Essential oils and their components are becoming increasingly popular as naturally occurring antimicrobial agents. In this work the chemical composition and the antimicrobial properties of Thymus essential oils and of their main components were determined. Three essential oils obtained from different species of Thymus growing wild in Sardinia and a commercial sample of Thymus capitatus oil were analysed. The essential oil components were identified by GC/MS analysis. The antimicrobial activity of the oils and components was determined against a panel of standard reference strains and multiple strains of food‐derived spoilage and pathogenic bacteria, using a broth microdilution method. The GC/MS analysis showed that the major constituents of the oils were monoterpene hydrocarbons and phenolic monoterpenes, but the concentration of these compounds varied greatly among the oils examined. The results of the antimicrobial assay showed that essential oils extracted from Sardinian Thymus species have an antimicrobial activity comparable to the one observed in other thyme oils. It seems also confirmed that the antimicrobial properties of thyme essential oils are mainly related to their high phenolic content. Among the single compounds tested carvacrol and thymol turned out to be the most efficient against both reference strains and food‐derived bacteria. The results of this study confirmed the possibility of using thyme essential oils or some of their components in food systems to prevent the growth of foodborne bacteria and extend the shelf‐life of processed foods.

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Twenty-three Lactobacillus strains of dairy origin were evaluated for some functional properties relevant to their use as probiotics. A preliminary subtractive screening based on the abilities to inhibit the growth of microbial pathogens and hydrolyze conjugated bile salts was applied, and six strains were selected for further characterization including survival under gastrointestinal environmental conditions, adhesion to gut epithelial tissue, enzymatic activity, and some safety properties. All selected strains maintained elevated cell numbers under conditions simulating passage through the human gastrointestinal tract, well comparable to the values obtained for the probiotic strain Lactobacillus rhamnosus GG, and were able to adhere to Caco-2 cells to various extents (from 3 to 20%). All strains exhibited high aminopeptidase, and absent or very low proteolytic and strong β-galactosidase activities; none was found to be haemolytic or to produce biogenic amines and all were susceptible to tetracycline, chloramphenicol, erythromycin, ampicillin, and amoxicillin/clavulanic acid. Our results indicate that the Lactobacillus strains analyzed could be considered appropriate probiotic candidates, due to resistance to GIT simulated conditions, antimicrobial activity, adhesion to Caco-2 cell-line, and absence of undesirable properties. They could be used as adjunct cultures for contributing to the quality and health related functional properties of dairy products.

The purpose of this study was to assess the chemical and microbial characteristics of 12 batches of artisanal Fiore Sardo, a protected designation of origin (PDO) hard cheese made from raw ewe's milk without addition of starters, during maturation. High standard deviations were observed for moisture percentage, total solids percentage and NaCl percentage content, possibly owing to differences in manufacturing processes and/or milk composition. Total mesophilic bacteria varied between 10 log10 cfu/g in 48‐h‐old cheese samples and 3 log10 cfu/g in 9‐month‐old samples. Total coliforms and staphylococci showed the highest counts at 48 h of ripening then decreased significantly, dropping to levels below 2 log10 cfu/g at 3 months of maturation. Lactic acid bacteria and enterococci were the dominant micro‐organisms throughout maturation. They were mainly represented by the species Lactococcus lactis ssp. lactis, Enterococcus faecium, Lactobacillus plantarum and Lactobacillus casei group. Low levels of yeasts were detected throughout the maturation period of the cheese. Debaryomyces hansenii and Kluyveromyces lactis var. lactis were the prevalent yeast species isolated.

In this work, six Kluyveromyces strains isolated from artisanal Fiore Sardo cheese were evaluated for some functional properties relevant to their use as probiotics. All strains were able to grow in the presence of conjugated bile salts after 72 h of incubation, and four were able to hydrolyse both sodium glycodeoxycholate and taurodeoxycholate. All strains survived well under simulated gastric conditions (pH 3.0), but Kl. marxianus strains presented the best survival rates values (83–100%) after exposure to artificial duodenum juice. Autoaggregation ability showed a certain variability with mean values ranging between 39.1 and 59.2%, while the hydrophobicity index was higher than 50% in five strains. All strains were able to adhere to Caco-2 cells (values ranging from 4 to 68%), with two Kl. lactis strains exhibiting significantly higher percentage adhesion than S. boulardii Codex used as control (P < 0.05). Kl. lactis strains also showed the broadest inhibitory range against pathogens. Finally, all strains were non-hemolytic and sensitive to the antimycotic agents tested. In conclusion, our results indicate that Kluyveromyces strains isolated from artisanal cheese possess interesting functional traits and absence of undesirable properties, and could be considered appropriate probiotic candidates

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1 In¯ammatory bowel disease (IBD) is characterized by oxidative and nitrosative stress, leukocyte in®ltration, and increased expression of the adhesion molecules intercellular adhesion molecule 1 (ICAM-1) in the colon. Recent evidence also suggests that the cyclopentenone prostaglandin (PG) 15-deoxy-D 12,14 -PGJ 2 (15d-PGJ 2 ) functions as an early anti-in¯ammatory signal. 2 The aim of the present paper is to investigate the e ects of 15d-PGJ 2 in rats subjected to experimental colitis. 3 Colitis was induced in rats by intra-colonic instillation of dinitrobenzene sulphonic acid (DNBS). 15d-PGJ 2 was administered daily as intraperitoneal injection (20 or 40 mg kg 71 ). On day 4, animals were sacri®ced and tissues were taken for histological and biochemical analysis. 4 15d-PGJ 2 signi®cantly reduced the degree of haemorrhagic diarrhoea and weight loss caused by administration of DNBS. 15d-PGJ 2 also caused a substantial reduction of (i) the degree of colonic injury, (ii) the rise in myeloperoxidase (MPO) activity (mucosa), (iii) the increase in the tissue levels of malondialdehyde (MDA) and (iv) of the pro-in¯ammatory cytokines tumour necrosis factoralpha (TNF-a) and interleukin-1b (IL-1b). 5 Furthermore, 15d-PGJ 2 reduced the increase in immunohistochemical staining for (i) inducible nitric oxide synthase (iNOS), (ii) nitrotyrosine and (iii) poly (ADP-ribose) polymerase (PARP), as well as (iv) the increased expression of ICAM-1 caused by DNBS in the colon. 6 Electrophoresis mobility shift assay (EMSA) of in¯amed colon revealed that 15d-PGJ 2 also caused a substantial reduction of the activation of nuclear factor-kappaB (NF-kB). Furthermore, 15d-PGJ 2 stimulates the activation of heat shock protein 72 (hsp72) in the in¯amed colon, as assessed by Western blot analysis. 7 In conclusion, 15d-PGJ 2 reduces the development of experimental colitis.

The peroxisome proliferator‐activated receptor‐γ (PPAR‐γ) is a member of the nuclear receptor superfamily of ligand‐dependent transcription factors related to retinoid, steroid and thyroid hormone receptors. The thiazolidinedione rosiglitazone and the endogenous cyclopentenone prostaglandin (PG)D2 metabolite, 15‐deoxy‐Δ12,14‐PGJ2 (15d‐PGJ2), are two PPAR‐γ ligands, which modulate the transcription of target genes. The aim of this study was to investigate the effect of rosiglitazone and 15d‐PGJ2 on the tissue injury caused by ischaemia/reperfusion (I/R) of the gut. I/R injury of the intestine was caused by clamping both the superior mesenteric artery and the coeliac trunk for 45 min, followed by release of the clamp allowing reperfusion for 2 or 4 h. This procedure results in splanchnic artery occlusion (SAO) shock. Rats subjected to SAO developed a significant fall in mean arterial blood pressure, and only 10% of the animals survived for the entire 4 h reperfusion period. Surviving animals were killed for histological examination and biochemical studies. Rats subjected to SAO displayed a significant increase in tissue myeloperoxidase (MPO) activity and malondialdehyde (MDA) levels, significant increases in plasma tumour necrosis factor (TNF)‐α and interleukin (IL)‐1β levels and marked injury to the distal ileum. Increased immunoreactivity to nitrotyrosine was observed in the ileum of rats subjected to SAO. Staining of sections of the ileum obtained from SAO rats with anti‐intercellular adhesion molecule (ICAM‐1) antibody resulted in diffuse staining. Administration at 30 min prior to the onset of gut ischaemia of the two PPAR‐γ agonists (rosiglitazone (0.3 mg kg−1 i.v.) and 15d‐PGJ2 (0.3 mg kg−1 i.v.)) significantly reduced the (i) fall in mean arterial blood pressure, (ii) mortality rate, (iii) infiltration of the reperfused intestine with polymorphonuclear neutrophils (MPO activity), (iv) lipid peroxidation (MDA levels), (v) production of proinflammatory cytokines (TNF‐α and IL‐1β) and (vi) histological evidence of gut injury. Administration of rosiglitazone and 15d‐PGJ2 also markedly reduced the nitrotyrosine formation and the upregulation of ICAM‐1 during reperfusion. In order to elucidate whether the protective effects of rosiglitazone and 15d‐PGJ2 are related to the activation of the PPAR‐γ receptor, we also investigated the effect of a PPAR‐γ antagonist, bisphenol A diglycidyl ether (BADGE), on the protective effects of rosiglitazone and 15d‐PGJ2. BADGE (1 mg kg−1 administered i.v. 30 min prior to the treatment of rosiglitazone or 15d‐PGJ2) significantly antagonised the effect of the two PPAR‐γ agonists and thus abolished the protective effect against gut I/R. These results demonstrate that the two PPAR‐γ agonists, rosiglitazone and 15d‐PGJ2, significantly reduce I/R injury of the intestine. British Journal of Pharmacology (2003) 140, 366–376. doi: