RESUMO
Medicinal plants have been used for many years by communities to treat illnesses. The need for scientific proof of these vegetable's curative effects is as necessary as the proof of the inexistence of toxicity related to the use of extracts with therapeutic potential. Annona squamosa L. (Annonaceae), popularly known as "pinha", "ata" or "fruta do conde", has been used in traditional medicine for its analgesic and antitumor activities. The toxic effects attributed to this plant have also been explored as a pesticide and an insecticide. The aim of the present study was to investigate the toxicity of the methanolic extract of A. squamosa seeds and pulp against human erythrocytes. Blood samples were treated with methanolic extract at different concentrations, osmotic fragility was determined using saline tension assays and morphological analyzes were performed using optical microscopy. The extracts were analyzed using high performance liquid chromatography with diode array detection (HPLC-DAD) for phenolic quantification. The seed's methanolic extract showed toxicity above 50% from a concentration of 100 µg/mL, while also presenting echinocytes in the morphological analysis. The pulp's methanolic extract did not show toxicity to red blood cells or morphological changes at the concentrations tested. HPLC-DAD analysis revealed the presence of caffeic acid in the seed extract and gallic acid in the pulp extract. The seed's methanolic extract is toxic and the pulp's methanolic extract showed no toxicity against human erythrocytes.
RESUMO
Microbial resistance has become a worrying problem in recent decades after the abusive use of antibiotics causing the selection of resistant microorganisms. In order to circumvent such resistance, researchers have invested efforts in the search for promising natural substances, such as essential oils. Thus, the objective of this work was to determine the chemical composition of the essential oil of Acritopappus confertus leaves, to evaluate its intrinsic effect and its effects in combination with drugs against pathogenic fungi and bacteria, in addition to verifying the inhibition of virulence in Candida strains. To this end, the oil was verified by gas chromatography coupled with mass spectrometry (GC/MS). Candida strains were used for antifungal assays by means of the serial microdilution technique, in order to determine the average inhibitory concentration (IC50), and for the modification assays, sub-inhibitory concentrations (MIC/8) were used. Finally, the natural product's ability to inhibit the formation of filamentous structures was evaluated. In antibacterial tests, the MIC of the oil against strains of Staphylococcus aureus and Escherichia coli and its modifying effects in association with gentamicin, erythromycin, and norfloxacin were determined. The major constituent of the essential oil was the monoterpene myrcene (54.71%). The results show that the essential oil has an antifungal effect, with C. albicans strains being the most susceptible. Furthermore, the oil can potentiate the effect of fluconazole against strains of C. tropicalis and C. albicans. Regarding its effect on micromorphology, the oil was also able to inhibit the filaments in all strains. In combination with antibiotics, the oil potentiated the drug's action by reducing the MIC against E. coli and S. aureus. It can be concluded that the essential oil of A. confertus has potential against pathogenic fungi and bacteria, making it a target for the development of an antimicrobial drug.
RESUMO
Species of the genus Miconia are used in traditional medicine for the treatment of diseases, such as pain, throat infections, fever, and cold, and they used as depuratives, diuretics, and sedatives. This work reviewed studies carried out with Miconia species, highlighting its ethnomedicinal uses and pharmacological and phytochemical potential. This information was collected in the main platforms of scientific research (PubMed, Scopus, and Web of Science). Our findings show that some of the traditional uses of Miconia are corroborated by biological and/or pharmacological assays, which demonstrated, among other properties, anti-inflammatory, analgesic, antimutagenic, antiparasitic, antioxidant, cytotoxic, and antimicrobial activities. A total of 148 chemical compounds were identified in Miconia species, with phenolic compounds being the main constituents found in the species of this genus. Such phytochemical investigations have demonstrated the potential of species belonging to this genus as a source of bioactive substances, thus reinforcing their medicinal and pharmacological importance.
