Banca de DEFESA: KAREN SARTORI JEUNON GONTIJO
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.STUDENT : KAREN SARTORI JEUNON GONTIJO
DATE: 17/02/2025
TIME: 13:30
LOCAL: https://meet.google.com/mac-ndvw-qof
TITLE:
Detection and characterization of antiviral action in plant species Smilax brasiliensis and Phyllanthus brasiliensis against Mayaro virus
KEY WORDS:
Keywords: Alphavirus; Arbovirus; Antivirals; Medicinal Plants
PAGES: 98
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUBÁREA: Microbiologia Aplicada
SUMMARY:
Mayaro virus (MAYV), restricted to a sylvatic cycle among non-human primates and mosquitoes Haemagogus, was considered the cause of sporadic human infections, with incidences limited to riverine populations in the northern region of the country. However, MAYV has been detected or has suspected cases in at least 11 states, with Goiás standing out, suggesting a geographical expansion into urban areas. Currently, there are no specific antivirals or licensed vaccines against MAYV, highlighting the importance of research into therapeutic alternatives. In this context, plant extracts and compounds have shown promise in the search for new antivirals. The present study evaluated the antiviral activity of extracts, enriched fractions, and isolated compounds from the plant species Smilax brasiliensis and Phyllanthus brasiliensis against MAYV. The study determined the most promising extracts, explored the mechanisms of action, and further investigated the lignans phyllanthostatin A and tuberculatine, isolated from P. brasiliensis. Initially, cytotoxicity was assessed to determine the 50% cytotoxic concentration (CC50). Then, the 50% protective effective concentration (EC50) was obtained, and the selectivity index (SI) was determined. For the most promising extracts, potential mechanisms of action were investigated. For S. brasiliensis, the data showed that fractions enriched with fatty acids (AG) and methyl esters (FAME) exhibited antiviral activity with EC50 values of 6.0 and 1.9 μg/mL and SI of 7.3 and 75.6, respectively. Regarding P. brasiliensis, four evaluated extracts demonstrated potent antiviral activity, with EC50 values ranging from 1.4 to 6.0 μg/mL and SI ranging from 90 to 337. The hexane (16HEX) and hydroethanolic (19HET-60 and 22HET-95) extracts showed virucidal effects, which were not observed for the ethanolic extract (18ET-100), with no impact on the viral particle. The 19HET-60 and 22HET-95 extracts exhibited strong inhibitory effects on the virus's adsorption to the host cell. The viral penetration step, which is dependent on cellular enzymes, was affected only by the 22HET-95 extract. In the evaluation of isolated compounds, potent and selective antiviral activity was detected for phyllanthostatin A and tuberculatin, both of which significantly reduced viral load through different mechanisms of action. Phyllanthostatin A was effective at the viral adsorption stage, while tuberculatin exhibited a strong virucidal effect. Electron microscopy analysis revealed that, in addition to these effects, both lignans also affect intracellular steps of the viral cycle, and in silico molecular target screening revealed that lignans interact with viral capsid protein C (pC). Taken together, the data show that the plant species are very promising against MAYV, and their compounds are highly relevant for future in vivo assays.
BANKING MEMBERS:
Presidente - 1673648 - JOSE CARLOS DE MAGALHAES
Interna - 1742677 - JAQUELINE MARIA SIQUEIRA FERREIRA
Externa à Instituição - THAIS DE FATIMA SILVA MORAES
Externo à Instituição - GERALDO CÉLIO BRANDÃO - UFOP
Externa à Instituição - ARIANE COELHO FERRAZ
Externo à Instituição - DANILO BRETAS DE OLIVEIRA - UFVJM