Category:Astringents

An astringent is a herbal medicine whose principal action is the precipitation of tissue proteins through tannin-binding, producing local tissue contraction, reduced membrane permeability, and reduced secretion. The clinical use is in diarrhoea (intestinal tannin-mediated reduction of secretion), in haemorrhage (topical and selected internal use for haemoptysis, haematuria, menorrhagia, and minor wound bleeding), in inflammatory dermatoses (the topical contracting effect), in oral and pharyngeal inflammation (gargles), and in haemorrhoidal indications.

The active fraction across the category is the tannins, a structurally diverse group of polyphenolic compounds that bind and precipitate proteins. The hydrolyzable tannins (gallotannins, ellagitannins) are more common in oak, sumac, witch hazel; the condensed tannins (proanthocyanidins) are more common in cranberry, grape seed, hawthorn, pine bark; the dimeric and trimeric pyran-containing tannins of cinnamon are intermediate. The clinical effect of any astringent herb depends on the tannin concentration (typically 5 to 20 percent in the standard preparations), on the preparation form (decoction extracts more tannin than infusion; alcoholic tincture preserves the tannins well), and on the mucosal surface to which it is applied.

The foundational astringents of European herbal use are oak bark (Quercus robur or Q. petraea; the strongest standard astringent, used in decoction); agrimony (Agrimonia eupatoria; the gentler intestinal astringent of British use); raspberry leaf (Rubus idaeus; the women's-reproductive astringent, used in late pregnancy and postpartum); yarrow (Achillea millefolium; astringent and vulnerary); lady's mantle (Alchemilla vulgaris; gynaecological astringent); cinquefoil (Potentilla erecta; the British strong astringent); tormentil (Potentilla tormentilla); bistort (Persicaria bistorta); witch hazel (Hamamelis virginiana; the Native American medicine, principally topical); and rhatany (Krameria triandra; the South American oral-mucositis astringent).

Oak bark (Quercus robur), agrimony (Agrimonia eupatoria), raspberry leaf (Rubus idaeus), yarrow (Achillea millefolium), lady's mantle (Alchemilla vulgaris), cinquefoil (Potentilla erecta), tormentil, bistort (Persicaria bistorta), witch hazel (Hamamelis virginiana), rhatany (Krameria triandra), the TCM astringent Wu Mei (smoked plum, Prunus mume), the green tea (Camellia sinensis; for its catechin-mediated astringency), the cranberry (Vaccinium macrocarpon; cross-listed for urological use), the bilberry (Vaccinium myrtillus), pomegranate rind (Punica granatum; the Unani-tradition astringent), and the various Indian tannin-rich Terminalia species (chebula, bellirica) of Triphala fame.

The boundary of this category is "herb whose principal action is tannin-mediated tissue contraction and reduced secretion." Astringents are often combined with demulcents in clinical practice (the agrimony-marshmallow combination for diarrhoea and gastric inflammation) to balance their drying effect with mucosal protection. Several astringent herbs have other primary indications (raspberry leaf as women's-reproductive, cranberry as urological); they are cross-listed under their primary indication.

This category page is an encyclopedia article about its subject. The actual index of herbs belonging to the category is generated automatically by the wiki engine, from category-membership declarations on the individual herb pages, and appears at the foot of the page below the references.