Abstract
The AcrAB/TolC efflux pump-mediated drug resistance in gram-negative bacteria might be controlled by efflux pump inhibitors (EPIs). This study was planned to discover a compound from plants that can be used as an EPI. Forty isolates of K. pneumoniae and 33 different plants were collected. The methanolic extracts of parts of plants were prepared. Chloramphenicol, tetracycline, and Ciprofloxacin were used for the sensitivity assay. Plant extracts were tested for EPI activity using Berberine and Ethidium bromide assays. Only 2/40 isolates of K. pneumoniae were found to contain MDR-containing AcrAB-TolC efflux pumps. In 8/33, EPI activity was observed. T. chebula extract had maximum EPI activity and inhibited K. pneumoniae growth in vitro. Compounds were extracted and characterized from T. chebula. The compounds were tested against K. pneumoniae in combination with tetracycline, ciprofloxacin, and chloramphenicol. Ethyl gallate (C9H10O5) isolated from T. chebula has EPI activity against MDR K. pneumoniae. Compounds like ethyl gallate inhibit the efflux pump in bacteria and are highly effective in killing bacteria even at very low concentrations since they inhibit the efflux pump. Ethyl gallate is a novel Efflux pump inhibitor that when co-administered with antibiotic compositions helps to overcome drug resistance.