Gallic acid (3,4,5-trihydroxybenzoic acid), found in many plants either in free-form or part of
tannins, is known to possess anti-microbial,
antioxidant and cytotoxic properties. NFκB regulates the expression of several genes involved in
carcinogenesis. These include anti-apoptotic,
cytokines and cell cycle-regulatory genes. It is well established that the transcriptional factor NFκB is deregulated in many forms of
cancer. Thus, agents that can suppress NFκB activation have the potential of suppressing
carcinogenesis. In the present investigation,
gallic acid was isolated from Alchornea glandulosa (Euphorbiaceae) and eight
esters were synthesised. These compounds were evaluated against TNF-α-induced NFκB activation with stably transfected 293/NFκB-Luc human embryonic kidney cells. Gallates with IC(50) values in a range of 10-56 µM mediated inhibitory activity higher than
gallic acid (IC(50) 76.0 ± 4.9 µM). In addition to inhibiting NFκB activation,
gallic acid mediated a modest cytotoxic effect, and some of the gallates affected cell viability at the tested concentrations. Based on these results, suppression of NFκB activation by gallate
esters could play a chemopreventive role in
carcinogenesis.