Antibacterial and Antifungal Activities of New Acylated Derivatives of Epigallocatechin Gallate

Abstract

(−)-Epigallocatechin-3-O-gallate (EGCG) has useful antiviral, antimicrobial, antitoxin, and antitumor properties. Previously, Mori et al. (2008) found that addition of long acyl chains (C16–18) to EGCG enhanced its anti-influenza virus activity up to 44-fold. The chemical stability of EGCG against oxidative degradation was also enhanced by acylation. We further evaluated the in vitro activity spectrum of the EGCG derivatives against a wide range of bacteria and fungi. A series of EGCG O-acyl derivatives were synthesized by lipase-catalyzed transesterification. These derivatives exhibited several-fold higher activities than EGCG, particularly against Gram-positive organisms. Antifungal MICs of the derivatives were also two to fourfold lower than those of EGCG. The activities of the EGCG derivatives against Gram-negative bacteria were not distinguishable from those of EGCG. Among the derivatives evaluated, MICs of dioctanoate and palmitate (C16) for 17 Staphylococcus aureus strains were 4–32 μg/ml, although MIC of EGCG for these 17 strains was ≥128 μg/ml. C16 demonstrated rapid bactericidal activity against methicillin-resistant S. aureus (MRSA) ATCC43300 at ≥16 μg/ml. The enhanced activity of C16 against S. aureus was supported by its increased membrane-permeabilizing activity determined by increased SYTOX Green uptake. The EGCG derivatives were exported in Escherichia coli using the efflux pump AcrAB–TolC. The tolC deletion mutant exhibited higher sensitivity to EGCG and the derivatives than wild-type. Addition of long alkyl chains to EGCG significantly enhanced its activities against several bacteria and fungi, particularly against S. aureus including MRSA. C16 might potentially become under specified circumstances an alternative or supplement to antibiotics and disinfectants in the future.

Anti‐infective properties of epigallocatechin‐3‐gallate (EGCG), a component of green tea

“…In a small prospective cohort study it was reported that gargling with tea catechins extracts was effective in preventing influenza infection in elderly residents of a nursing home (Yamada et al, 2006). In addition, in another randomized, double-blind, placebo-controlled trial, the consumption of catechins for 5 months had a statistically significant preventive effect on clinically defined influenza infection and was well tolerated (Matsumoto et al, 2012). The results of these trials indicate these catechins have a protective effect against influenza virus; however, large-scale studies are needed to confirm this.…”

Effects of the medicinal plants Curcuma zedoaria and Camellia sinensis on halitosis control

“…Matsumoto et al, 11 studying the effects of extracts of Camellia sinensis, observed that several bacteria and fungi were sensitive to the extracts. Among them were Escherichia coli and strains of Staphylococcus aureus.…”

“…10,11 Lodhia et al 12 observed reductions in VSC in vivo immediately after the use of green tea powder, and Zeng and others 13 observed a reduction in the levels of CH 3 SH and H 2 S in vitro after the use of a green tea extract.…”

Antiviral effects of green tea (<i>Camellia sinensis</i>) against pathogenic viruses in human and animals (a mini-review)

“…The green tea extract inhibited the replication of influenza viruses by preventing acidification of intracellular compartment, such as lysosomes and endosomes (Lee et (Sahaa et al 2010). It has been demonstrated that consumption of catechins for 5 months produced significant inhibitory effects on influenza virus infection, and they were well tolerated (Matsumoto et al 2012). Yang et al (2014) compared in vitro antiviral activity of various components of green tea in influenza virus A and B.…”