ecotoxicological effects of C. camphora pruning waste, indicating that the harmless disposal of pruning waste requires much attention and exploration in the future.

Copper formulations in bacterial blight control and toxic effects on coffee seedlings

Bacterial blight of coffee (Pseudomonas syringae pv. garcae) is an important coffee disease and can be controlled using antibiotics and copper-based compounds. However, copper-based compounds raise doubts among coffee growers regarding bacterial blight control efficiency and phytotoxic potential. In this work, coffee plants were sprayed with different copper molecules in order to study their efficiency on bacterial blight control and the phytotoxic potential. Seven copper formulations, cuprous oxide, copper oxychloride, copper nitrate, copper hydroxide 1 (water-dispersible granules) and 2 (concentrated suspension), copper sulfate 1 (complexed with gluconic acid) and 2 (Bordeaux mixture) were studied. The copper formulations efficiency was compared with the antibiotic kasugamycin, saline solution, and control. In controlled environmental conditions of temperature, relative humidity, and photoperiod, coffee seedlings were sprayed with the treatments and after 24 hours they were inoculated with Pseudomonas syringae pv. garcae suspension. Disease incidence and severity assessments were performed in a 2-day interval during a 16-day period. Phytotoxicity incidence and severity, mapping, and quantification of copper on the leaf tissue surface, dried leaves weight, and total copper leaf content were assessed 16 days after pathogen inoculation. Data were submitted to the Scott-Knott test (p < 0.05). Cuprous oxide and copper sulfate 2 proved most efficient to bacterial blight control, causing lower phytotoxicity effect, best covering, and persistence on leaf tissues. Copper nitrate and copper sulfate complexed with gluconic acid were more phytotoxicity compared to other copper formulations.

A comprehensive investigation of toxicity and pollution potential of municipal solid waste landfill leachate.

It is evident from the literature that research on the treatment of leachate generated from municipal solid waste (MSW) landfills has been a focus area of environmental management. However, the available information is discrete because most studies have reported only one or a couple of aspects of either closed or active MSW landfill leachate treatment. Hence, this investigation has focused on comprehensive attributes of both closed landfill leachate (CLL) and active landfill leachate (ALL), including generation, characterisation, and toxicity assessment to quantify and establish their pollution potential. The results indicated that CLL generation is higher (188.59 m3/d) than ALL (49.53 m3/d). The concentrations of principal physical, chemical, and biological constituents and concomitant leachate pollution index were higher in CLL (33.20) than in ALL (26.65). Furthermore, the germination indices of CLL (57.48) and ALL (79.14) and tail DNA damage of CLL (56.49%) and ALL (23.8%) ratified greater phytotoxicity and genotoxicity potential, respectively of CLL over ALL. The reasons for the variations in the generation, characteristics, and toxicity of CLL and ALL were discussed in detail. Evaluation of the commonly used landfill leachate treatment methods through the analytical hierarchy process confirmed that the activated sludge process and Fenton oxidation process are the most and least preferred treatment methods. The comprehensive investigation of CLL and ALL have established their pollution potential and the inevitable necessity for their treatment. The findings of this investigation will serve as a ready reference for researchers from academia and industry who work on the monitoring, treatment, and management of landfill leachate.

Assessment of phytotoxic potential and pathogenic bacteria removal from secondary effluents during ozonation and UV/H2O2.

Wastewater reuse is an important strategy for water resource management. For this reason, the disinfection process must be appropriated, eliminating pathogenic microorganisms. Ozonation (O3) and UV/H2O2 treatments can be used for effluent disinfection, but few studies just address the Escherichia coli quantification. In this study, secondary effluents from two wastewater treatment plants with different characteristics were exposed to O3 (5 and 10mgL-1) or UV/H2O2 (H2O2: 90mgL-1) treatments and evaluated by BD Phoenix ™ 100 (Becton Dickinson, USA) and MALDI-TOF for the characterization of the indigenous microorganisms in the effluents, before and after treatments. Additionally, all the samples were tested for phytotoxicity by Lactuca sativa bioassay. The results showed that the highest ozone dose and the UV/H2O2 treatment were effective in removing E. coli. UV/H2O2 was more efficient as it eliminated most of the microorganisms. Acinetobacter sp., Aeromonas and Pseudomonas were still found after O3 treatment. Bacillus sp. was found after O3 and UV/H2O2 treatments. The results with L. sativa showed inhibition of root growth for all dry period (low rainfall) samples of one of the WWTP, due to the high concentration of the phytotoxicity compounds. For environmental and human health safety, treated effluents should be evaluated for their toxic and pathogenic potential before being released into the environment. Pathogens evaluation on treated effluents should cover a wider range of pathogenic microorganisms than those routinely required by legislation.

Exploring the use of chamomile (Matricaria chamomilla L.) bioactive compounds to control flixweed (Descurainia sophia L.) in bread wheat (Triticum aestivum L.): Implication for reducing chemical herbicide pollution

Intensive chemical herbicide use has resulted in human health and environmental issues. This study evaluated the phytotoxic potential of chamomile extract as a bioherbicide to minimize chemical herbicide use in wheat production. Treatments including four concentrations (0, 50, 100, and 150 mL/L) of three different chamomile plant parts (root, shoot, and root + shoot) extracts were applied to flixweed as a major weed in wheat production. Except for 50 mL/L of root extract, other concentrations of chamomile extracts decreased the germination rate of flixweed. Germnaiton rate of wheat increased with chamomile extracts except at 150 mL/L concentration of shoot extract at which the germination rate of flixweed and wheat reduced by 71.7 and 35.4%, respectively, compared to respective controls. Compared to wheat, malondialdehyde and proline in flixweed were increased fivefold in flixweed and compared to the control, ranged from 84–473 and 240–1422%, respectively. Chamomile extract also declined cell viability much quicker in flixweed than in wheat reflecting on greater inhibitory effect for flixweed control. Chamomile shoot extract reduced seedling weight and vigor index of flixweed by 63.75 and 59.4%, respectively, compared to the respective control. Results of liquid chromatography mass spectrometry of chamomile extract indicated polyphenols, flavonoids, terpenoids, and bioactive phenolic coumarins, glycosylated derivatives, quercetin and its derivatives, herniarin, umbelliferone, P-cymene, chamazulene, farnesol, amitrole, 1,8-cineole, and limonene were effective in inhibiting the germination and growth of flixweed. We concluded that 150 mg/L of chamomile shoot extract could be used as a bioherbicide to sustainably suppress flixweed in wheat production.

Reduction of Weed Growth under the Influence of Extracts and Metabolites Isolated from Miconia spp.

Weeds pose a problem, infesting areas and imposing competition and harvesting difficulties in agricultural systems. Studies that provide the use of alternative methods for weed control, in order to minimize negative impacts on the environment, have intensified. Native flora represents a source of unexplored metabolites with multiple applications, such as bioherbicides. Therefore, we aimed to carry out a preliminary phytochemical analysis of crude extracts and fractions of Miconia auricoma and M. ligustroides and to evaluate these and the isolated metabolites phytotoxicity on the growth of the target species. The growth bioassays were conducted with Petri dishes with lettuce, morning glory, and sourgrass seeds incubated in germination chambers. Phytochemical analysis revealed the presence of flavonoids, isolated myricetin, and a mixture of quercetin and myricetin. The results showed that seedling growth was affected in a dose-dependent manner, with the root most affected and the seedlings of the lettuce, morning glory, and sourgrass as the most sensitive species, respectively. Chloroform fractions and myricetin were the most inhibitory bioassays evaluated. The seedlings showed structural changes, such as yellowing, nonexpanded cotyledons, and less branched roots. These results indicate the phytotoxic potential of Miconia allelochemicals, since there was the appearance of abnormal seedlings and growth reduction.

Assessment of phytotoxic, genotoxic and enzyme inhibition potential of.

To evaluate Sterculia diversifolia stem bark and leaves for phytotoxic, genotoxic and enzymes inhibition potential. Phytotoxic activity of both stem bark and leaves were screened using Lemna minor. The genotoxic activity of Sterculia diversifolia stem bark and leaves extracts were tested using comet assay protocol while enzyme inhibition activity of crude extract and various fractions of both stem bark and leaves were evaluated using acetyl cholinesterase, lipoxygenase, β-glu-curonidase, urease, xanthine oxidase and carbonic anhydrase. Phytotoxic activity showed significant results in dose dependant manner in both stem bark (ethyl acetate and n-butanol) and leaves (ethyl acetate, n-butanol and n-hexane) fractions. In genotoxic activity, dichloromethane fraction showed significant activity followed by ethyl acetate fraction. Acetyl cholinesterease inhibitory activity showed significant results in both stem bark and leaves fractions, while significant lipoxygenase inhibition was shown by ethyl acetate, dichloromethane, crude extract and n-hexane fractions of both stem bark and leaves. β-glucuronidase, urease and carbonic anhydrase inhibitory activity showed highly significant results in ethyl acetate fraction of both stem bark and leaves, while xanthine oxidase inhibition was shown by dichloromethane fraction of stem bark and leaves extracts. This study emphasizes the important phytotoxic, genotoxic and enzyme inhibition effects of Sterculia diversifolia stem bark and leaves. Hence, it is clear that Sterculia diversifolia stem bark and leaves possess phytotoxic, genotoxic and enzyme inhibitory agents.

Allelopathic Potential of Aqueous Extracts from Fleagrass (Adenosma buchneroides Bonati) against Two Crop and Three Weed Species

This study aimed to assess the phytotoxic potential of fleagrass (Adenosma buchneroides) on weeds and crops. We assessed the effects of applying aqueous extracts of fleagrass on the seed germination and seedling growth of three weeds (Bidens pilosa, Paspalum thunbergia, and Bromus japonicus) and two crops (Oryza sativa and Zea mays). The influence of six doses of fleagrass aqueous extract on seed germination and seedling growth was assessed through a Petri dish experiment. The aqueous extract of fleagrass was qualitatively characterized using widely targeted metabolomics analysis and found to mainly comprise flavonoids, phenolic acids, alkaloids, polysaccharides, phenylpropanoids, terpenoids, phenolamides, and quinones. The mean IC50 for crop seed germination was 168,796, and the mean IC50 for weed seed germination was 11,454. The inhibition effect on the tested species, from highest to lowest, followed the order of B. japonicus > B. Pilosa > P. thunbergii > O. sativa > Z. mays. These results indicate the remarkable species-specific sensitivity of seed germination and seedling growth to fleagrass extract treatment, and that crops are more tolerant than weeds. Elucidation of the details of the fleagrass–weed/crop interaction can serve as a basis for intercropping fleagrass with crops in weed management strategies aimed at controlling weeds.

Phytochemical Profile and Herbicidal (Phytotoxic), Antioxidants Potential of Essential Oils from Calycolpus goetheanus (Myrtaceae) Specimens, and in Silico Study.

The essential oil (EO) of Calycolpus goetheanus (Myrtaceae) specimens (A, B, and C) were obtained through hydrodistillation. The analysis of the chemical composition of the EOs was by gas chromatography coupled with mass spectrometry CG-MS, and gas chromatography coupled with a flame ionization detector CG-FID. The phytotoxic activity of those EOs was evaluated against two weed species from common pasture areas in the Amazon region: Mimosa pudica L. and Senna obtusifolia (L.) The antioxidant capacity of the EOs was determined by (DPPH•) and (ABTS•+). Using molecular docking, we evaluated the interaction mode of the major EO compounds with the molecular binding protein 4-hydroxyphenylpyruvate dioxygenase (HPPD). The EO of specimen A was characterized by β-eudesmol (22.83%), (E)-caryophyllene (14.61%), and γ-eudesmol (13.87%), while compounds 1,8-cineole (8.64%), (E)-caryophyllene (5.86%), δ-cadinene (5.78%), and palustrol (4.97%) characterize the chemical profile of specimen B’s EOs, and specimen C had α-cadinol (9.03%), δ-cadinene (8.01%), and (E)-caryophyllene (6.74%) as the majority. The phytotoxic potential of the EOs was observed in the receptor species M. pudica with percentages of inhibition of 30%, and 33.33% for specimens B and C, respectively. The EOs’ antioxidant in DPPH• was 0.79 ± 0.08 and 0.83 ± 0.02 mM for specimens A and B, respectively. In the TEAC, was 0.07 ± 0.02 mM for specimen A and 0.12 ± 0.06 mM for specimen B. In the results of the in silico study, we observed that the van der Waals and hydrophobic interactions of the alkyl and pi-alkyl types were the main interactions responsible for the formation of the receptor–ligand complex.