Roll- 614Registration No- Ha 2927Dept. of Genetic Engineering and BiotechnologyUniversity of Dhaka

Antibacterial Activity of Methanolic Extract of Bangladeshi Black Tea

Common Enteric and Oral bacteria

Pathogenic bacteria Disease

Escherichia coli Diarrhea, Gastroenteritis, urinary tract infections

Salmonella typhi Typhoid fever 

Shigella spp. Shigellosis

Vibrio cholerae Cholera

Pseudomonas aeruginosa Opportunistic infections, swimmer’s ear, hot tub itch,

cellulitis, pneumonia etc.

Klebsiella pneumoniae  Klebsiella pneumonia

Staphylococcus aureus Food poisoning, wound infections, toxic shock

syndrome etc.

Streptococcus mutans Tooth decay, dental caries

Why do We Need Alternate Treatment Option for Bacterial

Disease???

Antibiotic Resistance-Bangladesh Scenario

• Unregulated dispensing and manufacture of antimicrobials

• Truncated antimicrobial therapy• • Drugs of questionable quality

• Inadequate access to effective drugs and overall poverty

Antibiotics Sensitivity (%)

Resistance (%)

Amoxycillin 7.9 90.1

Penicillin 33.7 64.4

Ampicillin 36.6 61.4

Erythromycin 57.4 39.6

Azithromycin 53.5 34.7

Cephradine 81.2 15.8

Antibiotic Resistance-Bangladesh Scenario cont…

• Escherichia coli : 40-95% resistant to MDR

• Salmonella typhi : 57-75% resistant to MDR

• Vibrio cholerae: 55-96% resistant to MDR

• Pseudomonas aeruginosa : 45-50% resistant to MDR

Antibiotic Resistance-Bangladesh ScenarioCont……..

Arising antibiotic resistant bacteria

Use and misuse of antibiotics

Treatment of such pathogen is an emerging problem

Development of herbal medicine

Potential solution

Alternate of Treating Drug Resistant Bacteria

Advantages of Using Herbal Medicine

Chemical Drugs Natural/herbal compound

May cause resistance in

pathogen

Not involved to develop resistance

Potential side effects

No or minimal side effects

High cost Low cost

Not accessible to all group of people

Easily accessible

Could Tea have Antibacterial Property??

About Tea (Camellia sinensis)

•Worldwide : 76-78% Black tea 20-22% Green tea <2% Oolong

• Bangladesh : 97% Black tea 3% Green & other tea

Consumption

Health Benefit of Tea

• Reducing arthritis and rheumatoid arthritis• Removing free radicals from the body• Reducing the risk of blood clot and the

hardening of the arteries • Reducing the risk of heart diseases and

stroke• Aiding in cancer prevention and reducing

tumor growth• Providing oral care and natural fluoride

which helps prevent cavities and tooth decay

Major Components of Tea

• Catechins• Flavonoids• polyphenols

• Theaflavin• thearubigins

• Against 10 pathogenic bacteria - Enteric and oral pathogen

• Qualitative assay - By agar well diffusion method

• Quantitative assay - MIC and MBC determination

Antibacterial Activity Examined

Physical Properties of Tea Extract

Initial amount of dried

black tea

Tea extract

obtained

% of extract

obtainedColor Texture Aroma Taste

50 g 4.5 g 9% Black Grainy Sweet aroma

Slightly bitter

Black Tea Inhibits Bacterial Growth

Shigella boydii

50 mg/ml

200mg/ml

400mg/ml

200mg/ml

400mg/ml

Zone of inhibition

Vibrio cholerae

Escherichia coli

No effective inhibition

Effective inhibition

50 mg/ml

200mg/ml

400mg/ml

50 mg/ml

200mg/ml

400mg/ml

control

control

Black Tea Inhibits Bacterial Growth cont…….

Organism Diameter of zone of inhibition (mm)

50 mg/ml 200 mg/ml 400 mg/ml

Shigella boydii 23 28 30Shigella dysenteriae 11 14 15

Vibrio cholerae 17 24 26Salmonella typhi 12 22 24

Salmonella paratyphi 13 19 20

Escherichia coli 6 10 12Pseudomonas aeruginosa 8 11 14

Klebsiella pneumoniae 9 15 17

Staphylococcus aureus 8 13 18

Streptococcus mutans 7 12 16

Black Tea Inhibits Bacterial Growth cont…….

Shigella boydii

Shigella dysenteriae

Salmonella typhi

Salmonella paratyphi

Vibrio cholerae

Pseudomonas aeruginosa

Klebsiella pneumoniae

Staphylococcus aureus

Escherichia coli

E. coli- NA 2

E. coli- NA 4

Streptococcus mutans

0 1000 2000 3000 4000

MBC (μg/ml) MIC (μg/ml)

µg/ml

Black Tea Inhibits Bacterial Growth cont…….

Future Studies

• Identification of active compound responsible for antibacterial activity

• Purification of active compound• Explore the possible mode of action

Question????

Drink tea and live healthy

Thank you

The End