Flourensia fiebrigii S.F. Blake in combination with Lactobacillus paracasei subsp. paracasei CE75. A novel anti-pathogenic and detoxifying strategy

Abstract

Natural products from the useful native species Flourensia fiebrigii S.F. Blake (Asteraceae, Heliantheae) were obtained from an Argentinean collection of Cañon del Ocre at 2750 m a.s.l. Piceol/4-hidroxyacetophenone was one of the main volatile compounds isolated and identified for the first time in this species. F. fiebrigii chloroformic extract, a mid-polarity fraction, piceol, or 2,4-dihydroxychalcone (12.5–50 μg/mL) increased bacterial auto-aggregation, biofilm formation, and surface/interfacial activity of Lactobacillus paracasei subsp. paracasei CE75. In fact, supernatants obtained from cultures grown with piceol (25 μg/mL) reduced Pseudomonas aeruginosa HT5 and Staphylococcus aureus HT1 biofilms (72.01% and 43.39%, respectively) due to anti-adhesive effects. The ability of L. paracasei subsp. paracasei CE75 to degrade phenolic compounds was determined by GC-EIMS. After 5 days of static incubation, detoxification percentages were 99.89% for piceol (25 μg/mL) and 100% for phenol (100 μg/mL). This detoxifying capacity was correlated with the occurrence of phenoloxidases and glycoproteins with a significant surfactant activity. Scanning electron microscopy also showed bacterial surface protrusions as an adaptive response to chemical stress. Our results indicate that the stimulated lactic acid bacterium constitutes a novel strategy with a high detoxifying capacity of phenolic compounds and a promising tool against food- and waterborne pathogen biofilms.