Publications by authors named "Raimundo Braz-Filho"

Three new quinones were isolated from , identified as sennaquinone A (), quinquangulin-6--[α-L-rhamnopyranoside-(1→6)-β-D-glucopyranoside] () and rubrofusarin-6--[β-(6'-()-crotonylglucopyranoside] (), and nine other known compounds identified as quinquangulone () rubrofusarin-6--[-L-rhamnopyranoside-(1→6)-β-D-glucopyranoside] (), norrubrofusarin-6--β--glucopyranoside (cassiaside) (), rubrofusarin-6--β-D-glucopyranoside (), vanillic acid (), protocatechuic acid (), quercetin-3--sambubioside (), resveratrol (), and vomifoliol (). These compounds were determined by HR-ESI-MS, 1D and 2D NMR analyses and ECD calculation. The cytotoxicity of compounds , , and was first assessed in BV-2 microglial cell line by MTT assay.

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Climate change has intensified the proliferation of disease vectors, such as , the primary transmitter of dengue, chikungunya, and zika viruses. Although the two recently licensed dengue vaccines represent a significant advancement, vector management remains the primary strategy for preventing these urban arboviruses. In this context, the development of pesticides that offer safer alternatives for the environment and human health has become urgent.

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Geopropolis is a natural antibiotic produced by stingless bees, supplemented with earth and clay. Bee products are a promising source of natural bioactive compounds with potential for the development of new drugs for neglected tropical diseases, such as Chagas disease. This study analyzed extracts of geopropolis from the Bosque da Barra da Tijuca (RJ, Brazil) and evaluated their activity against .

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Diplopods are terrestrial arthropods important for the dynamics of terrestrial ecosystems. One of the reasons for that can be their low predation rate due to their defensive secretion. Thus, Orthoporus fuscipes, a species belonging to this group and endemic to northeastern Brazil, was investigated as to its population structure and chemical constituents of defensive secretion.

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Neglected Tropical Diseases are a significant concern as they encompass various infections caused by pathogens prevalent in tropical regions. The limited and often highly toxic treatment options for these diseases necessitate the exploration of new therapeutic candidates. In the present study, the lignan methylpiperitol was isolated after several chromatographic steps from Persea fulva L.

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Introduction: The botanical family Acanthaceae (order Lamiales) potentially comprises 4900 species in 191 genera with extensive morphological, habit and habitat diversity. The family is widely distributed throughout the world but is especially rich in tropical and subtropical regions. Many of its species have great ornamental importance and are broadly used for medicinal purposes in several countries of Asia and Africa.

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Ethnopharmacological Relevance: The Tabernaemontana genus belongs to the Apocynaceae family of which 30 species are found in Brazil. Some Tabernaemontana species are used by Brazilian indigenous people and other communities, or are listed in the Yanomami Pharmacopeia. Ethnopharmacological data include use(s) for muscle problems, depressed sternum, back pain, abscess, indigestion, eye irritation, earache, itching, vaginal discharge, as an aid for older people who are slow and forgetful, mosquito and snake bites, infection by the human botfly larvae, calmative, and fever.

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Myrtaceae is one of the most diverse and abundant botanical families, exhibiting wide diversity in the chemical composition of essential oils (EOs). EOs have various biotechnological applications such as controlling the populations of organisms that negatively impact humans. This study aimed to extract EOs from Myrtaceae species, chemically characterize them, and evaluate their larvicidal and fungicidal effects.

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Article Synopsis
  • A new cyclic natural compound, formed from succinic acid and two alanine amino acid units, was isolated from honey extract and its structure was determined through various NMR techniques.
  • In cell culture studies, this compound reduced the number of tachyzoites (a parasitic stage) by 40-56% within 24 hours, and 25-50% over 72 hours, in a dose-dependent manner.
  • The compound showed no toxicity to glial cells at concentrations up to 25 µg/mL and was associated with increased nitric oxide levels, suggesting a potential impact on DNA synthesis and protein production in affected cells.
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This study involves aporphine alkaloids identified through C Nuclear Magnetic Resonance (NMR) spectroscopic data. For the present publication, articles were selected from several databases on aporphine alkaloids from 1994 to 2021. In this class, more than 700 compounds have been registered, with 221 were included in this section, among which 122 were characterized for the first time in the investigated period.

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The dual inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) is considered as an important strategy for the treatment of Alzheimer's disease. In this study, we applied the bioguided fractionations of Ocotea daphinifolia ethyl acetate active extract to furnish a fraction with high inhibitory activity for AChE and BuChE (82% and 92%, respectively). High-performance liquid chromatography semipreparative purification of this fraction provided two new natural products: 1-β-D-galactopyranosyl-glycerol-2,3-heptanedionate, (1) whose complete chemical structural elucidation was made with spectrometric analysis (MS, 1D, and 2D NMR) and its minor derivative 1-β-D-gulopyranosyl-glycerol-2,3-heptanedionate; (2) which could be characterized by 2D H- C heteronuclear single-quantum correlation spectra analysis.

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The alkaloid Aspidocarpine was isolated from the bark of Aspidosperma desmanthum. Its structure was elucidated by the spectral data of 1H and 13C-NMR (1D and 2D) and high-resolution mass spectrometry (HRESIMS). The antihypertensive activity was investigated by intravenous infusion in Wistar rats.

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Nordine was reported to be an unusual humulene-type macrocyclic sesquiterpenoid that contains an ether-bridged bicyclic ring between C-10 and C-6 with a hydroxy group at position 2. Here, we report the structure revision of nordine based on incongruities found for carbon chemical shifts in the originally proposed structure, in addition to formation of a diacetylated derivative. As expected, a single-crystal X-ray diffraction analysis unambiguously confirmed our proposal that the nordine () structure contains an ether-bridged bicyclic ring between C-10 and C-7 and hydroxy groups at C-2 and C-6.

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COVID-19, caused by SARS-CoV-2, is a viral infection that has generated one of the most significant health problems in the world. Spike glycoprotein is a crucial enzyme in viral replication and transcription mediation. There are reports in the literature on using bile acid in the fight against this virus through tests.

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Lindl. is an important genus of the Apocynaceae family, not only as ornamental plants but also for its medicinal uses. In Brazil, species are indicated to treat asthma and skin infections, their anti-inflammatory potential and wound healing properties are also reported in the literature.

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Herein, the isolation of secondary metabolites from the aerial parts of guided by HPLC-MS and molecular networking analyses is reported. Twenty-two known compounds were dereplicated. Three new lignans (aequilabrines A-C (-)) and three known compounds (lariciresinol-4'-β-glucose (), roseoside (), and allantoin ()) were obtained.

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Non-domesticated species may represent a treasure chest of defensive molecules which must be investigated and rescued. Clitoria fairchildiana R. Howard is a non-domesticated Fabacea, native from the Amazonian Forest whose seeds are exquisitely refractory to insect predation.

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A new nor--kaurene diterpene and ten other compounds were isolated from stems, including four kaurene diterpenes, three alkamides, one sesquiterpene and two steroids. Their chemical structures were elucidated using spectroscopic methods, including 1D-, 2D-NMR, and HRESIMS. The absolute configuration of compounds , , , and was confirmed by CD experiments.

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New cycloartane, 22-hydroxy-25-hydroperoxycycloart-23-en-3-one (), along with six known analogues () and three steroids (), were isolated from the leaves of . Structures were elucidated mainly on the basis of the analysis of 1D and 2D NMR (H and C) and HRESIMS spectroscopic data, involving comparison with data of the literature. The cytotoxic activities of and isolated compounds were also evaluated against human leukemia cell line Molt-4 (acute lymphoblastic) and exhibited good cytotoxic activity with IC values ranging from 10.

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Ethnopharmacological Relevance: Different species of the Simaroubaceae family are used in traditional medicine to treat malaria. Among these is Homalolepis suffruticosa (syn. Simaba suffruticosa and Quassia suffruticosa), which is native to Central Brazil and popularly known as calunga.

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Phytochemical studies of Cespedesia spathulata (Ochnaceae) leaves using 1H, 13C NMR, and GC-MS have led to the isolation of some metabolites identified for the first time in these species such as cathechin, epicatechin, vitexin, orientin, 6''-O-acetyl-vitexin, sitosterol, stigmasterol, phytol, 4,5-dihydrovomifoliol and a mixture of aliphatic methyl esters, together with ochnaflavone, which was previously isolated from this plant. The modulating activity of some fractions and compounds from Cespedesia spathulata towards tyrosinase enzyme was assayed by spectroscopic and theoretical means/experiments. The dichloromethane fraction (133 μg mL-1) and ochnaflavone (333 μM) inhibited tyrosinase activity by 20 % and 2.

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Plants have historically been a rich source of successful anticancer drugs and chemotherapeutic agents, with research indicating that this trend will continue. In this contribution, we performed high-throughput cytotoxicity screening of 702 extracts from 95 plant species, representing 40 families of the Brazilian Cerrado biome. Activity was investigated against the following cancer cell lines: colon (Colo205 and Km12), renal (A498 and U031), liver (HEP3B and SKHEP), and osteosarcoma (MG63 and MG63.

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The genus P. Browne, which belongs to the Meliaceae family, has eighteen species. Trees of this genus are of economic interest due to wood quality, as well as being the focus of studies because of relevant biologic activities as in other Meliaceae species.

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Article Synopsis
  • * The study assessed the chemical composition and nematicidal activity of C. citratus extracts, finding they were effective against specific nematode species and revealed significant ovicidal effects in multiple fractions at high concentrations.
  • * Ultrastructural analysis demonstrated that C. citratus treatments caused physical deformations in nematodes, including damage to their cuticle, muscle, intestinal cells, and mitochondria, indicating its potential as a biological control agent in sheep farming.
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