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Dimeric cyclic or acyclic lignan derivatives have been obtained from isoeugenol under light induced oxidations (mainly by MB-sensitized photooxygenation in water/CH(3)CN or di-tert-butyl peroxide photo-oxidation). Coniferyl alcohol gives lignans only under peroxide-mediated photo-oxidation while ferulic acid was unreactive under both conditions.

Seven new cinnamic ester derivatives ( 1- 7) were isolated from a methanol extract of the fresh leaves and twigs of Oxalis pes-caprae (Bermuda buttercup). The structures of these new compounds were determined by spectroscopic data interpretation. The effects of compounds 1- 7 on the germination and growth of Lactuca sativa (lettuce) were studied.

Transformation of tamoxifen has been observed in water by prolonged sunlight irradiation. The main photoproducts, isolated by chromatographic techniques, have been identified by spectroscopic means. Photoisomerization, photocyclization and, to a lesser extent, photooxygenation appear to be involved in the degradation of the drug. The acute and chronic toxicity of the parent drug and its photoproducts were tested on non-target aquatic organisms (Brachionus calyciflorus, Thamnocephalus platyurus, Daphnia magna and Ceriodaphnia dubia). Exposure to all the compounds induced mainly chronic effects without significant differences among the parental and derivative compounds.

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 beta-ionone derivative 27, previously only known as a synthetic compound, together with 26 known compounds. The structures of the new products were determined by (1)H-, (13)C-, 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.

Cinnamic acid, 4-hydroxy-cinnamic acid, ferulic acid, methyl ferulate, sinapic acid, methyl 3-(4-hydroxy-3-methoxyphenyl)propanoate, 4-(1-hydroxyethyl)-2-methoxyphenol, vanillyl alcohol, 4-(hydroxymethyl)-2-methoxyphenol, 4-hydroxy-3-methoxybenzoic acid, 4-vinylphenol, 4-methylbenzaldehyde, N-[2-(1H-indol-3-yl)ethyl]acetamide, pinoresinol, syringaresinol, lariciresinol, 5,5'-dimethoxy-lariciresinol, threo-guaiacylglycerol-3-beta-4-syringaresinol ether and two new sesquilignans, namely, threo-guaiacylglycerol-alpha-O-methyl-beta-O-4-syringaresinol ether and threo-syringylglycerol-alpha-O-methyl-beta-O-4-syringaresinol ether, were isolated and identified as components of Chenopodium album. Constitutions were established on the basis of spectroscopic data, including two-dimensional NMR analyses.

Two dimeric phenylethanoids isolated from olive oil mill wastewaters have been synthesized from cathecol, tyrosol and 3,4-dihydroxyphenylacetic acid.

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-alpha-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.

Isolation, chemical characterization and phytotoxicity of nine polyhydroxylated terpenes (five C13nor-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, 5alpha-spirostan-3beta,12beta,15alpha-triol, and 26-O-(3'-isopentanoyl)-beta-d-glucopyranosyl-5alpha-furost-20(22)-ene-3beta,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.

The leaves of Chenopodium album were infused in H2O/MeOH. The extract treated with cold acetone gave heavy precipitation, which was removed by centrifugation. Solid material was fractionated into acidic and neutral fractions. The acidic material was subjected to different silica-gel column chromatographies, and then it was purified by reversed-phase HPLC to afford four known ecdysteroids and the new 3beta,14alpha-dihydroxy-5beta-pregn-7-ene-2,6,20-trione that were characterized by extensive spectroscopic investigation, especially by 1D- and 2D-NMR. Their effects on germination and growth of Lactuca sativa L. have been studied. The results are reported as percentage differences of germination, root elongation and shoot elongation, from the control at concentrations ranging from 10(-4) to 10(-7) M.

Five C13 norisoprenoids, one of them glucosilated, have been isolated from the leaves of Brassica fruticulosa (Brassicaceae). The structure (3S,4R,7E,9S)-3,4,9-trihydroxy-5,7-megastigmadiene, has been assigned to the new compound. All the structures have been determined by spectroscopic means and chemical correlations.

The isolation and the structure determination of an unusual xyloside from the plant Chenopodium album is reported. The structure has been attributed by means of its spectral data.

Two new dimeric phenanthrenoids have been isolated by the methanol extract of rhizomes of Juncus acutus. The structures have been determined on the basis of their spectroscopic properties and by chemical correlation. The compounds showed in vitro phytotoxicity against Selenastrum capricornutum, a microalga used in aquatic tests.

Sunlight exposure of aqueous suspensions of carboxin (1) causes its phototransformation to sulfoxide 2 and minor components. Similar effects are observed in the presence of humic acid or nitrate or at different pH values. Photoproducts 2-9 were isolated by chromatographic techniques and/or identified by spectroscopic means. Carboxin 1 and its main photoproduct sulfoxide 2 were tested to evaluate acute toxicity to primary consumers typical of the aquatic environment: the rotifer Brachionus calyciflorus and two crustaceans, Daphnia magna and Thamnocephalus platyurus. Chronic tests comprised a producer, the alga Pseudokirchneriella subcapitata, and a consumer, the crustacean Ceriodaphnia dubia.

The roots of Chenopodium album were infused in MeOH, and the extract was partitioned between AcOEt and H2O. AcOEt-Soluble material was subjected to different silica-gel column chromatographies and then purified by reverse-phase HPLC to afford a new cinnamic acid amide alkaloid as a racemic mixture. The new compound, named chenoalbicin (1), was characterized by extensive spectroscopic investigation, especially 1D and 2D NMR spectroscopy. Its effects on the germination and growth of Lactuca sativa L. has been studied. The results are reported as percentage differences of germination, root elongation, and shoot elongation from the control at concentrations ranging from 10(-4) to 10(-7) M.

Two new compounds (1, 2) and 16 apocarotenoids (3-18) were isolated from the weed Chenopodium album. The structures of new apocarotenoids were determined to be (3R,6R,7E,9E,11E)-3-hydroxy-13-apo-alpha-caroten-13-one (1) and (6S,7E,9E,11E)-3-oxo-13-apo-alpha-caroten-13-one (2) by spectroscopic, NMR, and MS analysis. Five of the known compounds (5, 6, 13, 15, and 17) were previously reported only as synthetic compounds. Effects of these compounds on germination and growth of Lactuca sativa (lettuce) were studied in the 10(-4)-10(-7) M concentration range.

The aqueous fraction of fresh leaves of Cestrum parqui and its organic fractions have been assayed for their phytotoxicity on Lactuca sativa, Lycopersicon esculentum, and Allium cepa. The tests showed that the bioactivity was retained in the organic fractions. Chromatographic processes led to isolation and characterization of the N-(p-carboxymethylphenyl)-p-hydroxybenzamide together with 17 low molecular weight phenols and 2 flavones. The phytotoxicity tests showed a good activity of these compounds on the target species. Comparison of some metabolites with commercial herbicides revealed a major activity of the natural compounds at lower concentrations.

Photooxidation of cathecol (1) is carried out in aqueous solution at lambda > 300 nm using different sensitizers: rose bengal (RB), 9,10-dicyanoanthracene (DCA), 2,4,6-triphenylpyrylium tetrafluoroborate (Pyryl). The highest degradation is observed in the UV/RB-sensitized reaction (66% after 15 h of irradiation), mineralization and formation of dimers are the final events. This procedure has been extended to tyrosol (2), caffeic acid (3), vanillic acid (4), 4-hydroxycinnamic acid (5) and 4-hydroxybenzoic acid (6) as well as to a mixture of all phenols. A reduced toxicity of the UV/RB-irradiated solutions of cathecol and tyrosol towards alga Ankistrodesmus braunii is also verified.

A new lignan 1-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-6-(3-acetyl-4-hydroxy-5-methoxyphenyl)-3,7-dioxabicyclo[3.3.0]octane, the secoiridoid 2H-pyran-4-acetic acid,3-hydroxymethyl-2,3-dihydro-5-(methoxycarbonyl)-2-methyl-, methyl ester, the phenylglycoside 4-[beta-D-xylopyranosyl-(1-->6)]-beta-D-glucopyranosyl-1,4-dihydroxy-2-methoxybenzene and the lactone 3-[1-(hydroxymethyl)-1-propenyl] delta-glutarolactone were isolated and identified on the basis of spectroscopic data including two-dimensional NMR, as components of olive oil mill waste-waters. The known aromatic compounds catechol, 4-hydroxybenzoic acid, protocatechuic acid, vanillic acid, 4-hydroxy-3,5-dimethoxybenzoic acid, 4-hydroxyphenylacetic acid, 3,4-dihydroxyphenylacetic acid, tyrosol, hydroxytyrosol, 2-(4-hydroxy-3-methoxy)phenylethanol, 2-(3,4-dihydroxy)phenyl-1,2-ethandiol, p-coumaric acid, caffeic acid, ferulic acid, sinapic acid, 1-O-[2-(3,4-dihydroxy)phenylethyl]-(3,4-dihydroxy)phenyl-1,2-ethandiol, 1-O-[2-(4-hydroxy)phenylethyl]-(3,4-dihydroxy)phenyl-1,2-ethandiol, D(+)-erythro-1-(4-hydroxy-3-methoxy)-phenyl-1,2,3-propantriol, p-hydroxyphenethyl-beta-D-glucopyranoside,2(3,4-dihydroxyphenyl)ethanol 3beta-D-glucopyranoside, and 2(3,4-dihydroxyphenyl)ethanol 4beta-D-glucopyranoside were also confirmed as constituents of the waste-waters.

Twenty-five 9,10-dihydrophenanthrenes, four phenanthrenes, a dihydrodibenzoxepin, and a pyrene, isolated from the wetland plant Juncus acutus, were tested to detect their effects on the green alga Selenastrum capricornutum. Nine of the compounds were isolated and identified for the first time. Most of the compounds caused inhibition of algal growth. The 9,10-dihydrophenanthrenes 1, 5, 21, and 22 were the most active.

Light exposure of aqueous suspensions of prednisolone and dexamethasone causes their partial phototransformation. The photoproducts, isolated by chromatographic techniques, have been identified by spectroscopic means. Prednisolone, dexamethasone and their photoproducts have been tested to evaluate their acute and chronic toxic effects on some freshwater chain organisms. The rotifer Brachionus calyciflorus and the crustaceans Thamnocephalus platyurus and Daphnia magna were chosen to perform acute toxicity tests, while the alga Pseudokircheneriella subcapitata (formerly known as Selenastrum capricornutum) and the crustacean Ceriodaphnia dubia to perform chronic tests. The photochemical derivatives are more toxic than the parent compounds. Generally low acute toxicity was found. Chronic exposure to this class of pharmaceuticals caused inhibition of growth population on the freshwater crustacean C. dubia while the alga P. subcapitata seems to be less affected by the presence of these drugs.

Twelve C(13) 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.

Seven cinnamic acid amides have been isolated from Chenopodium album. The structures have been attributed by means of their spectral data. One of them, N-trans-4-O-methylferuloyl 4'-O-methyldopamine, is described for the first time. Their effects on germination and growth of dicotyledons Lactuca sativa L. (lettuce) and Lycopersicon esculentum L. (tomato) and of monocotyledon Allium cepa L. (onion) as standard target species have been studied in the range concentration 10(-4)-10(-7) M.

Five lignans, five neolignans, two sesquilignans, and a dilignan were identified from a phytotoxic extract of Brassica fruticulosa L. Compounds 8, 9, 12, and 13 have been isolated for the first time. Structures were determined on the basis of their spectroscopic features. Their effects on the germination and growth of two dicotyledons, Lactuca sativa (lettuce) and Lycopersicon esculentum (tomato), and a monocotyledon, Allium cepa (onion), as standard target species have been studied.

Two natural cyanohydrins, isolated from Sambucus nigra, have been synthesised from mandelonitrile and penta-O-acetyl-beta-galactopyranose. The synthesis confirmed the stereochemistry of the compounds, which had been assigned on biogenetic grounds.

Solar simulator irradiation of an aqueous suspension of prednisone, a widely prescribed drug, produces seven photochemical derivatives. The compounds have been identified on the basis of their physical features. All the chemicals have been tested to evaluate their toxic effects on freshwater organisms from different trophic levels. The rotifer Brachionus calyciflorus and two crustaceans, the cladoceran Daphnia magna and the anostracan Thamnocephalus platyurus, were used to perform acute toxicity tests. Chronic toxicity tests have been performed on the alga Pseudokirchneriella subcapitata (formerly known as Selenastrum capricornutum) and the crustacean Ceriodaphnia dubia. The results showed low acute and chronic toxicity of prednisone. Some of the photoproducts had high toxic effects on C. dubia.

Androst-4-ene-3,17-dione (1) and 17alpha-methyltestosterone (2) are dimerized in the solid-state by UV radiation. These substances were selected by a search in the CSD among the steroid enones presenting in the crystalline state an intermolecular short contact between a hydrogen alpha to a carbonyl group and the oxygen of an enone system. Dimerization occurs by transfer of the hydrogen to the oxygen and connection between the two involved carbons. Androst-4-ene-3,17-dione (1) affords dimer 3 and trimer 4, both formed by connection of the C-16 of a molecule with the C-3 of a near one. Irradiation of 17alpha-methyltestosterone (2) gives the isomeric trienones 5 and 6. These compounds are reasonably formed by dehydration of unisolated intermediate products 7 and/or 8 obtained by coupling of two molecules through a linkage between the C-2 and the C-3' carbons. The formation mechanisms of the photoproducts are satisfactory explained on the basis of the molecular arrangement of the monomers in the crystal state. Modeling of the dimeric molecules was done using molecular mechanics calculations. A single-crystal X-ray of the dimer of androst-4-ene-3,17-dione confirms the structural interpretation of spectral data. The conformer found in the solid-state agrees well with the results of molecular mechanics calculations.

Twenty ent-labdane diterpenes, isolated from the aquatic plants Ruppia maritima and Potamogeton natans, were tested to detect their effects on aquatic organisms from different trophic levels. Toxicity tests were performed on aquatic producers (the alga Selenastrum capricornutum), and consumers including a rotifer (Brachionus calyciflorus), a cladoceran crustacean (Daphnia magna), and two anostracan crustaceans (Thamnocephalusplatyurus and Artemia salina). Furano-ent-labdanes exhibited high toxicity toward all of these organisms. 15,16-Epoxy-12(S)-hydroxy-8(17),13(16),14-ent-labdatrien-20.19-olide had a high toxicity only toward the algae and the rotifers. It was inactive for the crustaceans.

Seven natural 9,10-dihydrophenanthrenes were isolated from the common reed Juncus effusus by means of chromatographic processes and identified by spectroscopic means. Furthermore, mimics of natural isolated compounds were synthesized to try to evaluate the influence of functional groups on the dihydrophenanthrene skeleton. Syntheses of compounds were based on the cross-coupling of 1-(2-iodo-5-methoxy)phenyl-ethanol with variously substituted iodobenzenes by zerovalent nickel. All the chemicals were tested to evaluate their effects on freshwater organisms from different trophic levels. Toxicity tests were performed on reducers (the bacterium Escherichia coli); producers (the alga Raphidocelis subcapitata, previously known as Selenastrum capricornutum); and consumers including a rotifer (Brachionus calyciflorus), a cladoceran (Daphnia pulex), and an anostracan (Thamnocephalus platyurus). Results suggested no one organism was uniquely sensitive to the chemicals tested. Toxicity depended on the kind and position of substituents on the aromatic skeleton.

Crystalline cholest-4-en-3-one undergoes solid-state dimerization by UV radiation to give two ring A - ring A connected dimers. No dimerization occurs in solution. The first dimer, characterized by a cyclobutane ring, is formed by connection of C-2 and C-3 of a moiety with C-5' and C-6' of another moiety, respectively. The latter dimer has a six-membered ketal ring formed by connection of C-2 with C-5' and of O, linked to C-3, with C-3'. The structures have been determined by spectroscopic means. X-ray analysis of title compound evidences the proximity of the axial H-2 of a molecule to the C-4' of a molecule in the upper layer. The transfer of the hydrogen and the connection between C-2 and C-5' might be the driving force of dimerization.

Two new sterols have been isolated from the aquatic plant Ruppia maritima and their structures were established as (24R) ergosta-8,22-diene-3 beta,6 beta,7 alpha-triol (1) and (24R) ergosta-8(14),22-diene-3 beta,6 beta,7 alpha-triol (2) on the basis of spectroscopic analysis.