Effects of Biochemical and Molecular Inhibitors of Plant Extracts on Pathogenic Bacteria

The study aimed to evaluate the effect of the green alga Ulva lactuca and medicinal plant Nigella sativa extract on the activity of Staphylococcus aureus and Pseudomonas aeruginosa. The bacteria were incubated with the crude extracts and extracellular free potassium and phosphorus ions were measured in the medium. The levels of potassium and phosphorous were the maximum in the medium of S. aureus treated with N. sativa extract. The medium of P. aeruginosa incubated with U. lactuca extract was found to have the lowest phosphorous and the greatest potassium levels. The highest activity against P. aeruginosa was noticed with U. lactuca extract, where it caused reduction in the dry weight and glucose consumption of bacteria estimated by 28.41% and 41.09%, respectively. The antibacterial activity of N. sativa extract was the greatest against S. aureus and recorded 32.59% and 39.96% reduction in the bacterial dry weight and glucose uptake, respectively. Scanning Electron Microscopy study showed morphological changes in the cell wall of treated bacteria. The treatment of bacteria with the tested extract induced gene mutations. The results assessed the possible application of U. lactuca and N. sativa as a source of pharmacological benefits.