Inhibitory Effect on Biofilm Formation of Pathogenic Bacteria Induced by Rubrolide Lactam Analogues

Abstract

A series of 32 novel potential bacterial biofilm inhibitor analogues of rubrolides and their lactam derivatives were synthesized. The compounds were prepared and tested against Staphylococcus aureus and Staphylococcus epidermidis. In general, γ-alkylidene-γ-lactams are more active than the corresponding γ-alkylidene-γ-lactones, and the two derivatives are more effective in inhibiting bacterial planktonic growth (IC 50 of 1.8 and 5.6 μg mL −1 ) than natural rubrolides. Compounds showing little effect on planktonic growth were assayed for their ability to inhibit biofilm formation. As biofilm inhibitors, none of the new compounds were effective against S. epidermidis, whereas the three Z-lactam derivatives were very active against S. aureus (IC 50 = 0.9−3.3 μg mL −1 ). The strong antibiofilm formation activity displayed by some γ-alkylidene-γ-lactams indicates that this may represent a promising class of compounds for the development of novel antimicrobial agents against clinically relevant Grampositive bacteria.

Montmorillonite K10 Clay Catalyzed Synthesis of Novel β‐Aminocarbonyl Compounds and Their Biological Evaluation

“…The antibacterial assay was carried out by micro dilution method in order to determine the antibacterial activity of compounds tested against the pathogenic bacteria [27–28] . The indicator strains used were Staphylococcus aureus MTCC 737, Klebsiella planticola MTCC 2277, Bacillus cereus MTCC 430, S. aureus MLS16 MTCC 2940, Escherichia coli MTCC 1687 and Pseudomonas aeruginosa MTCC 424.…”

“…The antibacterial assay was carried out by micro dilution method in order to determine the antibacterial activity of compounds tested against the pathogenic bacteria. [27][28] The indicator strains used were Staphylococcus aureus MTCC 737, Klebsiella planticola MTCC 2277, Bacillus cereus MTCC 430, S. aureus MLS16 MTCC 2940, Escherichia coli MTCC 1687 and Pseudomonas aeruginosa MTCC 424. The bacterial pathogens were inoculated in Muller-Hinton broth along with different concentrations of test compounds including 300, 150, 75, 37.5, 18.75, 9.37, 4.68, 2.34, 1.17 and 0.58 μg/mL.…”

Effects of Synthetic Tetronamides and Methylated Denigrins on Bacterial Quorum Sensing and Biofilm Formation

“…Over the past years, motivated by the findings of butenolides as biofilm inhibitors, our groups have synthesized different analogues of natural butenolides and tested their antibiofilm activities. − Among them, a rubrolide analogue 3 and its lactam derivative 4 reduced the biofilm formation of P. aeruginosa with IC 50 values of 3.9 and 0.6 μg/mL, respectively …”

Synthesis of Alkyne-Substituted Dihydropyrrolones as Bacterial Quorum-Sensing Inhibitors of Pseudomonas aeruginosa

“…[ 11 , 12 ] Several DHPs were found to possess antimicrobial activity, QS, and biofilm inhibitory activities [ 13 ] such as those reported by our group [ 14 , 15 , 16 ], including DHPs with a thioether [ 17 ] or a seleno-urea [ 18 ] moiety. In addition, the biological activities of DHP-related compounds were also studied by other research groups [ 19 , 20 , 21 , 22 ], including rubrolide derivatives, which showed antibacterial [ 23 ], anticancer [ 24 ], and herbicidal [ 25 ] activities. Moreover, a recent paper by Ma et al also reported the synthesis and anti-virulence activities of several furanones and aryl-substituted pyrrolidone derivatives as quorum sensing inhibitors [ 26 ].…”