Green tea extract: Possible mechanism and antibacterial activity on skin pathogens

► Aqueous extract of green tea was studied against skin infection causing bacteria. ► Bacterial strains were sensitive to aqueous extract via disc diffusion assay. ► MIC was determined via NBT assay (0.156–0.313mg/ml). ► Aqueous extract was not toxic to Vero cell-line (via MTT assay). ► Aqueous extract inhibits the adhesion of bacteria to Vero cells at its MIC value. Camellia sinensis (tea) is known for its therapeutic properties (anti-inflammatory, anti-microbial, anti-tumour, anti-oxidative and anti-ageing). Although, anti-microbial properties of green tea have been studied, its role against bacterial strains related to skin infections and mechanism of action is not well understood. We focussed on exploring anti-microbial activity and the basic mechanism of aqueous green tea leaf extract on selected bacterial strains. Staphylococcus epidermidis, Micrococcus luteus, Brevibacterium linens, Pseudomonas fluorescens and Bacillus subtilis were found to be sensitive to green tea extract via disc diffusion assay (zone of inhibition ⩾7mm). Minimal inhibitory concentration (MIC) was determined via nitro blue tetrazolium (NBT) assay (0.156–0.313mg/ml). Moreover, the aqueous extract was found to be not toxic to the Vero cell-line up to a concentration of 500μg/ml. The effect of aqueous extract on adhesion of different bacteria to Vero cells indicated that it inhibits the adhesion at its MIC value.