Epigallocatechin gallate and gallic acid affect colonization of abiotic surfaces by oral bacteria

2020 ◽  
Vol 120 ◽  
pp. 104922 ◽  
Author(s):  
Yi Wang ◽  
Antonia T.W. Lam
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ali Mahmoud Muddathir ◽  
Ebtihal Abdalla M. Mohieldin ◽  
Tohru Mitsunaga

Abstract Background Dental caries and periodontal disease are the most common chronic infectious oral diseases in the world. Acacia nilotica was commonly known in Sudan as Garad or Sunt has a wide range of medicinal uses. In the present study, antibacterial activity of oral bacteria (Streptococcus sobrinus and Porphyromonas gingivalis), inhibitory activity against glucosyltransferase (GTF) enzyme and antioxidant activity were assayed for methanolic crude extract of A. nilotica bark and its fractions. Methods Methanoilc crude extract of A. nilotica bark was applied to a Sephadex LH-20 column and eluted with methanol, aqueous methanol, and finally aqueous acetone to obtain four fractions (Fr1- Fr4). Furthermore, the crude extract and fractions were subjected to analytical high performance liquid chromatography (HPLC). The crude extract and its fractions were assayed for antibacterial activity against S. sobrinus and P. gingivalis using a microplate dilution assay method to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), as well as GTF inhibition and antioxidant activity using ABTS radical scavenging method. Results Fractions (Fr1 and Fr2) exhibited MIC values of 0.3 mg/ml against the P. gingivalis. Additionally, Fr2 displayed MBC value of 1 mg/ml against two types of bacteria. Fr4 showed an especially potent GTF inhibitory activity with IC50 value of 3.9 μg/ml. Fr1 displayed the best antioxidant activity with IC50 value of 1.8 μg/ml. The main compound in Fr1 was identified as gallic acid, and Fr2 was mostly a mixture of gallic acid and methyl gallate. Conclusions The results obtained in this study provide some scientific rationale and justify the use of this plant for the treatment of dental diseases in traditional medicine. A. nilotica bark, besides their antibacterial potentiality and GTF inhibitory activity, it may be used as adjuvant antioxidants in mouthwashes. Further studies in the future are required to identify the rest of the active compounds.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Helena Abramovič ◽  
Blaž Grobin ◽  
Nataša Poklar Ulrih ◽  
Blaž Cigić

Trolox, gallic acid, chlorogenic acid, caffeic acid, catechin, epigallocatechin gallate, and ascorbic acid are antioxidants used as standards for reaction with chromogenic radicals, 2,2-diphenyl-1-picrylhydrazyl (DPPH⋅) and 2,2′-azino-bis-3-ethylbenzotiazolin-6-sulfonic acid (ABTS⋅+), and Folin–Ciocalteu (FC) reagent. The number of exchanged electrons has been analyzed as function of method and solvent. A majority of compounds exchange more electrons in FC assay than in ABTS and DPPH assays. In reaction with chromogenic radicals, the largest number of electrons was exchanged in buffer (pH 7.4) and the lowest reactivity was in methanol (DPPH) and water (ABTS). At physiological pH, the number of exchanged electrons of polyphenols exceeded the number of OH groups, pointing to the important contribution of partially oxidized antioxidants, formed in the course of reaction, to the antioxidant potential. For Trolox, small impact on the number of exchanged electrons was observed, confirming that it is more suitable as a standard compound than the other antioxidants.


Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1003 ◽  
Author(s):  
Francesco Balestri ◽  
Giulio Poli ◽  
Carlotta Pineschi ◽  
Roberta Moschini ◽  
Mario Cappiello ◽  
...  

Aldose reductase (AKR1B1), the first enzyme in the polyol pathway, is likely involved in the onset of diabetic complications. Differential inhibition of AKR1B1 has been proposed to counteract the damaging effects linked to the activity of the enzyme while preserving its detoxifying ability. Here, we show that epigallocatechin gallate (EGCG), one of the most representative catechins present in green tea, acts as a differential inhibitor of human recombinant AKR1B1. A kinetic analysis of EGCG, and of its components, gallic acid (GA) and epigallocatechin (EGC) as inhibitors of the reduction of L-idose, 4-hydroxy2,3-nonenal (HNE), and 3-glutathionyl l-4-dihydroxynonanal (GSHNE) revealed for the compounds a different model of inhibition toward the different substrates. While EGCG preferentially inhibited L-idose and GSHNE reduction with respect to HNE, gallic acid, which was still active in inhibiting the reduction of the sugar, was less active in inhibiting HNE and GSHNE reduction. EGC was found to be less efficient as an inhibitor of AKR1B1 and devoid of any differential inhibitory action. A computational study defined different interactive modes for the three substrates on the AKR1B1 active site and suggested a rationale for the observed differential inhibition. A chromatographic fractionation of an alcoholic green tea extract revealed that, besides EGCG and GA, other components may exhibit the differential inhibition of AKR1B1.


2008 ◽  
Vol 46 (6) ◽  
pp. 744-750 ◽  
Author(s):  
Mi-Sun Kang ◽  
Jong-Suk Oh ◽  
In-Chol Kang ◽  
Suk-Jin Hong ◽  
Choong-Ho Choi

2010 ◽  
Vol 24 (7) ◽  
pp. 851-858 ◽  
Author(s):  
Ren-Jye Lee ◽  
Viola S. Y. Lee ◽  
Jason T. C. Tzen ◽  
Maw-Rong Lee

Author(s):  
ISHFAQ KHAN ◽  
NEHA CHAUHAN ◽  
CHAUHAN PK ◽  
MOHD. AZHAR KHAN

Objectives: The main focus of the present study was to evaluate the antimicrobial efficacy (against oral pathogenic bacteria), free radical scavenging activity, and total phenolic and flavonoids content (TPC and TFC) of methanolic extract (ME) of J. regia obtained from Kashmir region. Methods: The plant part was collected and its ME was prepared. ME was subjected to antibacterial activity against oral bacteria such as Staphylococcus aureus, Streptococcus mutans, and Pseudomonas aeruginosa. The free radical scavenging activity was determined using 2,2-diphenyl- 1-picrylhydrazylhydrate (DPPH) assay. TPC and TFC were also determined using a standard curve equation of gallic acid and quercetin. A standard curve using different concentrations of gallic acid and quercetin was drawn from which the concentration of phenols in the test sample was calculated and expressed in mg/g. Results: The ME of J. regia was found effective against all the strains of microorganisms responsible for oral infection understudy. It was also observed that scavenging of DPPH increased with the increase in concentration for both standard ascorbic and methanolic bark extract of J. regia showing its antioxidant potential. The TPC and TFC of ME was found to be 43.35±0.079 and 17.28±0.125. Conclusions: The results obtained from the study clearly indicate that the walnut bark from Kashmir region can be a good candidate for employment as an antibacterial against oral pathogens. J. regia bark was found to be a good source of healthy compounds such as phenolic and flavonoids, suggesting that its bark could be useful to prevent diseases in which free radicals are present.


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