Plant Derived Natural Products against Pseudomonas aeruginosa and Staphylococcus aureus: Antibiofilm Activity and Molecular Mechanisms

Abstract

Bacteria are social organisms able to build complex structures, such as biofilms, that are highly organized surface-associated communities of microorganisms, encased within a self- produced extracellular matrix. Biofilm is commonly associated with many health problems since its formation increases resistance to antibiotics and antimicrobial agents, as in the case of Pseudomonas aeruginosa and Staphylococcus aureus, two human pathogens causing major concern. P. aeruginosa is responsible for severe nosocomial infections, the most frequent of which is ventilator-associated pneumonia, while S. aureus causes several problems, like skin infections, septic arthritis, and endocarditis, to name just a few. Literature data suggest that natural products from plants, bacteria, fungi, and marine organisms have proven to be effective as anti-biofilm agents, inhibiting the formation of the polymer matrix, suppressing cell adhesion and attachment, and decreasing the virulence factors’ production, thereby blocking the quorum sensing network. Here, we focus on plant derived chemicals, and provide an updated literature review on the anti-biofilm properties of terpenes, flavonoids, alkaloids, and phenolic compounds. Moreover, whenever information is available, we also report the mechanisms of action.

Potential and Prophylactic Use of Plants Containing Saponin-Type Compounds as Antibiofilm Agents against Respiratory Tract Infections

“…e high eradication of the bacterial biofilm after the treatment with Bacoside A was presented by SEM images qualitatively. MTT analysis also determined the percentage of mortality of bacterial cells in a treated biofilm (200 µg/mL) [19,20].…”

Screening Papaveraceae as Novel Antibiofilm Natural-Based Agents

“…This apparent discrepancy may be explained by the fact that quercetin acts in a strain-dependent manner and its concentration may be too low to eradicate the biofilm of this particular reference pseudomonal strain we used in our study. However, various phenolic compounds including flavonols and phenolic-rich extracts are often reported for their general antimicrobial properties [ 39 , 40 , 41 , 42 ]. It is noteworthy that the results concerning the biofilm of P. aeruginosa indicate an increase of the metabolic activity of cells ( Table 3 ) after exposure to extracts.…”

Novel Treatments and Preventative Strategies Against Food-Poisoning Caused by Staphylococcal Species

“…Moreover, allylisothiocyanate is the product responsible for the pungent taste of mustard, radish, or wasabi, and it is an efficient biofilm inhibitor of many different bacteria, including S. aureus [35,88]. There are many more antibiofilm compounds produced by plants, including terpenes, flavonoids, and other phenolic compounds, with variable effectiveness [35,101].…”