Antimicrobial and synergistic properties of green tea catechins against microbial pathogens

Bacterial diseases caused by pathogenic bacteria are one of the health problems in recent times. The continuous use of antibiotics and increased hospitalization increased drug resistance. The increased drug resistance has led to the development of novel lead molecules. Hence, alternate medicine or secondary metabolites from plant sources is a possible therapeutic option to treat bacterial infection alone or with existing drugs. The present study aimed to evaluate the antimicrobial property of green tea extract, catechin, benzoyl peroxide and a combination of antibiotics against acne-causing Staphylococcus epidermidis, Staphylococcus aureus, and Propionibacterium acnes isolated from the skin surface of the clinical subjects. The aqueous and solvent extract of green tea showed antibacterial activity against the screened bacteria and it was further improved by combing with existing drugs. The Minimum Inhibitory Concentration (MIC) was performed using the broth dilution method and showed the least MIC value (<2.5 µg/mL). The tea extract exhibited a catechin compound and was determined using High Performance Liquid Chromatography. The mechanism of action of catechin on bacterial pathogens was determined. The catechin treated bacterial cells exhibited morphological changes, structural changes in the cell walls, separation of cells and membrane rupture. The effect of catechin in combination with antibiotics on both Gram-positive and Gram-negative bacteria was antagonistic and synergistic activity. Therefore crude green tea extract and catechin can reduce bacterial infection in acne.