Medicinal plants and Medicinal plants and medical plant medical plant materials that materials that contain tannic contain tannic

substancessubstances

Tannins are astringent, bitter plant Tannins are astringent, bitter plant polyphenols that either bind and polyphenols that either bind and

precipitate or shrink proteins.precipitate or shrink proteins. The astringency from the tannins is what causes the dry and The astringency from the tannins is what causes the dry and

puckery feeling in the mouth following the consumption of puckery feeling in the mouth following the consumption of unripened fruit or red wine. unripened fruit or red wine.

Tannins are polyphenolic secondary metabolites of higher plants, and are either galloyl esters and their derivatives, in which galloyl moieties or their derivatives are attached to a variety of polyol-, catechin and triterpenoid cores (gallotannins, ellagotannins and complex tannins), or they are oligomeric and polymeric proantocyanidins that can possess different interflavanyl coupling and substitution patterns (condensed tannins).

Gallic acid

The word tannin is very old and reflects a traditional technology. "Tanning" (waterproofing and preserving) was the word used to describe the process of transforming animal hides into leather by using plant extracts from different plant parts of different plant species.

HHDP – hexahydroxy diphenic acid

Classification of tanninsI. Procter’s classification (1894):Tannins decompose at 180-200 degree (without air) and yield pyrogallol , pyrocatechin.

Pyrogallol Pyrocatechin

Two main groups of tannins are usually Two main groups of tannins are usually recognized; these are the hydrolysable recognized; these are the hydrolysable tannins and the condensed tannins tannins and the condensed tannins (proanthocyanidins).(proanthocyanidins).

Hydrolysable tanninsHydrolysable tannins

They may be hydrolysed by acids or enzymes They may be hydrolysed by acids or enzymes such as tannase. They are formed from several such as tannase. They are formed from several molecules of phenolic acids such as gallic and molecules of phenolic acids such as gallic and hexahydroxydiphenic acids which are united by hexahydroxydiphenic acids which are united by ester linkages to a central glucose molecule.ester linkages to a central glucose molecule.

Gallic acid

Three principal types of hydrolysable Three principal types of hydrolysable tannins are: tannins are:

- gallitannins (ethers of gallic acid and - gallitannins (ethers of gallic acid and sugars);sugars);

- ellagitannins (ethers of - ellagitannins (ethers of hexahydroxydiphenic (ellagic) acid and hexahydroxydiphenic (ellagic) acid and sugars);sugars);

- non-sugar ethers of phenolcarbolic - non-sugar ethers of phenolcarbolic acids(quinic acid).acids(quinic acid).

Condensed tannins Condensed tannins (proanthocyanidins)(proanthocyanidins)

Unlike hydrolysable tannins, these are Unlike hydrolysable tannins, these are not readily hydrolysed to simpler not readily hydrolysed to simpler molecules and they do not contain a molecules and they do not contain a sugar moiety. They are related to the sugar moiety. They are related to the flavonoid pigments and have polymeric flavonoid pigments and have polymeric flavan-3-ol structures.flavan-3-ol structures.

Flavone

They are divided into 3 groups as well:They are divided into 3 groups as well:

- derivatives of flavanols-3;- derivatives of flavanols-3;

- derivatives of flavandiols-3,4;- derivatives of flavandiols-3,4;

- derivatives of oxystilbens - derivatives of oxystilbens (diphenilethylene).(diphenilethylene).

Occurrence of tanninsOccurrence of tannins

Tannins are of wide occurrence in plants Tannins are of wide occurrence in plants and are usually found in greatest quantity and are usually found in greatest quantity in dead or dying cells. They exert an in dead or dying cells. They exert an inhibitory effect on many enzymes due to inhibitory effect on many enzymes due to protein precipitation and, hence, they protein precipitation and, hence, they may contribute a protective function in may contribute a protective function in barks and heartwoods. barks and heartwoods.

Properties and testsProperties and tests Tannins are soluble in water, dilute Tannins are soluble in water, dilute

alkalis, glycerol and acetone, but alkalis, glycerol and acetone, but generally only sparingly soluble in other generally only sparingly soluble in other organic solvents. Solutions precipitate organic solvents. Solutions precipitate heavy metals, alkaloids, glycosides and heavy metals, alkaloids, glycosides and gelatin.gelatin.

Tannins can be extracted with hot water, Tannins can be extracted with hot water, and after that extract should be purified and after that extract should be purified by chlorophorm, diethyl ether and ethyl by chlorophorm, diethyl ether and ethyl acetate respectively. acetate respectively.

IdentificationIdentification

Gelatin test. Solutions of tannins Gelatin test. Solutions of tannins precipitate a solution of gelatin.precipitate a solution of gelatin.

Tannins also precipitate alkaloids.Tannins also precipitate alkaloids. With iron-ammonium alum, hydrolysable With iron-ammonium alum, hydrolysable

T. give blue-black colour and condensed T. give blue-black colour and condensed T. brownish-green colour.T. brownish-green colour.

Condensed T. with vanillin and Condensed T. with vanillin and concentrated hydrochloric acid or 70% concentrated hydrochloric acid or 70% sulfuric acid give red colour.sulfuric acid give red colour.

With lead acetate in acetic acid hydrolysable With lead acetate in acetic acid hydrolysable tannins precipitate, and condensed stay in tannins precipitate, and condensed stay in solution.solution.

Free ellagic acid can be identified Free ellagic acid can be identified by adding by adding several chrystals of sodium nitrate several chrystals of sodium nitrate and 3-4 and 3-4 drops of acetic acid, a red-violet colour drops of acetic acid, a red-violet colour develops.develops.

Bound ellagic acidBound ellagic acid (HHDP) (HHDP) can be can be determined with sodium nitrdetermined with sodium nitraate and te and 0,10,1hydrochloric or hydrochloric or 0,1 0,1 sulfuric acid. sulfuric acid. Develops red colour which becomes blue.Develops red colour which becomes blue.

Chromatography is used to identify low-Chromatography is used to identify low-molecular tannins.molecular tannins.

Biological action and uses Biological action and uses of tanninsof tannins

Tannins may be employed medicinally in antidiarrheal, Tannins may be employed medicinally in antidiarrheal, haemostatic, and antihaemorrhoidal compounds.haemostatic, and antihaemorrhoidal compounds.

The anti-inflammatory effect of tannins helps control all The anti-inflammatory effect of tannins helps control all indications of gastritis, esophagitis, enteritis, and irritating indications of gastritis, esophagitis, enteritis, and irritating bowel disorders. Diarrhea is also treated with an effective bowel disorders. Diarrhea is also treated with an effective astringent medicine that does not stop the flow of the astringent medicine that does not stop the flow of the disturbing substance in the stomach; rather, it controls the disturbing substance in the stomach; rather, it controls the irritation in the small intestine.irritation in the small intestine.

Tannins not only heal burns and stop bleeding, but they also Tannins not only heal burns and stop bleeding, but they also stop infection while they continue to heal the wound stop infection while they continue to heal the wound internally. The ability of tannins to form a protective layer over internally. The ability of tannins to form a protective layer over the exposed tissue keeps the wound from being infected the exposed tissue keeps the wound from being infected even more. Tannins are also beneficial when applied to the even more. Tannins are also beneficial when applied to the mucosal lining of the mouth.mucosal lining of the mouth.

They have also been reported to have anti-viral They have also been reported to have anti-viral effects. When incubated with red grape juice and effects. When incubated with red grape juice and red wines with a high content of condensed red wines with a high content of condensed tannins, the poliovirus, herpes simplex virus, and tannins, the poliovirus, herpes simplex virus, and various enteric viruses are inactivated. various enteric viruses are inactivated.

Tannins can also be used to pull out poisons from Tannins can also be used to pull out poisons from poison oak or from bee stings, causing instant poison oak or from bee stings, causing instant relief. The tannins help draw out all irritants from relief. The tannins help draw out all irritants from the skin because tannin is an astringent that the skin because tannin is an astringent that tightens pores and pulls out liquids.tightens pores and pulls out liquids.

MP and MPM MP and MPM containing tanninscontaining tannins

Sumach leaf – Sumach leaf – RhoisRhois coriariaecoriariae f folia olia

Rhus coriaria- Sumach, Sicilian Rhus coriaria- Sumach, Sicilian sumacsumacAnacardiaceae (cashew or sumac Anacardiaceae (cashew or sumac family)family)

Constituents. Constituents. Sumac leaves Sumac leaves contain 13-25% of tannins, contain 13-25% of tannins, flavonoids, ether oil, ascorbic flavonoids, ether oil, ascorbic acid.acid.

Uses.Uses. Sumac leaves are Sumac leaves are used to get tannin, which is used to get tannin, which is part of “part of “Galascorbin”Galascorbin” and and Novikov’s liquidNovikov’s liquid..

Smoke tree leaf – Smoke tree leaf – CotiniCotini coggygriae coggygriae Folia Folia Cotinus coggygria- Cotinus coggygria- Common Smoketree, Common Smoketree, SmokebushSmokebushAnacardiaceaeAnacardiaceae Constituents.Constituents. Gallotannin, Gallotannin,

flavonoids, volatile oilsflavonoids, volatile oils

Uses.Uses. Medicines- Medicines- Galascorbin Galascorbin has astringent has astringent and P-vitaminic action, and P-vitaminic action, FlacuminFlacumin, which contains , which contains up to 75% of flavonoids up to 75% of flavonoids and has cholagogue and has cholagogue action.action.

Bergenia rhizome – Bergenia rhizome – Bergeniae Rhizomata Bergeniae Rhizomata Bergenia crassifolia – Badan, Bergenia crassifolia – Badan, Elephant’s ears, Siberian teaElephant’s ears, Siberian teaSaxifragaceaeSaxifragaceae

Constituents.Constituents. MPM MPM contains blend of contains blend of gallotannins and condensed gallotannins and condensed tannins (21-25%), arbutin tannins (21-25%), arbutin (up to 5%), katekhin, gallic (up to 5%), katekhin, gallic acid, traces of rutin and acid, traces of rutin and quercetinquercetin

Uses.Uses. Decoction is used to Decoction is used to treat infectious colitis and treat infectious colitis and enterocolitis, externally- to enterocolitis, externally- to treat mouth ulcers. In treat mouth ulcers. In gynaecology- to treat gynaecology- to treat cervical erosioncervical erosion

Alder fruit – Alni Fructus Alder fruit – Alni Fructus Alnus incana, alnus glutinosa –Alnus incana, alnus glutinosa –GreyGrey or Speckled Alderor Speckled AlderAlnus glutinosa- Alnus glutinosa- Black Alder, Black Alder, European Alder or Common European Alder or Common AlderAlderBetulaceaeBetulaceae

Constituents. Constituents. MPM contains MPM contains ellagotannins, gallotannins, free ellagotannins, gallotannins, free gallic and ellagic acids up to gallic and ellagic acids up to 15%.15%.

Uses.Uses. Fruits are used as Fruits are used as astringent, anti-inflammatory astringent, anti-inflammatory and haemostatic agent; they are and haemostatic agent; they are part of stomach mixes, part of stomach mixes, “Kamilal”“Kamilal” (suppositories). (suppositories). “Altan”“Altan” is used is used as anti-inflammation and pain-as anti-inflammation and pain-killing drug to treat indigestionkilling drug to treat indigestion

Oak bark – QuercusCortex Oak bark – QuercusCortex

Quercus robur- Quercus robur- Pedunculate Oak or Pedunculate Oak or English oakEnglish oakFagaceaeFagaceae Constituents.Constituents. Bark contains Bark contains

tannins, mainly of condensed tannins, mainly of condensed type (12%), free gallic and type (12%), free gallic and ellagic acids, flavonoids, ellagic acids, flavonoids, saponins, carbohydrates.saponins, carbohydrates.

Uses.Uses. Oak bark is used Oak bark is used medicinally for its astringent medicinally for its astringent and anti-inflammation and anti-inflammation properties to treat gingivitis and properties to treat gingivitis and stomatitis, burns and frostbite. stomatitis, burns and frostbite. Oak bark is included to anti-Oak bark is included to anti-haemorrhoidal mixes and haemorrhoidal mixes and complex medicines.complex medicines.

Bilberry leaf, fruit – Bilberry leaf, fruit – Myrtilli Fructus Myrtilli Fructus Myrtilli Folia Myrtilli Folia Vaccinium myrtillus- BilberryVaccinium myrtillus- BilberryEricaceae (Heather family)Ericaceae (Heather family)

Constituents.Constituents. Fruits contain Fruits contain condensed tannins (12%); condensed tannins (12%); anthocyanidins, organic acids, anthocyanidins, organic acids, carotene, pectin. carotene, pectin.

Leaves contain condensed tannins Leaves contain condensed tannins (7-20%), phenols- neomyrtillin, (7-20%), phenols- neomyrtillin, myrtillin (2%), arbutin (1%), myrtillin (2%), arbutin (1%), flavonoids.flavonoids.

Uses.Uses. Fruits are used as mild Fruits are used as mild astringent agent to treat diarrhea in astringent agent to treat diarrhea in children and acute enterocolitis in children and acute enterocolitis in adults. Myrtillin reduces sugar level adults. Myrtillin reduces sugar level in blood and thus is part of in blood and thus is part of antidiabetics collection antidiabetics collection “Arphazetin”.“Arphazetin”.