ANTIMICROBIAL PROPERTIES OF VARIOUS GREEN TEA PRODUCTS WITH AND

WITHOUT THE ADDITION OF SUGAR

T3 Members:Samantha Acevedo, Conan Chen, Ethan France, Brian

Goldspiel, Anna Kim, Amanda Li, Florence Ma, Sana Siddiqui, Stephanie Tarlowe, Anthony Yakely, Leanna Zhan

Advisor: Mrs. Rachel SandlerAssistant: Gillian Bradley

What is Green Tea?• Camellia sinensis plant

leaves• Fermentation

– Green, oolong, and black teas

• Types– Matcha: powdered

leaves– Sencha: Uji leaves– Loose: dried leaves– Bagged: filtered tea bag– Bottled: Snapple ®

brand– Instant: powdered mix

http://www.plantoftheweek.org/week046.shtml 

Chemical Composition

http://www.nature.com/onc/journal/v25/n13/fig_tab/1209227f1.html

Streptococcus mutans

• Gram-positive bacteria produce lactic acid– Breaks down tooth enamel– Causes cavities and bad breath

• Unique genes serve as drug targets

http://en.wikipedia.org/wiki/File:Streptococcus_mutans_Gram.jpg

Health Benefits• Multiple studies have been conducted

– LDL– Obesity– Diabetes– Cancer– Dental Health

• Antimicrobial propertiesdue to low degree of fermentation– May destroy catechins

http://www.bostonteacampaign.com/en-us/7_5/encyclopedia-of-tea.html

http://www.bitemarket.com/store/index.php?main_page=product_info&cPath=1_40&products_id=237http://awesomebeautysupply.com/diet-snapple-singles-to-go-antioxidants-green-tea/

Preparation of Teas

• 240 mL boiled, deionized water

• Cooled to 90°• Steep 15 minutes• 15 g sugar per

sample• Diet Snapple ® On-

the-Go powder

Process of Diffusion

• Cover plates with bacterial lawn– None on control

• Soak disks 5 minutes

• Place on plate• Incubate ~48 hours

at 37° C• Measure zones of

inhibition

In Vitro Procedure• Sterilize loop• Inoculate and make

line on plate• Submerge loop in

liquid– 2 minutes– 10 second intervals

• 5 in liquid, 5 in air– Stir gently

• Scope ®– 30 seconds– Constant agitation

• Swab loop and make line on plate

Paper Disk Diffusion:Zone of Inhibition

• Scope ® mouthwash– 1.77 cm diameter

• Antimicrobial compounds– Alcohol– Poloaxamer– Polysorbate– Sodium benzoate

• No observable zone of inhibition around disks of any teas

Paper Disk Diffusion: Possible Errors

• Contaminated plates– Open disks exposed

to fungus in lab– Lapses in aseptic

technique– Excess liquid on

disks

Paper Disk Diffusion:Zone of Growth

• Lipton ® tea with sugar– 0.95 cm diameter

• No growth on control

• Sugar may have boosted

• Inconclusive Gram stain

• More research needed

In Vitro:Results

• Control had more bacteria before than after• All results compared to control

– Less bacteria not necessarily significant

• Sugar appeared to have no effect

Control (Water) Matcha with Sugar

In Vitro:Best Results

Loose Leaves Scope ®

In Vitro:Results Discussion

• More subjective and qualitative– Visual observation

• Little clear evidence of antimicrobial benefits against S. mutans

• Loose tea leaves had strongest effect

In Vitro:Alternate Method for Scope ®

• Known antibacterial agent• Loop immersed in Scope ® for 30

seconds• Simulated difference between rinsing

with mouthwash and sipping a beverage

• May have attributed to differing results

In Vitro:Errors

• Preparation method• Small sample size• Discrepancies

Future Research

• Different preparation methods• Potency of green tea on other

microbes• Chemical compositions of teas

– Loose leaf tea (in vitro)

• Effects of sugar• Modeled after realistic experience• Different concentrations

Conclusions

• Scope ® is most effective• Loose sencha leaves (in vitro)• Sugar inconclusive

– Possibly detrimental in one case

Acknowledgements

• John and Laura Overdeck• The Crimmins Family Charitable Foundation• NJGSS Alumni and Parents (1984-2011)• Bristol-Myers Squibb• Roche• Kinder Morgan• Bain Capital• GlaxoSmithKline• Novartis• Bayer HealthCare• Dr. Miyamoto, Dr. Surace, Dr. Quinn, Myrna

Papier, Mrs. Sandler, Gillian Bradley