José Augusto Pereira

Multinuclear NMR and potentiometric studies on the interaction of zinc and cadmium with cytidine and glycylglycine. The effect of the anion

Abstract The stability constants for binary complexes formed between Zn 2+ and Cd 2+ with cytidine and glycylglycine and for the ternary complexes with the same ligands were determined by spectroscopic ( 1 H and 13 C NMR) and, except those involving Zn 2+ and cytidine, by potentiometric pH titrations in aqueous solution. The calculated values show that cadmium binds much more strongly to cytidine than zinc, and that a small but significant increase in the stability of zinc/cytidine interaction, but not for cadmium/cytidine, is observed in the presence of glycylglycine. The chemical shifts observed for cytidine with zinc show a marked dependence on the anion, being much larger for the chloride salt than for the nitrate and increase upon addition of glycylglycine, although the calculated stability constants are identical for both salts. Finally, the choice of reference chemical shifts used in the spectroscopic titrations and the effect of charged species on the values of the acidity constants are discussed.

Further constituents of Achillea ageratum

Further study of the aerial parts of Achillea ageratum yielded the new ageratriol derivative 1-O-acetylageratriol, a new oplopane 7β-hydroxyoplop-11-enone and the phenoxychromone 6-demethoxycapillarisin.

New Cyclotetrapeptides and a New Diketopiperzine Derivative from the Marine Sponge-Associated Fungus Neosartorya glabra KUFA 0702

Two new cyclotetrapeptides, sartoryglabramides A (5) and B (6), and a new analog of fellutanine A (8) were isolated, together with six known compounds including ergosta-4, 6, 8 (14), 22-tetraen-3-one, ergosterol 5, 8-endoperoxide, helvolic acid, aszonalenin (1), (3R)-3-(1H-indol-3-ylmethyl)-3,4-dihydro-1H-1,4-benzodiazepine-2,5-dione (2), takakiamide (3), (11aR)-2,3-dihydro-1H-pyrrolo[2,1-c][1,4]benzodiazepine-5,11(10H,11aH)-dione (4), and fellutanine A (7), from the ethyl acetate extract of the culture of the marine sponge-associated fungus Neosartorya glabra KUFA 0702. The structures of the new compounds were established based on extensive 1D and 2D spectral analysis. X-ray analysis was also used to confirm the relative configuration of the amino acid constituents of sartoryglabramide A (5), and the absolute stereochemistry of the amino acid constituents of sartoryglabramide A (5) and sartoryglabramides B (6) was determined by chiral HPLC analysis of their hydrolysates by co-injection with the d- and l- amino acids standards. Compounds 1–8 were tested for their antibacterial activity against Gram-positive (Escherichia coli ATCC 25922) and Gram-negative (Staphyllococus aureus ATCC 25923) bacteria, as well as for their antifungal activity against filamentous (Aspergillus fumigatus ATCC 46645), dermatophyte (Trichophyton rubrum ATCC FF5) and yeast (Candida albicans ATCC 10231). None of the tested compounds exhibited either antibacterial (MIC > 256 μg/mL) or antifungal activities (MIC > 512 μg/mL).

A New Meroditerpene and a New Tryptoquivaline Analog from the Algicolous Fungus Neosartorya takakii KUFC 7898.

A new meroditerpene sartorenol (1), a new natural product takakiamide (2) and a new tryptoquivaline analog (3) were isolated, together with nine known compounds, including aszonapyrone A, chevalone B, aszonalenin, acetylaszonalenin, 3′-(4-oxoquinazolin-3-yl) spiro[1H-indole-3,5′-oxolane]-2,2′-dione, tryptoquivalines L, F and H, and the isocoumarin derivative, 6-hydroxymellein, from the ethyl acetate extract of the culture of the algicolous fungus Neosartorya takakii KUFC 7898. The structures of the new compounds were established based on 1D and 2D NMR spectral analysis, and, in the case of sartorenol (1) and tryptoquivaline U (3), X-ray analysis was used to confirm their structures and to determine the absolute configuration of their stereogenic carbons. Compounds 1, 2 and 3 were evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria, and multidrug-resistant isolates from the environment; however, none exhibited antibacterial activity (MIC ˃ 256 mg/mL). The three new compounds did not show any quorum sensing inhibition in the screening protocol based on the pigment production by Chromobacterium violaceum (ATCC 31532).

A New Ergosterol Analog, a New Bis-Anthraquinone and Anti-Obesity Activity of Anthraquinones from the Marine Sponge-Associated Fungus Talaromyces stipitatus KUFA 0207

A new ergosterol analog, talarosterone (1) and a new bis-anthraquinone derivative (3) were isolated, together with ten known compounds including palmitic acid, ergosta-4,6,8(14),22-tetraen-3-one, ergosterol-5,8-endoperoxide, cyathisterone (2), emodin (4a), questinol (4b), citreorosein (4c), fallacinol (4d), rheoemodin (4e) and secalonic acid A (5), from the ethyl acetate extract of the culture of the marine sponge-associated fungus Talaromyces stipitatus KUFA 0207. The structures of the new compounds were established based on extensive 1D and 2D spectral analysis, and in the case of talarosterone (1), the absolute configurations of its stereogenic carbons were determined by X-ray crystallographic analysis. The structure and stereochemistry of cyathisterone (2) was also confirmed by X-ray analysis. The anthraquinones 4a–e and secalonic acid A (5) were tested for their anti-obesity activity using the zebrafish Nile red assay. Only citreorosein (4c) and questinol (4b) exhibited significant anti-obesity activity, while emodin (4a) and secalonic acid A (5) caused toxicity (death) for all exposed zebrafish larvae after 24 h.

New Polyketides and New Benzoic Acid Derivatives from the Marine Sponge-Associated Fungus Neosartorya quadricincta KUFA 0081.

Two new pentaketides, including a new benzofuran-1-one derivative (1) and a new isochromen-1-one (5), and seven new benzoic acid derivatives, including two new benzopyran derivatives (2a, b), a new benzoxepine derivative (3), two new chromen-4-one derivatives (4b, 7) and two new benzofuran derivatives (6a, b), were isolated, together with the previously reported 2,3-dihydro-6-hydroxy-2,2-dimethyl-4H-1-benzopyran-4-one (4a), from the culture of the marine sponge-associated fungus Neosartorya quadricincta KUFA 0081. The structures of the new compounds were established based on 1D and 2D NMR spectral analysis, and in the case of compounds 1, 2a, 4b, 5, 6a and 7, the absolute configurations of their stereogenic carbons were determined by an X-ray crystallographic analysis. None of the isolated compounds were active in the tests for antibacterial activity against Gram-positive and Gram-negative bacteria, as well as multidrug-resistant isolates from the environment (MIC > 256 μg/mL), antifungal activity against yeast (Candida albicans ATTC 10231), filamentous fungus (Aspergillus fumigatus ATTC 46645) and dermatophyte (Trichophyton rubrum FF5) (MIC > 512 µg/mL) and in vitro growth inhibitory activity against the MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and A375-C5 (melanoma) cell lines (GI50 > 150 µM) by the protein binding dye SRB method.

Bis-Indolyl Benzenoids, Hydroxypyrrolidine Derivatives and Other Constituents from Cultures of the Marine Sponge-Associated Fungus Aspergillus candidus KUFA0062

A previously unreported bis-indolyl benzenoid, candidusin D (2e) and a new hydroxypyrrolidine alkaloid, preussin C (5b) were isolated together with fourteen previously described compounds: palmitic acid, clionasterol, ergosterol 5,8-endoperoxides, chrysophanic acid (1a), emodin (1b), six bis-indolyl benzenoids including asterriquinol D dimethyl ether (2a), petromurin C (2b), kumbicin B (2c), kumbicin A (2d), 2″-oxoasterriquinol D methyl ether (3), kumbicin D (4), the hydroxypyrrolidine alkaloid preussin (5a), (3S, 6S)-3,6-dibenzylpiperazine-2,5-dione (6) and 4-(acetylamino) benzoic acid (7), from the cultures of the marine sponge-associated fungus Aspergillus candidus KUFA 0062. Compounds 1a, 2a–e, 3, 4, 5a–b, and 6 were tested for their antibacterial activity against Gram-positive and Gram-negative reference and multidrug-resistant strains isolated from the environment. Only 5a exhibited an inhibitory effect against S. aureus ATCC 29213 and E. faecalis ATCC29212 as well as both methicillin-resistant S. aureus (MRSA) and vancomycin-resistant enterococci (VRE) strains. Both 1a and 5a also reduced significant biofilm formation in E. coli ATCC 25922. Moreover, 2b and 5a revealed a synergistic effect with oxacillin against MRSA S. aureus 66/1 while 5a exhibited a strong synergistic effect with the antibiotic colistin against E. coli 1410/1. Compound 1a, 2a–e, 3, 4, 5a–b, and 6 were also tested, together with the crude extract, for cytotoxic effect against eight cancer cell lines: HepG2, HT29, HCT116, A549, A 375, MCF-7, U-251, and T98G. Except for 1a, 2a, 2d, 4, and 6, all the compounds showed cytotoxicity against all the cancer cell lines tested.

Antibacterial and antibiofilm activities of the metabolites isolated from the culture of the mangrove-derived endophytic fungus Eurotium chevalieri KUFA 0006

Five previously undescribed metabolites, including acetylquestinol, two prenylated indole 3-carbaldehyde derivatives, an anthranilic acid derivative and an isochromone derivative, were isolated, in addition to eleven known compounds: palmitic acid, ergosterol 5,8-endoperoxide, emodin, physcion, questin, questinol, (11S, 14R)-cyclo(tryptophylvalyl), preechinulin, neoechinulin E, echinulin and eurocristatine, from the culture of the endophytic fungus Eurotium chevalieri KUFA 0006. The structures of the previously undescribed compounds were established based on an extensive 1D and 2D NMR spectral analysis as well as HRMS and IR data. In case of 2-(2, 2-dimethylcyclopropyl)-1H-indole-3-carbaldehyde and 6, 8-dihydroxy-3-(2S-hydroxypropyl)-7-methylisochromone, the absolute configurations of their stereogenic carbons were established based on comparison of their experimental and calculated ECD spectra. All the compounds, except for palmitic acid and ergosterol 5, 8-endoperoxide, were evaluated for their antibacterial and antibiofilm activities against two Gram-positive and two Gram-negative bacteria, as well as multidrug-resistant isolates from the environment. Emodin not only exhibited moderate antibacterial activity against the Gram-positive bacteria but also showed strong synergistic association with oxacillin against MRSA Staphylococcus aureus.

Secondary Metabolites from the Culture of the Marine Sponge-Associated Fungi Talaromyces tratensis and Sporidesmium circinophorum

Wortmin (1), meso-1,4-bis(4-methoxybenzyl)-2,3-butanediol (2), and a new isocoumarin derivative tratenopyrone (3) were isolated from the marine sponge-associated fungus Talaromyces tratensis KUFA 0091. A new diphenyl ether derivative, circinophoric acid (4), was isolated, together with the previously reported anthraquinones catenarin and physcion, the benzophenone monomethylsoluchrin, and β-ergosterol-5,8-endoperoxide, from the marine sponge-associated fungus Sporidesmium circinophorum KUFA 0043. The structures of the new compounds were established based on an extensive analysis of 1D and 2Du2009NMR spectra, and, in the case of compounds 2-4, also by X-ray analysis. All of the isolated compounds were tested for their antibacterial activity against Gram-positive and Gram-negative bacteria, and multidrug-resistant isolates from the environment, as well as for their anti-quorum sensing based on the pigment production of Chromobacterium violaceum ATCC 31523. None of the compounds exhibited either antibacterial (MIC >u2009256u2009µg/mL) or anti-quorum sensing activities. The compounds were also inactive in the antifungal (MIC >u2009512u2009µg/mL) and cancer cell line (GI50 >u2009150u2009µM) assays.

A New Dihydrochromone Dimer and Other Secondary Metabolites from Cultures of the Marine Sponge-Associated Fungi Neosartorya fennelliae KUFA 0811 and Neosartorya tsunodae KUFC 9213

A previously unreported dihydrochromone dimer, paecilin E (1), was isolated, together with eleven known compounds: β-sitostenone, ergosta-4,6,8 (14), 22-tetraen-3-one, cyathisterone, byssochlamic acid, dehydromevalonic acid lactone, chevalone B, aszonalenin, dankasterone A (2), helvolic acid, secalonic acid A and fellutanine A, from the culture filtrate extract of the marine sponge-associated fungus Neosartorya fennelliae KUFA 0811. Nine previously reported metabolites, including a chromanol derivative (3), (3β, 5α, 22E), 3,5-dihydroxyergosta-7,22-dien-6-one (4), byssochlamic acid, hopan-3β,22-diol, chevalone C, sartorypyrone B, helvolic acid, lumichrome and the alkaloid harmane were isolated from the culture of the marine-sponge associated fungus Neosartorya tsunodae KUFC 9213. Paecilin E (1), dankasterone A (2), a chromanol derivative (3), (3β, 5α, 22E)-3,5-dihydroxyergosta-7,22-dien-6-one (4), hopan-3β,22-diol (5), lumichrome (6), and harmane (7) were tested for their antibacterial activity against Gram-positive and Gram-negative reference and multidrug-resistant strains isolated from the environment. While paecilin E (1) was active against S. aureus ATCC 29213 and E. faecalis ATCC 29212, dankastetrone A (2) was only effective against E. faecalis ATCC 29212 and the multidrug-resistant VRE E. faecalis A5/102. Both compounds neither inhibit biofilm mass production in any of the strains at the concentrations tested nor exhibit synergistic association with antibiotics.