Publications by authors named "Lidilhone Hamerski"

Article Synopsis
  • * The introduction of vaccines in late 2020 helped decrease fatalities, but combating COVID-19 and other potential pandemics still requires continuous research and drug development.
  • * Coumarins, versatile compounds with unique properties, show promise in drug design to effectively target SARS-CoV-2, emphasizing the importance of developing new treatments to manage COVID-19 and similar viral threats.
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Alzheimer's disease (AD) is a neurodegenerative, progressive, and fatal disorder characterized by marked atrophy of the cerebral cortex and loss of basal forebrain cholinergic neurons. The main pathological features of AD are related to neuronal degeneration and include extracellular deposition of amyloid beta plaques (Aβ plaques), intracellular formation of neurofibrillary tangles (NFTs), and neuroinflammation. So far, drugs used to treat AD have symptomatic and palliative pharmacological effects, disappearing with continued use due to neuron degeneration and death.

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Article Synopsis
  • Corals face threats from global warming, with bleaching caused by the loss of symbiotic dinoflagellates being a significant immediate impact.
  • The study explores how increased temperatures affect the biochemical and cellular characteristics of these important endosymbionts, showing that heat stress leads to an increase in oxygen levels while causing a decrease in key proteins and pigments.
  • Observations via transmission electron microscopy reveal that heat stress compromises the structural integrity of the dinoflagellates, resulting in thinner cell walls, chloroplast deformation, and an accumulation of lipid droplets after just three days at elevated temperatures.
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Due to the lack of effective pharmacotherapy options to treats Alzheimer's disease, new strategies have been approached in the search for multi-target molecules as therapeutic options. In this work, four indole alkaloids, geissoschizoline, geissoschizone, geissospermine, and 3',4',5',6'-tetradehydrogeissospermine were isolated from Geissospermum vellosii (Pao pereira) and evaluated for their anticholinesterase activities. While geissospermine inhibited only butyrylcholinesterase (BChE), the other alkaloids behaved as non-selective inhibitors of acetylcholinesterase (AChE) and BChE.

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This review presents the chemical diversity and pharmacological properties of secondary metabolites produced by endophytic fungi associated with various genera of Rubiaceae. Several classes of natural products are described for these endophytes, although, this study highlights the importance of some metabolites, which are involved in antifungal, antibacterial, anti-protozoal activities; neurodegenerative diseases; cytotoxic activity; anti-inflammatory and antioxidant activity; and hyperglycemic control.

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Pigmented bacterial symbionts play major roles in the health of coral holobionts. However, there is scarce knowledge on the diversity of these microbes for several coral species. To gain further insights into holobiont health, pigmented bacterial isolates of Fabibacter pacificus (Bacteroidetes; n = 4), Paracoccus marcusii (Alphaproteobacteria; n = 1), and Pseudoalteromonas shioyasakiensis (Gammaproteobacteria; n = 1) were obtained from the corals Mussismilia braziliensis and Montastraea cavernosa in Abrolhos Bank, Brazil.

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The high diversity of species in the marine environment gives rise to compounds with unique structural patterns not found as natural products in other systems and with great potential for pharmacological, cosmetic and nutritional use. The genus Tubastraea (Class Anthozoa, Order Scleractinia, Family Dendrophylliidae) is characterized as a hard coral without the presence of zooxanthellae. In species of this genus alkaloids derived from the compound aplysinopsin with pharmacological activity are known.

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This study presents new inhibitors of the nucleoside hydrolase from (NH) with leishmanicidal activity. Biological screening of 214 Brazilian plant extracts was performed to select plants with enzyme inhibitory activity. Two plants were selected for their results, and for their lack of prior phytochemical description: DC.

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Background: The influenza virus can cause seasonal infections with mild to severe symptoms, circulating worldwide, and it can affect people in any age group. Therefore, this infection is a serious public health problem that causes severe illness and death in high-risk populations. Every year, 0.

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Extracts of Serjania lethalis A. St.-Hil leaves and stems were tested in order to identify potential agents against Leishmania amazonensis.

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Chemical investigation of Guarea kunthiana fruits, guided by their effect on the reproductive cycle of engorged females of the cattle tick Rhipicephalus (Boophilus) microplus-a major economic problem to the livestock industry worldwide-led to isolation of 3β-O-tigloylmelianol, a new protolimonoid, from the bioactive hexane phase obtained by partitioning the crude ethanol extract. An adult immersion test was performed. The compound strongly inhibited egg-laying and hatchability (99.

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Ethanol extracts from six selected species from the Cerrado of the Central-Western region of Brazil, which are used in traditional medicine for the treatment of infectious diseases and other medical conditions, namely Erythroxylum suberosum St. Hil. (Erythroxylaceae), Hyptis crenata Pohl.

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A total of 73 ethanol extracts from different anatomical parts of 44 plant species belonging to 24 families, native to the Mid-Western region of Brazil, were assessed in vitro for their effect on the reproductive cycle of engorged females of the cattle tick Rhipicephalus (Boophilus) microplus, using the adult immersion test. All extracts were evaluated at the concentration of 0.2 % and, among the extracts tested, the one obtained from the fruits of Guarea kunthiana (Meliaceae) proved to be highly efficacious, showing 99.

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Two flavonoids 3,5,7,3',4'-pentahydroxy-6-prenylflavonol (1) and 3,5,7,3',4'-pentahydroxy-8-methyl-6-prenylflavonol (2) were isolated from the ethyl acetate extract of sheaths of Vellozia kolbekii Alves (Velloziaceae). This is the first time that compound 2 has been described. The crude extract and flavonoids were found to be active as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavengers and were able to the increase tolerance of the eukaryotic microorganism Saccharomyces cerevisiae to oxidative stress generated by H(2)O(2).

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A total of 42 ethanolic extracts from 30 different plant species, native to the Pantanal and Cerrado of the West-Central region of Brazil, have been evaluated for their larvicidal activity against Aedes aegypti larvae, the vector of dengue and dengue hemorrhagic fevers. Among the extracts tested, that obtained from the trunk bark of Ocotea velloziana was the most active. Using a bioassay-directed fractionation of this extract, the active constituent was isolated and characterized as the aporphine alkaloid (+)-dicentrine.

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Two new triterpene glucosides, beta-D-glucopyranosyl 2alpha,3beta,24-trihydroxyolean- 12-en-28-oate and beta-D-glucopyranosyl 2alpha,3beta,23,24-tetrahydroxyurs-12-en-28-oate, in addition to nine known compounds belonging to three different triterpene classes (oleanane-, ursane- and lupane-type) have been isolated from the stems of a specimen of Combretum laxum growing in the "Pantanal" of the central-western region of Brazil. Among the known triterpenes, beta-D-glucopyranosyl 2alpha,3beta,6beta-trihydroxyolean-12-en-28-oate is reported for the first time in the Combretaceae, while bellericoside and asiatic acid are described for the first time in the genus Combretum. The structures of the isolated compounds have been established on the basis of spectral techniques (1D-, 2D-NMR and MS).

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Phenylpropanoid glycosides, 1'-O-benzyl-alpha-L-rhamnopyranosyl-(1''-->6')-beta-D-glucopyranoside (1) and alpha-L-xylopyranosyl-(4''-->2')-(3-O-beta-D-glucopyranosyl)-1'-O-E-caffeoyl-beta-D-glucopyranoside (2), together with the known derivatives, 1,6-di-O-caffeoyl-beta-D-glucopyranoside (3), 1-O-(E)-caffeoyl-beta-D-glucopyranoside (4) and 1-O-(E)-feruloyl-beta-D-glucopyranoside (5), were isolated from leaves of Coussarea hydrangeifolia. Their structures were determined by IR, HRESIMS, and 1D and 2D NMR experiments, and their antioxidant activities, evaluated by assaying the free radical scavenging capacity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical as substrate. The antioxidant activities of 3 and 4 (IC50 values of 15.

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An iridoid glucoside: randinoside, along with five known iridoids: galioside, deacetylasperulosidic acid methyl ester, scandoside methyl ester, geniposide and gardenoside, were isolated from the stems of Randia spinosa. The structures were determined by spectroscopic analysis, including 2D NMR techniques.

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