Tannins from Foods to Combat Diseases

Abstract

Tannins are a group of phytochemicals found to be present in various concentrations in many fruits and vegetables consumed by human. Studies reveal that the phytoconstitutents belonging under the umbrella of tannins possess potent antioxidant activity; some exhibit radical scavenging activity as well. Studies also showed the presence of tannins in various pharmacologically potent leaves, barks and fruit extracts. Proper experimental and clinical evaluation of the protective activity of tannins from foods in various oxidative stress mediated pathological conditions can pave a new path for mankind in development of modern drugs and designing new and alternative pharmacological agents. On the other hand, inclusion of recommended fruits, beverages, leaves etc. containing tannins in one's daily diet can help to prevent and also combat various types of health ailments, the underlying mechanism being the radical scavenging and antioxidant potential of tannins.

Full text

International Journal of Pharma Research & Review, May 2015; 4(5):40-44 ISSN: 2278-6074
Debosree Ghosh, IJPRR 2015; 4(5) 40
Review Article
Tannins from Foods to Combat Diseases
*Debosree Ghosh
Department of Physiology, Ramananda College, Bishnupur, Bankura 722122, West Bengal, India.
ABSTRACT
Tannins are a group of phytochemicals found to be present in various concentrations in many fruits and
vegetables consumed by human. Studies reveal that the phytoconstitutents belonging under the umbrella
of tannins possess potent antioxidant activity; some exhibit radical scavenging activity as well. Studies
also showed the presence of tannins in various pharmacologically potent leaves, barks and fruit extracts.
Proper experimental and clinical evaluation of the protective activity of tannins from foods in various
oxidative stress mediated pathological conditions can pave a new path for mankind in development of
modern drugs and designing new and alternative pharmacological agents. On the other hand, inclusion of
recommended fruits, beverages, leaves etc. containing tannins in one’s daily diet can help to prevent and
also combat various types of health ailments, the underlying mechanism being the radical scavenging and
antioxidant potential of tannins.
Keywords: Tannins, antioxidant, radicals, phytoconstituents, oxidative stress
Received 30 March 2015 Received in revised form 13 April 2015 Accepted 17 April 2015
*Address for correspondence:
Debosree Ghosh,
Department of Physiology, Ramananda College, Bishnupur, Bankura 722122, West Bengal, India.
E-mail: ghoshdebosree@gmail.com
________________________________________________________________________________________________________________________
INTRODUCTION
Antioxidants are substances that are
capable of scavenging free radicals from
within the body of living organisms. Plants,
herbs, fruits and vegetables have been
known to be rich sources of natural
antioxidants. Those natural antioxidants are
of various chemical nature and have varied
molecular mechanism of action. Natural
antioxidants have been revealed
experimentally to possess potent
capabilities to combat various diseased
conditions in experimental animals [1] and
humans [2]. Antioxidants have been
reported to exert a wide range of
pharmacological effects which includes
anticancer, anti-inflammatory, antitoxic,
antiallergic etc. and various other different
types of medicinal activities [2-5].
Antioxidants are being investigated to
possess antiteratogenicity and
antimutagenicity [4, 5]. Tannins are a
widely distributed phenolic antioxidant,
present in various barks, leaves, fruits and
vegetables and have been reported to
possess medicinal and therapeutic
potentials [6]. Tannic acid is one such magic
molecule with potent antioxidant activity.
Tannic acid in foods
Human consumption of fruits and
vegetables and beverages rich in
polyphenols have been found to be directly
linked with inhibition of occurrence of
deadly diseases like cancer [6],
cardiovascular disorders [7], nephropathy
[8] and also have been found to be related
to detoxification of toxic effects of exposure
to toxic heavy metals like lead [9] and
cadmium [10].
Tannins have been reported to be present
in fruits and vegetables like bananas,
sorghum, grapes, raisins, spinach, red wine,
persimmons, chocolate etc. Beverages like
tea and coffee have also been recognised to
be rich source of tannins [11]. The colour of
tea also depends on the tannin content.
Darker the tea, more is the content of tannin
in it [11]. Tannic acid has a hydrophobic
central ‘core’ containing glucose and a
hydrophilic ‘shell’ is the structural
specificity of the molecule responsible for
the antioxidant property of tannic acid.

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Debosree Ghosh, IJPRR 2015; 4(5) 41
They have ten galloyl groups and tannins
are soluble in water [12]. Phenolic
compounds are known to exhibit
antioxidant activity by virtue of their redox
property because of which they can
scavenge oxygen radicals and donate
hydrogen to neutralise reactive oxygen
species [12, 13]. Studies revealed protective
ability of tannic acid against skin, lung and
stomach tumors [14].
Both black and green tea, wine and
chocolate and certain fruits and vegetables
rich in tannin can be consumed in definite
amount to maintain a healthy and disease
free life and to restrict oxidative damages
brought about due to generation of free
radicals in animal and plant organisms.
More than forty herbs have reported to
contain tannin [15]. Curry leaves are one of
the worth mentioning herbs containing
tannins, which are available easily and
consumed frequently and usually by the
South East Asian countries as spice herb
[15]. Several medicinal herbs also have
been reported to contain tannin [15].
Besides, cinnamon, thyme, black cohosh and
feverfew also contain tannin. Tannins are
contributors of the particular flavour of
wine. Tannins in wine come from from the
fruits like grape from which wine is
manufactured. Tea is a rich and well known
source of tannin and the quantitative
content of tannin in a particular type of tea
depends on the amount of tannin in the tea
leaves or bark from which the tea has been
derived [16].
Types of tannins
Tannins are classified into two classes. One
group is comprised of hydrolysable
polyhydric alcohol in which the hydroxyl
groups are partially or completely esterified
by gallic acid or similar kind of compounds
[17]. The other group is composed of
tannins which are formed by condensation
of phenolic compounds. Those are non
hydrolysable and are known as condensed
tannins [18]. Condensed tannins are found
in grapes, pomegranates etc., have high
molecular weights and have been reported
to possess therapeutic potentials18. The
condensed tannins are more stable and are
not easily decomposed. Condensed tannins
are also not easily hydrolyzed by acids [18].
The basic component of condensed tannin
is (epi) catechin. Several monomeric uits of
catechin condense to form the oligomeric or
the polymer structure of condensed tannin
[18].
Figure1: Types of tannins and their basic structures
Tannins in therapeutics
Researchers around the world are in search
of potent molecules from plants for
developing useful drugs with least or no
side effects and cytotoxicity. Tannic acid
from herbs and fruits can thus be of
immense use in endeavours of drug
development from natural sources.
According to a report by WHO, almost 80%
of the total population of the world are
dependent on medicines derived from
natural sources. Tannic acid imparts the
astringent taste to unripe fruits.
During the late 19th and beginning of the
20th century, tannic acid has been reported
to be in use for treating toxicity due to

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Debosree Ghosh, IJPRR 2015; 4(5) 42
substances like strychnine, mushroom etc.
Condensed tannins have been reported to
be effective against allergies, tumours,
cardiovascular disorders etc. Besides,
studies reveal that condensed tannin has
the potency to treat tumours, platelet
aggregation and also can reduce the risk of
cancer [19, 20].
Use of tannic acid for treating burn injuries
reduced the number of deaths occurring
due to burn [21]. Strong, luke warm tea in
place of tannic acid can be used for treating
burn injuries [21]. During the second World
War, burn injuries due to bombs, lewisite or
mustard gas were treated with tannic acid.
Tannic acid was used for dressing such burn
injuries [22].
Tannins from various plants and fruits are
of diverse type and this variation is due to
their degree of polymerization and
concentration in respective plant which in
turn decides their biological activity. Tannin
has been reported in many plant species
including R. apiculata and R. Mangle [22].
We have also found presence of tannic aid
in Murraya koenigii [15]. It is difficult to
isolate and characterize tannins from plants
and fruits due to the complex stuture of
highly polymerized tannins. The tannins
from R. apiculata and R. Mangle has been
reported to possess antibacterial and
antiviral activity [23]. Whereas tannins
from Murraya koenigii have been found to
be one of the important components of the
leaves of the plant which are responsible for
imparting the antioxidant capacity of the
same [22]. Murraya koenigii has been found
to be effective in combating heavy metal
induced oxidative stress mediated damages
in heart [23], liver [23], kidneys [9, 23] and
blood tissues [24] in experimental rats.
Tannic acid being a recognized antioxidant
component of the leaves of Murraya koenigii
can be considered to have contributions to
the protective effect of the leaves against
heavy metal induced cardio toxicity,
hepatotoxicity, nephrotoxicity and
hematotoxicity.
Studies reveal the use of tannic acid in
healing wounds and various other different
types of ailments in human beings. Tannins
have been reported to be used in treating
gastric ulcers, diarrhoea, snake bites,
inflammations [25] etc. Hydrolyzable
tannins are found in high concentrations in
nutgalls growing on Rhus semialata, Quercus
infectoria, the seedpods of Caesalpinia
spinosa and the fruits of Terminalia chebula
[26]. Well known souces of condensed
tannins are the heartwood of Schinopsis
lorentzii and S. balansa, the bark and/or
heartwood of Acacia catechu and A.
mollisima, and the bark of Rhizophora and
Eucalyptus species [27].
The hydrolysable form of tannin is
extensively used in medicine and is called
as "acidum tannicum" or tannic acid.
Though studies suggest that both the types
of tannins i.e., condensed tannin and the
hydrolysable one have potent therapeutic
potentials in various kind of diseases and
ailments, yet the hydrolysable one is
considered as a ready to use drug in the
European and American countries [28, 29].
Whereas, the condensed form of tannin is
considered and has been reported to be
extensively used in countries like China [30,
31].
Tannic acid has been reported to be used in
cold sores and fever blisters, prickly heat,
sore throat, inflamed tonsils, acute
dermatitis etc. Tannic acid is also used for
bleeding, chronic diarrhoea, dysentery,
hematuria, painful joints, persistent coughs
[32] etc.
Tannins have been reported to have
synergistic therapeutic activity [33]. We
also have observed that use of Murraya
koenigii leaves containing tannins have
enhanced the protective activity of
melatonin against lead induced toxic effects
in various organs in rats [24,34,35].
CONCLUSION
Tannins thus form a large group of natural
product and they are biologically active
entities easily available from our foods.
Tannins have extensive health benefits and
have therapeutic potentials for treating
various disease conditions. We may take
care of including components containing
tannins in our daily diet and thus can
simply step away from many diseases.
Continuous administration of purified
tannins in experimental animals has been
reported to be detrimental for hepatic and
renal tissues of the animal but on the other
hand studies reveal that intake of tannins
present in food is safe [36,37]. Till date

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Debosree Ghosh, IJPRR 2015; 4(5) 43
there is no adverse effect reported in
humans or experimental animals for
consuming tannin containing foods. So,
purified tannins when used for therapeutic
purpose must be extensively
experimentally verified and checked and
should be used at permissible, safe and
recommended doses only. Whereas, foods
containing tannins, like tea, wine, fruits,
herbs and chocolates can be consumed
without worries and the beneficial effects of
tannins can be thus extracted and enjoyed
for a healthy life with reduced load of
diseases and ailments.
REFERENCES
1. Devasagayam, T.P., Tilak, J.C., Boloor, K.K.,
Sane, K.S., Ghaskadbi, S.S., Lele, R.D., Review:
free radicals and antioxidants in human
health: current status and future prospects. J.
Assoc. Physicians., 2004, 52, 794.
2. Ghosh, D., Dey, M, Ghosh, A.K.,
Chattopadhyay, A. and Bandyopadhyay, D.,
Melatonin protects against lead acetate-
induced changes in blood corpuscles and
lipid profile of male Wistar rats. J. Pharm.
Res., 2014, 8(3), 336-342.
3. Butterfielda, D. A., Castegnaa, A., Pocernicha,
C. B., Drakea, J., Scapagninib, G. and
Calabrese, V.,Nutritional approaches to
combat oxidative stress in Alzheimer’s
disease. J. Nutr. Biochem., 2002,13, 444.
4. Reiter, R.J., Tan, D.X., Mayo, J.C., Sainz, R.M.,
Leon, J., Czarnocki, Z., Melatonin as an
antioxidant: biochemical mechanisms and
pathophysiological implications in humans.
Act. Biochim. Pol., 2003, 50(4),1129-1146..
5. Chandrashekaran, G., Pradhan, S. C., Indian
herbal medicines in the treatment of liver
diseases: problems and promises.
Fundamental & Clinical Pharmacology, 26,
2012, 180-189.
6. The Use of Tannic Acid in the Local
Treatment of Burn Wounds: Intriguing Old
and New Perspectives .Wounds. 2001, 13(4).
http://www.medscape.com/viewarticle/407
583_2
7. Bandyopadhyay, D., Ghosh, D. and
Chattopadhyay, A., Lead Induced Oxidative
Stress Mediated Myocardial Injury: A Review.
Int. J. Pharm. Sci. Rev. Res., 29(2), 2014, 67-
71.
8. Bandyopadhyay, D., Mitra, E ., Ghosh, D.,
Firdaus, S. B., Chattopadhyay, A., Dey, M.,
Ghosh, A. K., Use of Curry Leaves in
Protection Against Stress-Induced Disorders.
Indian Journal of Physiology and Allied
Sciences, 66(3), 2012, 104-121.
9. Ghosh, D., Firdaus, S. B., Mitra, E .,
Chattopadhyay, A., Pattari, S. K., Jana K., and
Bandyopadhyay,D., Ameliorative Effect of
Curry Leaf Aqueous Extract Against Lead
Acetate- Induced Oxidative Stress In Rat
Kidneys. Int. J. Pharm. Pharm. Sci., 2013, 5(4),
546-556.
10. Mitra, E., Ghosh, D., Ghosh,A. K., Basu, A,
Chattopadhyay, A., Pattari, S. K., Datta, S., and
Bandyopadhyay, D., Aqueous Tulsi Leaf
(Ocimum Sanctum) Extract Possesses
Antioxidant Properties And Protects Against
Cadmium-Induced Oxidative Stress In Rat
Heart. Int. J. Pharm. Pharm. Sci., 2014,6(1),
500-513.
11. Tannin levels in tea;
http://www.livestrong.com/article/527907-
tannin-levels-in-teas/.
12. Haslam, E., Chemistry of Vegetable Tannins.
London, UK: Academic Press, 1966,14-65.
13. Foti, M.C., Antioxidant properties of phenols ,
J. Pharm. Pharmacol., 2007 , 59(12),1673-
1685.
14. Chung, K.T., Wong, T.Y., Wei, C.I., Huang, Y.W.,
Lin, Y., Tannins and human health: a review.
Crit. Rev. Food. Sci. Nutr. 1998, 38(6), 421-
64.
15. Ghosh, D., Mitra, E., Firdaus S. B., Dey, M.,
Ghosh A. K., Chattopadhyay, A.,
Bandyopadhya,D., In vitro studies on the
antioxidant potential of the aqueous extract
of Curry leaves (Murraya koenigii L.)
collected from different parts of the state of
West Bengal. Indian Journal of Physiology
and Allied Sciences, 2012, 66(3), 77-95.
16. Tannins in tea.
http://ratetea.com/topic/tannins-in-tea/70/
17. Ashok , P. V., and Upadhyaya, K., Tannins are
Astringent, 1(3), Journal of Pharmacognosy
and Phytochemistry, 2012, 1(3) , 45-50.
18. Haslam, E., Types of tannic acid, Chemistry of
Vegetable Tannins, London, UK: Academic
Press, 1966, 14-65.
19. Deutsches Arzneibuch. Acidum tannicum -
Gerbsäure. Berlin, Germany: R. v. Decker's
Verlag, 1926:32-33.
20. Pharmacopée Française, 6th edition. Tannin
officinale, acidum tannicum. Rennes, France:
Imprimeries Oberthur, 1937:1017-9.
21. Pharmacopoeia of the United States of
America, 10th Decennial Revision. Acidum
tannicum, tannic acid. Philadelphia, PA: JB
Lippincott Company, 1926:28-9.
22. http://www.rsc.org/chemistryworld/2014/
04/tannins-tea-leather-antioxidant-podcast
23. Sulaima, S., Ibrahim, D., Kassim, J., and Sheh-
Hong, L.,Antimicrobial and antioxidant
activities of condensed tannin from

International Journal of Pharma Research & Review, May 2015; 4(5):40-44 ISSN: 2278-6074
Debosree Ghosh, IJPRR 2015; 4(5) 44
Rhizophora apiculata barks. J. Chem. Pharm.
Res., 2011, 3(4),436-444.
24. Ghosh, D., Firdaus, S. B., Mitra, E., Dey, M., and
Bandyopadhyay, D., Protective effect of
aqueous leaf extract of Murraya koenigi
against lead induced oxidative stress in rat
liver, heart and kidney: a dose response
study. Asian Journal of Pharmaceutical and
Clinical Research, 2012,, 5( 4), 54-58.
25. Ghosh, D., Paul, S., Firdaus, S. B., Mishra, S.
and Bandyopadhyay, D., Aqueous extract of
Murraya koenigii in combination with
melatonin provides better protection against
lead induced alterations in blood corpuscles
and lipid profile of male Wistar rats. Science
and Culture, 2014, .
26. Chung, K.T., Wong, T.Y., Wei, C.I., Huang, Y.W.,
Lin, Y., Tannins and human health: a review.
Crit Rev Food Sci Nutr. 1998, 38(6), 421-64.
27. Mussche, R. Isolering, struktuurbepaling en
industriële toepassingen van
hydrolyseerbare plantaardige looistoffen.
Farm Tijdschr België 1989, 66(1),2-6.
28. Gnamm H. Die Gerbmittel; allgemeine
Beschreibung der pflanzlichen Gerbmittel. In:
Bergmann M, Gnamm H, Vogel W (eds). Die
Gerbung mit Pflanzengerbstoffe; Gerbmittel
und Gerbverfahren. Wien, Austria: Verlag
von Julius Springer, 1931,1-100.
29. Pharmacopée Française, 6th edition. Tannin
officinale, acidum tannicum. Rennes, France:
Imprimeries Oberthur, 1937:1017-9.
30. Pharmacopoeia of the United States of
America, 10th Decennial Revision. Acidum
tannicum, tannic acid. Philadelphia, PA: JB
Lippincott Company, 1926:28-9.
31. Anonymous. Studies on the toxic effects of
certain burn escharotic herbs. Chinese. Med
.J., 1978,4(5), 388-93.
32. Yang, C.C., Xiao, Y.R., Li, Y.Y., Management of
the burn wound. In: Yang CC, Hsu WS, Shih
TS (eds). Treatment of Burns. Berlin,
Germany: Springer Verlag, 1982,41-105.
33. Comprehensive medicines; Natural database.
http://naturaldatabase.therapeuticresearch.
com/nd/PrintVersion.aspx?id=217&AspxAut
oDetectCookieSupport=1.
34. Chang, T.L., Wang, C.H., Combination of
quercetin and tannic acid in inhibiting 26S
proteasome affects S5a and 20S expression,
and accumulation of ubiquitin resulted in
apoptosis in cancer chemoprevention. Biol.
Chem., 2013, 394(4), 561-575.
35. Firdaus, S. B., Ghosh,D., Chattyopadhyay,A.,
Jana K., and Bandyopadhyay, D.A
combination of aqueous curry (Murraya
koenigii) leaf extract and melatonin protects
against piroxicam induced gastric ulcer in
male albino rats: Involvement of antioxidant
mechanism(s). J. Pharm. Res, 2014,8(3),428-
436.
36. Ghosh,D., Firdaus, S. B., Ghosh, A. K., Paul,
S.,and Bandyopadhyay D.,Protection against
lead-induced oxidative stress in liver and
kidneys of male Wistar rats using melatonin
and aqueous extracts of the leaves of
Murraya koenigii – A novel combinatorial
therapeutic approach. J. Pharm. Res.,
2014,8(3),385-399.
37. Select Committee on GRAS Substances
(SCOGS) Opinion: Tannic acid (hydrolyzable
gallotannins)
http://www.fda.gov/Food/IngredientsPacka
gingLabeling/GRAS/SCOGS/ucm261485.htm