Piperine Exhibits Potential Antibiofilm Activity Against Pseudomonas aeruginosa by Accumulating Reactive Oxygen Species, Affecting Cell Surface Hydrophobicity and Quorum Sensing

Enhanced polysaccharide production through quorum sensing system in Cordyceps militaris

This study aimed to enhance extracellular polysaccharide (EPS) production in Cordyceps militaris by constructing a quorum sensing (QS) system to regulate the expression of biosynthetic enzyme genes, including phosphoglucomutase, hexokinase, phosphomannomutase, polysaccharide synthase, and UDP-glucose 4-epimerase genes. The study found higher EPS concentrations in seven recombinant strains compared to the wild-type C. militaris, indicating that the overexpression of key enzyme genes increased EPS production. Among them, the CM-pgm-2 strain exhibited the highest EPS production, reaching a concentration of 3.82 ± 0.26 g/L, which was 1.52 times higher than the amount produced by the wild C. militaris strain. Additionally, the regulatory effects of aromatic amino acids on the QS system of the CM-pgm-2 strain were investigated. Under the influence of 45 mg/L tryptophan, the EPS production in CM-pgm-2 reached 4.75 ± 0.20 g/L, representing a 1.90-fold increase compared to wild C. militaris strains. This study provided an effective method for the large-scale production of EPSs in C. militaris, and opened up new avenues for research into fungal QS mechanisms.

Application of cuminaldehyde and ciprofloxacin for the effective control of biofilm assembly of Pseudomonas aeruginosa: A combinatorial study

Pseudomonas aeruginosa is widely associated with biofilm-mediated antibiotic resistant chronic and acute infections which constitute a persistent healthcare challenges. Addressing this threat requires exploration of novel therapeutic strategies involving the combination of natural compounds and conventional antibiotics. Hence, our study has focused on two compounds; cuminaldehyde and ciprofloxacin, which were strategically combined to target the biofilm challenge of P. aeruginosa. The minimum inhibitory concentration (MIC) of cuminaldehyde and ciprofloxacin was found to be 400 μg/mL and 0.4 μg/mL, respectively. Moreover, the fractional inhibitory concentration index (FICI = 0.62) indicated an additive interaction prevailed between cuminaldehyde and ciprofloxacin. Subsequently, sub-MIC doses of cuminaldehyde (25 μg/mL) and ciprofloxacin (0.05 μg/mL) were selected for an array of antibiofilm assays which confirmed their biofilm inhibitory potential without exhibiting any antimicrobial activity. Furthermore, selected doses of the mentioned compounds could manage biofilm on catheter surface by inhibiting and disintegrating existing biofilm. Additionally, the test combination of the mentioned compounds reduced virulence factors secretion, accumulated reactive oxygen species and increased cell-membrane permeability. Thus, the combination of cuminaldehyde and ciprofloxacin demonstrates potential in combating biofilm-associated Pseudomonal threats.

Inhibitory effect of natural compounds on quorum sensing system in Pseudomonas aeruginosa: a helpful promise for managing biofilm community

Pseudomonas aeruginosa biofilm is a community of bacteria that adhere to live or non-living surfaces and are encapsulated by an extracellular polymeric substance. Unlike individual planktonic cells, biofilms possess a notable inherent resistance to sanitizers and antibiotics. Overcoming this resistance is a substantial barrier in the medical and food industries. Hence, while antibiotics are ineffective in eradicating P. aeruginosa biofilm, scientists have explored alternate strategies, including the utilization of natural compounds as a novel treatment option. To this end, curcumin, carvacrol, thymol, eugenol, cinnamaldehyde, coumarin, catechin, terpinene-4-ol, linalool, pinene, linoleic acid, saponin, and geraniol are the major natural compounds extensively utilized for the management of the P. aeruginosa biofilm community. Noteworthy, the exact interaction of natural compounds and the biofilm of this bacterium is not elucidated yet; however, the interference with the quorum sensing system and the inhibition of autoinducer production in P. aeruginosa are the main possible mechanisms. Noteworthy, the use of different drug platforms can overcome some drawbacks of natural compounds, such as insolubility in water, limited oral bioavailability, fast metabolism, and degradation. Additionally, drug platforms can deliver different antibiofilm agents simultaneously, which enhances the antibiofilm potential of natural compounds. This article explores many facets of utilizing natural compounds to inhibit and eradicate P. aeruginosa biofilms. It also examines the techniques and protocols employed to enhance the effectiveness of these compounds.

Piperine, a phytochemical prevents the biofilm city of methicillin-resistant Staphylococcus aureus: A biochemical approach to understand the underlying mechanism

Methicillin-resistant Staphylococcus aureus (MRSA), a drug-resistant human pathogen causes several nosocomial as well as community-acquired infections involving biofilm machinery. Hence, it has gained a wide interest within the scientific community to impede biofilm-induced MRSA-associated health complications. The current study focuses on the utilization of a natural bioactive compound called piperine to control the biofilm development of MRSA. Quantitative assessments like crystal violet, total protein recovery, and fluorescein-di-acetate (FDA) hydrolysis assays, demonstrated that piperine (8 and 16 μg/mL) could effectively compromise the biofilm formation of MRSA. Light and scanning electron microscopic image analysis confirmed the same. Further investigation revealed that piperine could reduce extracellular polysaccharide production by down-regulating the expression of icaA gene. Besides, piperine could reduce the cell-surface hydrophobicity of MRSA, a crucial factor of biofilm formation. Moreover, the introduction of piperine could interfere with microbial motility indicating the interaction of piperine with the quorum-sensing components. A molecular dynamics study showed a stable binding between piperine and AgrA protein (regulator of quorum sensing) suggesting the possible meddling of piperine in quorum-sensing of MRSA. Additionally, the exposure to piperine led to the accumulation of intracellular reactive oxygen species (ROS) and potentially heightened cell membrane permeability in inhibiting microbial biofilm formation. Besides, piperine could reduce the secretion of diverse virulence factors from MRSA. Further exploration revealed that piperine interacted with extracellular DNA (e-DNA), causing disintegration by weakening the biofilm architecture. Conclusively, this study suggests that piperine could be a potential antibiofilm molecule against MRSA-associated biofilm infections.

Piperine: Chemistry and Biology

Piperine is a plant-derived promising piperamide candidate isolated from the black pepper (Piper nigrum L.). In the last few years, this natural botanical product and its derivatives have aroused much attention for their comprehensive biological activities, including not only medical but also agricultural bioactivities. In order to achieve sustainable development and improve survival conditions, looking for environmentally friendly pesticides with low toxicity and residue is an extremely urgent challenge. Fortunately, plant-derived pesticides are rising like a shining star, guiding us in the direction of development in pesticidal research. In the present review, the recent progress in the biological activities, mechanisms of action, and structural modifications of piperine and its derivatives from 2020 to 2023 are summarized. The structure-activity relationships were analyzed in order to pave the way for future development and utilization of piperine and its derivatives as potent drugs and pesticides for improving the local economic development.

Bioactive Compounds from P. pertomentellum That Regulate QS, Biofilm Formation and Virulence Factor Production of P. aeruginosa

Pseudomonas aeruginosa is an opportunistic pathogen responsible for many nosocomial infections. This bacterium uses Quorum Sensing (QS) to generate antimicrobial resistance (AMR) so its disruption is considered a novel approach. The current study describes the antibiofilm and QS inhibitory potential of extract and chemical components from Piper pertomentellum. The methodo- logy included the phytochemical study on the aerial part of the species, the determination of QS inhibition efficacy on Chromobacterium violaceum and the evaluation of the effect on biofilm formation and virulence factors on P. aeruginosa. The phytochemical study led to the isolation and identification of a new piperamide (ethyltembamide 1), together with four known amides (tembamide acetate 2, cepharadione B 3, benzamide 4 and tembamide 5). The results indicated that the ethanolic extract and some fractions reduced violacein production in C. violaceum, however, only the ethanolic extract caused inhibition of biofilm formation of P. aeruginosa on polystyrene microtiter plates. Finally, the investigation determined that molecules (1-5) inhibited the formation of biofilms (50% approximately), while compounds 2-4 can inhibit pyocyanin and elastase production (30-50% approximately). In this way, the study contributes to the determination of the potential of extract and chemical constituents from P pertomentellum to regulate the QS system in P. aeruginosa.