Anotace:
The intriguing discovery of antibiotics that led to innumerable accomplishments in the past is slowly losing its efficiency in the clinical society. The emergence of antibiotic-resistant pathogens, such as those which can hydrolyze β-lactam antibiotics with the help of enzymes such as Extended Spectrum β-lactamases (ESBLs) has created an urgent necessity to witness innovation in the current drug therapy, and develop new antimicrobial agents. Keeping the current clinical adversity in mind, the present study was carried out to investigate the antibacterial activity of Pimenta dioica (L.) Merr. extracts, prepared in various chemical solvents with the help of soxhlet apparatus, and its synergistic activity with ampicillin. The antibacterial activity of these extracts was verified against 45 ESBL producing bacteria. Our study revealed chloroform extract to exhibit maximum antibacterial activity evident with the zones of inhibition (12-17 mm) showed by agar diffusion method, and their observed Minimum Bactericidal Concentrations (MBC) in the range of 2-5 mg.ml-1. The MBC of ampicillin was found to decrease from 10 mg.ml-1 to 300-500 µg.ml-1 in presence of chloroform extracts of P. dioica (L.) Merr. leaves, indicating a synergistic activity between them. In addition, the TLC bioautography of chloroform extract was carried out using 2, 3, 5-Trimethyl tetrazolium chloride as a chromogen, and the separated bioactive components were analyzed with the help of GC-MS which showed eugenol as a major constituent. Moreover, the scanning electron microscope analysis confirmed a visible deformation in the cell membrane of E. coli treated with chloroform extracts of P. dioica (L.) Merr., indicating stress and cellular damage in presence of these extracts.