Gallic acid

Gallic acid forms colourless needles or a crystalline, slightly brownish powder. The acid is poorly soluble in cold water and better soluble in warm water. Furthermore, the acid is well soluble in ethanol, glycerol and acetone. Gallic acid oxidizes easily and acts as a reducing agent.

Naturally in oak bark, chestnut leaves, gall apples, garnet roots, divi-divi, sumac each as a component of tannin (see there).

Medically, gallic acid is used in the form of tannin. In this respect its medical use (antiseptic, astringent) is equivalent to tannin.

Cosmetically, gallci acid (INCI) is used in cosmetic formulations. As Gallus extract they act as moisturizing ketis dispenser.

The name "gallic acid" is derived from the bile, which is found in the leaves of various species of gall wasps. trees (e.g. oaks). The gallic acid can be extracted from the gall apples hydrolytically or by enzymatic cleavage. Tannin which is obtained from gall apples and oak bark contains various glucose esters of gallic acid.

Gallic acid is still used today for the production of the iron gall ink which is true to documents. The tanning agent tannin is suitable for the tanning of leather (plays a role in the contact sensitization against leather treated with chromium salts). In the chemical industry, gallic acid is required for the production of pyrogallol/salts.

The esters/salts of gallic acid are called gallates.

1. Lima KG et al (2016) Gallic acid reduces cell growth by induction of apoptosis and reduction of IL-8 in HepG2 cells. Biomed Pharmacother 84:1282-1290.
2. BenSaad LA et al. (2017) Anti-inflammatory potential of
3. ellagic acid, gallic acid and punicalagin A&B isolated from Punica granatum. BMC Complement Altern Med 17:47.
4. de Cristo Soares Alves A et al (2016) Nanoencapsulation of gallic acid and evaluation of its cytotoxicity and antioxidant activity. Mater Sci Eng C Mater Biol Appl 60:126-134.
5. Dwivedi GR et al.(2016) Gallic acid-based indanone derivative interacts synergistically with tetracycline by inhibiting efflux pump in multidrug resistant E. coli. Appl Microbiol Biotechnol 100:2311-2325.
6. Lu J et al (2016) Antibacterial Effect of Gallic Acid against Aeromonas hydrophila and Aeromonas sobria Through Damaging Membrane Integrity. Curr Pharm Biotechnol 17:1153-1158.