Keeping your teeth healthy mandates a new strategy …

Pu-erh Tea Inhibits Bacterial
Attachment to Dental Plaque

By Will Block


n Chinese traditional medicine, Pu-erh tea has been known for nearly two thousand years for its preventative and curative properties. But much of this period was pre-scientific. Recently, Pu-erh has been shown to protect the human body from obesity and from infections, and to delay aging in the elderly (see “Pu-erh Tea Delays Aging” in the December 2012 issue) by reversing age-related immune decline. Pu-erh has also been found to help prevent cancer, to protect kidney function, and possibly to ward off metabolic syndrome. Altogether, it is clear that this remarkable tea goes far beyond promoting weight loss: it also provides a wide variety of enhanced health benefits, including antioxidant, anticancer, and cholesterol lowering effects, not to mention lowering blood pressure and blood sugar, and improving bacterial flora in the intestines. And there is something more … healthier teeth.

Oral Cavity Bacterial Inhibition

Plant extracts and phytochemicals can inhibit bacterial attachment to abiotic and biotic surfaces, such as your teeth, by altering cell surface properties including hydrophobicity, and surface charge, and by the presence of structures such as flagella. Tea is one such potential attachment inhibitor, and has been thought to promote oral health by inhibiting bacterial attachment to tissues in the oral cavity. However, most studies have focused on prevention of bacterial attachment to hard surfaces such as enamel.

A new study investigated the effect of five commercial tea extracts (green, oolong, black, Pu-erh and chrysanthemum) and tea components (epigallocatechin gallate and gallic acid) on the attachment of five oral pathogens (two strains of Streptococcus mutans, and one each of S. mitis, S. salivarius and Actinomyces naeslundii) to human gingival fibroblasts (HGF-1).1 Oral Streptococci such as S. mutans are pathogens commonly associated with dental plaque and the formation of caries.

The Steptococci are involved in many infections—some quite serious—including strep throat, pink eye, bacterial pneumonia, endocarditis, erysipelas (red skin, an acute streptococcus bacterial infection of the upper dermis and superficial lymphatics), and necrotizing fasciitis. Staphylococcus is one of the largest groups of bacteria with 40 subspecies. It is normally found in small amounts on your skin. A normal immune system can deal with it or antibiotics can be used if the bacteria cause an infection. Recently, however, antibiotic-resistant strains have appeared, called MRSA (multidrug-resistant Staphylococcus aureus), which is probably best known for causing the “flesh eating disease,” known also as necrotizing fasciitis (mentioned above).

Nanofibrous Membranes Battle Microbes

These are not the only microbes that Pu-erh has been found to be effective against. Others include M. pneumonia, M. orale, and even Escherichia coli, which can cause serious food poisoning in humans. A recent study indicates that Pu-erh tea’s nanofibrous membranes provide significant antibacterial activities against E. coli.2

Returning to the recent study, extracts of two of the teas (Pu-erh and chrysanthemum) significantly reduced attachment of all the Streptococcus strains while the effects of other teas and components were small. Pu-erh and chrysanthemum tea may have the potential to reduce attachment of oral pathogens to gingival tissue and improve the health of oral soft tissues (see sidebar).

Pu-erh without Side Effects;
Not So with Chrysanthemum

While Pu-erh tea has no side effects, chrysanthemum tea has many. Often called mums or chrysanths, chrysanthemums are members of the daisy family, Asteraceae. One common side effect of chrysanthemum tea in any form is contact dermatitis, which can produce symptoms like inflammation of the skin, itching and appearance of red patches.1 One or more of the chemical components of the flower irritates the skin.

Also, chrysanthemum irritation may result in photosensitivity dermatitis, where skin becomes highly sensitive to sunlight.2 Alantolactone, a component of chrysanthemum, is the prime suspect for this kind of skin sensitivity.

Chrysanthemum tea also often interferes with the effects of other medicines. Those who are diabetic and are taking insulin should avoid use of chrysanthemum tea as it may interact with insulin. This herbal tea has sedative properties, and has the potential to lower blood pressure. Hence, it may conflict with high blood pressure medications or sedatives as it may increase the medicinal effect of these drugs manyfold. For the same reason, those who are under anticancer, antibacterial and anti-inflammatory medicines should not drink this tea.


  1. Mak RK, White IR, White JM, McFadden JP, Goon AJ. Lower incidence of sesquiterpene lactone sensitivity in a population in Asia versus a population in Europe: an effect of chrysanthemum tea? Contact Dermatitis. 2007 Sep:57(3)163-4.
  2. Kar HK, Langar S, Arora TC, Sharma P, Raina A, Bhardwaj M. Occurence of plant sensitivity among patients of photodermatoses: a control-matched study of 156 cases from New Delhi. Indian J Dermatol Venereol Leprol. 2009 Sep-Oct;75(5):483-7.

Pu-erh Inhibits Biofilm Attachment

In an earlier study published on the heels of the current one, the same authors had investigated the mechanisms of the effects of tea extracts on the attachment, biofilm formation.3 A biofilm is any group of microorganisms in which cells stick to each other on a surface. The researchers noted that tea in general has been found to inhibit the attachment of Streptococcus mutans to surfaces and subsequent biofilm formation.

Five commercial tea extracts were screened for their ability to inhibit attachment and biofilm formation by two strains of S. mutans on glass and hydroxyapatite (bone mineral) surfaces. The mechanisms of these effects were investigated using scanning electron microscopy and phytochemical screening. The researchers found that extracts of oolong tea most effectively inhibited attachment and extracts of Pu-erh tea most effectively inhibited biofilm formation.

Microscopic images showed that the S. mutans cells treated with extracts of oolong tea, or grown in medium containing extracts of Pu-erh tea, were coated with tea components and were larger with more rounded shapes. Interestingly, the coatings on the cells consisted of flavonoids, tannins and indolic compounds. The ratio of tannins to simple phenolics in each of the coating samples was approximately 3:1.

This study points to mechanisms by which tea components may inhibit the attachment and subsequent biofilm formation of S. mutans on tooth surfaces, such as modification of cell surface properties and blocking of the activity of proteins and the structures used by the bacteria to interact with surfaces.

The Importance of Oral Health

It is increasingly clear that bad oral health is related to a number of diseases, including type 2 diabetes mellitus,4 developmental disabilities in children,5 and cardiovascular disease.6

Dental plaque is an archetypal biofilm composed of a complex microbial community. It is the casual agent for major dental diseases such as dental caries and periodontal disease. These dental diseases result from a cross-talk between the dental plaque biofilm and the host tissue response. When our oral health is good, both plaque biofilm and adjacent tissues (such as gums) maintain a balanced harmonious relationship.

Nonetheless, changes may occur during the disease process transforming this “healthy” dental plaque into a “pathogenic” biofilm. Thus, it is imperative to use remedies, when available, in order to prevent biofilm pathogenicity. Pu-erh tea appears to fill this role by inhibiting biofilm formation, and reducing attachment to non-enamel surfaces, such as plaque. One thing more to contemplate: oral health status is directly related to socioeconomic position across the socioeconomic gradient in almost all populations.7 The more glowing your smile, the more successful you are likely to be.


  1. Wang Y, Chung FF, Lee SM, Dykes GA. Inhibition of attachment of oral bacteria to immortalized human gingival fibroblasts (HGF-1) by tea extracts and tea components. BMC Res Notes. 2013 Apr 11;6(1):143.
  2. Su Y, Zhang C, Wang Y, Li P. Antibacterial property and mechanism of a novel Pu-erh tea nanofibrous membrane. Appl Microbiol Biotechnol. 2012 Feb;93(4):1663-71.
  3. Wang Y, Lee SM, Dykes GA. Potential mechanisms for the effects of tea extracts on the attachment, biofilm formation and cell size of Streptococcus mutans. Biofouling. 2013;29(3):307-18.
  4. Leite RS, Marlow NM, Fernandes JK. Oral health and type 2 diabetes. Am J Med Sci. 2013 Apr;345(4):271-3.
  5. Norwood KW Jr, Slayton RL; Council on Children With Disabilities; Section on Oral Health. Oral health care for children with developmental disabilities. Pediatrics. 2013 Mar;131(3):614-9.
  6. Lam OL, Zhang W, Samaranayake LP, Li LS, McGrath C. A systematic review of the effectiveness of oral health promotion activities among patients with cardiovascular disease. Int J Cardiol. 2011 Sep 15;151(3):261-7.
  7. Moysés SJ. Inequalities in oral health and oral health promotion. Braz Oral Res. 2012;26 Suppl 1:86-93.

Will Block is the publisher and editorial director of Life Enhancement magazine.

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