Background/Objectives: Wine pomace is a rich source of bioactive phenolic compounds with potential health benefits. This study aimed to evaluate the antipathogenic and antioxidant properties of ethanol and ethyl acetate extracts from wine pomace of three grape varietals (Tannat, Bonarda, and Malbec) to explore their potential as natural alternatives for mitigating bacterial virulence in Pseudomonas aeruginosa. Methods: Successive exhaustion extractions were performed using solvents of increasing polarity (ethyl acetate and ethanol). The phenolic content was quantified, and the antioxidant activity was evaluated using standard assays. The antipathogenic activity against P. aeruginosa was assessed by measuring biofilm formation, elastase and protease activity, pyocyanin production, and swarming motility. Quorum sensing (QS) inhibition was tested using a violacein production assay in Chromobacterium violaceum. Results: Ethanol was more effective at extracting phenolic compounds, with Tannat exhibiting the highest total phenolic content (162.5 µg GAE/mg). HPLC-DAD analysis identified 16 phenolic acids, 18 flavonoids, and 3 stilbenes across the extracts. The ethanol extracts showed strong antioxidant activity (phosphomolybdenum reducing capacity 67–128 μg AAE/mg, ABTS•+ scavenging 37–71 µg/mL, Fe3+ reducing power 31–68 µg/mL) and inhibited biofilm formation (up to 61%), elastase (up to 41%), and protease (up to 46%) activities in P. aeruginosa. The extracts also reduced pyocyanin production (up to 78%) and swarming motility (up to 68%), suggesting interference with QS. Moreover, the extracts inhibited violacein production in C. violaceum, confirming QS inhibition (up to 26%). Conclusions: Among the extracts, ethanol-extracted Tannat pomace showed the most substantial antipathogenic and antioxidant activities. The results add value to wine pomace by suggesting its use as natural extracts rich in phenolic compounds, capable of controlling the bacterial virulence of Pseudomonas aeruginosa without promoting the development of resistance.

Juglans australis is a tree from the Juglandaceae family found in the southernmost region of America. Its small edible nuts are not commercialized, and their bioactive characteristics are unknown. This study first reports the antioxidant, antiradical, and antibacterial activity of extracts from this native walnut against phytopathogenic bacteria and compared with its commercial counterpart, J. regia L. Different extracts from the woody endocarp (shells) were obtained using methanol and ethyl acetate. Methanolic extracts significantly inhibited phytopathogenic growth at all concentrations tested (0.1, 1, and 10 mg/mL). The best activity was reported against Xanthomonas. Highest total phenolics and the most significant antioxidant activity were determined in methanolic extracts (TPC: 121 mg gallic acid equivalent (GAE)/g of dried peel, FRAP: 58.6 mmol Trolox/100 g of peel dried and 9.7 mM Trolox/100 g of dried peel). Extracts from both species demonstrated congruent patterns. Gallic acid was the most abundant compound in the methanolic extract. However, extracts demonstrated superior efficiency, suggesting a potential synergistic effect among their components. Antioxidant and antimicrobial activity of methanolic extracts against Xanthomonas make them potential control agents

This study provides a comprehensive investigation of lactic acid bacteria (LAB) isolated from Argentinean Capsicum annum L. This research covers important aspects, including genotypic characterization, bacterial stress tolerance, adhesion ability, safety evaluation, and functional and technological properties. The predominant isolates were identified as Lactilactobacillus curvatus and Lactiplantibacillus plantarum. A Rep-PCR analysis grouped the isolates into 11 clonal groups. Lp. plantarum LVP 40 and LV 46, Levilactobacillus brevis LVP 41, Pediococcus pentosaceus LV P43, and Lt. curvatus LVP44 displayed both safety and resilience against adverse conditions such as a slow pH, bile, and simulated gastric and intestinal juices. Moreover, the LAB strains exhibited high hydrophobicity and auto-aggregation percentages, NaCl tolerance, and a substantial acidifying capacity. LAB supernatants demonstrated promising surfactant and emulsifying properties. Likewise, they differentially inhibited Staphylococcus aureus and Pseudomonas aeruginosa biofilms, showcasing their potential as antipathogenic agents. Noteworthily, some strains displayed considerable co-aggregation with these pathogens, and several isolates showed an effective antimutagenic and detoxifying power, further emphasizing their multifaceted capabilities. Five pepper bacterial strains showcased beneficial properties, suggesting their potential for gut health enhancement. In summary, these LAB strains hold promise as vegetable fermentation starters, contributing to food safety and versatile applications in food science.

The escalating prevalence of antibiotic-resistant bacteria poses a grave threat to human health, necessitating the exploration of novel alternatives to conventional antibiotics. This study investigated the impact of extracts derived from the supernatant of four lactic acid bacteria strains on factors contributing to the pathogenicity of three Staphylococcus aureus strains. The study evaluated the influence of lactic acid bacteria supernatant extracts on the growth, biofilm biomass formation, biofilm metabolic activity, and biofilm integrity of the S. aureus strains. Additionally, the impact on virulence factors (hemolysin and coagulase) was examined. Gas chromatography coupled with mass spectrometry was used to identify the bioactive compounds in the extracts, while molecular docking analyses explored potential interactions. Predominantly, the extracts contain eight 2,5-diketopiperazines, which are cyclic forms of peptides. The extracts demonstrated inhibitory effects on biofilm formation, the ability to disrupt mature biofilms, and reduce the biofilm cell metabolic activity of the S. aureus strains. Furthermore, they exhibited the ability to inhibit α-hemolysin production and reduce coagulase activity. An in silico docking analysis reveals promising interactions between 2,5-diketopiperazines and key proteins (SarA and AgrA) in S. aureus, confirming their antivirulence and antibiofilm activities. These findings suggest that 2,5-diketopiperazines could serve as a promising lead compound in the fight against antibiotic-resistant S. aureus.

Hydroalcoholic extracts from Malbec and Torrontés wine pomaces (Vitis vinifera L.) originating from the high-altitude vineyards of Argentina's Calchaquí Valleys were characterized. Total phenolics, hydroxycinnamic acids, orthodiphenols, anthocyanins, non-flavonoid phenolics, total flavonoids, flavones/flavonols, flavanones/dihydroflavonols, and tannins were quantified through spectrophotometric methods, with the Malbec extract exhibiting higher concentrations in most of phytochemical groups when compared to Torrontés. HPLC-DAD identified more than 30 phenolic compounds in both extracts. Malbec displayed superior antiradical activity (ABTS cation, nitric oxide, and superoxide anion radicals), reduction power (iron, copper, and phosphomolybdenum), hypochlorite scavenging, and iron chelating ability compared to Torrontés. The cytotoxicity assessments revealed that Torrontés affected the viability of HT29-MTX and Caco-2 colon cancer cells by 70% and 50%, respectively, at the highest tested concentration (1 mg/mL). At the same time, both extracts did not demonstrate acute toxicity in Artemia salina or in red blood cell assays at 500 µg/mL. Both extracts inhibited the lipoxygenase enzyme (IC50: 154.7 and 784.7 µg/mL for Malbec and Torrontés), with Malbec also reducing the tyrosinase activity (IC50: 89.9 µg/mL), and neither inhibited the xanthine oxidase. The substantial phenolic content and diverse biological activities in the Calchaquí Valleys' pomaces underline their potentialities to be valorized for pharmaceutical, cosmetic, and food industries.

The comparative metabolic profiling and their biological properties of eight extracts obtained from diverse parts (leaves, flowers, roots) of the medicinal plant Flourensia fiebrigii S.F. Blake, a chemotype growing in highland areas (2750 m a.s.l.) of northwest Argentina, were investigated. The extracts were analysed by GC-MS and UHPLC-MS/MS. GC-MS analysis revealed the presence of encecalin (relative content: 24.86 %) in ethereal flower extract (EF) and this benzopyran (5.93 %) together sitosterol (11.35 %) in the bioactive ethereal leaf exudate (ELE). By UHPLC-MS/MS the main compounds identified in both samples were: limocitrin, (22.31 %), (2Z)-4,6-dihydroxy-2-[(4-hydroxy-3,5-dimethoxyphenyl)methylidene]-1-benzofuran-3-one (21.31 %), isobavachin (14.47 %), naringenin (13.50 %), and sternbin, (12.49 %). Phytocomplexes derived from aerial parts exhibited significant activity against biofilm production of Pseudomonas aeruginosa and Staphylococcus aureus, reaching inhibitions of 74.7-99.9 % with ELE (50 μg/mL). Notably, the extracts did not affect nutraceutical and environmental bacteria, suggesting a selective activity. ELE also showed the highest reactive species scavenging ability. This study provides valuable insights into the potential applications of this chemotype.

This study provides a comprehensive investigation of lactic acid bacteria (LAB) isolated from Argentinean Capsicum annum L. The research covers important aspects, including genotypic characterization, bacterial stress tolerance, adhesion ability, safety evaluation, and functional and technological properties. The predominant isolates were identified as Lactilactobacillus curvatus and Lactiplantibacillus plantarum. Rep-PCR analysis grouped the isolates into 11 clonal groups. Lp. plantarum LVP 40 and LV 46; Levilactobacillus brevis LVP 41, Pediococcus pentosaseus LV P43, and Lt. curvatus LVP44, displayed both safety and resilience against adverse conditions such a slow pH, bile, and simulated gastric and intestinal juices. Moreover, the LAB strains exhibited high hydrophobicity and auto-aggregation percentages, NaCl tolerance, and substantial acidifying capacity. LAB supernatants demonstrated promising surfactant and emulsifying properties. Likewise, they differentially inhibited Staphylococcus aureus and Pseudomonas aeruginosa biofilms, showcasing their potential as antipathogenic agents. Noteworthy some strains displayed considerable co-aggregation with these pathogens, and several isolates showed an effective antimutagenic and detoxifying power, further emphasizing their multifaceted capabilities. Five pepper bacterial strains showcased probiotic properties, suggesting their potential for gut health enhancement. In summary, these LAB strains hold promise as vegetable fermentation starters, contributing to food safety and versatile applications in food science.

The present study evaluates the chemical compositions and antioxidant and antipathogenic properties of commercial orange (Citrus sinensis (L.) Osbeck) essential oils obtained using the cold-press method (EOP) and the cold-press method followed by steam distillation (EOPD). The chemical compositions of the volatilizable fractions, determined by gas chromatography-mass spectrometry, were similar in both samples. A relatively large amount of γ-terpinene was found in the EOPD (1.75%) as compared to the EOP (0.84%). Monoterpene hydrocarbons with limonene (90.4–89.8%) followed by myrcene (3.2–3.1%) as the main compounds comprised the principal phytochemical group. The non-volatile phenolics were eight times higher in the EOP than in the EOPD. Several assays with different specificity levels were used to study the antioxidant activity. Although both essential oils presented similar reducing capacities, the radical elimination ability was higher for the EOP. Regarding the antipathogenic properties, the EOs inhibited the biomass and cell viability of Staphylococcus aureus and Pseudomonas aeruginosa biofilms. Furthermore, both EOs similarly attenuated the production of elastase, pyocyanin, and quorum-sensing autoinducers as assessed using Gram-negative bacteria. The EOP and EOPD showed important antioxidant and antipathogenic properties, so they could represent natural alternatives to extend the shelf life of food products by preventing oxidation and contamination caused by microbial spoilage.

Capsicum annuum extracts of different polarities were tested for their antimicrobial, antibiofilm, and anti -Quorum sensing (QS) activity against several pathogenic microorganisms and possible toxic effects using an in vivo model (Galleria mellonella L.). Hexane (HE) and Chloroform extract (CE) were the most active in inhibiting biofilm formation of the eight bacteria tested, with inhibition percentages between 22 and 88% for a concentration of 100 mu g/mL. These extracts were potent inhibitors of Staphylococcus aureus biofilm, and microscopy analysis confirmed a significant reduction in adhered cells. Moreover, polystyrene surfaces coated with these extracts decreased Staph. aureus adhesion resulting in biofilm formation and activity inhibition. In addition, they interfere with the hemolysin and coagulase activities. The extracts inhibited biofilm formation and swarming motility in Gram-negative bacteria. Furthermore, in Pseudomonas aeruginosa, elastase activity and pyocyanin production were reduced. In the most active extracts, the main compound was linoleic acid, followed by oleic and hexadecanoic acids. Paprika extracts capable of controlling bacterial virulence represent a promising alternative as a natural preservative to restrict contamination or spoilage of food.

The reuse of agricultural waste is essential to mitigate environmental pollution problems. Consequently, this work focused on the valorization of the most extensive olive processing residue, alperujo, in terms of its ability to interfere with the virulence processes of Pseudomonas aeruginosa and Staphylococcus aureus contaminating food and reference strains. The activity of alperujo extracts of different polarities on virulence factors producing bacteria, and its relationship with antioxidant capacity and polyphenolic content was comparatively evaluated. The results indicated that the polar extracts significantly reduced the biofilm formed by both bacteria. They were also able to act against a previously formed biofilm by reducing its biomass and the cells' metabolism. Ethanolic extracts, rich in polyphenolic compounds, exhibited antioxidant capacity and Quorum sensing (QS) inhibitory activity against Chromobacterium violaceum. Additionally, they limited the spread of P. aeruginosa by restricting swarming and swimming movements. They also interfere in other QS controlled phenotypes like elastase and pyocyanin. The antipathogenic ability of the polar extracts could be mainly due to the synergistic effect of several phenolic compounds identified by LC–MS/MS analysis, such as luteolin, vanillic acid hexoside, oleuropein and derivates, quinic acid, apigenin, among others. As a result, this study contributes to the developing of sustainable strategies to revalorize a polluting waste into a value-added byproduct that could be used in the food and sanitary industries.

The present study describes how flour and phenolic enriched extracts (PEE) are obtained from seed (food waste) of 10 different P. alba (algarrobo blanco) clones and their characterization to be used as non-conventional sources of potential functional ingredients. Seed flour and PEE obtained from Argentinian P. alba cultivars were chemically characterized. The antioxidant capacity was also determined. The results showed variability in macronutrient composition of seed flour obtained from different clones. Among them, seed flour obtained from P4, P5, P6, P10, P12, and P13 clones showed a higher protein and fiber content than the other clones. On the other hand, PEE obtained from P6, P7, and P10 clones showed the highest content of phenolic component (7.32–8.58 mg GAE/g flour). The extracts obtained from them also showed high antioxidant activity (scavenging activity on ABTS•+, HO•, and H2O2). C-glycosyl flavones, including vicenin II, isoschaftoside, schaftoside, vitexin, and isovitexin were the major components extracted in all clones. These compounds have remarkable properties for disease prevention linked to oxidative stress. Therefore, the P. alba seed could be considered as functional food waste with a great potential to be used as a novel renewable and sustainable material for the production of bioactive food formulations.

The treatments being investigated for the pandemic associated with a severe acute respiratory syndrome caused by the new coronavirus (SARS-CoV2) aim to inhibit viral replication or inhibit enzymatic elastase in the lung, responsible for the SARS-CoV cell entry mechanism and the pathogenesis of severe pneumonia caused by infection. There is also a need to improve alveolar surfactant capacity and inhibition of the exacerbated inflammatory response. Current knowledge allows us to infer that Citrus essential oils could be considered an individual or a complementary highly valuable alternative for the viral infection caused by SARS-CoV due to its antiviral activity, particularly against coronavirus, anti-elastase, anti-inflammatory, antibacterial and antibiofilm properties. Furthermore, its proven capacity of biosurfactants, antioxidants, and pain inhibitors would help to treat acute respiratory syndrome. This review aims to encourage the development of more detailed studies on Citrus essential oils as a new multi-objective strategy to treat SARS-CoV2 infection.

Micro-organisms have showed the ability to produce biologically active compounds associated with neurotransmission in higher organisms. In particular, serotonin- and melatonin-producing microbes are valuable sources for the development of eco-friendly bioproducts. Serotonin and melatonin are indoleamines that have received special attention due to their positive effects on human health. These biomolecules exert a critical role in several physiological or pathological processes, including some mental and neurological disorders. This article includes a review of the microbial production of serotonin and melatonin, their functions in micro-organisms and their potential uses as therapeutic and/or preventive agents to improve human health. A description of the quantification methods employed to detect indoleamines and the evidence found concerning their microbial production at laboratory and industrial scale-for application in biotechnological products-is also provided. The microbial ability to synthesize beneficial indoleamines should be further studied and harnessed, to allow the development of sustainable bioprocesses to produce foods and pharmaceuticals for human health.

The chemical composition of three Citrus limon oils: lemon essential oil (LEO), lemon terpenes (LT) and lemon essence (LE), and their influence in the virulence factors production and motility (swarming and swimming) of two Pseudomonas aeruginosa strains (ATCC 27853 and a multidrug-resistant HT5) were investigated. The main compound, limonene, was also tested in biological assays. Eighty-four compounds, accounting for a relative peak area of 99.23%, 98.58% and 99.64%, were identified by GC/MS. Limonene (59–60%), γ-terpinene (10–11%) and β-pinene (7–15%) were the main compounds. All lemon oils inhibited specific biofilm production and bacterial metabolic activities into biofilm in a dose-dependent manner (20–65%, in the range of 0.1–4 mg mL−1) of both strains. Besides, all samples inhibited about 50% of the elastase activity at 0.1 mg mL−1. Pyocyanin biosynthesis decreases until 64% (0.1–4 mg mL−1) for both strains. Swarming motility of P. aeruginosa ATCC 27853 was completely inhibited by 2 mg mL−1 of lemon oils. Furthermore, a decrease (29–55%, 0.1–4 mg mL−1) in the synthesis of Quorum sensing (QS) signals was observed. The oils showed higher biological activities than limonene. Hence, their ability to control the biofilm of P. aeruginosa and reduce the production of virulence factors regulated by QS makes lemon oils good candidates to be applied as preservatives in the food processing industry.

Bacterial spoilage of food and other infections are a coordinated mechanism controlled by quorum sensing (QS), which regulate the expression of virulence factors, such as biofilm. The antimicrobial, antibiofilm, anti-QS and anti-swarming properties of hexane (HE), chloroform (CE), ethyl acetate (EAE), methanolic (ME) and total methanolic (TME) extracts of coriander grown in Argentina were investigated. In vivo extracts toxicity using Galleria mellonella L. model and chemical composition (GC-MS) were also assessed. The antibiofilm activity of polystyrene surfaces coated with the most active extracts was evaluated. At non-inhibitory growth concentrations, extracts showed a strong antibiofilm capacity and a slight anti-swarming and anti-QS activities. Likewise, none of the extracts were toxic up to 2500 mg/kg. For all bacteria tested (Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa and Staphylococcus aureus), HE and CE of coriander were the most active extracts for inhibiting the formation and the metabolic activity of biofilm, especially for S. aureus. The anti-staphylococcal biofilm activity was confirmed by fluorescence and scanning electron microscopy. Extract-coated polystyrene surfaces decreased bacterial adhesion and subsequent biofilm formation, even after washing. A total of 11 and 14 chemical compounds were identified from the HE and CE, respectively, being oleic acid the main compound in both extracts. Particularly, the strong inhibitory activity of coriander HE against S. aureus biofilms is emphasizing. These results suggest the possible application of these extracts either as an antibiofilm agent or by generating anti-adherent surfaces in the food industry and in the clinical area.

En la industria de alimentos, el biofilm es la principal causa de contaminación. Debido a normativas alimentarias, solo pocos compuestos pueden ser usados como conservantes o estar en contacto con alimentos durante su elaboración y a la vez deben ser económicos. Una alternativa es el uso de subproductos o residuos de agroindustrias. Una de las principales industria alimenticias de Iberoamérica es la vitivinicultura. La presente investigación utiliza orujo y escobajo de vino varietal Torrontés, para inhibir la virulencia bacteriana controlada por Quorum sensing (QS) y principalmente su motilidad (swarming y swimming), lo que permitiría el desplazamiento y formación de biofilm en alimentos. Realizamos extracciones con solventes de polaridad creciente (hexano, cloroformo, acetato de etilo y metanol). Enfrentamos 250 y 500 µg/ml de extractos (E) a las cepas de Pseudomonas aeruginosa ATCC 27853 y LVP65. Los E metanólicos de orujo y escobajo inhibieron más del 50 la motilidad swarming de ambas cepas. Los E acetato de etilo inhibieron swimming (25-30%). La actividad anti-QS de los E se ensayó con las cepas Chromobacterium violaceum ATCC 12472 y CV026. Determinando una inhibición de los E metanólicos y de acetato sobre el sistema de QS. Las bioactividades encontradas convierten a estos desechos en una novedosa alternativa para la preservación de alimentos

Parastrephia lucida (Meyen) Cabrera is an endemic species from the Argentinean Puna used in traditional medicine to relieve inflammation. To give scientific support to the ethnopharmacological claim, a bio-guided fractionation of a P. lucida extract was carried out according to its antioxidant activity (in vitro by different primary and secondary methodologies and in vivo on Caenorhabditis elegans) and its ability to inhibit proinflammatory enzymes (hyaluronidase and xanthine oxidase). Acute toxicity and genotoxicity of P. lucida were also studied by using Artemia salina and C. elegans bioassays, and Ames test, respectively. Compound characterization of P. lucida extracts and fractions was performed through UHPLC-quadrupole Orbitrap mass spectrometry. P. lucida total methanolic (MeOH) and dichloromethane (DCM) extracts (obtained from the partition of MeOH), showed high flavonoid contents (25.6 and 28.0 mu g QE/mg DW) and significant inhibition of proinflammatory enzymes (IC50: 320.0 and 280.0 mu g/mL on hyaluronidase, and IC50: 53.0 and 44.0 mu g/mL on xanthine oxidase, respectively), as well as in vitro and in vivo antioxidant capacity. From DCM, fractions E and F, showed a lack of toxicity or genotoxic, inhibited the xanthine oxidase activity 4-fold than DCM extract, and exhibited high in vivo antioxidant activity, evidenced by the protection of C. elegans against oxidative damage caused by H2O2 and Paraquat between 20 and 30 %. Besides, fractions E and F extended the nematode lifespan between 19 and 38%. Sixty-three metabolites, including several phenolic acids, coumarins, methoxylated flavonoids, tremetone derivates, and clerodane diterpenes, were accurately identified in the DCM fractions of P. lucida. This work not only scientifically supports P. lucida traditional use but also contributes to the search for new natural compounds aimed to treat processes related to inflammatory diseases, associated with oxidative stress. (c) 2020 SAAB. Published by Elsevier B.V. All rights reserved.

Antimicrobial, antibiofilm, anti-Quorum sensing (QS) and virulence factors inhibitory capacity of different polarity Laurus nobilis extracts against several pathogenic microorganisms were studied. Some extracts exhibited antibiotic effect against Staphylococcus aureus multidrug-resistant strains. However, all extracts (100 mu g/mL) inhibited to some extent the biofilm of most bacteria tested (until 40% for Gram-negative and 76% for Grampositive). Hexane (HE) and chloroform extract (CE) were potent inhibitors of S. aureus biofilm and the microscopies further confirmed an important reduction in adherent cells. Polystyrene surfaces coated with these extracts showed a decrease in bacterial adhesion with the resulting inhibition of S. aureus biofilm formation and biofilm activity. Moreover, they also interfere with the coagulase and hemolysin activities of this bacterium. With respect to Gram-negative bacteria, these extracts showed anti-QS activity against Chromobacterium violaceum and inhibited biofilm formation, swarming motility, pyocyanin production, and elastase activity of Pseudomonas aeruginosa. Chemical analysis of HE and CE revealed that the fatty acids were the main compounds, particularly linolenic, oleic and hexadecanoic acids followed by the oxygenated monoterpenes. Non-toxic laurel extracts offer a natural alternative to control contamination and/or spoilage of food, as well as infectious diseases, by attacking the biofilm and the virulence of Gram-positive and Gram-negative bacteria.

Citrus essential oils are used in food to confer flavor and aromas. The citrus essential oils have been granted as GRAS and could be used as antimicrobial additives to control bacterial quorum sensing from potential food bacterial pathogens. The chemical composition and inhibitory activity of Citrus paradisi (grapefruit) essential oils obtained by cold-pressed method (EOP) and cold-pressed method followed by steam distillation, against Pseudomonas aeruginosa were determined. The GC-MS analyses of the oil indicated the amount of the essential oil components was highest with D-limonene in both cases. However, the extraction method modified the chemical composition. EOP had higher amount of coumarins and flavonoid as well as less oxygenated terpenoids. At 0.1 mg/mL essential oils were not able to modify the bacterial development but inhibited the P. aeruginosa biofilm production between 52% and 55%, sessile viability between 45% and 48%, autoinducer production and elastase activity between 30% and 56%. Limonene was less effective at inhibiting P. aeruginosa than the essential oils, suggesting a synergistic effect of the minor components. According to our results, grapefruit essential oils could be used as a food preservative to control P. aeruginosa virulence.

This work investigated chloroform extracts from culture supernatants of two human probiotic bacteria, Lactobacillus casei CRL 431 and Lactobacillus acidophilus CRL 730 for the production of virulence factors and quorum sensing (QS) interference against three Pseudomonas aeruginosa strains. Both extracts inhibited biofilm biomass (up to 50%), biofilm metabolic activity (up to 39%), the production of the enzyme elastase (up to 63%) and pyocyanin (up to 77%), and decreased QS, without presenting any antibacterial acgivity. In addition, the chloroform extracts of both strains disrupted preformed biofilms of the three strains of P. aeruginosa analyzed (up to 40%). GC-MS analysis revealed that the major compounds detected in the bioactive extracts were four diketopiperazines. This study suggests that the metabolites of L. casei and L. acidophilus could be a promising alternative to combat the pathogenicity of P. aeruginosa.