1,721,038 research outputs found
Physiological and oxidative stress responses of lettuce to cleomside A: a thiohydroximate, as a new allelochemical from Cleome arabica L.
Full text linkThe 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
Toxicity and Risk of Transformation Products of Emerging Contaminants for Aquatic Organisms: Pharmaceutical Case Studies
No full textDiscussion 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
Two new polyhydroxylated sterols from Ruppia maritima
No full textTwo new sterols have been isolated from the aquatic plant Ruppia maritima and their structures were established as (24R) ergosta-8,22-diene-3β,6β,7α-triol (1) and (24R) ergosta-8(14),22-diene-3β,6β,7α-triol (2) on the basis of spectroscopic analysis
Enantioselective synthesis of phenylpropanetriols
No full textThe four stereomer 1-(4-hydroxy-3-methoxy)-phenyl-1,2,3-propanetriols were obtained in about 30% yields starting from ferulic acid by synthesis based on osmium catalyzed asymmetric dihydroxylation
New Insights into Chemical and Biological Properties of Funicone-like Compounds
No full textFunicone-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
Linolenic acid as a potential allelochemical released by Eichhornia crassipes (Mart.) Solms in a continuous trapping apparatus.
No full textLinolenic acid as a potential allelochemical released by Eichhornia crassipes (Mart.) Solms in a continuous trapping apparatus.
No full textPOLYOXYGENATED OLEANANE TRITERPENES FROM HYDROCOTYLE RANUNCULOIDES
No full textThree new triterpenes, i.e. 3-oxo-15α,16α,21β,22α,28-pentahydroxy-Δ1,12-oleanane, 3-oxo-15α,16α,21β, 22α,28-pentahydroxy-Δ12-oleanane and 17,22-seco-3-oxo-22,23-dihydroxy-Δ12,16-oleanonic acid, have been isolated from Hydrocotyle ranunculoides. The structures have been attributed on the basis of their physical features. © 1994
Influence of Phenanthrenes on Microalgal Growth
No full textThe 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
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