... , also known as 3,4,5-trihydroxybenzoic acid, found in gallnuts, sumac, witch hazel, tea leaves, oak bark ... formula is C6H2(OH)3COOH. Gallic acid is found both free and as part of tannins. ... the Folin-Ciocalteau assay; results are reported in gallic acid equivalents.Gallic acid can also be ... human cells against oxidative damage. Gallic acid was found to show cytotoxicity against cancer cells, without ...