Publications by authors named "Hianna A M F Silva"

Article Synopsis
  • Snails of the genus Biomphalaria are hosts for Schistosoma mansoni, which causes schistosomiasis affecting millions globally, and controlling snail populations is a recommended strategy for disease reduction.
  • Plumbagin, a natural compound, was tested and demonstrated effective molluscicidal activity against different developmental stages of B. glabrata and killed S. mansoni cercariae after 60 minutes at specific concentrations.
  • While plumbagin did not affect the reproduction of snails, it caused DNA damage and increased hemocyte count, indicating potential side effects, but its moderate toxicity to a commonly used test organism suggests it could be a viable control agent.
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Usnic acid is the best-studied lichen metabolite, presenting several biological activities, such as antibacterial, immunostimulating, antiviral, antifungal, anti-inflammatory, and antiparasitic agents; despite these relevant properties, it is a hydrophobic and toxic molecule. In this context, scientific research has driven the development of innovative alternatives, considering usnic acid as a source of raw material in obtaining new molecules, allowing structural modifications (syntheses) from it. The purpose is to optimize biological activities and toxicity, with less concentration and/or response time.

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Schistosomiasis is a public health problem in many developing countries. The mollusc Biomphalaria glabrata is the most important vector of Schistosoma mansoni in South America. The population control of this vector to prevent the spread of schistosomiasis is currently done with the application of highly toxic molluscicide to the environment.

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Waste produced in homes is one of the main sources of pollutants in freshwater ecosystems. Therefore, it is imperative to implement methodologies that aid in environmental monitoring procedures. The use of organisms as biomonitors has grown increasingly prevalent as they are models that provide data that can be adequately evaluated.

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Article Synopsis
  • The study tested the effects of divaricatic acid on Schistosoma mansoni worms, evaluating its impact on motility and mortality using various analysis methods, including Scanning Electron Microscopy.
  • Results indicated that divaricatic acid caused significant lethality to the worms after 24 hours at concentrations of 100-200 μM, along with observable changes in their movement at lower doses and extensive damage to their outer layer.
  • Importantly, divaricatic acid was found to be non-toxic to human peripheral blood mononuclear cells, suggesting it could be a safe treatment against S. mansoni without harming human cells.
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  • Industrial development has improved quality of life but has also increased the use of toxic chemicals that harm ecosystems, necessitating knowledge on pollution monitoring techniques and organisms.
  • This study focused on using the mollusk Biomphalaria glabrata to examine the effects of industrial sewage sludge on its health and vitality through various biomarker and biomonitoring tests.
  • Results showed that while embryos exposed to the sludge had similar viability rates compared to controls, significant cellular and genetic damage in hemocytes was detected, particularly at higher sludge concentrations, indicating that this mollusk is effective for monitoring freshwater ecosystem health.
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In this study, the molluscicidal activities against Biomphalaria glabrata and cercaricidal activities against Schistosoma mansoni of the ether extract of Ramalina aspera were evaluated. Additionally, toxicity parameters were evaluated at sublethal doses in terms of the influence of the extract on the fertility and fecundity of snails, as well as morphological alterations and quantification of their immunological cells. A test with Artemia salina was also carried out, in order to verify the environmental toxicity of the compound.

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Chemicals released from anthropogenic activities such as industry and agriculture often end up in aquatic ecosystems. These substances can cause serious damage to these ecosystems, thus threatening the conservation of biodiversity. Among these substances are pesticides, such as oxyfluorfen, a herbicide used for the control of grasses and weeds.

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Article Synopsis
  • Several substances, including the flavonoid quercetin, have been studied for their ability to protect against damage from ionizing radiation due to their antioxidant effects.
  • The research aimed to evaluate quercetin's potential to reduce chromosome damage in human lymphocytes after exposure to different doses of radiation.
  • Results indicated that lymphocytes treated with quercetin showed fewer chromosomal aberrations compared to those not treated, suggesting that quercetin may help mitigate the harmful effects of radiation through decreased inflammatory responses.
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This study evaluated the biological activity of an ether extract and barbatic acid (BAR) from on embryos and adult mollusks of , cercariae of and the microcrustacean . The ether extract and BAR were obtained by successive extractions with diethyl ether. The obtained extracts were analyzed using thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), proton nuclear magnetic resonance (¹H-NMR) and infrared (IR) spectroscopy.

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