Green tea (Camellia sinensis) leaf extract inhibits the activity of β-lactamases

The most emerging resistance mechanism against β-lactam antibiotics present in bacteria is the production of β-lactamases. The aim of this study was to explore the phytocompounds of Camellia sinensis (green tea) that can inhibit the activity of β-lactamases. Moreover, the antibacterial effect of its extract with a combination of antibiotics against resistant bacterial strains was also appraised. In silico docking was carried out against the resistance causing enzymes such as AmpC and SHV-1. Antimicrobial susceptibility testing against bacterial strains, i.e., Klebsiella pneumoniae and Escherichia coli, was performed. Then, for exploring the synergistic effects, both antibiotics and green tea extract were applied in combination. The docking studies revealed that the inhibitors like epigallocatechin gallate with AmpC, and myricetin with SHV-1 enzyme displayed high binding affinities of -8.2 kJ/mol, and -7.5 kJ/mol, respectively. The in vitro combination of C. sinensis extract with ampicillin and penicillin also potentiated the antibacterial activity of these antibiotics. Thus, the study elucidated that the phytochemicals of C. sinensis could inhibit β-lactamases produced by the pathogens. Also, it has enhanced antimicrobial effects when combined with antibiotics.