Gallic acid

Gallic acid is a trihydroxybenzoic acid with the formula C6H2(OH)3CO2H[1]. It is classified as a phenolic acid and is found in various plants, including gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants[1]. Gallic acid is a white solid, although samples are typically brown due to partial oxidation[1]. Salts and esters of gallic acid are termed "gallates"[1].

Gallic acid is found in a number of land plants, such as the parasitic plant Cynomorium coccineum, the aquatic plant Myriophyllum spicatum, and the blue-green alga Microcystis aeruginosa[1]. It is also found in various oak species, Caesalpinia mimosoides, and in the stem bark of Boswellia dalzielii, among others[1]. Many foodstuffs contain various amounts of gallic acid, especially fruits (including strawberries, grapes, bananas), as well as teas, cloves, and vinegars[1][2]. Carob fruit is a rich source of gallic acid (24–165 mg per 100 g)[1].

Gallic acid has antioxidant, antimicrobial, and potentially even anti-obesity properties[2]. It has been used from the 12th to 19th centuries as a major component of iron gall ink, the standard writing ink in Europe[2]. Today, it’s becoming more recognized for its potential health benefits[2]. Gallic acid may help modulate the immune system and act as a natural defense mechanism against microbial infections[2]. It has also been found to improve the shelf life of fresh black truffles by reducing microbial growth[2].

Gallic acid has received increasing attention for its powerful anti-inflammatory properties[3]. It has been shown to weaken the inflammatory response by reducing the release of inflammatory cytokines, chemokines, adhesion molecule, and cell infiltration[3]. The anti-inflammatory mechanisms of gallic acid mainly involve MAPK and NF-κB signaling pathways[3]. It is expected to be a potential candidate for the treatment of various inflammation-related diseases[3].

In skincare, Diglucosyl Gallic Acid is a potent active derived through bioengineering practices that visibly brightens skin[4]. It is activated through the skin’s microbiome and has huge epidermal benefits, including brightening the skin, decreasing inflammation, and enhancing the skin’s photo-protection abilities[4]. It also has powerful retexturizing capabilities and can promote an even and brighter complexion[4].

Gallic acid is available as an ACS reagent with a purity of ≥98.0% and is sold as a powder[5]. It has a melting point of 252 °C (dec.) (lit.) and is combustible[5].

Citations:

[1] https://en.wikipedia.org/wiki/Gallic_acid

[2] https://www.healthline.com/nutrition/gallic-acid

[3] https://pubmed.ncbi.nlm.nih.gov/33212373/

[4] https://111skin.com/en-us/blogs/111journal/diglucosyl-gallic-acid-in-skincare

[5] https://www.sigmaaldrich.com/US/en/product/sial/398225