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Introduction. Cryptococcal biofilms have been associated with persistent infections and antifungal resistance. Therefore, strategies, such as the association of natural compounds and antifungal drugs, have been applied for the prevention of biofilm growth. Moreover, the Caenorhabditis elegans pathogenicity model has been used to investigate the capacity to inhibit the pathogenicity of Cryptococcus neoformans sensu stricto.Hypothesis. Anthraquinones and antifungals are associated with preventing C. neoformans sensu stricto biofilm formation and disrupting these communities. Antraquinones reduced the C. neoformans sensu stricto pathogenicity in the C. elegans model.Aim. This study aimed to evaluate the in vitro interaction between aloe emodin, barbaloin or chrysophanol and itraconazole or amphotericin B against growing and mature biofilms of C. neoformans sensu stricto.Methodology. Compounds and antifungal drugs were added during biofilm formation or after 72 h of growth. Then, the metabolic activity was evaluated by the MTT reduction assay, the biomass by crystal-violet staining and the biofilm morphology by confocal laser scanning microscopy. C. neoformans sensu stricto's pathogenicity was investigated using the nematode C. elegans. Finally, pathogenicity inhibition by aloe emodin, barbarloin and chrysophanol was investigated using this model.Results. Anthraquinone-antifungal combinations affected the development of biofilms with a reduction of over 60 % in metabolic activity and above 50 % in biomass. Aloe emodin and barbaloin increased the anti-biofilm activity of antifungal drugs. Chrysophanol potentiated the effect of itraconazole against C. neoformans sensu stricto biofilms. The C. elegans mortality rate reached 76.7 % after the worms were exposed to C. neoformans sensu stricto for 96 h. Aloe emodin, barbaloin and chrysophanol reduced the C. elegans pathogenicity with mortality rates of 61.12 %, 65 % and 53.34 %, respectively, after the worms were exposed for 96 h to C. neoformans sensu stricto and these compounds at same time.Conclusion. These results highlight the potential activity of anthraquinones to increase the effectiveness of antifungal drugs against cryptococcal biofilms.

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ETHNOPHARMACOLOGICAL RELEVANCE: Species of Vismia (Hypericaceae), known in Brazil as "lacre", are commonly used in traditional Amazonian medicine for the treatment of skin lesions, including those caused by Leishmania infection. AIM OF THE STUDY: Hexane extracts from the leaves of Vismia cayennensis, V. gracilis, V. sandwithii and V. guianensis, as well as from the fruits of the latter, in addition to the anthraquinones vismiaquinone, physcion and chrysophanol isolated from these species were explored for their anti-promastigote and anti-amastigote activity on Leishmania amazonensis. MATERIALS AND METHODS: Extracts were prepared by static maceration with n-hexane. The compounds, isolated by chromatographic techniques, were identified by spectroscopic methods (1H and 13C NMR). Promastigotes of L.amazonensis were incubated with hexane extracts (1-50 µg/mL) or anthraquinones (1-50 µM) and the parasite survival analyzed. The action of compounds on reactive oxygen species (ROS) production, mitochondrial membrane potential, and membrane integrity of promastigotes were evaluated by flow cytometer, and the cytotoxicity on mammalian cells using MTT assay. Furthermore, the activity of compounds against amastigotes and nitric oxide production were also investigated. RESULTS: Vismiaquinone and physcion were obtained from the leaves of V. guianensis. Physcion, as well as chrysophanol, were isolated from V. sandwithii. Vismia cayennensis and V. gracilis also showed vismiaquinone, compound detected in lower quantity in the fruits of V. guianensis. All extracts were active against the parasite, corroborating the popular use. The greatest activity against promastigotes was achieved with V. guianensis extract (IC50 4.3 µg/mL), precisely the most used Vismia species for treating cutaneous leishmaniasis. Vismiaquinone and physcion exhibited relevant activity with IC50 12.6 and 2.6 µM, respectively. Moreover, all extracts and anthraquinones tested induced ROS production, mitochondrial dysfunction, membrane disruption and were able to kill intracellular amastigote forms, being worthy of further in vivo studies as potential antileishmanial drugs. CONCLUSIONS: The overall data achieved in the current investigation scientifically validate the traditional use of Vismia species, mainly V. guianensis, as an anti-Leishmania agent. Furthermore, the promising results presented here indicate species of Vismia as potentially useful resources of Brazilian flora for the discovery of therapeutic solutions for neglected diseases.

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The World Health Organization reported that tuberculosis remains on the list of the top ten threats to public health worldwide. Among the main causes is the limited effectiveness of treatments due to the emergence of resistant strains of Mycobacterium tuberculosis. One of the main drug targets studied to combat M. tuberculosis is DNA gyrase, the only enzyme responsible for regulating DNA topology in this specie and considered essential in all bacteria. In this context, the present work tested the ability of 2824 anthraquinones retrieved from the PubChem database to act as competitive inhibitors through interaction with the ATP-binding pocket of DNA gyrase B of M. tuberculosis. Virtual screening results based on molecular docking identified 7122772 (N-(2-hydroxyethyl)-9,10-dioxoanthracene-2-sulfonamide) as the best-scored ligand. From this anthraquinone, a new derivative was designed harbouring an aminotriazole moiety, which exhibited higher binding energy calculated by molecular docking scoring and free energy calculation from molecular dynamics simulations. In addition, in these last analyses, this ligand showed to be stable in complex with the enzyme and further predictions indicated a low probability of cytotoxic and off-target effects, as well as an acceptable pharmacokinetic profile. Taken together, the presented results show a new synthetically accessible anthraquinone with promising potential to inhibit the GyrB of M. tuberculosis.

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A new method based on Ultraviolet spectrophotometry was developed and compared with that based on high-performance liquid chromatography for the determination and quantification of anthraquinones in the extracts of Rhamnus purshiana bark. A validated quantitative analysis of cascaroside A, cascaroside B, emodin, and aloe-emodin in these herbal products has been previously performed using high-performance liquid chromatography coupled with a diode array detector. In the high-performance liquid chromatography analysis, all the anthraquinones showed satisfactory regression (r2 > 0.98) within the test ranges, and the recovery was in the range of 94-117%. The limits of detection and quantification were 0.008-0.010 and 0.029-0.035 µg/mL, respectively. Hierarchical cluster analysis and principal component analysis showed differences in the anthraquinones determined from herbal samples. Subsequently, a simple and low-cost ultraviolet spectrophotometric methodology for the quantitative analysis of the same compounds in the extracts was applied, and all the contents were determined. A paired t-test confirmed that there were no significant differences between the two methods. Our results revealed that the developed method is simple and provides the ability to discriminate and control the quality of anthraquinones in herbal products.

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Plants that produce secondary metabolites with allelopathic activity or phytotoxicity can be biotechnologically important, serving as sources of allelochemicals, and thus contributing to the agroindustrial sector. Vismia japurensis (Hypericaceae) is an Amazonian species that grows in clumps called vismiais, from which most other plants are absent. Accordingly, the objective of this study was to identify possible phytotoxicity effects of hexane and methanol extracts of Vismia japurensis leaves and branches in vivo and from seedlings grown in vitro on Lactuca sativa. In addition, fresh and dry leaves were assayed by the sandwich method in order to determine their ability to release allelochemicals. The hexanic extract from in vitro seedlings reduced germination by 10%, while the methanol extract produced a 16% reduction in germination speed. Root growth of Lactuca sativa was inhibited by 64.7% when subjected to hexane leaf extract, by 39.3% under the influence of hexane branch extract, and by 96.09% for in vitro seedling hexanic extract. When analysed by thin layer chromatography and 1H nuclear magnetic resonance, extracts showed evidence of terpenes, anthraquinones and flavonoids, with greater intensity of signals in the aromatic region of in vitro seedling hexanic extract. Clearly, Vismia japurensis has a high biotechnological potential in terms of the production of substances of low polarity with capacity to interfere in plant development.

Plantas que produzem metabólitos secundários com atividade alelopática ou fitotóxica podem ser biotecnologicamente importantes, servindo como fontes de aleloquímicos e, assim, contribuindo para o setor agroindustrial. Vismia japurensis (Hypericaceae) é uma espécie amazônica que cresce em grupos, formando vismiais. Assim, o objetivo deste estudo foi identificar possíveis efeitos fitotóxicos de extratos hexânicos e metanólicos de folhas e ramos de Vismia japurensis in vivo e de plântulas cultivadas in vitro sobre Lactuca sativa. Além disso, folhas frescas e secas foram analisadas pelo método sanduíche, a fim de determinar sua capacidade de liberação de aleloquímicos. O extrato hexânico de plântulas in vitro reduziu a germinação em 10% e o extrato metanólico promoveu uma redução de 16% na velocidade de germinação. O crescimento radicular de Lactuca sativa foi inibido em 64,7% quando submetido ao extrato hexânico das folhas, em 39,3% sob influência do extrato hexânico dos galhos e em 96,09% para o extrato de hexânico das plântulas in vitro. Quando analisados por cromatografia em camada delgada e ressonância magnética nuclear de 1H, os extratos mostraram evidências de terpenos, antraquinonas e flavonoides, com maior intensidade de sinais na região aromática do extrato hexânico das plântulas in vitro. Assim, Vismia japurensis possui elevado potencial biotecnológico em termos de produção de substâncias de baixa polaridade com capacidade de interferência no desenvolvimento de plantas.

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Abstract Plants that produce secondary metabolites with allelopathic activity or phytotoxicity can be biotechnologically important, serving as sources of allelochemicals, and thus contributing to the agroindustrial sector. Vismia japurensis (Hypericaceae) is an Amazonian species that grows in clumps called vismiais, from which most other plants are absent. Accordingly, the objective of this study was to identify possible phytotoxicity effects of hexane and methanol extracts of Vismia japurensis leaves and branches in vivo and from seedlings grown in vitro on Lactuca sativa. In addition, fresh and dry leaves were assayed by the sandwich method in order to determine their ability to release allelochemicals. The hexanic extract from in vitro seedlings reduced germination by 10%, while the methanol extract produced a 16% reduction in germination speed. Root growth of Lactuca sativa was inhibited by 64.7% when subjected to hexane leaf extract, by 39.3% under the influence of hexane branch extract, and by 96.09% for in vitro seedling hexanic extract. When analysed by thin layer chromatography and 1H nuclear magnetic resonance, extracts showed evidence of terpenes, anthraquinones and flavonoids, with greater intensity of signals in the aromatic region of in vitro seedling hexanic extract. Clearly, Vismia japurensis has a high biotechnological potential in terms of the production of substances of low polarity with capacity to interfere in plant development.

Resumo Plantas que produzem metabólitos secundários com atividade alelopática ou fitotóxica podem ser biotecnologicamente importantes, servindo como fontes de aleloquímicos e, assim, contribuindo para o setor agroindustrial. Vismia japurensis (Hypericaceae) é uma espécie amazônica que cresce em grupos, formando vismiais. Assim, o objetivo deste estudo foi identificar possíveis efeitos fitotóxicos de extratos hexânicos e metanólicos de folhas e ramos de Vismia japurensis in vivo e de plântulas cultivadas in vitro sobre Lactuca sativa. Além disso, folhas frescas e secas foram analisadas pelo método sanduíche, a fim de determinar sua capacidade de liberação de aleloquímicos. O extrato hexânico de plântulas in vitro reduziu a germinação em 10% e o extrato metanólico promoveu uma redução de 16% na velocidade de germinação. O crescimento radicular de Lactuca sativa foi inibido em 64,7% quando submetido ao extrato hexânico das folhas, em 39,3% sob influência do extrato hexânico dos galhos e em 96,09% para o extrato de hexânico das plântulas in vitro. Quando analisados por cromatografia em camada delgada e ressonância magnética nuclear de 1H, os extratos mostraram evidências de terpenos, antraquinonas e flavonoides, com maior intensidade de sinais na região aromática do extrato hexânico das plântulas in vitro. Assim, Vismia japurensis possui elevado potencial biotecnológico em termos de produção de substâncias de baixa polaridade com capacidade de interferência no desenvolvimento de plantas.

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Plants that produce secondary metabolites with allelopathic activity or phytotoxicity can be biotechnologically important, serving as sources of allelochemicals, and thus contributing to the agroindustrial sector. Vismia japurensis (Hypericaceae) is an Amazonian species that grows in clumps called vismiais, from which most other plants are absent. Accordingly, the objective of this study was to identify possible phytotoxicity effects of hexane and methanol extracts of Vismia japurensis leaves and branches in vivo and from seedlings grown in vitro on Lactuca sativa. In addition, fresh and dry leaves were assayed by the sandwich method in order to determine their ability to release allelochemicals. The hexanic extract from in vitro seedlings reduced germination by 10%, while the methanol extract produced a 16% reduction in germination speed. Root growth of Lactuca sativa was inhibited by 64.7% when subjected to hexane leaf extract, by 39.3% under the influence of hexane branch extract, and by 96.09% for in vitro seedling hexanic extract. When analysed by thin layer chromatography and 1H nuclear magnetic resonance, extracts showed evidence of terpenes, anthraquinones and flavonoids, with greater intensity of signals in the aromatic region of in vitro seedling hexanic extract. Clearly, Vismia japurensis has a high biotechnological potential in terms of the production of substances of low polarity with capacity to interfere in plant development.

Plantas que produzem metabólitos secundários com atividade alelopática ou fitotóxica podem ser biotecnologicamente importantes, servindo como fontes de aleloquímicos e, assim, contribuindo para o setor agroindustrial. Vismia japurensis (Hypericaceae) é uma espécie amazônica que cresce em grupos, formando vismiais. Assim, o objetivo deste estudo foi identificar possíveis efeitos fitotóxicos de extratos hexânicos e metanólicos de folhas e ramos de Vismia japurensis in vivo e de plântulas cultivadas in vitro sobre Lactuca sativa. Além disso, folhas frescas e secas foram analisadas pelo método sanduíche, a fim de determinar sua capacidade de liberação de aleloquímicos. O extrato hexânico de plântulas in vitro reduziu a germinação em 10% e o extrato metanólico promoveu uma redução de 16% na velocidade de germinação. O crescimento radicular de Lactuca sativa foi inibido em 64,7% quando submetido ao extrato hexânico das folhas, em 39,3% sob influência do extrato hexânico dos galhos e em 96,09% para o extrato de hexânico das plântulas in vitro. Quando analisados por cromatografia em camada delgada e ressonância magnética nuclear de 1H, os extratos mostraram evidências de terpenos, antraquinonas e flavonoides, com maior intensidade de sinais na região aromática do extrato hexânico das plântulas in vitro. Assim, Vismia japurensis possui elevado potencial biotecnológico em termos de produção de substâncias de baixa polaridade com capacidade de interferência no desenvolvimento de plantas.

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Plants that produce secondary metabolites with allelopathic activity or phytotoxicity can be biotechnologically important, serving as sources of allelochemicals, and thus contributing to the agroindustrial sector. Vismia japurensis (Hypericaceae) is an Amazonian species that grows in clumps called vismiais, from which most other plants are absent. Accordingly, the objective of this study was to identify possible phytotoxicity effects of hexane and methanol extracts of Vismia japurensis leaves and branches in vivo and from seedlings grown in vitro on Lactuca sativa. In addition, fresh and dry leaves were assayed by the sandwich method in order to determine their ability to release allelochemicals. The hexanic extract from in vitro seedlings reduced germination by 10%, while the methanol extract produced a 16% reduction in germination speed. Root growth of Lactuca sativa was inhibited by 64.7% when subjected to hexane leaf extract, by 39.3% under the influence of hexane branch extract, and by 96.09% for in vitro seedling hexanic extract. When analysed by thin layer chromatography and 1H nuclear magnetic resonance, extracts showed evidence of terpenes, anthraquinones and flavonoids, with greater intensity of signals in the aromatic region of in vitro seedling hexanic extract. Clearly, Vismia japurensis has a high biotechnological potential in terms of the production of substances of low polarity with capacity to interfere in plant development.(AU)

Plantas que produzem metabólitos secundários com atividade alelopática ou fitotóxica podem ser biotecnologicamente importantes, servindo como fontes de aleloquímicos e, assim, contribuindo para o setor agroindustrial. Vismia japurensis (Hypericaceae) é uma espécie amazônica que cresce em grupos, formando vismiais. Assim, o objetivo deste estudo foi identificar possíveis efeitos fitotóxicos de extratos hexânicos e metanólicos de folhas e ramos de Vismia japurensis in vivo e de plântulas cultivadas in vitro sobre Lactuca sativa. Além disso, folhas frescas e secas foram analisadas pelo método sanduíche, a fim de determinar sua capacidade de liberação de aleloquímicos. O extrato hexânico de plântulas in vitro reduziu a germinação em 10% e o extrato metanólico promoveu uma redução de 16% na velocidade de germinação. O crescimento radicular de Lactuca sativa foi inibido em 64,7% quando submetido ao extrato hexânico das folhas, em 39,3% sob influência do extrato hexânico dos galhos e em 96,09% para o extrato de hexânico das plântulas in vitro. Quando analisados por cromatografia em camada delgada e ressonância magnética nuclear de 1H, os extratos mostraram evidências de terpenos, antraquinonas e flavonoides, com maior intensidade de sinais na região aromática do extrato hexânico das plântulas in vitro. Assim, Vismia japurensis possui elevado potencial biotecnológico em termos de produção de substâncias de baixa polaridade com capacidade de interferência no desenvolvimento de plantas.(AU)

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This study aimed to evaluate the in vitro effect of aloe emodin, barbaloin and chrysophanol on growing and mature biofilms of Cryptococcus neoformans sensu stricto. The compounds were added at the moment of inducing biofilm growth or after growth for 72 h to evaluate their effects on growing and mature biofilms, respectively. Then, biofilm biomass was evaluated by crystal violet staining and metabolic activity by the XTT reduction assay. Morphological alterations were also evaluated by laser scanning confocal microscopy. Aloe emodin and barbaloin affected growing biofilms and disrupted mature biofilms, reducing metabolic activity by > 60% and biomass by > 70%. Chrysophanol only inhibited mature biofilms, but to a lesser extent. In conclusion, anthraquinones, especially aloe emodin and barbaloin, show a relevant effect against growing and mature biofilms of C. neoformans sensu stricto.

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Anthracene and anthracene derivatives have been extensively studied over the years because of their interesting photophysical, photochemical, and biological properties. They are currently the subject of research in several areas, which investigate their use in the biological field and their application in OLEDs, OFETs, polymeric materials, solar cells, and many other organic materials. Their synthesis remains challenging, but some important preparative methods have been reported, especially in the last decade. This review presents an update of the recent strategies that have been employed to prepare anthracene derivatives. It encompasses papers published over the last twelve years (2008-2020) and focuses on direct and indirect methods to construct anthracene and anthraquinone frameworks.