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 Sandler
Assistant: 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
http://en.wikipedia.org/wiki/File:Streptococcus_mutans_Gram.jpg
• Gram-positive bacteria produce lactic acid
– Breaks down tooth enamel
– Causes cavities and bad breath
• Unique genes serve as drug targets
Health Benefits
• Multiple studies have been conducted
–
–
–
–
–
LDL
Obesity
Diabetes
Cancer
Dental Health
• Antimicrobial properties
due 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=237
http://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 ® Onthe-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