Antibacterial Activity of Black Tea Extract against S. mutans, S. aureus, L. acidophilus, Klebsiella and E. coli

Corresponding Author:
Dr. Pinky Goswami,
Assistant Professor,
Department of Dentistry,
JMCH, Jorhat, Assam, India.
E-mail: pinkyjmcjorhat@gmail.com

ABSTRACT

BACKGROUND

Drinking tea has antioxidant, anti-inflammatory and anti-carcinogenic properties. In addition, tea is also considered beneficial for cardiovascular health and oral health. Health benefits of green tea are attributed to its polyphenol content. Catechins are the major polyphenols in green tea and in black tea the catechins are oxidized to theaflavins. Polyphenols present in tea have exhibited antimicrobial effects against a wide range of pathogenic bacteria. Studies have shown that green tea catechins are bioavailable in both plasma and urine. The aim of the present study is to evaluate the antibacterial activity of black tea extract against standard strains of S. mutans, S. aureus, L. acidophilus, Klebsiella and E. coli.

METHODS

Black tea extract was prepared by boiling black tea leaves in distilled water. It was then filtered, and the filtrate was treated with chloroform and ethyl acetate. The ethyl acetate was evaporated in a rotary evaporator and a brown coloured residue was obtained. Its antibacterial activity was studied against standard strains of five common bacteria i.e.; S. mutans, L. acidophilus, S. aureus, Klebsiella spp, and E. coli and the MIC of the black tea extract was determined using serial dilution method.

RESULTS

Black tea extract showed sufficient antibacterial activity against the tested bacteria. The MIC of black tea extract was lowest against Staphylococcus aureus.

CONCLUSIONS

Tea extracts have significant antimicrobial activity at varying concentrations against different bacterial pathogens.

KEY WORDS

Black Tea Extract, Antibacterial Activity, Catechins, Theaflavins