Corchorus olitorius aqueous extract attenuates quorum sensing-regulated virulence factor production and biofilm formation

Objective:To investigate the effect of Corchorus olitorius aqueous fraction (COAF) on quorum sensing (QS)-regulated virulence factors and biofilm formation in Pseudomonas aeruginosa (PAO1). Methods:The preliminary screening of the anti-QS effect of COAF was performed by evaluating the anti-pathogenic activity against Chromobacterium violaceum CV026 biosensor strain. Next, the inhibitory effects of COAF on QS-regulated pyocyanin production, proteolytic and elastolytic activities, swarming motility, and biofilm formation were evaluated in PAO1.Results:The results showed that the treatment of COAF significantly decreased the biofilm biomass, attenuated virulence factors, and inhibited swarming motility of PAO1 without affecting the growth of the bacteria in a dose-dependent manner. COAF at 2000 μg/mL significantly decreased Las B elastase activity in PAO1 culture, exopolysaccharide production, swarming motility, pyocyanin level, and biomass of PAO1 by 55％ (P<0.05), 60％ (P<0.01), 61％ (P<0.01), 65％(P<0.01) and 73％ (P<0.01), respectively. In addition, the production of violacein was decreased by 62％ (P<0.01) with the treatment of a high dose of COAF. Conclusions:These findings indicate that COAF can be a potential source of anti-QS agents.

Anti-Quorum Sensing Potential of Antioxidant Quercetin and Resveratrol

ABSTRACT Quorum sensing system plays an active role in the regulation of pathogenicity of many microorganisms. Inhibition of pathogenicity or virulence factors will increase the success of treatment by preventing the development of antibiotic resistance. In this study, anti-quorum sensing activities of quercetin and resveratrol compounds, which have antioxidant property without damaging to host, have been determined via using biosensor bacteria: Chromobacterium violaceum ATCC 12472 and Chromobacterium violaceum CV026. As quorum sensing inhibitors, quercetin and resveratrol's cutting off the bacterial communication will prevent the treatment failures caused by the development of bacterial resistance. The development of layered drugs with antioxidant compounds such as quercetin and resveratrol will pave the way for new horizons for new therapeutic strategies.

Antibacterial, anti-swarming and anti-biofilm formation activities of Chamaemelum nobile against Pseudomonas aeruginosa

Chamomile ( Chamaemelum nobile ) is widely used throughout the world, and has anti-inflammatory, deodorant, bacteriostatic, antimicrobial, carminative, sedative, antiseptic, anti-catarrhal, and spasmolytic properties. Because of the increasing incidence of drug-resistant bacteria, the development of natural antibacterial sources such as medical herbs for the treatment of infectious diseases is necessary. Extracts from different plant parts such as the leaves, flowers, fruit, and bark of Combretum albiflorum, Laurus nobilis , and Sonchus oleraceus were found to possess anti-quorum sensing (QS) activities. In this study, we evaluated the effect of C. nobile against Pseudomonas aeruginosa biofilm formation

Phytochemical screening, anti-acetylcholinesterase, / Монголын эм зүй, эм судлал

Introduction:Saxifraga spinulosa Adams (S.spinulosa) belongs to the Saxifragaceae family and it is used for treating conjunctivitis, gynecopathy, larynx, pleural cavity in traditional Tibetan and Russian medicine. Study on antioxidant activity on this plant have also been carried out previously. However, no work has been reported on its anti-acetylcholinesterasic and anti-quorum sensing activity.Goal: The purpose of this research was to perform phytochemical, anti-acetylcholinesterase and anti-quorum sensing activities on the extracts of aerial parts of Saxifraga spinulosa Adams.Methods and materials: Anti-acetylcholinesterase activity was evaluated by colorimetric method. Extracts of aerial parts of S.spinulosa were tested for anti-quorum sensing activity by the Chromobacterium violaceum assay using the standard disc-diffusion method. Extracts were chromatographed with thin layer chromatography method. Phytochemical screening of crude extracts S. spinulosa Adams was carried out to detect saponins (Kokate, 1999), ferric chloride and lead acetate test was for tannin and phenolic contents and the detection of gum (Whistler, 1993) and Fehling test of carbohydrates respectively. Results: Plant extraction and fractionation was made earlier. Acetylcholinesterase activity screening was performed on its 4 extracts, prepared from aerial parts of Saxifraga spinulosa Adams. Non-polar chloroform fraction showed more active with 45.7% compared to the aceton extract (36%), water residue (35,5%) and n-butanol fraction (37,5%). Anti-quorum sensing activity was observed with 7 extracts of S. spinulosa aerial part. From them, fractions A (21 mm), B (20 mm), C (20 mm) showed significant activity and others were moderate. No antibacterial activity (for Chromobacterium violaceum) was observed. Thin layer chromatography (TLC) fingerprinting indicated the presence of the phenolic components and flavonoids. Phytochemical screening revealed that phenolic contents, tannins, saponins, carbohydrates, gums were present in the whole plant. Conclusion: This study shows that, S. spinulosa has anti-acetylcholinesterase and anti-quorum sensing activity and we determined that this plant mainly contains polyphenolics compounds. Key words: anti-quorum sensing, anti-acethylcholinesterase, Saxifraga spinulosa Adams

Inhibition of quorum sensing in Chromobacterium violaceum by Syzygium cumini L. and Pimenta dioica L

Objective: To investigated into the anti-quorum sensing (QS) activity of Syzygium cumini L. (S. cumini) and Pimenta dioica L. (P. dioica) using Chromobacterium violaceum (C. violaceum) strains. Methods:In this study, anti-QS activity of ethanol extract of Syzygium cumini L. and Pimenta dioica L. were screened using C. violaceum CV026 biosensor bioassay. By bioassay guided fractionation of S. cumini and P. dioica, ethyl acetate fraction (EAF) with strong anti-QS activity was separated. Inhibition of QS regulated violacein production in C. violaceum ATCC12472 by EAF was assessed at different concentrations. The effect of EAF on the synthesis of autoinducer like N-acyl homoserine lactone (AHL) was studied in C. violaceum ATCC31532 using its mutant C. violaceum CV026 by standard methods. Results: EAF inhibited violacein production in C. violaceum ATCC12472 in a concentration dependent manner without significant reduction in bacterial growth. Complete inhibition of violacein production was evidenced in 0.75-1.0 mg/mL concentration of EAF without inhibiting the synthesis of the AHL. TLC biosensor overlay profile of EAF revealed two translucent spots in S. cumini and P. dioica that inhibited C6-AHL mediated violacein production in C. violaceum CV026. Conclusions:This study indicates the anti-QS activity of the tested medicinal plants against C. violaceum.

Anti-quorum sensing and antimicrobial activities of some traditional Chinese medicinal plants commonly used in South-East Asia

Aims: Traditional Chinese medicine (TCM) has been used for relief and treatment of ailments dating back thousands of years and continues to the present day, with rapidly increasing interest in evidence-based evaluation of its efficacy. Studies of TCM plants have demonstrated that several have antimicrobial properties but few have explored their anti-quorum sensing potential. Quorum sensing (QS), also known as bacterial cell-to-cell communication, is used by a number of opportunistic pathogenic bacteria in the regulation of virulence expression. Compounds that interfere with QS signals and attenuate bacterial virulence without killing them may offer an alternative therapeutic solution with less pressure of antibiotic resistance developing. This study screened TCM plants for anti-quorum sensing properties and antimicrobial activities. Methodology and Results: Twenty TCM plants commonly used in South-East Asia were screened for QS inhibitors using two biomonitor strains, Chromobacterium violaceum CV026 and Pseudomonas aeruginosa PAO1. Ten of these selected TCM plant (50%) were found to have QS inhibitory properties: Angelica sinensis (Umbelliferae), Cnidium monnieri (Umbelliferae), Astragalus membranaceus (Leguminosae), Crataegus cuneata (Rosaceae), Dioscorea nipponica (Dioscoreaceae), Lilium brownii (Liliaceae), Aloe barbadensis (Liliaceae), Magnolia officinalis (Magnoliaceae), Ephedra sinica (Ephedraceae) and Panax pseudoginseng (Araliaceae). Of these, six (30%) also showed varying antimicrobial activity against C. violaceum and P. aeruginosa. Conclusion, significance and impact of study: The results suggest that traditional Chinese medicinal plants could be a prospective source to explore for useful compounds in the fight against bacterial infections.