Cell experiment:

KB cells, a human mouth epithelial cell line, are treated with Methyl gallate (1-8 mg/mL) for 24 h. Cytotoxicity of Methyl gallate is assessed by a modified MTT assay[1].

Methyl gallate is a plant phenolic with antioxidant, anticancer, and anti-inflammatory activities. Methyl gallate also shows bacterial inhibition activity.

The growth of A. viscosus is inhibited completely by a low dose of Methyl gallate (MIC=1 mg/mL). S. mutans and . sobrinus show intermediate sensitivity to Methyl gallate (MIC=2-4 mg/mL), whereas the growth of Lactobacillus spp. is inhibited completely at a relatively high concentration (MIC=8 mg/mL)[1]. Methyl gallate, in a concentration of 100 mM, could alleviate lipid peroxidation of the cells exposed to a short-term H2O2 treatment. In addition, Methyl gallate-treated cells could prevent intracellular glutathione (GSH) from being depleted following an exposure of H2O2 (8.0 mM) for a 3 h period[2]. Methyl gallate inhibits Treg cell-suppressive effects on effector CD4+ T cells and Treg migration toward tumor environment. Furthermore, forkhead box P3 (Foxp3) expression is also significantly decreased by methyl gallate[3].

[1]. Kang MS, et al. Inhibitory effect of methyl gallate and gallic acid on oral bacteria. J Microbiol. 2008 Dec;46(6):744-50. [2]. Hsieh TJ, et al. Protective effect of methyl gallate from Toona sinensis (Meliaceae) against hydrogen peroxide-induced oxidative stress and DNA damage in MDCK cells. Food Chem Toxicol. 2004 May;42(5):843-50. [3]. Lee H, et al. Methyl gallate exhibits potent antitumor activities by inhibiting tumor infiltration of CD4+CD25+ regulatory T cells. J Immunol. 2010 Dec 1;185(11):6698-705.