Publications by authors named "Edith M Antunes"

Article Synopsis
  • Four new triterpenoid saponins (manniosides G, H, I, and J) were identified from the leaves of a plant, alongside several known compounds.* -
  • Their structures were determined using advanced techniques like NMR analysis and mass spectrometry.* -
  • The extracts and some isolated compounds were tested for antibacterial properties but showed no significant antioxidant activity.*
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Article Synopsis
  • * Researchers extracted three known metabolites and utilized NMR to identify their structures, then loaded these compounds onto gold nanoparticles (sAuNPs) made from brown seaweed extract to improve their targeting capability.
  • * The resulting compound-AuNP conjugates demonstrated over 90% effectiveness in penetrating cancer cells (specifically MCF-7), suggesting that this method may address the challenges faced in developing new anticancer drugs.
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The use of natural products as chemotherapeutic agents is well established; however, many of these are associated with undesirable side effects, including high toxicity and instability. Furthermore, the development of drug resistant cancers makes the search for new anticancer lead compounds a priority. In this study, the extraction of an sp.

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Five known (1, 2, 4, 6 and 7) halogenated monoterpenes together with 1Z,3R∗,4S∗,5E,7Z)-1-bromo-3,4,8-trichloro-7-(dichloromethyl)-3-methylocta-1,5,7-triene (3) and (3R∗,4S∗)-3,4,6,7-tetrachloro-3,7-dimethyl-octen-1-ene (5) were isolated from the red macroalga Plocamium suhrii and their structures deduced from their spectroscopic data. The seven compounds from P. suhrii together with five related compounds from Plocamium cornutum have been evaluated for their cytotoxic effects on an esophageal cancer cell line (WHCO1).

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The synthesis of phosphorous oxide triazatetrabenzcorroles (TBC) tetra- (9, 11) or octa- (13) substituted on the ring with halogenated functional groups is reported. The complexes are not aggregated in dimethylsulfoxide (DMSO) and show solubility in solvents such as pyridine. The Q band absorption spectra of the complexes are red-shifted compared to unsubstituted PTBC.

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Four new halogenated monoterpene aldehydes (1-4) have been isolated from the South African marine red alga Plocamium corallorhiza, along with the known compounds 4,6-dibromo-1,1-dichloro-3,7-dimethyl-2E,7-octadiene (5) and 1,4,8-tribromo-3,7-dichloro-3,7-dimethyl-1E,5E-octadiene (10). The structures of the new compounds were determined by interpretation of their spectroscopic data and synthesis and mass spectrometric analysis of their pentafluorobenzyloxime (PFBO) derivatives.

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This review presents the structure, biological activity, biosynthetic studies and, where applicable, references to syntheses of 81 marine alkaloids containing either tetra-, hexa- or octa-hydrogenated variants of pyrrolo[4,3,2-de]quinoline, pyrrolo[4,3,2-de]pyrrolo[2,3-h]quinoline and pyrido[2,3-h]pyrrolo[4,3,2-de]quinoline core skeletons. The literature describing the isolation of pyrroloiminoquinones, and related metabolites, from marine sponges is littered with taxonomic inconsistencies and recent efforts to clarify the taxonomy of the sponges that produce this group of metabolites are discussed.

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An examination of organic extracts of four new species of South African latrunculid sponges, Tsitsikamma pedunculata, T. favus, Latrunculia bellae, and Strongylodesma algoaensis, yielded 13 known and eight new pyrroloiminoquinone alkaloids, 3-dihydro-7,8-dehydrodiscorhabdin C (4), 14-bromo-3-dihydro-7,8-dehydrodiscorhabdin C (5), discorhabdin V (6), 14-bromo-1-hydroxydiscorhabdin V (7), tsitsikammamine A N-18 oxime (10), tsitsikammamine B N-18 oxime (11), 1-methoxydiscorhabdin D (12), and 1-aminodiscorhabdin D (13). Standard spectroscopic methods provided the structures of the pyrroloiminoquinone metabolites, while chiral GC-MS analysis of the acylated ozonolysis products of 21 confirmed the stereochemistry of the l-histidine residue in this compound.

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Ultraviolet (UV) light is known to induce the generation of free radicals in biological tissues such as skin. Of these free radicals, the O2-. and particularly the.

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