Evaluation of the Antibacterial Activity of Clove Extract (Syzygium aromaticum) on Clinical Isolates of Escherichia coli

Abstract

Antibiotic resistance to conventional antibiotics has remained a significant therapeutic challenge in clinical settings. To this end, alternative therapeutic approaches are being sought after. One such approach is the use of antimicrobial inhibitors from natural sources like medicinal plants. This study aimed to explore the antibacterial potential of aqueous and ethanolic extracts of Clove (Syzygium aromaticum) against Escherichia coli, a common pathogen associated with gastrointestinal infections from clinical sources in Port Harcourt, Nigeria. The plant samples of S. aromaticum were obtained from Elekahia market, Port Harcourt, Rivers State, Nigeria. The plant samples were processed according to standard methods. The antibacterial activity of S. aromaticum extracts against E. coli was determined in vitro in aqueous and ethanolic extracts at four different extract concentrations: 200mg/ml, 100mg/ml, 50mg/ml, 25mg/ml and 12.5mg/ml. Analysis of phytoconstituents revealed the presence of Flavonoid, Saponins, Alkaloids and Eugenol. The aqueous and ethanolic extracts revealed a significant degree of antibacterial activity against E. coli isolates at concentrations of 200mg/ml, with zones of inhibition of 26mm and 29mm, respectively. The antibacterial activity of the aqueous extract of S. aromaticum was evaluated at various concentrations. The result of the aqueous extract showed that. E coli had a zone of inhibition of 26 mm at 200 mg/ml, 19mm at 100mg/ml, and 18mm at 50mg/ml concentration. Likewise, the ethanolic extract had an inhibition zone of 29mm at 200mg/ml, 22mm at 100mg/ml and 19mm at 50mg/ml. Antibiotic susceptibility testing revealed that E. coli was susceptible to Ciprofloxacin. Notably, the antibacterial activity of S. aromaticum extract was comparable to that of Ciprofloxacin because the zone of inhibition was at par with those observed with the ethanolic extract. This study suggests that S. aromaticum extract may be a promising natural antibacterial agent for combating Escherichia coli infections at high concentrations. Based on the results, further research is recommended using even higher concentrations of the extract and various extract media such as methanol, chloroform, and acetone to observe and compare their inhibitory effects on Escherichia coli.