Publications by authors named "Orlando Santos"

Cancer represents a significant societal, public health, and economic challenge. Conventional chemotherapy is based on systemic administration; however, it has current limitations, including poor bioavailability, high-dose requirements, adverse side effects, low therapeutic indices, and the development of multiple drug resistance. These factors underscore the need for innovative strategies to enhance drug delivery directly to tumours.

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Chordomas are a low-to-intermediate-grade slow-growing subtype of sarcoma, but show propensity to grow and invade locally with recurrence and metastasis in 10-40% of cases. We describe the first case of spontaneous regression of a solid tumor (histologically and immunohistochemically proven chordoma) after COVID-19. A female patient with clival chordoma underwent occipitocervical fixation prior to tumor resection.

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is a Brazilian species that has yet to be the subject of scientific investigation. However, it represents a potential source of new antibacterial and anticancer drugs, given it belongs to the Salicaceae family. The objective of this study was to investigate the potential biological activities and chemical composition of this species.

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(DC) is an important botanical source of Brazilian green propolis and have many compounds with potential antihypertensive activity. However, little is known about the specific antihypertensive properties of DC, or the mechanisms involved. Here we aimed to chemically characterise an ethanolic DC extract (eDC), test its antihypertensive properties and the involvement of neurogenic mechanisms using an animal model of salt-dependent hypertension.

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Millions of people worldwide are affected by leishmaniasis, caused by the parasite. Effective treatment is challenging due to the biological complexity of the parasite, drug toxicity, and increasing resistance to conventional drugs. To combat this disease, the development of specific strategies to target and selectively eliminate the parasite is crucial.

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Chagas disease (CD) is a worldwide public health problem. Benznidazole (BZ) is the drug used to treat it. However, in its commercial formulation, it has significant side effects and is less effective in the chronic phase of the infection.

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The treatment of skin and soft tissue infections (SSTIs) can be challenging due to bacterial resistance, particularly from strains like MRSA and biofilm formation. However, combining conventional antibiotics with natural products shows promise in treating SSTIs. The objective of this study is to develop a nanoemulsion-based hydrogel containing extract and mupirocin and evaluate its potential for the treatment of SSTIs.

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Article Synopsis
  • Melanoma, mainly caused by UV radiation from the sun, can be prevented using sunscreens, but synthetic options can harm the environment.
  • This study highlights the potential of essential oils (EO) derived from plants for their natural photoprotective and anti-cancer properties, presenting a more eco-friendly alternative.
  • Results showed that nanoemulsified essential oil (NE-EO) was effective in providing photoprotection and had higher cytotoxic effects on melanoma cells compared to non-cancerous cells, indicating its promise for melanoma prevention and treatment, although more research is needed.
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Leishmaniasis is an infectious disease responsible for a huge rate of morbidity and mortality in humans. Chemotherapy consists of the use of pentavalent antimonial, amphotericin B, pentamidine, miltefosine, and paromomycin. However, these drugs are associated with some drawbacks such as high toxicity, administration by parenteral route, and most seriously the resistance of some strains of the parasite to them.

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The broad pharmacological spectrum of plants is related to their secondary metabolism, which is responsible for the synthesis of different compounds that have multiple effects on cellular physiology. Among the biological effects presented by phytochemicals, their use for the prevention and treatment of cancer can be highlighted. This occurs due to several mechanisms of antitumor action demonstrated by these compounds, including regulation of the cell signaling pathways and inhibition of tumor growth.

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Unlabelled: The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China and its spread worldwide has become one of the biggest health problem due to the lack of knowledge about an effective chemotherapy. Based on the current reality of the SARS-CoV-2 pandemic, this study aimed to make a review literature about potential anti-coronavirus natural compounds guided by an in silico study. In the first step, essential oils from native species found in the Brazilian herbal medicine market and Brazilian species that have already shown antiviral potential were used as source for the literature search and compounds selection.

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The new severe acute respiratory syndrome coronavirus (SARS-CoV-2) recently emerged as a worrying pandemic, with many confirmed cases and deaths globally. Therefore, there is a clear need for identifying effective therapeutic options and a review of secondary metabolites related to Brazilian herbal medicines was performed as a strategy for the discovery of new antiviral agents. To confirm this potential, an in silico screening of the identified compounds identified was also evaluated.

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A viscous solution of low molecular weight chitosan (CH) at 5% w/v (10.2 kDa, 75 % deacetylated, 1451 cP at 25 °C) was associated with a microemulsion (ME) that undergoes a phase transition after water absorption in situ (≈28 % w/w), forming a more viscous liquid crystal, which was potentially evaluated as a topical vehicle. The ME was selected from a phase diagram, selecting a composition based on Tween® 80 (52 %), myristate isopropyl (28 %), and the aqueous phase (water and polyethylene glycol 400, 60:40 w/w) (20 %), which was after replaced by CH and herbal medicines (HM).

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Bladder cancer has a high incidence and recurrence rate among patients worldwide. This study aimed to evaluate the cytotoxic activity of fractions of L. flower extracts on bladder carcinoma cells (T24 cells) and human fibroblast cells (MRC-5).

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Article Synopsis
  • Osteoporosis is a bone disease that makes bones weak and prone to breaking, affecting millions of people each year.
  • Alendronate is a medication used to help prevent fractures in people with osteoporosis, and scientists studied its effects on bone healing in rats.
  • The results showed that while healthy bones healed completely, the bones treated with alendronate were still in the repair stage, suggesting that more research on humans is needed to better understand how this drug affects bone healing.
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Systemic arterial hypertension (SAH) is a major health problem around the world and its development has been associated with exceeding salt consumption by the modern society. The mechanisms by which salt consumption increase blood pressure (BP) involve several homeostatic systems but many details have not yet been fully elucidated. Evidences accumulated over the last 60 decades raised the involvement of the immune system in the hypertension development and opened a range of possibilities for new therapeutic targets.

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Essential oils are potential antimicrobial agents and can be used as active ingredients in the pharmaceutical, food and cosmetics industries. This work intends to evaluate the antibacterial activity and design a strategy for the proposition of the mechanism of action of Melaleuca leucadendra essential oil. Optimum concentration of the bacteria and the phase where they had the highest pathogenic activity were determined.

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The aim of this study was to analyse the antitumor effect of the essential oil and on bladder cancer cells RT4 and T24, with different status. The oil was extracted by hydrodistillation and the gas chromatography coupled to the mass spectrometry was used for characterisation. analysis was carried out by Pass online software.

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The physicochemical characteristics of nanostructured suspensions are important prerequisites for the success of new drug development. This work aimed to develop nanometric systems containing leaf essential oil and to evaluate their antimicrobial activity. The essential oil was isolated by hydrodistillation from leaves and analyzed by GC-MS.

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The research for new treatments of skin and soft tissue infections (SSTIs) is important due to their high prevalence and number of hospitalizations. The purpose of this review is to address the pathophysiology of SSTIs to highlight the advantages of herbal medicines to their treatment, showing examples of species and compounds with multi-targets action. SSTIs have a complex physiopathology involving the microorganism, as well as inflammation and difficult healing.

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Ethnopharmacological Relevance: Protium spruceanum (Burseraceae) is used in Brazilian traditional medicine as anti-inflammatory, but the factors involved in this activity were not yet characterized.

Aims Of The Study: analyze the aspects involved in the anti-inflammatory activity of polar fractions obtained from extracts of leaves and branches.

Materials And Methods: Hydromethanolic fraction was obtained by liquid-liquid partition from crude ethanolic extract and its compounds were identified by LC-DAD-MS.

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Propolis has demonstrated potential use as food preservative but it presents strong and unpleasant flavor that alters the sensory characteristics foods. A nanoemulsion was proposed to carry the Brazilian propolis extracts for use as natural food preservative. Antimicrobial and antioxidant activities and chemical constituents of the extracts were investigated.

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Unlabelled: Although the current medical literature is limited, hydropneumothorax was described as far back as the 5th century BC. It is characterized by the presence of air and fluid in the pleural cavity and is an infrequent finding. Causes include trauma, iatrogenesis following thoracentesis, the presence of gas-forming organisms, tuberculosis and malignancy.

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