Tanning agents (overview)

Substances that lead to tanning of the skin. These include inorganic (alum, chromium salts) and vegetable substances.

The group of tanning agents includes:

• vegetable tanning agents and their subgroup, the medicinally used tanning agent drugs, e.g. gallotannins (gallic acid, galloylgallic acid, tannin), ellagitannins. A 10% catechin extract ( epigallocatechin gallate [Veregen®]) is available as a therapeutic agent for condylomata acuminata.
• Synthetic tanning agents
• Inorganic tanning agents: The main representatives of inorganic tanning agents are chromium salts and aluminium salts (see their importance as antiperspirants). Among the naturally occurring aluminium salts is the aseptic and astringent alum stone (potassium aluminium sulphate) also called alunite. Alum stones are used as antiperspirants and after shaving to stop bleeding.

Medicinal use of vegetable tanning agents see below Tanning agent drugs

Further use of tanning agents: Some tannins form very stable colour complexes with metal salts, mainly iron salts, which were formerly used for the production of writing ink.

Tannins in wine: Grapes contain tannins as constituents of stems, seeds and berry skins, which contribute to the taste of wine, especially red wine. The tannin content is considered a quality factor of the wine if it is in a harmonious relationship with other taste components (acidity, residual sugar, the various aromas).

1. de Jesus NZ et al (2012) Tannins, peptic ulcers and related mechanisms. Int J Mol Sci 13:3203-3228.
2. Sieniawska E (2015) Activities of Tannins--From In Vitro Studies to Clinical Trials. Nat Prod Commun 10:1877-1884.