Inhibitory Activity of Cuscuta monogyna Bioactive Compounds against Pseudomonas aeruginosa

Four active compounds i.e., saponins, alkaloids, glycosides and tannins were extracted from cuscuta (Cuscuta monogyna vahl.). Six concentrations (5, 10, 25, 50, 75 and 100 g/L) of these extracted were prepared, and their inhibitory activity was tested against Pseudomonas aeruginosa, a Gram-negative bacterium isolated from burns and respiratory infections. All concentrations of the extracts demonstrated inhibitory activity against the tested bacteria. The highest inhibitory activity was observed at a concentration of 5 g/L for the saponin extract with an average of 22.4 mm. Additionally, the bacteria isolated from burns were found to be more susceptible to the inhibitory effects of the extracts showing average inhibition zones of 23.55 mm for saponin 19.75 mm for alkaloid 21.83 mm for glycoside and 25.81 mm for tannin respectively. In bacteria isolated from burns the concentration of 5 g/L was the most effective in inhibiting bacteria growth across all active extracts studied with average inhibition zone diameters of 30.3, 24.3, 28.3 and 38 mm for saponins, alkaloids, glycosides and tannins, respectively. For bacteria isolated from respiratory infections, the most effective concentrations varied by extract. In the saponin extract the concentration of 10 and 25 g/L were most effective showing average inhibition zone diameters of 21 and 21.3 mm, respectively. For the alkaloid extract the concentration of 25 g/L was the most effective with an average inhibition zone diameter of 21 mm. In the glycoside extract the concentrations 75 and 100 g/L were the most effective with average inhibition zone diameters of 21.7 and 21.3 mm, respectively. Finally, in the tannin extract the concentration of 100 g/L was the most effective producing an average inhibition zone diameter of 18.7 mm.