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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. • Alperujo extracts attenuate the biofilm formed by P. aeruginosa and S. aureus. • They disrupt a preformed biofilm and decrease its metabolic activity. • They limit the spread of P. aeruginosa by restricting swarming and swimming movements. • Alperujo polar extracts inhibit Quorum sensing , pyocyanin and elastase activity. • Ethanolic extracts rich in polyphenolic compounds exhibit antioxidant capacity. [ABSTRACT FROM AUTHOR]

Abstract: Laherradurin is an annonaceous acetogenin (ACG) extracted from the seeds of Annona cherimolia (Annonaceae). It has been shown to increase biofilm production of Pseudomonas plecoglossicida J26, a polycyclic aromatic hydrocarbon degrading bacterium. It is not an autoinducer agonist, and is indirectly involved in quorum sensing mechanism by inducing a stress related increase in autoinducer production, which in turn results in more biofilm formation without any significant detriment on bacterial growth rates. The results of the analysis of cells and supernatants obtained from J26 cell cultures by chromatographic techniques (TLC revealed with the Kedde reagent and RP-HPLC) and mass spectrometry (EI-MS) allowed us to determine that the ACG laherradurin and squamocin are located in the bacterial pellet, as was expected given their theoretical log p values. Thus, results suggest that these ACG act as bacterial membrane natural stressors. [Copyright &y& Elsevier]

Abstract: The effects of squamocin and laherradurin, two annonaceous acetogenins (ACG) from Annona cherimolia seeds on naphthalene degradation and biofilm formation of Pseudomonas plecoglossicida J26 were evaluated. These PAHs degrading bacteria have been shown to increase their biofilm formation when small concentrations of squamocin or laherradurin were added to the culture medium. An increase of initial naphthalene degradation rate was observed in ACG treated cultures that permitted us to establish that there is a relationship between naphthalene consumption and biofilm formation. The stimulation of biofilm formation led to increased consumption of naphthalene. Naphthalene consumption rate has been tripled in presence of ACG. This fact could be employed to increase biofilm formation and efficiency of PAHs bioremediation. [Copyright &y& Elsevier]

Abstract: Squamocin, an annonaceous acetogenin (ACG) extracted from Annona cherimolia (Annonaceae), has been shown to increase biofilm production of Pseudomonas plecoglossicida J26 (closely related to P. plecoglossicida), a polycyclic aromatic hydrocarbon degrading bacterium. PAHs have become priority pollutants for bioremediation due to their carcinogenicity and toxicity. The effect of various stressful stimuli (naphthalene, octanol, HCl, and NaCl) on cell growth, biofilm formation and autoinducer production of P. plecoglossicida were evaluated and compared with the effect of squamocin to establish its mode of action on biofilm formation. All stressors that inhibited growth stimulated autoinducer production while squamocin was growth stimulant at concentrations above 2.5 μg ml−1. Despite structural similarities, squamocin is not an autoinducer agonist. It indirectly stimulates autoinducer production and increases P. plecoglossicida J26 cell growth. This is the first report on an ACG mode of action in the formation of biofilm in a naphthalene-degrading strain. [Copyright &y& Elsevier]

Abstract: Antibacterial and molluscicidal activities of methanol and chloroform extracts of 16 plant species belonging to the families Compositae and Melastomataceae were evaluated. The chloroform extract of Vernonanthura tweediana and the methanol extract of Senecio santelisis resulted to be very toxic to brine shrimp nauplii (LC50 =1 μg/ml). Chloroform extracts of S. santelisis and Senecio leucostachys as well as the methanol extract of Wedelia subvaginata displayed molluscicidal effects on Biomphalaria peregrina showing LC100 <100 μg/ml. Moderate antibacterial action was produced by the chloroform extracts of Flaveria bidentis, Grindelia scorzonerifolia and Vernonia incana against two strains of Staphylococcus aureus. [Copyright &y& Elsevier]