In vitro antibacterial activity of cocoa ethanolic extract against Escherichia coli

Cocoa Ethanolic Extract (CEE) was observed for antibacterial activity against Escherichia coli. CEE at different concentrations in E. coli-seeded Mueller-Hinton agar medium, resulted zone of inhibition after 24 h incubation in 37°C. CEE concentrations at 15.6, 31.25, 62.5, 125, 250, 500 and 1,000 mg/ml, developed annular radius of inhibition 0.4, 1.0, 1.9, 3.3, 4.5, 5.3 and 6.31 mm respectively, while 8 μg/ml Ceftriaxone as positive control resulted zone of inhibition 6.48 mm. Minimum Inhibitory Concentration (MIC) to suppress E. coli growth was 835 mg/ml. Scanning Electron Microscopy (SEM) observation showed that CEE and Ceftriaxone caused bacteria cell elongation. CEE concentration above 15.6 mg/ml induced E. coli cells fragmentation suggesting permanent damage. This research finding clearly indicates that CEE could be an alternative to be used as antibacterial agent with respect to overcome the bacterial resistance.