Jussara P. Barbosa

Bio: Jussara P. Barbosa is an academic researcher from Oswaldo Cruz Foundation. The author has contributed to research in topics: Dictyotales & Neuraminidase. The author has an hindex of 11, co-authored 14 publications receiving 397 citations. Previous affiliations of Jussara P. Barbosa include Federal Fluminense University.

In vitro antiviral diterpenes from the Brazilian brown alga Dictyota pfaffii.

Abstract: Specimens of Dictyota pfaffii from Atol das Rocas, Northeast Brazil, afforded the rare dolabellane diterpene 10,18-diacetoxy-8-hydroxy-2, 6-dolabelladiene (1) and the new 10-acetoxy-8,18-di-hydroxy-2,6-dolabelladiene (2). Reduction of 1 yielded 8,10,18-trihydroxy-2,6-dolabelladiene (3), also present in the crude ex-tract of D. pfaffii. All three structures were assigned by 1D and 2D NMR spectral data. These substances showed strong anti-HSV-1 activity in vitro but only 3 inhibited the reverse transcriptase enzyme of HIV-1.

The Effects of the Diterpenes Isolated from the Brazilian Brown Algae Dictyota pfaffii and Dictyota menstrualis against the Herpes Simplex Type-1 Replicative Cycle

Abstract: We describe in this paper that the diterpenes 8,10,18-trihydroxy-2,6-dolabelladiene ( 1) and (6 R)-6-hydroxydichotoma-4,14-diene-1,17-dial ( 2), isolated from the marine algae DICTYOTA PFAFFII and D. MENSTRUALIS, respectively, inhibited HSV-1 infection in Vero cells. We initially observed that compounds 1 and 2 inhibited HSV-1 replication in a dose-dependent manner, resulting in EC (50) values of 5.10 and 5.90 microM, respectively, for a multiplicity of infection (MOI) of 5. Moreover, the concentration required to inhibit HSV-1 replication was not cytotoxic, resulting in good selective index (SI) values. Next, we found that compound 1 sustained its anti-herpetic activity even when added to HSV-1-infected cells at 6 h after infection, while compound 2 sustained its activity for up to 3 h after infection, suggesting that these compounds inhibit initial events during HSV-1 replication. We also observed that both compounds were incapable of impairing HSV-1 adsorption and penetration. In addition, the tested molecules could decrease the contents of some HSV-1 early proteins, such as UL-8, RL-1, UL-12, UL-30 and UL-9. Our results suggest that the structures of compounds 1 and 2, Brazilian brown algae diterpenes, might be promising for future antiviral design.

Novel aminonaphthoquinone mannich bases derived from lawsone and their copper(II) complexes: synthesis, characterization and antibacterial activity

Abstract: A series of novel Mannich bases (HL1-HL13) derived from 2-hydroxy-1,4-naphthoquinone (lawsone), substituted benzaldehydes [C6H2R1R2R3C(O)H] and various primary amines (NH2R4, R4 = n-butyl, benzyl, allyl, 2-furfuryl), and their Cu2+ complexes, [Cu(L1)2]-[Cu(L13)2], have been synthesized and fully characterized by analytical and spectroscopic methods. The structures of complexes 1(R1 = R2 = R3 = H; R4 = Bu), 2(R1 = R3 = H; R2 = NO2; R4= Bu) and 7 (R1 = OH; R2 = R3 = H; R4= Bu) were determined by single crystal X-ray diffraction studies. All complexes crystallize in centrosymmetric space groups, with a copper atom in the inversion centre. Two L- coordinate through the naphthalen-2-olate oxygen and secondary amine-N atoms, forming six-membered chelate rings around the copper atom in a trans-N2O2 environment; spectroscopic data confirm that the other complexes exhibit similar molecular arrangement. The antimicrobial activity of all compounds has been tested on seven different strains of bacteria: Bacillus cereus, Bacillus subtilis, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosaand Staphylococcus aureus. In general, Mannich bases were more active than complexes, HL11(R1 = OH; R2 =H; R3 = Me; R4= Bn) and HL13(R1 = OH; R2 = H; R3 = Br; R4= Bn) being the most potent inhibitors. The MIC for the most active compound HL11against S. Coliwas 20 µmol L-1 (8 µg mL-1), better than Chloramphenicol (90 µmol L-1) and well below most values reported for other naphthoquinones.

A dolabellane diterpene from the brown alga Dictyota pfaffii as chemical defense against herbivores

Abstract: Laboratory and field experiments assessed the defensive properties of the crude extract and major secondary metabolite found in the Brazilian brown alga Dictyota pfaffii. Natural concentrations of the crude organic extract of D. pfaffii significantly inhibited feeding by the sea urchin Lytechinus variegatus and generalist herbivore fishes in the field. In contrast, the crude extract did not inhibit feeding by the crab Pachygrapsus transversus. Chemical defensive action against the sea urchin and the generalist fishes was due to the diterpenoid 10,18-diacetoxy-8-hydroxy-2,6-dolabelladiene found as the major natural product in D. pfaffii. However, this compound did not inhibit feeding by P. transversus as readily as the crude extract. This is the first report showing that Dictyota species produce dolabellane diterpenes as chemical defense against herbivory. In addition, these results widen the action spectrum of secondary metabolites found in species of this brown algal genus. Since dolabellanes constitute the major skeleton type found in Dictyota, we suggest that these diterpenes may play an important ecological function as defenses to the Dictyota species worldwide.

Bioactive potential and possible health effects of edible brown seaweeds

Abstract: Marine macroalgae (seaweeds) are rich in bioactive compounds that could potentially be exploited as functional ingredients for both human and animal health applications. Despite the intensive efforts that are being made to isolate and identify new compounds with potential medicinal, health or pharmaceutical activities, very few compounds with real potency are available. Bioactive compounds that are most extensively researched include sulfated polysaccharides, phlorotannins and diterpenes. These compounds have been reported to possess strong anti-viral, anti-tumor and anti-cancer properties. At the same time, the prebiotic health potential of the polysaccharides from seaweeds is also increasingly being studied either by feeding whole seaweeds or purified polysaccharides to laboratory and farm animals. The present review discusses the pharmaceutical, health and research potential of different bioactive compounds present in brown seaweeds.