Banca de DEFESA: RAFAEL SILVA ALMEIDA
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.DISCENTE : RAFAEL SILVA ALMEIDA
DATA : 17/02/2021
HORA: 14:00
LOCAL: Instituto Multidisciplinar em Saúde
TÍTULO:
Bio-guided fractionation of the ethanolic extract of the leaves of Mimosa tenuiflora (Willd.) Poiret and antimicrobial activity of fractions, subfractions and sorbifolin on Streptococcus mutans ATCC 700610.
PALAVRAS-CHAVES:
Black jurema, antibiofilm, anticariogenic, 5,6,4'-trihydroxy-7-methoxyflavone, caries.
PÁGINAS: 9696
GRANDE ÁREA: Ciências Biológicas
ÁREA: Farmacologia
RESUMO:
Mimosa tenuiflora is popularly known as “black jurema”, widely distributed in northeastern Brazil, and used in many communities to treat various diseases. Streptococcus mutans is gram-positive microorganism that form pathogenic biofilms and the main etiological agent associated with the development of dental caries. In this work, a bioguided study of fractionation of the ethanolic extract of M. tenuiflora leaves and analysis of antimicrobial activity in vitro against S. mutans ATCC 700610. Ethanol extract (EEMT), hexane fractions, dichloromethane (FDMT) and ethyl acetate (FEAMT), and subfractions of FDMT were tested in the determination of minimal inhibitory concentration (MIC) and bactericidal (CBM), inhibition of cell adhesion (MIC) with planktonic cells of S. mutans. Compounds were identified in the FDMT and in active subfractions by gas chromatography coupled to the mass spectrum (GC-MS), and the compound 5,6,4'-trihydroxy-7-methoxyflavone (sorbifolin) was identified by 1H-NMR. The antimicrobial activity of FDMT was evaluated in vitro for inhibition of biofilm formation, inhibition of the glycolytic pathway (polysaccharide formation), inhibition of acid production (pH drop), inhibition of acidity (proton permeability), inhibition of the production of extracellular DNA (quantification of eDNA). Phytochemical analysis of extracts by thin layer chromatography revealed the presence of alkaloids, steroids, flavonoids, phenolic acids, polyphenols, saponins and tannins. Bioactive compounds identified in FDMT were ethyl gallate (14.25%), sorbifolin (4.66%), gallic acid (3.55%), lactic acid (3.24%), palmitic acid (1.42%), salicylic acid (0.23%) and 4-hydroxybenzoic acid (0.22%), and in the subfractions were propylene glycol, lactic acid, oxalic acid, R-(3) hydroxybutyric acid, salicylic acid, 4-hydroxybenzoic acid, vanillic acid, protocatechuic acid, ethyl gallate, gallic acid, palmitic acid and sorbifolin, in different concentrations and distribution. EEMT presented MIC - 31.25 µg/mL, MBC - 62.5 µg/mL and MICA - 15.75 µg/mL, and FDMT was the most bioactive fraction MIC - 15.62 µg/mL, MBC - 31.25 µg/mL and MICA - 7.875 µg/mL. Sorbifolin showed only bacteriostatic activity (MIC 125 µg/mL) against S. mutans and is present in FDMT and its subfractions D5.8, D6.6, D6.7, D5.8.1 and D6.6.1. FDMT 6.25 mg/mL (200 x MBC) demonstrated bactericidal activity (decreased CFU/biofilm), reduced production of soluble (FDMT 3.125 mg/mL) and insoluble (FDMT 3.125 and 6.25 mg/mL) polysaccharides, decreasing levels of eDNA (FDMT 3.125 and 6.25 mg/mL) in mature biofilms formed in relation to the vehicle group (Ethanol 10%, v/v) (p < 0.05). FDMT (3.125 mg/mL) reduced the acid production of the S. mutans biofilm in the period of 30 to 120 min compared to the vehicle (p < 0.05). The final pH in 120 min was 6.83 for chlorhexidine, 5.36 for FDMT and 4.4 for vehicle. FDMT (6.25 mg/mL) reduced proton permeability of the S. mutans cell membrane in 80, 82 and 120 min compared to the vehicle (p < 0.05). Thus, the dichloromethane fraction has several bioactive compounds that act synergistically in inhibiting the formation of cariogenic biofilm with bacteriostatic / bactericidal activity, acting mainly in inhibiting the main virulence factors of S. mutans, such as the production of extracellular polysaccharides, extracellular DNA, and decreased acid tolerance and acidogenic capacity. This is the first report of sorbifolin identified in leaves of M. tenuiflora and bacteriostatic activity on S. mutans. Thus, M. tenuiflora is a promising source for the development of new phytotherapics and phytopharmaceuticals with anti-plaque and /or anti-caries activities, and further studies in vivo should be carried out in the future.
MEMBROS DA BANCA:
Presidente - 1553274 - REGIANE YATSUDA
Interno(a) - 1788171 - BRUNO OLIVEIRA MOREIRA
Externo(a) ao Programa - 2342538 - GUILHERME BARRETO CAMPOS