Jay Jooyoung Oh

Publications (2)3.45 Total impact

• Article: Antimicrobial activity and biofilm formation inhibition of green tea polyphenols on human teeth

  Yun-Seok Cho, Jay Jooyoung Oh, Kye-Heon Oh
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  ABSTRACT: The antimicrobial effects and biofilm formation inhibition of tea polyphenols (TPP) extracted from Korean green tea (Camellia sinensis L) were evaluated against 12 oral microorganisms. Effective antimicrobial activity against all microorganisms tested, including Lactobacillus spp. (Lactobacillus acidophilus and Lactobacillus plantarum), Streptococcus spp. (Streptococcus mutans, Streptococcus sanguis, Streptococcus sobrinus, Streptococcus mitis, and Streptococcus salivarius), Staphylococcus aureus, Neisseria meningitidis, Escherichia coli, Enterobacter cloacae, Enterococcus faecalis, and Candida albicans, was shown at 2,000 μg/mL TPP within 5 min of incubation. Scanning electron microscopy (SEM) analysis revealed various morphological changes, such as the presence of perforations, the formation of cell aggregates, and the leakage of cytoplasmic materials from cells treated with TPP, depending on the bacteria. The potential role of TPP in biofilm formation inhibition on human teeth was evaluated in BHI broth with 2 mixed strains of S. mutans and S. sanguis. SEM analysis showed biofilm formation on the surface of a tooth shaken only in saline solution, whereas almost no biofilm was observed on a tooth incubated in TPP solution. This result suggests that TPP is effective against adherent cells of S. mutans and S. sanguis. Thus, TPP would be useful for development as an antimicrobial agent against oral microorganisms, and has great potential for use in mouthwash solutions for the prevention and treatment of dental caries. Keywordsgreen tea polyphenols-antimicrobial activity-oral microorganism-dental care
  Biotechnology and Bioprocess Engineering 04/2012; 15(2):359-364. · 1.28 Impact Factor
• Article: Synergistic anti-bacterial and proteomic effects of epigallocatechin gallate on clinical isolates of imipenem-resistant Klebsiella pneumoniae.

  Yun-Seok Cho, Jay Jooyoung Oh, Kye-Heon Oh
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  ABSTRACT: Imipenem-resistant Klebsiella pneumoniae (IRKP) were used to explore the synergistic anti-bacterial and proteomic effects of imipenem alone or in combination with epigallocatechin gallate (EGCg). The minimal inhibitory concentrations (MICs) of EGCG for 12 clinically isolated IRKP strains ranged from 300 to 650 μg/ml. Each of the 12 IRKP strains experienced a 4- to 64-fold reduction in the MIC of imipenem upon co-incubation with 0.25 × MIC level of EGCg. The time-kill method was used on the 12 IRKP clinical isolates to evaluate the bactericidal activities of imipenem alone or with EGCg. Compared to imipenem alone, EGCg with imipenem demonstrated enhanced bactericidal activity. Two-dimensional polyacrylamide gel electrophoresis identified eight down-regulated and four up-regulated proteins in the IRKP strain upon exposure to 1 × MIC of EGCg. Analysis of the outer membrane protein profiles of IRKP cultures treated with EGCg revealed unique changes in outer membrane proteins. In addition, scanning electron microscopic analysis demonstrated the presence of cells with wrinkled surfaces containing perforations and irregular rod-shaped forms after treatment with EGCg or imipenem. These studies demonstrate that EGCg can synergize the bacterial activity of imipenem and differentially stimulate the expression of various proteins in IRKP.
  Phytomedicine: international journal of phytotherapy and phytopharmacology 05/2011; 18(11):941-6. · 2.17 Impact Factor