TOXICITY OF PREDNISOLONE, DEXAMETHASONE AND THEIR PHOTOCHEMICAL DERIVATIVES ON AQUATIC ORGANISMS

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

Physiological and oxidative stress responses of lettuce to cleomside A: a thiohydroximate, as a new allelochemical from Cleome arabica L.

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

Degradation of lansoprazole and omeprazole in the aquatic environment

Lansoprazole and omeprazole degrade in water leading to sulfides, benzimidazolones and a red complex material. Degradation is accelerated in acid medium and by solar simulator irradiation. Benzimidazoles, dianilines and pyridines have also been identified

Photooxygenation of furans in water and ionic liquid solutions

Photooxygenation of differently functionalized furans is investigated in aqueous solutions and in ionic liquids [emim]Br and [bmim]BF4. The reaction is generally selective and the final products derive from rearrangement of the intermediate endoperoxides, depending mainly on the polarity and/or nucleophilic nature of the solvent

Phototransformation Products of Tamoxifen by Sunlight in Water. Toxicity of the Drug and Its Derivatives on Aquatic Organisms

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

Transformation and Ecotoxicity of Carbamic Pesticides in Water

N-methylcarbamate insecticides are widely used chemicals for crop protection. This study examines the hydro- lytic 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. Suspensions of benfuracarb, carbosulfan and carbo- furan 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 Cerio- daphnia dubia. 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. Ef- fects 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 pesti- cides and phenol exhibited acute and higher chronic toxicity towards the aquatic organisms tested. 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. 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

Unusual sesquiterpene glucosides from Amaranthus retroflexus

Abstract—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

Chemical fate and genotoxic risk associated with hypochlorite treatment of nicotine

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

Allelopathic Effects of Water Hyacinth [Eichhornia crassipes]

Eichhornia crassipes (Mart) Solms is an invasive weed known to out-compete native plants and negatively affect microbes including phytoplankton. The spread and population density of E. crassipes will be favored by global warming. The aim here was to identify compounds that underlie the effects on microbes. The entire plant of E. crassipes was collected from El Zomor canal, River Nile (Egypt), washed clean, then air dried. Plant tissue was extracted three times with methanol and fractionated by thin layer chromatography (TLC). The crude methanolic extract and five fractions from TLC (A–E) were tested for antimicrobial (bacteria and fungal) and anti-algal activities (green microalgae and cyanobacteria) using paper disc diffusion bioassay. The crude extract as well as all five TLC fractions exhibited antibacterial activities against both the Gram positive bacteria; Bacillus subtilis and Streptococcus faecalis; and the Gram negative bacteria; Escherichia coli and Staphylococcus aureus. Growth of Aspergillus flavus and Aspergillus niger were not inhibited by either E. crassipes crude extract nor its five fractions. In contrast, Candida albicans (yeast) was inhibited by all. Some antialgal activity of the crude extract and its fractions was manifest against the green microalgae; Chlorella vulgaris and Dictyochloropsis splendida as well as the cyanobacteria; Spirulina platensis and Nostoc piscinale. High antialgal activity was only recorded against Chlorella vulgaris. Identifications of the active antimicrobial and antialgal compounds of the crude extract as well as the five TLC fractions were carried out using gas chromatography combined with mass spectroscopy. The analyses showed the presence of an alkaloid (fraction A) and four phthalate derivatives (Fractions B–E) that exhibited the antimicrobial and antialgal activities