antibacterial efficacy has become paramount [9]. Food preservation that does not affect the taste or nutritional value but ensures food safety and a long shelf-life is essential for the food industry [10]).The development of natural antimicrobial substances such as food additives for controlling foodborne pathogens has become a hot topic [9,11], and therefore, many researchers are now interested in discovering and researching new preservative compounds from natural extracts. Those from various medicinal plants have revealed antioxidant and antimicrobial properties due to their active compounds, such as flavonoids, alkaloids, terpenoids, and tannins [12]. Many plant extracts, such as ginger, garlic, basil, and tea exhibit antibacterial activity against both gram-positive and gram-negative bacteria [13,14].Coffee is one of the more intriguing plants to be researched as a food additive, and coffee extract has been reported to exhibit antimicrobial activity against both gram-negative and gram-positive bacteria such as Bacillus spp., S. aureus, Enterococcus spp., E. coli, and P. aeruginosa, among others [15][16][17]. Duangjai et al. [18] revealed the antibacterial activity of coffee pulp extract against gram-positive bacteria (S. aureus and S. epidermidis) and gramnegative bacteria (P. aeruginosa and E. coli). Several researchers have reported that the antibacterial activities and antioxidant properties of coffee extract could be due to phenolic acids, tannin, CGA, caffeine, malic acid and other compounds [19,20]. One possible mechanism may enable these compounds to disrupt cell membrane permeability [19]. Moreover, some researchers believe that coffee melanoidins inhibit bacterial growth via metal chelation [21,22]. However, the mechanism of action of coffee extracts on bacterial cells is still unclear.Consequently, in this study, we investigated the phytochemicals and antibacterial activity of Coffea robusta leaf extract (RLE), and further, we examined the antibacterial mechanism on bacterial membrane damage concerning the potential disruption in the membrane of microorganisms.The purpose of this study was to examine the phytochemical compounds and antibacterial activity of Coffea robusta leaf extract (RLE). The results indicated that chlorogenic acid (CGA) is a major component of RLE. The minimum inhibitory concentrations (MICs) of RLE against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Salmonella Typhimurium were 6.25, 12.5, 12.5, and 12.5 mg/ml, respectively. RLE effectively damages the bacterial cell membrane integrity, as indicated by the high amounts of proteins and nucleic acids released from the bacteria, and disrupts bacterial cell membrane potential and permeability, as revealed via fluorescence analysis. Cytotoxicity testing showed that RLE is slightly toxic toward HepG2 cells at high concentration but exhibited no toxicity toward Caco2 cells. The results from the present study suggest that RLE has excellent potential applicability as an antimicrobial in the food industry.