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International audience; We have previously demonstrated that out of the butyrolactones series synthesized based on the natural lichen metabolite lichesterinic acid, compound (B-13) was the most effective against oral bacteria. However, its antibacterial mechanism is still unknown. In this study, we have investigated its bacterial localization by synthesizing a fluorescently labeled B-13 with NBD while maintaining its antibacterial activity. We showed that this compound binds to Streptococcus gordonii cell surface, as demonstrated by HPLC analysis. By adhering to cell surface, B-13 induced cell wall disruption leading to the release of bacterial constituents and consequently, the death of S. gordonii, a Gram-positive bacterium. A Gram-negative counterpart, Porphyromanas gingivalis, showed also cracked and ruptured cells in the presence of B-13. Besides, we also demonstrated that the analog of B-13, B-12, has also induced disruption of P. gingivalis and S. gordonii. This study revealed that butyrolactones can be considered as potent antibacterial compounds against oral pathogens causing medical complications.

International audience; The genus Roseburia consists of obligate Gram-positive anaerobic bacteria that are slightly curved, rod-shaped and motile by means of multiple subterminal flagella. It includes five species: Roseburia intestinalis, R. hominis, R. inulinivorans, R. faecis and R. cecicola. Gut Roseburia spp. metabolize dietary components that stimulate their proliferation and metabolic activities. They are part of commensal bacteria producing short-chain fatty acids, especially butyrate, affecting colonic motility, immunity maintenance and anti-inflammatory properties. Modification in Roseburia spp. representation may affect various metabolic pathways and is associated with several diseases (including irritable bowel syndrome, obesity, Type 2 diabetes, nervous system conditions and allergies). Roseburia spp. could also serve as biomarkers for symptomatic pathologies (e.g., gallstone formation) or as probiotics for restoration of beneficial flora.

Aim The purpose of this study was to conduct phytochemical analysis of sea buckthorn pulp oil and to evaluate the antimicrobial, anti-biofilm and antioxidant activities of its mouthwash form. Methods and results Fatty acid composition of the sea buckthorn pulp oil was determined by GC-MS analysis, which revealed that, mono-unsaturated fatty acid, palmitoleic acid and saturated fatty acid, palmitic acid, were the major constituents. The antimicrobial and the anti-biofilm capacities of sea buckthorn pulp oil mouthwash form were evaluated against Streptococcus gordonii, Porphyromonas gingivalis, Actinomyces viscosus and Candida albicans, according to the European Norms, and the Biofilm Ring Test® , respectively. These activities were then compared with those of chlorhexidine and herbal mouthwashes. The sea buckthorn-based mouthwash was bactericidal against S. gordonii and P. gingivalis, bacteriostatic against A. viscosus and showed no antifungal effect. Regardless of the strains used, complete inhibition of biofilm formation was achieved. The antioxidant activity of this experimental mouthwash was also assessed by DPPH and NBT assays. Conclusion Sea buckthorn mouthwash showed anti-biofilm activities against select single and multiple oral bacterial species. Significance and impact of the study In this study, a mouthwash derived from sea buckthorn (Hippophae rhamnoides) pulp oil has been experimented, for the first time, in order to overcome the problem of a large number of available synthetic mouthwashes which have side effects on teeth, gums and mucous membranes. This mouthwash seemed to be a suitable alternative for a preventive agent for periodontal inflammation.

International audience; Ludwigia peploides subsp. montevidensis and Ludwigia grandiflora subsp. hexapetala, form aquatic dense stands, which cause major ecological and economical problems in many aquatic ecosystems in France. However, these species are known to release allelopathic compounds. Here, antibacterial properties were assessed on samples from different plant organs, during June, July and August for L. peploides and throughout the development period, from April to September, for L. grandiflora. The disk diffusion method was used here to screen dimethylsulfoxide plant extracts against 5 Gram positive and 9 Gram negative bacterial strains. The sensitivity of the bacteria tested to L. grandiflora extracts was greater than that to those of L. peploides. Maximum antibacterial activity was measured in June, July or August, depending on the plant organ, principally in leaf and flower extracts. Activity also varied according to the bacterial strains tested. A principal component analysis (PCA) showed that sensitivity to the plant extracts did not depend' on whether the bacterial strains are Gram positive or Gram negative. Thus, we found that a Gram positive strain, Staphylococcus aureus (CIP 76.25), and a Gram negative strain, Salmonella enterica (DSM 10062), were similar in sensitivity. Antibacterial activities of certain leaf or flower extracts of both species of Ludwigia were revealed superior to those of several classic antibiotics tested. The interest of this study concerns the therapeutical potential of the two Ludwigia species. (C) 2014 Elsevier B.V. All rights reserved.