Banca de QUALIFICAÇÃO: RANIELI PAIVA LOPES
Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.STUDENT : RANIELI PAIVA LOPES
DATE: 28/04/2023
TIME: 13:30
LOCAL: Campus Centro Oeste Dona Lindu e Campus Alto Paraopeba (Via plataforma digital)
TITLE:
Antibacterial and antiviral activity against Chikungunya virus in extracts and compounds isolated from Tontelea micrantha (Celastraceae)
KEY WORDS:
Antibacterial, antiviral, arbovirus, terpene, virucidal.
PAGES: 76
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUBÁREA: Biologia e Fisiologia dos Microorganismos
SPECIALTY: Virologia
SUMMARY:
In the search for new biorenewable alternatives, research using plant extracts is gaining more and more importance in the control of infectious diseases, which currently represent the main cause of mortality in the world. Among them, numerous emerging or re-emerging viruses and bacteria stand out. In the present study, the activity of different extracts and compounds isolated from the plant species Tontelea micrantha (Celastraceae) was evaluated against different Gram negative and positive bacteria of medical importance and the Chikungunya virus (CHIKV). Chloroformic and hexane root extracts (ECR and EHR) showed promising antibacterial activity with a minimum inhibitory concentration (MIC) between 4.8 and 78mg/mL for Gram-positive Staphylococcus aureus, Bacillus subtilis and Gram-negative Klebsiella pneumoniae and Klebsiella oxytoca, and a minimum bactericidal concentration (MBC) between 312 and 2500mg/mL. In the search for mechanisms of action, tests regarding the effect on membrane permeability and release of nucleic acids showed that ECR and EHR do not affect membrane integrity, leaving the possibility of an intracellular effect such as inhibition of the synthesis of nucleic acids, proteins and others. Through a synergism assay, it was possible to demonstrate that the ECR and EHR extracts promote an excellent synergistic effect when combined with streptomycin, an antibiotic from the aminoglycoside group, whose target of action is protein synthesis. As for the antiviral action, the ethyl acetate and methanol extracts derived from leaves (EAEF, EMF) showed potent activity against CHIKV, at an effective protective concentration for 50% of infected cells (EC50) of 18mg/mL for EAEF, of 43ug/mL for EMF and a selectivity index (SI) of 12.50 and 8.16, respectively. The actions reduced virus production and viral cytopathic effect (CPE) in Vero cell cultures. Analyzing the mechanisms of antiviral action, EAEF and EMF were able to inhibit CHIKV, with a potent virucidal effect (p<0.001) at all concentrations tested (7.8 – 250ug/mL), that is, acting on the particle virus before contact with the host cell. On the other hand, compounds derived from fractions of these extracts do not show activity against CHIKV. Thus, our data so far show that root extracts, ECR and EHR, have promising antibacterial activity, while leaf-derived extracts, EAEF and EMF, stand out in terms of antiviral effect with probable virucidal effect. Other mechanisms or targets of antiviral action, such as the adsorption step of the virus to the cell, viral penetration or after penetration of the viral particle (Multiplicative cycle), will still be investigated.
BANKING MEMBERS:
Presidente - 1673648 - JOSE CARLOS DE MAGALHAES
Interna - 1742677 - JAQUELINE MARIA SIQUEIRA FERREIRA
Externa à Instituição - SAMYRA GIAROLA CECILIO
Externo à Instituição - LUIZ FELIPE LEOMIL COELHO - UNIFAL-MG