Norfloxacin and ursolic acid: in vitro association and postantibiotic effect against Staphylococcus aureus.

AIMS: We investigated the effectiveness in vitro of the association between norfloxacin (NOR) and ursolic acid (UA) against Staphylococcus aureus. METHODS AND RESULTS: The minimal inhibitory concentrations (MICs), the minimal bactericidal concentrations, the bacterial killing and the postantibiotic effect (PAE) of NOR and UA were determined both singly and in combination. A synergistic interaction was observed against Staph. aureus ATCC 29213: the mean PAEs were 3 h for NOR, -1.2 h for UA (1 × MIC) and 2.0 h for UA (2 × MIC). Synergism was observed with longer PAEs and postantibiotic sub-MIC effects after NOR/UA exposure. UA was also active against clinical isolates and methicillin-resistant Staph. aureus. CONCLUSIONS: The application of antimicrobial combinations may address the rising resistance to established classes of both systemic and topical agents. SIGNIFICANCE AND IMPACT OF THE STUDY: In vitro interactions between NOR and UA may contribute to the development of novel topical agents for the treatment of skin infections as well as for topical formulations.

Neuroprotective effects of almond skins in experimental spinal cord injury.

BACKGROUND & AIMS: Functional deficits following spinal cord injury (SCI) arise from both mechanical injury and from secondary tissue reactions involving inflammation. Natural almond skins (NS) were tested to evaluate anti-inflammatory effects on an animal model of SCI. METHODS: SCI was induced by the application of vascular clips to the dura via a four-level T5-T8 laminectomy. In the present study, to elucidate whether the protective effects of NS are related to the total phenolic content, we also investigated the effect of a blanched (BS) almond skins (industrially obtained by removing bran from the nut) in SCI. NS and BS (30 mg/kg respectively) were administered per os, 1 h and 6 h, after SCI. RESULTS: SCI in mice resulted in severe injury characterized by edema, tissue damage, production of inflammatory mediators and apoptosis (measured by Bax, Bcl-2 and Tunel assay). NS treatment, 1 and 6 h after SCI, reduced all parameters of inflammation as neutrophil infiltration, NF-κB activation, PAR formation, iNOS expression and apoptosis. However, treatment with BS did not exert any protective effect. CONCLUSIONS: Our results suggest that NS treatment, reducing the development of inflammation and tissue injury, may be useful in the treatment of SCI.

Antimicrobial potential of polyphenols extracted from almond skins.

AIMS: To evaluate the antimicrobial properties of flavonoid-rich fractions derived from natural and blanched almond skins, the latter being a by-product from the almond processing industry. METHODS AND RESULTS: Almond skin extracts were tested against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, Serratia marcescens), Gram-positive bacteria (Listeria monocytogenes, Enterococcus hirae, Staphylococcus aureus, Enterococcus durans) and the yeast Candida albicans. Almond skin fractions were found to have antimicrobial activity against L. monocytogenes and Staph. aureus in the range 250-500 microg ml(-1), natural skins showing antimicrobial potential against the Gram-negative Salm. enterica. The interactions between three almond skin flavonoids were also evaluated with isobolograms. CONCLUSIONS: Pairwise combinations of protocatechuic acid, naringenin and epicatechin showed both synergistic and indifferent interactions against Salm. enterica and Staph. aureus. Antagonism was observed against L. monocytogenes with all combinations tested. Further studies need to be performed to understand the mechanisms responsible for these interactions. SIGNIFICANCE AND IMPACT OF THE STUDY: Almond skins are a potential source of natural antimicrobials.