Antimicrobial activity of water and acetone extracts of some Eucomis taxa

To evaluate the antibacterial and antifungal properties of acetone and water extracts of selected Eucomis taxa.

The bulbs of Eucomis bicolor, Eucomis comosa (E. comosa) and E. comosa cv. were dried and examples from each experimental treatment were ground separately into powder. Each sample was divided into two groups with equal amounts of powder, and respectively extracted with water and a 70% solution of aqueous acetone. The crude water extracts were then filtered through a 0.2 μm filter. The 70% aqueous acetone extracts were next concentrated at 40 °C. After the evaporation of the acetone, the samples were additionally filtered through a 0.2 μm filter. The antibacterial and antifungal activities of the extracts against chosen microorganisms were then determined.

The results of the study demonstrated that the water and acetone extracts of Eucomis bulbs have an influence on the viability of Staphylococcus aureus and Bacillus atrophaeus strains. In the case of mediums containing E. comosa and E. comosa cv. extracts, a decrease in the number of gram-positive bacteria was dependent on the extract concentration. The best results were obtained in the case of the 25% extracts. The water and acetone extracts of Eucomis bulbs did not cause a decrease in the number of Escherichia coli cells. Additionally, antifungal activity against Aspergillus niger, Botrytis cinerea, Stachybotrys chartarum, Mucor circinelloides and Rhizopus oryzae cells were also not observed.

The tested gram-negative and fungi microorganisms show resistance towards acetone and water extracts of Eucomis bulbs. The highest activity is found in the case of Aspergillus clavatus, Staphylococcus aureus and Bacillus atrophaeus strains, which shows water and acetone extracts of 25%.