Vol 11, Issue 4, 2018
Online - 2455-3891
Print - 0974-2441
THE ROLE OF GREEN TEA IN ORAL HEALTH - A REVIEW
MEENAKSHI MOHAN*, GANESH JEEVANANDAN, MITHUN RAJA S
Department of Pediatric and Preventive Dentistry, Saveetha Dental College, Saveetha University, Chennai, Tamil Nadu, India.
Received: 13 November 2017, Revised and Accepted: 15 December 2017
Tea is the most widely consumed and a popular beverage in the world. Over the past decade, molecular components of teas and their health benefits on
humans have received increasing attention from researchers. Functional foods are foods with positive health benefits that extend beyond their normal
nutritional value. They interrupt the functions of the body and help in the management of specific health conditions and preventing pathologic changes.
One such nature’s gift is green tea. Green tea, a leading beverage in the Far East for the past thousand years, is an important source of polyphenol
antioxidants. (EGCG) epigallocatechin 3 gallate, a polyphenol, constitute the most interesting components in green tea leaves. There is an increasing
interest on the health benefits of green tea in the field of oral health. Green tea is renowned for its antioxidant, anti-cariogenic, anti inflammatory and
antimicrobial properties. This traditional beverage is also used in the management of chronic systemic diseases including carcinoma. Recent studies
has emphasized that in addition to the microbial activity, the host immuno-inflammatory reactions destroy the oral tissues to a greater extent. In such
cases green tea is considered to be a natural preventive and curative agent. There is a growing search of evidence for understanding the beneficial role
of green tea and its polyphenols in oral health. Numerous studies have shown the beneficial effects on the regular intake of green tea in maintaining
oral health. Even though studies demonstrate the health effects of green tea polyphenols, more clinical and biological studies to support guidelines for
green tea intake as part of prevention and treatment of specific oral pathologies are needed.
Keywords: Antioxidant, Green tea, Oral health, Polyphenols.
Green tea, an unoxidized tea, is derived from Camellia sinensis. Green tea
is obtained from C. sinensis by undergoing minimal oxidation during the
process . Green tea first originated in China and it was first cultivated
in 2737 BC during the period of Emperor Chen Nung. It is serving as
a beverage as well as a medicine over the years. Green tea has been
subjected to numerous scientific and medical studies to determine the
extent of its health benefits in recent years . There are three varieties
of tea, namely, green tea, black tea, and oolong. All the three varieties are
derived from C. sinensis plant, while the difference between them is the
method of processing . Green tea is unfermented (produced by drying
and steaming the leaves to inactivate the polyphenol oxidase, thus
no oxidation occurs), oolong is semi-fermented (produced when the
leaves are subjected to partial fermentation before drying), and black
tea is fully fermented (a post-harvest fermentation stage before drying
and steaming). Since fermenting results in a loss of various essential
components, green tea remains as the richest source of antioxidants
(Table 1), explicitly polyphenols . Hence, this review article elaborates
on the various beneficial effects of green tea on oral health.
EFFECT OF GREEN TEA ON ORAL HEALTH
Green tea and dental caries
Dental enamel is comprised of hydroxyapatite crystals. The solubility
of hydroxyapatite rises with the decrease in pH which is harmful to the
tooth enamel . The EGCG extract from the green tea causes a reduction
in acid production and maintains pH by inhibiting the enzyme lactate
dehydrogenase which is responsible for producing lactic acid from
pyruvate . Preventing the adhesion of bacteria to the glycoprotein
layer is an additional mechanism explaining the anticariogenicity.
A study has concluded that rinsing the mouth for 1 week with green
tea mouthwash significantly reduces the salivary levels of Streptococcus
mutans and Lactobacillus . Reports have proved that green tea
decreases the susceptibility of dental caries in both humans and
animals . Frequent intake of green tea can significantly decrease
caries formation, even in the presence of sugar in the diet . Green tea
extract also reduces ɑ-amylase activity in saliva which makes it act as an
anticariogenic agent [10,11].
Green tea and halitosis
Halitosis, due to dental caries and poor oral hygiene, is attributable
mainly due to volatile sulfur compounds. Few breath refreshing
chewing gums and mouth spray contain polyphenols, which are a major
ingredient of green tea . A study has reported that using green tea
mouthwash significantly reduces the volatile sulfur components level
in patients with gingivitis . Another study has demonstrated that
green tea extract had the ability to remove odorant sulfur .
Green tea and antiviral property
Polyphenols which act as antioxidant inhibit the enzymes that
damage the cell membrane and prevent penetration of the virus into
the cells . This property of green tea is quite essential as it can
prevent the oral viral diseases. EGCG is said to have ability to prevent
infection from influenza virus by attaching to viral hemagglutinin, thus
preventing its attachment to cellular target receptors . A study
revealed that EGCG, EGC, and ECG were found potent to inhibit influenza
virus by hemagglutination inhibition. EGCG and ECG suppress the viral
RNA synthesis, while EGC fails to exhibit this property . Green tea
is also stated to have its effect against human immunodeficiency virus
type 1, herpes simplex virus, Epstein–Barr virus, and adenoviruses .
Green tea and antifungal property
Candida albicans, a part of the indigenous microbial flora in humans, is
unique among opportunistic pathogens because it is a part of the normal
microbial flora of the host . Candidiasis is a most common outbreak
of C. albicans in the oral cavity. Amphotericin B (polyene antibiotics)
and fluconazole (azole antifungal agent) have the strongest antifungal
activity, especially against C. albicans. Antimycotic-resistant isolates of
C. albicans have appeared which act a major drawback . Hence, a
crude substitute was considered necessary. A study showed synergic
© 2018 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons.
org/licenses/by/4. 0/) DOI: http://dx.doi.org/10.22159/ajpcr.2018.v11i4.23628
Asian J Pharm Clin Res, Vol 11, Issue 4, 2018, 1-3
Mohan et al.
antifungal activity when a combination of EGC and antimycotics was
used against C. albicans. It also concluded that the combined use of EGC
and low dosage of amphotericin-B inhibited the growth of C. albicans,
and the action was proved to be fungicidal .
Green tea and periodontitis
Gingival sulcus, which harbors numerous microorganisms (mainly
anaerobes), deepens forming a periodontal pocket in cases of
periodontitis. In periodontitis, local infiltration of polymorphs and
serum exudates takes place. Anaerobic black-pigmented bacteria
such as Prevotella sp. and Porphyromonas digitalis are commonly
associated with periodontal disease . In vitro studies showed that
green tea catechin inhibits the growth of Porphyromonas gingivalis,
Prevotella intermedia, and Prevotella nigrescens, by inhibiting the
adherence of P. gingivalis onto human buccal epithelial cells and also
by inhibiting the production of toxic metabolites of P. gingivalis .
Green tea polyphenol also increases osteoblastogenesis and suppresses
osteoclastogenesis, thus preventing the bone from destruction and
preserving the periodontium . Green tea catechin given by local
delivery system using hydroxypropyl cellulose strips is said to inhibit
the growth of bacteria. Continuous application of green tea catechin was
reported as an effective method for improvement of periodontitis .
EGCG, with its ability to inhibit the formation of osteoclasts and induce
apoptosis cell death of osteoclasts, is also considered for improving
periodontal health . Green tea is also recognized for their roles in
host defense, human gingival cells, and inflammatory response [26,27].
Green tea and oral malignancy
Oral squamous cell carcinoma, a most common head and neck
malignancy, is characterized by high rates of morbidity and
mortality . Hamsters with induced buccal pouch tumor were given
green tea till the end of the experiment. It was noticed that hamsters
of the study group when compared with the control group showed
lesser pathological changes and tumor size [29,30]. Studies have been
conducted to show that green tea polyphenols may induce apoptosis
and delay in the cell cycle in tumor cells while not disturbing the
normal cells . Another study showed that tongue carcinoma culture
supplemented with EGCG causes inhibition of cell invasion. This was
furthermore confirmed by administering EGCG in SCC-induced mice,
which showed dose-dependent tumor growth inhibition and reduced
hepatocyte growth factor expression .
Over consumption of green tea
Over consumption of green tea is least likely to disrupt sleep quality
at night. Pregnant and breastfeeding women should drink no more
than 1–2 cups/day, as it can cause an increased heart rhythm. It is also
important to control the consumption of green tea in renal disorders,
due to its diuretic effects . Aluminum present in green tea, as revealed
by few studies, has a high capacity to cause neurological diseases .
Over intake of green tea catechins decreases the iron bioavailability
from the diet. In vivo study has proved that green tea polyphenols
can cause oxidative stress and liver toxicity at certain concentrations.
Patients on Warfarin are contraindicated to take green tea as green tea
contains Vitamin K. Green tea should also not be taken with aspirin
because it prevents platelets from clotting .
Other health benefits
Apart from oral health, review of literature shows various general
health befits of consuming green tea [3,35]. Some of them includes:
Anti-inflammatory activity, antimicrobial activity, antidiabetic
activity [36,37], anti-obesity effect , antihypertensive effect, cardiac
effects, blood pressure control, gastro and hepatoprotective effect, and
neuroprotective effect [33,37,38].
Drinking green tea is a healthy habit to maintain a healthy life. Various
studies have demonstrated that green tea possesses antioxidant,
antimutagenic, antidiabetic, anti-inflammatory, antibacterial, and
antiviral, and above all, cancer-preventive properties. Yet it is not
entirely clear whether green tea potency is because of its phenolic
ingredients or other nutritional components. More research is needed
to advocate the beneficial mechanisms of green tea. Review of the
literature concluded that green tea taken as a daily supplement can
improve the health status. Hence, it is considered to be a wholesome
drink for a healthy living.
Concept and collection of data - Meenakshi Mohan, Ganesh Jeevanandan.
Writing the article and critical review of article - Meenakshi Mohan,
Mithunraja. Final approval of the article - Ganesh Jeevanadan.
CONFLICT OF INTEREST
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Macronutrients Micronutrients Organic substance
Protein such as
enzymes- 15-20% of dry weight
Carbohydrates: Cellulose, pectin,
glucose, fructose, and sucros
e-1–7% of dry weight
Lipid components: Linoleic and
Sterols such as stigmasterol
Vitamins B, C, E.
Xanthic bases such as chlorophyll
Volatile components - aldehydes
Minerals and trace elements- Ca,
Mg, Mn, Cr, Fe, Al, F, K, Cu, Zn, Mo, Se,
Na, P, Co, Sr, Ni
Most important component of green tea is
Polyphenols of green tea are catechins (flavan-3-ols).
The four main catechins are:
(EGC) Epicatechin three gallate-13.6%
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