In Saudi Arabia, Cymbopogon schoenanthus (L.) has been traditionally used to treat a variety of diseases. This study aimed to investigate the crude methanolic extract of Cymbopogon schoenanthus (L.) phytochemical, chemical composition, and antibacterial activity. Phytochemical analysis revealed the presence of tannins, poly-tannins, steroids, alkaloids, essential oils, terpenoids, and flavonoids. The presence of functional groups such as -COOH, -OH, -C=O, and CH2 was revealed via FTIR spectroscopy. 13C and 1H NMR (nuclear magnetic resonance) were used to determine the types and number of protons (hydrogen atoms) and their electronic states. Using an agar well diffusion assay, methanolic extract of Cymbopogon schoenanthus (L.) inhibited the growth of some foodborne pathogenic bacteria in zones ranging from 8 to 25 mm in diameter. The minimum inhibitory concentration (MIC) for Staphylococcus aureus was 12.5 mg/mL, whereas it was 25 mg/mL for Bacillus cereus, Klebsiella pneumoniae, and Escherichia coli. The time-kill assay revealed a sharp decline in Staphylococcus aureus and Klebsiella pneumonia after 2 h at a concentration of 150 mg/mL, while Bacillus cereus and Escherichia coli showed a gradual decline with constant concentrations of 75 to 150 mg/mL. The minimum bactericide concentration (MBC) value for Bacillus cereus, Staphylococcus aureus, and Escherichia coli was 50 mg/mL, while it was 25 mg/mL for Klebsiella pneumoniae. In conclusion, our study revealed that Cymbopogon schoenanthus (L.) methanolic extract has a significant antibacterial effect, suggesting that it could be used to treat various foodborne pathogens.
Keywords: Cymbopogon schoenanthus (L.); FTIR and NMR; antibacterial; methanolic extract; phytochemical.