Antibacterial Screening of Kyllinga nemoralis (Hutch and Dalz) Ethanolic Rhizome Extract

Abstract

The challenges of global health in controlling new diseases and drug resistance drive pharmaceuticals and researchers alike to discover natural antimicrobial products from plants. Nature is a rich source of medicine waiting to be explored. This study aimed to screen the antibacterial activity of Kyllinga nemoralis (Hutch and Dalz) ethanolic rhizome extract against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Salmonella gallinarum. Broth microdilution technique was used to determine the minimum inhibitory concentration (MIC) and the inoculation of the clear wells into Mueller Hinton Agar was done to determine the minimum bactericidal concentration (MBC) of the extract. Qualitative phytochemical screening tests were done to detect groups of bioactive compounds available in the extract. The MIC against S. aureus and B. cereus was 1.88 mg/ml and 15 mg/ml for E. coli and S. gallinarum. MBC was noted only against S. aureus at 3.75 mg/ml which means that at the same dose, K. nemoralis rhizome extract was bactericidal to the organism. MBC values were not obtained for the other test bacteria indicating that K. nemoralis rhizome extract only exhibited bacteriostatic activity against these organisms. Penicillin and streptomycin displayed superior antibacterial activity than the rhizome extract with MIC ranging from 0.08 mg/ml to 1.25 mg/ml and MBC of zero (0) or no growth demonstrating equal capacity of these antibiotics to inhibit and kill the bacteria. The detection of alkaloids, tannins and flavonoids in the rhizome extract was inferred to be responsible for the antibacterial activity of the plant.