The effect of caraway oil-loaded bio-nanoemulsions on the growth and performance of barnyard grass and maize.

A proper formulation is crucial to improve the herbicidal effects of essential oils and their selectivity. In this study, we investigated the physicochemical properties of bio-based nanoemulsions (CNs) containing several concentrations of caraway (Carum carvi) essential oil stabilized with Eco Tween 80, as a surfactant, maintaining 1:1 proportions. Detailed physicochemical characteristics of the CNs revealed that their properties were most desired at 2% of the oil and surfactant, i.e., the smallest droplet size, polydispersity index, and viscosity. The CNs caused biochemical changes in maize and barnyard grass (Echinochloa crus-galli) seedlings, however, to a different extent. Barnyard grass has overall metabolism (measured as a thermal power) decreased by 39-82% when exposed to the CNs. The CNs triggered changes in the content and composition of carbohydrates in the endosperm of both species' seedlings in a dose-response manner. The foliar application of CNs caused significant damage to tissues of young maize and barnyard grass plants. The effective dose of the CN (ED50, causing a 50% damage) was 5% and 17.5% oil in CN for barnyard grass and maize tissues, respectively. Spraying CNs also decreased relative water content in leaves and affected the efficiency of photosynthesis by disturbing the electron transport chain. We found that barnyard grass was significantly more susceptible to the foliar application of CNs than maize, which could be used to selectively control this species in maize crops. However, further studies are needed to verify this hypothesis under field conditions.

Phytochemical profiling and allelopathic effect of garlic essential oil on barnyard grass (Echinochloa crusgalli L.).

In agriculture, barnyard grass (Echinochloa crusgalli L.) is one of the most harmful weeds in rice fields now. In order to identify active ingredients which had inhibiting effect on barnyard grass (Echinochloa crusgalli L.), we evaluated several possible natural plant essential oils. Essential oils from twelve plant species showed inhibitory activity against barnyard grass seedlings and root length. The garlic essential oil (GEO) had the most significant allelopathic effect (EC50 = 0.0126 g mL-1). Additionally, the enzyme activities of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) increased during the first 8 hours of treatment at a concentration of 0.1 g mL-1 and then declined. The activities of CAT, SOD and POD increased by 121%, 137% and 110% (0-8h, compared to control), and decreased (8-72h, compared to the maximum value) by 100%, 185% and 183%, respectively. The total chlorophyll content of barnyard grass seedlings decreased by 51% (0-72h) continuously with the same dosage treatment. Twenty constituents of GEO were identified by gas chromatography-mass spectrometry, and the herbicidal activity of two main components (diallyl sulfide and diallyl disulfide) was evaluated. Results showed that both components had herbicidal activity against barnyard grass. GEO had a strong inhibitory effect (~88.34% inhibition) on barnyard grass growth, but safety studies on rice showed it did not have much inhibitory effect on rice seed germination. Allelopathy of GEO provide ideas for the development of new plant-derived herbicides.

Bio-Herbicidal Potential of Nanoemulsions with Peppermint Oil on Barnyard Grass and Maize.

Bio-based nanoemulsions are part of green pest management for sustainable agriculture. This study assessed the physicochemical properties and the herbicidal activities of the peppermint essential oil nanoemulsions (PNs) in concentrations 1.0-10% stabilized by Eco-Polysorbate 80 on germinating seeds and young plants of maize and barnyard grass. Based on the design of experiment (DOE) results, the final nanoemulsion formulations were obtained with 1, 1.5, 2, and 5% of essential oil concentration. Biological analyses were conducted to select the most promising sample for selective control of barnyard grass in maize. Seedlings growing in the presence of PNs displayed an overall inhibition of metabolism, as expressed by the calorimetric analyses, which could result from significant differences in both content and composition of carbohydrates. Concentration-response sub estimation showed that leaf-sprayed concentration of PN causing 10% of maize damage is equal to 2.2%, whereas doses causing 50% and 90% of barnyard grass damage are 1.1% and 1.7%, respectively. Plants sprayed with PN at 5% or 10% concentration caused significant drops in relative water content in leaves and Chlorophyll a fluorescence 72 h after spraying. In summary, peppermint nanoemulsion with Eco-Polysorbate 80 at 2% concentration is a perspective preparation for selective control of barnyard grass in maize. It should be analyzed further in controlled and field conditions.

The Allelopathic Activity of Extracts and Isolated from Spirulina platensis.

We determined the allelopathic effects of crude organic (hexane, ethyl acetate, and methanol) extracts of the cyanobacterial Spirulina platensis on barnyardgrass (Echinochloa crus-galli (L.) Beauv.) and Chinese amaranth (Amaranthus tricolor L.). The crude ethyl acetate extract showed the highest inhibitory activity and was subsequently fractionated by column chromatography into 23 fractions based on thin-layer chromatography band pattern similarities. Four concentrations (2000, 1000, 500, and 250 ppm) of each fraction were tested for their allelopathic activity. Fractions E6 and E13 exhibited the most significant inhibitory effects against Chinese amaranth. The constituents of the highly active E6F3-E6F5 fractions determined by GC-MS, chromatography, and spectroscopy included the fatty acids, γ-linolenic acid 15, oleic acid 12, and predominantly palmitic acid 7; minor constituents included 2-ethyl-3-methylmaleimide 9 and C11 norisoprenoids (dihydroactinidiolide 10 and 4-oxo-ß-ionone 13). Isolation of E13 fraction by column chromatography revealed four C13 norisoprenoids: 3-hydroxy-ß-ionone 17, 3-hydroxy-5α,6α-epoxy-ß-ionone 18, 3-hydroxy-5ß,6ß-epoxy-ß-ionone 19, and loliolide 20. Their structures were elucidated by NMR spectroscopy. All six isolated norisoprenoids inhibited seed germination and seedling growth of Chinese amaranth at concentrations of 250-1000 ppm. Allelochemicals from S. platensis could be utilized in the development of novel bioactive herbicides.

Vanillin extracted from proso and barnyard millets induces cell cycle inhibition and apoptotic cell death in MCF-7 cell line.

CONTEXT: Consuming whole grain food has been motivated due to numerous health benefits arising from their bioactive components. AIMS: This study aims to study whether the active compound extracted from Proso and Barnyard millets inhibits cell proliferation and induces apoptotic cell death in MCF-7 cell line. MATERIALS AND METHODS: Cell proliferative effect was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay using MCF-7 cell line. Cytotoxicity was determined by release of lactate dehydrogenase (LDH) enzyme from cells. Apoptotic morphological changes in MCF-7 cells were observe under fluorescence microscope using double staining of Hoeschst 33342/propidium iodide (PI). Induction of apoptosis was analyzed using Annexin V-fluorescein isothiocyanate/PI through flow cytometry. RESULTS: In this study, cell proliferative effect of the bioactive compounds from proso millet (Compound 1) and barnyard millet (Compound 2) was evaluated using MCF-7 cell line. Both the compounds significantly inhibited the proliferation of MCF-7 cells after treated with 250 µg/ml and 1000 µg/ml concentration for 48 h. Cytotoxic activity of compounds was assessed by the release of LDH showed that these extracted compounds were not toxic to the cells. Apoptosis was confirmed by Hoechst 33,342/PI dual-staining, Annexin V-FTIC/PI staining, and flow cytometry results of cell cycle analysis shows that there was a significant cell arrest in the G0/G1 phase and increased the apoptotic cells in sub-G0 phase in a dose-dependent manner. CONCLUSIONS: This study suggests that the extracted vanillin compound from these millets have effectively induced apoptotic cell death in breast cancer cell line.

Morphological and palynological assessment of some taxa of genus Echinochloa through light and scanning electron microscopy.

The present study was undertaken to gather information on selected species of Echinochloa based on their morphological and palyonological examination through light and scanning electron microscopy. As the Echinochloa species are most problematic grass weeds and exhibit high interspecific and intraspecific variability so due to their great morphological diversity it is difficult to recognize them. A lot of variation was observed in morphological features of studied taxa. In the present study, E. colona had more or less spreading dense racemes whereas in E. crus-galli racemes were linear to ovate. Upper glume surface was pubescent in E. colona, hispid in E. crus-galli and spinose in E. walteri. E. colona was comprised of five-nerved glumes whereas in E. crus-galli glumes were three-nerved. Although pollen basic characters in family Poaceae remains consistent but great variation was observed in pollen of studied taxa. The pollen size was quite variable among the species of genus Echinochloa. In polar view, the size of pollen grains ranged from 27.5 (20-35) µm to 40 (30-50) µm. E. crus-galli was appeared to be the smallest in size whereas E. colona was the largest.). P/E ratio ranged from 0.84 to 1.15 µm among the species. The highest value of pollen fertility was found in E. colona as 93.33% and lowest was in E. crus-galli as 87.50%. The morphological key of studied taxa is also given to study variations. In conclusion, it was observed that microscopy of morphological and palynological assessment can play a vital role in identification of taxonomically problematic taxa.

Barnyard grass [Echinochloa crus-galli (L.) Beauv] leaves extract against tomato pests.

BACKGROUND: Tomato is one of the widely cultivated crops worldwide that is affected by several pests, such as fungi (Fusarium oxysoporum, Alternaria solani), bacteria (Pectobacterium carotovorum) and weeds (Cyperus iria L., Amaranthus spinosus). A growing interest has emerged for developing plant-derived pesticidal compounds to counteract these pests. One attractive alternative is to use barnyard grass (Echinochloa crus-galli), known to be widely resistant to synthetic herbicides, as a potential biopesticide compound source. RESULTS: Phytochemical screening of the crude extract showed that phenolic compounds were the most abundant component present in barnyard grass. The crude extract was evaluated for antifungal, antibacterial and herbicidal activities. Bioassays showed inhibition against F. oxysporum (10.73 ± 1.30%) and A. solani (20.47 ± 3.51%), the causative agent of Fusarium rot and early blight disease in tomato, respectively. Antibacterial activity against P. carotovorum gave a mean zone of inhibition (paper disc diffusion assay) of 17.00 ± 1.00 mm and an IC50 (dose-response assay) of 2.26 mg mL-1 was observed. Dose-responsive herbicidal activity on the lettuce seed germination bioassay produced an IC50 of 459.30 ppm. Selectivity studies showed inhibition towards C. iria and A. spinosus with no effect on tomato. Lastly, bioassay-guided fractionation coupled with untargeted metabolomics studies using ultra-performance liquid chromatography with diode array detection-tandem mass spectrometry mass analyses revealed loliolide and tricin as the putative metabolites present in barnyard grass. CONCLUSION: To date, this is the first reported study on using barnyard grass as a potential alternative biopesticide against tomato pests such as fungi, bacteria and weeds. © 2021 Society of Chemical Industry.

Antibacterial and herbicidal properties of secondary metabolites from fungi.

Twenty-eight compounds were isolated from endophytic, soil and marine fungi and their structures were elucidated through spectroscopic methods. The isolated compounds were tested for their antibacterial and herbicidal activities against phytopathogenic bacteria and barnyard grass weed for the first time. Methyleurotinone (14) was the most potent compound against Pectobacterium carotovorum subsp. carotovorum, Pseudomonas syringae pv. syringae, Rhizobium radiobacter and Ralstonia solanacearum with minimum inhibitory concentration (MIC) values of 31.3, 125, 31.3 and 125 mg/L, respectively. Compounds 13-15 were highly effective in reducing the development of potato tuber soft rot disease caused by P. carotovorum subsp. carotovorum. Furthermore, twelve of the tested compounds induced a significant reduction in seed germination of Echinochloa crus-galli at 2 mM with compounds 8 and 26 causing complete inhibition of seed germination. Also, compounds 4, 22, 5, 8, 18 and 25-27 induced remarkable reduction of root and shoot growth of E. crus-galli at 2 mM.

Sensitivity of yellow foxtail (Setaria glauca L.) and barnyardgrass (Echinochloa crus-galli L.) to aqueous extracts or dry biomass of cover crops.

BACKGROUND: The common weeds Echinochloa crus-galli L. and Setaria glauca L. were studied for their sensitivity to aqueous extracts or dry biomass of the following cover crops (CCs): Brassicaceae (Sinapis alba, Raphanus sativus var. Oleiformis, Camellina sativa), Fagopyrum esculentum and Guizotia abyssinica. RESULTS: Treating E. crus-galli with aqueous extracts of mixed CCs or individual brassica CC significantly reduced germination. Treating S. glauca with aqueous extracts of C. sativa or G. abyssinicia reduced germination. Aqueous extracts of all CCs significantly reduced radicle length of E. crus-galli and S. glauca, with C. sativa and mixed CCs showing the greatest effect. Aqueous extracts of nearly all CCs delayed start and middle germination of E. crus-galli and S. glauca, with S. alba and R. sativus showing the strongest effects. Aqueous extracts of Brassicaceae leaf and flower significantly reduced germination, coleoptile length, radicle length and seedling biomass of E. crus-galli and S. glauca. Brassicaceae leaves and flowers contained higher phenolics than other tissues. Adding 4 or 8% S. alba and R. sativus dry powder to soil significantly reduced growth of E. crus-galli and S. glauca; even concentrations of 1% measurably slowed growth of E. crus-galli. CONCLUSIONS: Brassicaceae may be allelopathic to S. glauca and E. crus-galli. Aqueous extracts of leaves and flowers showed greater phytotoxic activity than other tissues and also contained more phenolics. Therefore Brassicaceae CCs may be most effective against S. glauca and E. crus-galli if incorporated into soil during their flowering stage. © 2020 Society of Chemical Industry.

Inhibition of protein glycoxidation and advanced glycation end-product formation by barnyard millet (Echinochloa frumentacea) phenolics.

Protein glycation plays a vital role in the progression of various diabetes complications. Therefore, inhibition of protein glycation could be a key strategy to prevent these diabetic abnormalities. Evaluation of phenolic compositions and their antiglycation activity revealed that p-coumaric and chlorogenic acids were major phenolic acids in barnyard millet. These phenolics exhibited multiple antioxidant activities in various mechanisms and protected the oxidative DNA damage and hydroxyl radical-induced protein fragmentation. Millet phenolics were very effective in scavenging >78% reactive carbonyl intermediates in the reaction and protected protein thiol group oxidation. Furthermore, 68.3% inhibition of protein glycation and reduced formation of protein aggregates were also observed with millet phenolics. Besides, fluorescence intensity measurements indicated a significant decrease in advance glycated end products and protection against glycoxidation-induced protein conformational changes at 100 µg/ml phenolics. These results suggest the potential utility of barnyard millet as an ingredient in functional foods for controlling protein glycation associated diabetic complications.

Vanillin extracted from Proso and Barnyard millets induce apoptotic cell death in HT-29 human colon cancer cell line.

In the present study, we hypothesized that the active compound extracted from Proso and Barnyard millets inhibits cell proliferation and apoptosis induction in colon cancer cell line. The bioactive compounds from these millets were purified by supercritical fluid extraction and their structure was elucidated using spectroscopic methods. Extracted bioactive components from these millets were similar in chemical structure to the phenolic aldehyde-Vanillin [4-Hydroxy-3-methoxybenzaldehyde]. Cell proliferative effect was assessed by MTT assay using HT-29 cell line. Compound 1 significantly inhibited the proliferation of HT-29 cells when treated with concentrations of 250 µg/ml and 1,000 µg/ml for 48 h, while compound 2 moderately inhibited the proliferation of the HT-29 cell line at the same concentration and time period. Cytotoxic activity of extracted compounds by the release of lactate dehydrogenase confirms that these compounds were not toxic to the cells at 250 µg/ml of compounds 1 and 2. In addition, flow cytometry results show a significant cell arrest in the G0/G1 phase and increase in the apoptotic cells in sub G0 phase, in a dose-dependent manner when compared with the control. The conclusion of this study suggests that the anticancer property of these millets is mediated through the presence of vanillin.

Hepatoprotective studies on methanolic extract of caryopses of Echinochloa colona Link.

The caryopses (seeds) of Echinochloa colona Link of family Poaceae are traditionally used for the treatment of jaundice. The methanolic extract of caryopses of Echinochloa colona (ECME) was evaluated for its hepatoprotective activity in paracetamol (3g/kg per oral) and ethanol (5g/kg per oral) intoxicated rats while its antihepatotoxic activity against D-galactosamine (400mg/kg body weight intra peritoneal). The activity of the extract was assessed on the basis of improvement in the altered level of various serum biochemical parameters and in the changes occurred in the histology of liver of the rats. The extract was also investigated for its antioxidant potential by employing different in vitro methods. The extract exhibited ferrous ion reducing power, 1,1 Diphenyl-1-picryl hydrazyl (DPPH), superoxide, nitric oxide and hydroxyl radical scavenging activities. The significant (p<0.001) hepatoprotective and antioxidant activities exhibited by the extract ECME, in different in vivo models and in vitro studies respectively may be attributed to the flavonoids and phenolic compounds present in the extract.

Aldo-keto Reductase Metabolizes Glyphosate and Confers Glyphosate Resistance in Echinochloa colona.

Glyphosate, the most commonly used herbicide in the world, controls a wide range of plant species, mainly because plants have little capacity to metabolize (detoxify) glyphosate. Massive glyphosate use has led to world-wide evolution of glyphosate-resistant (GR) weed species, including the economically damaging grass weed Echinochloa colona An Australian population of E colona has evolved resistance to glyphosate with unknown mechanisms that do not involve the glyphosate target enzyme 5-enolpyruvylshikimate-3-P synthase. GR and glyphosate-susceptible (S) lines were isolated from this population and used for resistance gene discovery. RNA sequencing analysis and phenotype/genotype validation experiments revealed that one aldo-keto reductase (AKR) contig had higher expression and higher resultant AKR activity in GR than S plants. Two full-length AKR (EcAKR4-1 and EcAKR4-2) complementary DNA transcripts were cloned with identical sequences between the GR and S plants but were upregulated in the GR plants. Rice (Oryza sativa) calli and seedlings overexpressing EcAKR4-1 and displaying increased AKR activity were resistant to glyphosate. EcAKR4-1 expressed in Escherichia coli can metabolize glyphosate to produce aminomethylphosphonic acid and glyoxylate. Consistent with these results, GR E colona plants exhibited enhanced capacity for detoxifying glyphosate into aminomethylphosphonic acid and glyoxylate. Structural modeling predicted that glyphosate binds to EcAKR4-1 for oxidation, and metabolomics analysis of EcAKR4-1 transgenic rice seedlings revealed possible redox pathways involved in glyphosate metabolism. Our study provides direct experimental evidence of the evolution of a plant AKR that metabolizes glyphosate and thereby confers glyphosate resistance.

Diterpenoids with herbicidal and antifungal activities from hulls of rice (Oryza sativa).

Diterpenoids are the main secondary metabolites of plants and with a range of biological activities. In the present study, 7 compounds were isolated from the hulls of rice (Oryza sativa L.). Among them, 3 diterpenoids are new namely, 3,20-epoxy-3α-hydroxy- 8,11,13-abietatrie-7-one (1), 4,6-epoxy-3ß-hydroxy-9ß-pimara-7,15-diene (2) and 2-((E)-3- (4-hydroxy-3-methoxyphenyl) allylidene) momilactone A (3). While, 4 terpenoids are known, namely momilactone A (4), momilactone B (5), ent-7-oxo-kaur-15-en-18-oic acid (6) and orizaterpenoid (7). The structures of these diterpenoids were elucidated using 1D and 2D NMR in combination with ESI-MS and HR-EI-MS. Furthermore, all isolated compounds displayed antifungal activities against four crop pathogenic fungi Magnaporthe grisea, Rhizoctonia solani, Blumeria graminearum and Fusarium oxysporum, and phytotoxicity against paddy weed Echinochloa crusgalli. The results suggested that rice could produce plenty of secondary metabolites to defense against weeds and pathogens.

Chemical profiling, cytotoxicity and phytotoxicity of foliar volatiles of Hyptis suaveolens.

In the present study, the essential oil (EO) of Hyptis suaveolens has been explored for the first time for its phytotoxic and cytotoxic activities. The phytotoxic activity was assessed against rice (Oryza sativa) and its major troublesome weed, Echinochloa crus-galli, under laboratory and screenhouse conditions. GC-MS analysis revealed EO to be monoterpenoid (~ 79% monoterpenes) in nature with α-phellandrene (22.8%), α-pinene (10.1%) and limonene (8.5%) as the major chemical constituents. The laboratory bioassay showed a complete growth inhibitory effect of EO (≥ 2 mg mL-1) towards the germination and seedling growth of E. crus-galli. However, the inhibitory effect on rice was much less (~40% inhibition). EO caused visible injury, reduction in chlorophyll content, cell viability and ultimately led to complete wilting of E. crus-galli plants. In addition, EO altered the cell division in the meristematic cells of Allium cepa as depicted by ~63% decrease in mitotic index. EO exposure induced several aberrations at chromosomal (c-mitosis, anaphase bridges, chromosomal breakage, vagrant chromosomes, and sticky chromosomes) and cytological level (cytoplasm destruction, peripheral nuclei, and bi-nucleate cells). The present study concludes that H. suaveolens EO possesses phytotoxic activity due to its mito-depressive activity, and could serve as a natural herbicide under sustainable agricultural practices.

Evaluation of weed control efficacy and crop safety of the new HPPD-inhibiting herbicide-QYR301.

QYR301, 1,3-Dimethyl-1H-pyrazole-4-carboxylic acid 4-[2-chloro-3-(3,5-dimethyl-pyrazol-1-ylmethyl)-4-methanesulfonyl-benzoyl]-2,5-dimethyl-2H-pyrazol-3-yl ester, is a novel HPPD-inhibiting herbicide and was evaluated to provide a reference for post-emergence (POST) application under greenhouse and field conditions. The crop safety (180 and 360 g active ingredient (a.i.) ha-1 treatments) experiment revealed that wheat, paddy, garlic and corn were the only four crops without injury at both examined herbicide rates. The weed control efficacy (60 and 120 g a.i. ha-1) experiment showed that QYR301 exhibited high efficacy against many weeds, especially weeds infesting paddy fields. Furthermore, it is interesting that both susceptible and multiple herbicide resistant Echinochloa crus-galli (L.) Beauv. and Echinochloa phyllopogon (Stapf) Koss, two notorious weed species in paddy field, remained susceptible to QYR301. Further crop tolerance results indicated that 20 tested paddy hybrids displayed different levels of tolerance to QYR301, with the japonica paddy hybrids having more tolerance than indica paddy hybrids under greenhouse conditions. Results obtained from field experiments showed that QYR301 POST at 135 to 180 g a.i. ha-1 was recommended to provide satisfactory full-season control of E. crus-galli and Leptochloa chinensis (L.) Nees and to maximize rice yields. These findings indicate that QYR301 possesses great potential for the management of weeds in paddy fields.

[Simulated Desorption Kinetics of Lead by the Dominant Plant Roots Released Low Molecular Weight Organic Acids from the Water-Level-Fluctuating Zone in the Three Gorges Reservoir].

Vegetations grow vigorously in the water-level-fluctuating zone (WLFZ) of Three Gorges Reservoir (TGR) during the non-flooded period. Low molecular weight organic acids (LMWOAs) excreted from the roots of these plants may active the heavy metals in soil. In order to investigate the desorption kinetics of Pb in the vegetation covered soil of TGR, the LMWOAs released from Cynodon dactylon and Echinochloa crusgalli roots, which are the dominant species in WLFZ, were analyzed both qualitatively and quantitatively. Furthermore, single and mixed species of LMWOAs were also used in the simulation. The results showed that the variety and content of LMWOAs secreted from Cynodon dactylon roots were larger and higher than those of Echinochloa crusgalli. Citric acid, malonic acid, acetic acid and malic acid were the same LMWOAs released from the two types of plants. The contents of acetic acid were the highest among all LMWOAs, which were 0.765 and 0.261 mmol·kg-1 in Cynodon dactylon and Echinochloa crusgalli roots, respectively.Citric acid, malonic acid and acetic acid were the same LMWOAs detected from their rhizosphere soils. In the citric acid, malonic acid and acetic acid desorption test, the desorption captivities of Pb were inhibited when the concentration of LMWOAs was lower than 1 mmol·L-1. The desorption ability displayed a decreasing order of malonic acid > citric acid > acetic acid. However, the three LMWOAs promoted the desorption of Pb in soil when their concentrations were higher than 1 mmol·L-1, respectively. The desorption ability displayed a decreasing order of citric acid > malonic acid > acetic acid. During the entire process of desorption, 0-240 min was the fast reaction stage, and the remaining time was the slow reaction stage. The pseudo-second order kinetics equation could fit best for the kinetic process.

A Potent Phytotoxic Substance in Aglaia odorata Lour.

Aglaia odorata Lour. (Meliaceae) was found to have very strong allelopathic activity and a bioherbicide PORGANIC(™) was developed from its leaf extracts. However, the phytotoxic substances causing the strong allelopathic activity of the plants have not yet been determined. Therefore, we investigated allelopathic properties and phytotoxic substances in A. odorata. Aqueous EtOH extracts of A. odorata leaves inhibited root and shoot growth of garden cress (Lepidum sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), timothy (Phleum pratense), ryegrass (Lolium multiflorum), and Echinochloa crus-galli with the extract concentration-dependent manner. The extracts were then purified and a major phytotoxic substance with allelopathic activity was isolated and identified by spectral data as rocaglaol. Rocaglaol inhibited the growth of garden cress and E. crus-galli at concentrations > 0.3 and 0.03 µm, respectively. The concentrations required for 50% inhibition ranged from 0.09 to 2.5 µm. The inhibitory activity of rocaglaol on the weed species, E. crus-galli, was much greater than that of abscisic acid. These results suggest that rocaglaol may be a major contributor to the allelopathic effect of A. odorata and bioherbicide PORGANIC(™) .

Isolation of Lignan and Fatty Acid Derivatives from the Grains of Echinochloa utilis and Their Inhibition of Lipopolysaccharide-Induced Nitric Oxide Production in RAW 264.7 Cells.

Two new fatty acid derivatives, echinochlorins A (8) and B (9) and a racemic lignan, (±)-anti-1-(4-hydroxy-3-methoxyphenyl)-2-{4-[(E)-3-acetoxypropen-1-yl]-2-methoxyphenoxy}propan-1,3-diol 3-acetate (1), were isolated from Echinochloa utilis grains, along with six known lignans (2-7) and two fatty acid derivatives (10, 11). Their structures were established by spectroscopic data analyses (IR, UV, HR-FABMS, GC-MS, and 1D and 2D NMR). The configuration of 1 was determined by Mosher's method. Compound 5 displayed potential inhibitory activity on lipopolysaccharide-induced NO production in macrophage RAW 264.7 cells with an IC50 value of 4.8 ± 0.5 µM. These isolated compounds in crude EtOH extract were also quantitated by HPLC.

Mexican propolis flavonoids affect photosynthesis and seedling growth.

As a continuous effort to find new natural products with potential herbicide activity, flavonoids acacetin (1), chrysin (2) and 4',7-dimethylnarangenin (3) were isolated from a propolis sample collected in the rural area of Mexico City and their effects on the photosynthesis light reactions and on the growth of Lolium perenne, Echinochloa crus-galli and Physalis ixocarpa seedlings were investigated. Acacetin (1) acted as an uncoupler by enhancing the electron transport under basal and phosphorylating conditions and the Mg(2+)-ATPase. Chrysin (2) at low concentrations behaved as an uncoupler and at concentrations up to 100 µM its behavior was as a Hill reaction inhibitor. Finally, 4',7-dimethylnarangenin (3) in a concentration-dependent manner behaved as a Hill reaction inhibitor. Flavonoids 2 and 3 inhibited the uncoupled photosystem II reaction measured from water to 2,5-dichloro-1,4-benzoquinone (DCBQ), and they did not inhibit the uncoupled partial reactions measured from water to sodium silicomolybdate (SiMo) and from diphenylcarbazide (DPC) to diclorophenol indophenol (DCPIP). These results indicated that chrysin and 4',7-dimethylnarangenin inhibited the acceptor side of PS II. The results were corroborated with fluorescence of chlorophyll a measurements. Flavonoids also showed activity on the growth of seedlings of Lolium perenne and Echinochloa crus-galli.