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The presence of potential algicides in Juncus effusus was studied. Sequential Et2O and MeOH exts. were made of dried plants that had been collected in spring and summer, and phenanthrenes were purified from the exts. All the free dihydrophenanthrenes and tetrahydropyrenes inhibited the test alga, Selenastrum capricornutum. One substance (I) inhibited several algae in eutrophic ecosystems with activity similar to that of CuSO4. Glycosylation severely inhibited algicidal activity of all compds. examd.

Five hydroperoxysterols have been found in the ethereal extract of Arum italicum besides further eleven oxygenated stigmasterols. The structures have been defined by chemical and spectroscopic studies. The possibility that some sterols are artifacts arising from autoxidation is considered. © 1994, Taylor & Francis Group, LLC. All rights reserved.

Rare-earth elements (REEs) are in all respect a class of new contaminants that may have toxic effects on organisms and microorganisms and information on their interactions with natural ligands should be of value to predict and control their diffusion in natural environments. In the current study, we investigate interactions of tripositive cations of praseodymium, europium, holmium, and thulium with harzianic acid (H2L), a secondary metabolite produced by selected strains of fungi belonging to the Trichoderma genus. We applied the same techniques and workflow previously employed in an analogous study concerning lanthanum, neodymium, samarium, and gadolinium tripositive cations. Therefore, in the current study, HPLC-ESI-HRMS experiments, circular dichroism (CD), and UV-Vis spectrophotometric absorption data, as well as accurate pH measurements, were applied to characterize bonding interactions between harzianic acid and Pr3+, Eu3+, Ho3+, and Tm3+ cations. Problems connected to the low solubility of harzianic acid in water were overcome by employing a 0.1 M NaClO4/(CH3OH + H2O 50/50 w/w) mixed solvent. For Pr3+, Ho3+, and Tm3+, only the mono complexes PrL+, HoL+, and TmL+ were detected and their formation constant determined. Eu3+ forms almost exclusively the bis complex EuL2− for which the corresponding formation constant is reported; under our experimental conditions, the mono complex EuL+ is irrelevant. Combining the results of the present and previous studies, a picture of interactions of harzianic acid with rare-earth cations extending over 8 of the 17 REEs can be composed. In order to complement chemical information with toxicological information, a battery of bioassays was applied to evaluate the effects of praseodymium, europium, holmium, and thulium tripositive cations on a suite of bioindicators including Aliivibrio fischeri (Gram-negative bacterium), Raphidocelis subcapitata (green alga), and Daphnia magna (microcrustacean), and median effective concentration (EC50) values of Pr3+, Eu3+, Ho3+, and Tm3+ for the tested species were assessed.

We report herein an optimized procedure for preparation of carboxamides of 5,6-dihydroxyindole-2-carboxylic acid (DHICA), the main biosynthetic precursor of the skin photoprotective agents melanins, to get access to pigments with more favorable solubility properties with respect to the natural ones. The developed procedure was based on the use of a coupling agent (HATU/DIPEA) and required protection of the catechol function by easily removable acetyl groups. The O-acetylated compounds could be safely stored and taken to the reactive o-diphenol form just before use. Satisfactorily high yields (>85%) were obtained for all amides. The oxidative polymerization of the synthesized amides carried out in air in aqueous buffer at pH 9 afforded melanin-like pigmented materials that showed chromophores resembling those of DHICA-derived pigments, with a good covering of the UVA and the visible region, and additionally exhibited a good solubility in alcoholic solvents, a feature of great interest for the exploitation of these materials as ingredients of dermocosmetic formulations. © 2022 by the authors.

The lichen's special symbiotic structure enables it to produce bioactive substances. They have historically been recognized for their aesthetic and medicinal benefits. Furthermore, in recent years, they have performed in various fields, including perfumery, dyeing, and pharmacology due to their rich secondary metabolites. From our study, four compounds were isolated from organic extracts of Parmotrema hypoleucinum, Roccella phycopsis, and Xanthoria parietina and identified by spectroscopic investigation as atranorin, (+)-iso-usnic acid, methyl orsellinate, and parietin, respectively. The anti-inflammatory effects of lichens extracts, and pure compounds were evaluated on RAW 264.7 macrophages cells at different concentrations. At 25 μg/mL all treated samples did not show any effect on cell viability. Atranorin and (+)-iso-usnic acid showed an inhibitory effect on nitric oxide (NO) levels in lipopolysaccharide (LPS)-stimulated macrophages. Nitric oxide (NO) production was measured using Griess reagent, atranorin and (+)-iso-usnic acid showed a high anti-inflammatory potential (75.99 % and 57.27 % at 25 μg/mL). On the other hand, methyl orsellinate and the organic extracts of three lichens showed good anti-inflammatory activity ranging from 29.16 % at 25 μg/mL to 86.91 % at 100 μg/mL.

An undescribed 5,6-dihydropyran-2-one, namely diplopyrone C, was isolated and characterized from the cultures of an isolate of the fungus Diplodia corticola recovered from Quercus suber in Algeria. The structure and relative stereostructure of (5S,6S,7Z,9S,10S)-5-hydroxy-6-(2-(3-methyloxiran-2-yl)vinyl)-5,6-dihydro-2H-pyran-2-one were assigned essentially based on NMR and MS data. Furthermore, ten known compounds were isolated and identified in the same cultures. The most abundant product, the tetracyclic pimarane diterpene sphaeropsidin A, was tested for insecticidal effects against the model sucking aphid, Acyrthosiphon pisum. Results showed a toxic dose-dependent oral activity of sphaeropsidin A, with an LC50 of 9.64 mM.

Funicone-like compounds are a homogeneous group of polyketides that, so far, have only been reported as fungal secondary metabolites. In particular, species in the genus Talaromyces seem to be the most typical producers of this group of secondary metabolites. The molecular structure of funicone, the archetype of these products, is characterized by a γ-pyrone ring linked through a ketone group to a α-resorcylic acid nucleus. This review provides an update on the current knowledge on the chemistry of funicone-like compounds, with special emphasis on their classification, occurrence, and diverse biological activities. In addition, their potential relevance as mycotoxins is discussed.

Some Trichoderma strains are known for their capacity to produce harzianic acid, a metabolite belonging to the tetramic acid derivatives. Harzianic acid has interesting biological properties, such as antimicrobial activities against phytopathogenic fungi and promotion of plant growth. It also possesses remarkable chemical properties, including the chelating properties toward essential transition metals, which might be related to the biological activities. Increasing knowledge on chelating properties might be relevant for understanding the various beneficial effects of harzianic acid in the interaction between the producer fungi and plants. In this work, the coordination capacity of harzianic acid was studied to evaluate the formation and stability of complexes formed with toxic heavy metals (i.e., Cd2+, Co2+, Ni2+, and Pb2+), which might have a crucial role in the tolerance of plants growing in metal-contaminated soils and in abiotic stress.

Mitidjospirone, a new spiridioxynaphthalene, was isolated from the mycelial extract of a strain of Lasiodiplodia mitidjana, a recently described species belonging to the family Botryosphaeriaceae. Its structure was elucidated by extensive spectroscopic analysis and the absolute configuration was determined by electronic circular dichroism (ECD) experiment. Furthermore, several known compounds were identified during the screening of secondary metabolites produced by four strains of L. mitidjana.

The inclination toward natural products have led the onset for the discovery of new bioactive metabolites that could be targeted for specific therapeutic or agronomic applications. This study aimed to isolate bioactive compounds from Cleome arabica L., and subsequently determine the unexplored mechanism of action of the newly identified compounds on Lactuca sativa L. Chemical investigation of the ethyl acetate fraction of methanolic silique extract of C. arabica afforded seven secondary metabolites belonging to different classes such as flavonoids, triterpene, and a new thiohydroximate derivative, named cleomside A. Among phytotoxic assays, the growth of lettuce was totally inhibited by cleomside A compared to the other identified compounds. This effect was associated with the increased levels of electrolyte leakage, malondialdehyde, and hydrogen peroxide indicating disruption of membrane integrity and induction of oxidative stress. Activities of the antioxidant enzymes SOD, CAT, and APX were also elevated, thereby demonstrating the enhanced generation of reactive oxygen species upon identified allelochemical exposure. Thus, the changes caused by cleomside A described herein can contribute to better understanding the allelochemical actions of thiohydroximate and the potential use of these substances in the production of natural herbicides compared to the other identified flavonoids and triterpene.

Harzianic acid is a secondary metabolite of Trichoderma, structurally belonging to the dienyltetramic acid subgroup of the tetramic acids. Biological activities of harzianic acid are of great interest for its antimicrobial and plant growth-promoting activities, which might be related to its chelating properties. In the present work harzianic acid, isolated from cultures of a strain of Trichoderma pleuroticola associated to the gastropod Melarhaphe neritoides, was studied as a complexant agent of a number of biologically relevant transition metals (i.e., Zn2+, Fe2+, Cu2+, and Mn2+), using UV-VIS, potentiometry, MS and NMR techniques. Our findings show the coordination capacity of harzianic acid toward the above cations through the formation of neutral or charged complexes in a variable ratio depending on the metal and pH conditions.

Herein we report the preparation of 3,4-dibenzylfurans and some oxidized derivatives with lignan backbone. The compounds were prepared using the Friedel-Crafts reaction with BF3 etherate as catalyst, demethylation with iodocyclohexane, acetylation and oxidation reactions. The antimicrobial activity was evaluated through their capacity to inhibit the growth of Gram positive and Gram negative bacteria, and of the yeast Candida albicans. Among ten products assayed four furans displayed a good antimicrobial activity against Staphylococcus aureus, S. epidermidis and C. albicans; on the contrary, none of the compounds were active against Pseudomonas aeruginosa. One of them inhibited the growth of S. aureus, S. epidermidis (biofilm producer strain) and C. albicans at 16 μg/mL, showing a bactericidal activity already after one hour of treatment. In summary, the results suggest a possible use of these derivatives for general disinfection practices or antimicrobial agents in cosmesis skin-care.

Talarodiolide, a new 12-membered macrodiolide, was isolated and characterized from the culture filtrate of strain LT6 of Talaromyces pinophilus. The structure of (Z)-4,10-dimethyl-1,7-dioxa-cyclododeca-3,9-diene-2,8-dione was assigned essentially based on NMR and MS data. Furthermore, several known compounds were isolated and identified in the crude extract of the culture filtrate and mycelium of this strain. EI mass spectrum at 70 eV of all isolated metabolites was acquired and compiled in a custom GC/MS library to be employed to detect metabolites in the crude extracts.

Silybin is the major component (ca. 30%) of the silymarin complex extracted from the seeds of Silybum marianum , with multiple biological activities operating at various cell levels. As an ongoing effort toward the exploitation of natural products as scaffolds for chemical diversification at readily accessible positions, we present here an efficient synthetic procedure to obtain new 23-phosphodiester silybin conjugates with different labels. A key point in our approach is the new 3,5,7,20-tetra- O -acetylsilybin-23-phosphoramidite, useful for a variety of derivatizations following a reliable and well-known chemistry. The feasibility of the procedure has been demonstrated by preparing new 23-silybin conjugates, exploiting standard phosphoramidite chemistry.

Implementing the phytochemical study of the weed Amaranthus retroflexus, four new sesquiterpene glucosides were isolated from the methanolic extract of the plant. The structures of these metabolites are determined on the basis of the mass spectrometry, and 1D and 2D NMR spectroscopies (DQ-COSY, TOCSY, HSQC, HSQC-TOCSY, HMBC, and NOESY). Two compounds are characterized by a new aglycone and differed from the site of glucosylation. The other two compounds are dimeric diastereoisomers. All the glucoside sesquiterpenes were tested on the wild species Taraxacum officinale to evaluate the role of this weed in the habitat and on the seed of A. retroflexus to verify the potential autotoxic effect of the plant. © 2006 Elsevier Ltd. All rights reserved.

The phototransformation of naproxen Na in aqueous medium has been investigated. Irradiation of the drug in drinking water affords seven photoproducts. Three of them are dimeric photoproducts isolated for the first time. The compounds, isolated by chromatographic processes, have been identified by spectroscopic means. The toxicity of the photoproducts and the parent drug has been assayed on Daphnia magna and Vibrio fischeri. The results indicate that some photoproducts are more toxic than naproxen. © Springer-Verlag 2003.

Two cycloartane triterpenes and 10 sterols present in Zantedeschia aethiopica along with three lignans and 10 phenylpropanoids were identified by spectroscopic means. 3-(4-hydroxy-3-methoxy)-phenyl-1,2-propandiol and 1- (4-hydroxy-3-methoxy)-phenyl-2-[4-(2,3-dihydroxypropyl)-2-methoxy]-phenoxy- 1,3-propandiol have been isolated for the first time. Antialgal assays show good activity for some aromatic compounds.

In this study, a comparison of two carbamic pesticides, chlorpropham and phenisopham, was carried out in terms of both photodegradability and ecotoxicity. The photochemical behaviour of the two pesticides was investigated under environmental-like conditions (aqueous media, UVB or solar irradiation). The photochemical kinetic parameters were calculated by irradiating 5 × 10-5 M solutions (H2O-CH3CN, 9:1 v/v) using UVB lamps. For chlorpropham and phenisopham similar half-life times (39.0 and 55.0 min) were determined. Irradiation by sunlight leads to longer degradation half-life times (about 3 months), while it is possible to observe the formation of the same photoproducts. The well-known dechlorination reaction to a hydroxyphenylcarbamate was observed for chlorpropham. Phenisopham undergoes photo-Fries reaction to give rearranged products (hydroxybenzamides) and fragmentation products (hydroxyphenylcarbamate and N-ethylaniline). Acute and chronic toxicity tests of pesticides and their photoproducts were performed on organisms from two levels of the freshwater aquatic chain, the anostraca crustacean Thamnocephalus platyurus, the rotifer Brachionus calyciflorus and the alga Pseudokirchneriella subcapitata. The acute results showed that chlorpropham had median lethal concentrations for the crustacean T. platyurus and the rotifer B. calyciflorus of 10.16 and 35.19 mg L-1, respectively, and phenisopham did not show any acute toxicity as the derivatives up to 10 mg L-1. The only exception was N-ethylaniline which exhibited an acute LC50 value of 0.46 mg L-1. Phenisopham was the most toxic in the long term exposure while its five derivatives showed lower chronic potential for rotifers and algae. The same trend was observed for chlorpropham except for rotifers. This journal is © the Partner Organisations 2014.

Discussion about the environmental consequences of the presence of pharmaceuticals has taken place in the general absence of a systematic analysis of the potential risk. The lack of such an analysis means that, to date, decisions concerning environmental risk assessment criteria and/or regulatory thresholds have been somewhat arbitrary or based upon inappropriate groups of industrial chemicals. This chapter attempts to address this deficiency and collates examples of data relating to the ecotoxicity of existing pharmaceutical transformation photoproducts (TPs). The intention is to provide a perspective that will prove useful during the further development of assessment criteria. The database may also prove useful in the context of risk assessment of individual substances. There are mainly two different and independent approaches to assessing the risk associated with transformation product formation. We analyze these two approaches for transformation products coming from irradiation of pharmaceuticals under environment-like conditions.

Caffeine is ubiquitous in surface and ground waters and it has been proposed as a marker of the anthropogenic pressure on the environment. Sewage treatment plants based on active sludges seem to be not very efficient in its complete removal from effluents while addnl. disinfection treatments by chlorination are able to do it. In a simulation of the chlorination step herein we report that caffeine is transformed in six byproducts: 8-???chlorocaffeine, 1,???3-???dimethyl-???5-???azabarbituric acid, N,???N'-???dimethylparabanic acid, N,???N'-???dimethyloxalamide, N-???methylurea and N,???N'-???dimethylurea. The ecotoxicity of caffeine and identified compds. was evaluated on the rotifer Brachionus calyciflorus and the alga Pseudokirchneriella subcapitata to assess acute and chronic toxicity, while SOS Chromotest and Ames Test were used to detect the genotoxic potential of the investigated compds. Moreover, we assessed the possible antigenotoxic effect of the selected compds. using SOS Chromotest after co-???incubation with the std. genotoxin, 4-???nitroquinoline 1-???oxide. Chronic exposure to these compds. caused inhibition of growth population on the rotifer while the algae seemed to be unaffected. Results indicated that caffeine (1)???, N,???N'-???dimethyloxamide (4) and N,???N'-???dimethylparabanic acid (5) reduced ??-???galactosidase activity in comparison with pos. control, both at 1 and 5 mg???/L of 4-???NQNO with a good dose-???response.

A new oleanane glycoside, named ranuncoside VII, was identified as 3-0-[α-L-arabinopyranosyl-(l→6)-(β-D-glucopyranosyl]-13β,28-epoxyolean-ll-ene-3β\15α,16α,21β\22α-pentol by chemical and spectroscopic studies. The aglycone structure was confirmed by hemisynthesis from R1-barrigenol. © 1995, Taylor & Francis Group, LLC. All rights reserved.

Nicotine, the main alkaloid of tobacco, is a non-prescription drug to which all members of a tobacco-smoking society are exposed either through direct smoke inhalation or through second-hand passive 'smoking'. Nicotine is also commercially available in some pharmaceutical products and is used worldwide as a botanical insecticide in agriculture. Nicotine dynamics in indoor and outdoor environments as well as the human excretions and the manufacturing process are responsible for its entry in the environment through municipal and industrial wastewater discharges. The presence of nicotine in surface and ground waters points out that it survives a conventional treatment process and persists in potable-water supplies. Complete removal of nicotine is instead reported when additional chlorination steps are used. In this paper a simulation of STP chlorination of nicotine and a genotoxic evaluation of its main degradation products are reported. Under laboratory conditions removal of nicotine seems not to be due to mineralization but to transformation in oxidized and chlorinated products. The by-products have been isolated after fractionation by diverse chromatographic procedures and their structures determined using mass spectrometry and H-1 and C-13 NMR spectroscopy. Preliminary genotoxic SOS Chromotests with Escherichia coil PQ37 evidence no toxicity of the products. (C) 2012 Elsevier B.V. All rights reserved.

Four steroidal 5,6 epoxides have been isolated from Arum italicum and idenfied on the basis of their spectral features. A preliminar assay evidences their cytotoxic activity. © 1993, Taylor & Francis Group, LLC. All rights reserved.

Nine 9,10-dihydrophenanthrenes, seven of them described for the first time, have been isolated in a further investigation of Juncus effusus . The structures have been defined on the basis of the spectral properties of the compounds. All the dehydrophenanthrene metabolites present in the plant have been tested for their cytotoxic properties and many of them have been found to have a good in vitro activity.

Il testo propone una riflessione circa il compito con cui l’offĭcĭo filosofico può essere nuovamente aggiornato nella condizione attuale. Compito che per la filosofia non può essere che quello di un esercizio della differenza inteso come esercizio della critica.

Six novel 9,10-dihydrophenanthrene metabolites have been isolated from the aquatic plant Juncus effusus , together with the already known juncusol, juncunol and effusol. The structures of the compounds have been defined on spectroscopic grounds. Two of them showed a good antitumour activity.

Isolation, chemical characterization, and phytotoxicity of five new oxylipins, together with seven already known related compounds, from Cestrum parqui L'HERL. is reported. All the structures were elucidated on the basis of their spectral data, especially 1D- (1H- and 13C-NMR, DEPT) and 2D-NMR (COSY, TOCSY, HSQC, HMBC, and NOESY). The configurations of the stereogenic C-atoms were determined by the Mosher's method. The compounds have been assayed for their phytotoxicity on Lactuca sativa at concentrations ranging between 10-4 and 10-8 m. The results of the phytotoxicity tests on the germination and growth of the test species, obtained by a cluster analysis, showed interesting relationship between the chemical structures of the compounds and their biological effects. © 2008 Verlag Helvetica Chimica Acta AG, Zürich.

1. Subject and sourceCestrum parqui l’Her. 1788 (Solanaceae) is a shrub, indigenous to South America, widely distributed in theMediterranean area and known as ‘green Cestrum’. Plants of C. parqui were collected in Sant’Agata de’ Goti,near Caserta (Italy) in the spring 2004, and identified by Dr Assunta Esposito of the Second University of Naples.A voucher specimen (CE125) has been deposited at the Herbarium of the Dipartimento di Scienze della Vita ofthe Second University of Naples.2. Previous worksNot many papers are reported on the lignan composition of Cestrum species. Recently we have reported theisolation, characterization and the phytotoxicity of three new compounds, a sesquilignan, an oxyneolignan and a nor-lignan, from the aqueous fraction of C. parqui (D’Abrosca et al., 2006). Other class of chemicals has been isolatedfrom this plant such as saponins (Chaieb et al., 2005; Baquai et al., 2001; Abdel-Gwad et al., 1997; Torres et al.,1988), terpenoids (Pearce et al., 1992; D’Abrosca et al., 2004a) and phenols (D’Abrosca et al., 2004b).3. Present studyThe phytochemical study of the hydroalcoholic extract of green Cestrum has led to the isolation ofthe 18 compounds with lignan skeletons, which have been identified as four diepoxylignans 1e3 and 18, four epox-ylignans 4e7, three neolignans 8e10, fivesesquilignans 11, 12and 15e17, an oxyneolignan 13and a norlignan 14,onthe basis of their spectroscopic features (NMR spectra were recorded at 300 MHz for

The phototransformation of amlodipine in water was investigated under various conditions. A quantum yield ΦS2.2×10−4 and a half-life time t1/2 0.419 days were calculated when the drug in water (10−4 M) was exposed to sunlight. The only photoproduct found was its pyridine derivative. Formation of this product was explained on the basis of a radical cation intermediate. The acute and chronic toxicity of the drug and its photoproduct were evaluated on different organisms of the freshwater chain (Brachionus calyciflorus, Thamnocephalus platyurus, Daphnia magna, Ceriodaphnia dubia). The photoproduct exhibited a stronger toxic potential than the parent drug on the long time for C. dubia.

From the fresh leaves or twigs of Aptenia cordifolia, a total of 29 compounds were isolated, including the new tetranoroxyneolignan 18, the new dilignan 19, and the β-ionone derivative 27, previously only known as a synthetic compound, together with 26 known compounds. The structures of the new products were determined by 1H-, 13C-, and 2D-NMR, as well as HR-MS analyses. The phytotoxic effects of the isolates on the germination and growth of the dicotyledon Lactuca sativa L. (lettuce) were studied in the concentration range 10-4 to 10-7 m. Several constituents of A. cordifolia were found to be equally active as or superior to 4-hydroxybenzoic acid (HBA) used as positive control. © 2007 Verlag Helvetica Chimica Acta AG, Zürich.

Background. N-methylcarbamate insecticides are widely used chemicals for crop protection. This study examines the hydrolytic and photolytic cleavage of benfuracarb, carbosulfan and carbofuran under natural conditions. Their toxicity and that of the corresponding main degradation products toward aquatic organisms were evaluated. Methods. Suspensions of benfuracarb, carbosulfan and carbofuran in water were exposed to sunlight, with one set of dark controls, for 6 days, and analyzed by 1H-NMR and HPLC. Acute toxicity tests were performed on Brachionus calyciflorus, Daphnia magna, and Thamnocefalus platyurus. Chronic tests were performed on Pseudokirchneriella subcapitata, and Ceriodaphnia dubia. Results and Discussion. Under sunlight irradiation, benfuracarb and carbosulfan gave off carbofuran and carbofuran-phenol, while only carbofuran was detected in the dark experiments. The latter was degraded to phenol by exposure to sunlight. Effects of pH, humic acid and KNO3 were evaluated by kinetics on dilute solutions in the dark and by UV irradiation, which evidenced the lability of the pesticide at pH 9. All three pesticides and phenol exhibited acute and higher chronic toxicity towards the aquatic organisms tested. Conclusion. Investigation on the hydrolysis and photolysis of benfuracarb and carbosulfan under natural conditions provides evidence concerning the selective decay to carbofuran and/or phenol. Carbofuran is found to be more persistent and toxic. Recommendations and Outlook. The decay of benfuracarb and carbosulfan to carbofuran and the relative stability of this latter pesticide account for many papers that report the detection of carbofuran in water, fruits and vegetables. © 2006 ecomed publishers (Verlagsgruppe Hüthig Jehle Rehm GmbH).

Seven new sesquiterpenes, with nerolidol skeleton, have been isolated and characterized from the plant Amaranthus retroflexus, one of the major weeds of the world. The structures have been elucidated on the basis of spectroscopic data. The compounds have been characterized by the presence of hydroxyl groups or a glucopyranosyl moiety in the molecules. The configurations have been determined using Mosher's method. The compounds have been tested for their phytotoxicity on the test species Lactuca sativa. The bioassays showed an inhibitory effect on seed germination for all of compounds at the lowest concentrations. © 2005 Elsevier Ltd. All rights reserved.

The investigation of the extracts of plants Cestrum parqui, Brassica fruticulosa, and Chenopodium album led to the isolation of compounds belonging to different classes: C13 norisoprenoids, lignans and cinnamic acid amides. These compounds exhibit interesting activity on standard target species Lactuca sativa, Lycopersicon esculentum, and Allium cepa influencing seed germination and plant growth. Lignans are the most active products inhibiting lettuce germination, and the results show greater phytotoxic activity of these compounds with respect to commercial herbicides. © 2006 American Chemical Society.

Three new compounds, a sesquilignans, an oxyneolignan and a norlignan, have been isolated from the aqueous fraction of Cestrum parqui. All of the compounds have been identified on the basis of their spectroscopic properties and tested on the species Lactuca sativa and Lycopersicon esculentum to evaluate their phytotoxic activity. © 2006 Taylor & Francis.

A sesquiterpene and a tetrahydroxylated acyclic diterpene as well as two known monoterpenes, 6 C13nor-terpenes and 11 aromatic compounds were isolated from the water extract of Malva silvestris. The structures of the compounds were determined by spectroscopic NMR and MS analysis. Effects of these compounds on germination and growth of dicotyledon Lactuca sativa L. (lettuce) were studied in the 10-4-10-7M concentration range. © 2005 Elsevier Ltd. All rights reserved.

Forty-nine secondary metabolites were isolated from aqueous and alcoholic extracts of the aquatic plant Shoenoplectus lacustris. All compounds were characterized based on spectroscopic data. Eleven free and glycosylated low-molecular polyphenols, 17 cinnamic acid and dihydrocinnamic acid derivatives, 11 flavonoids, and 10 C13 nor-isoprenoids were identified. The structure of the new compound, 1-benzoyl-glycerol-2-α-l- arabinopyranoside, was elucidated by 2D NMR experiments (COSY, HSQC, HMBC, NOESY). To evaluate potential phytotoxic effects, all compounds were tested on the green alga Selenastrum capricornutum, a unicellular organism commonly used in tests of toxicity as a bioindicator of eutrophic sites. The most active compound was (-)-catechin, showing an inhibition similar to that of the algaecide CuSO4. © 2006 Springer Science + Business Media, Inc.

Isolation, chemical characterization and phytotoxicity of nine polyhydroxylated terpenes (five C13 nor-isoprenoids, two sesquiterpenes, a spirostane and a pseudosapogenin) from Cestrum parqui L'Herr are reported. In this work we completed the phytochemical investigation of the terpenic fraction of the plant and described the structural elucidation of polar isoprenoids using NMR methods. All the configurations of the compounds have been assigned by NOESY experiments. Four new structures have been identified as (3S,5R,6R,7E,9R)-5,6,9-trihydroxy-3-isopropyloxy-7-megastigmene, 5α-spirostan-3β,12β,15α-triol, and 26-O-(3′- isopentanoyl)-β-d-glucopyranosyl-5α-furost-20(22)-ene-3β, 26-diol, and as an unusual tricyclic sesquiterpene. The compounds have been assayed for their phytotoxicity on lettuce at the concentrations ranging between 10-4 and 10-7 M. The activities of some compounds were similar to that of the herbicide pendimethalin. © 2005 Elsevier Ltd. All rights reserved.

Twelve C13 nor-isoprenoids have been isolated from the leaves of Cestrum parqui (Solanaceae). The structure (2R,6R,9R)-2,9-dihydroxy-4- megastigmen-3-one has been assigned to the new compound. All the structures have been determined by spectroscopic means and chemical correlations. The compounds showed phytotoxic effect on the germination and growth of Lactuca sativa L. © 2003 Elsevier Ltd. All rights reserved.