In vitro evaluation of the activity of an essential oil from Pistacia vera L. variety Bronte hull against Candida sp.

BACKGROUND: Candida sp. represent the most common cause of fungal infections worldwide. In the present work, we have evaluated the activity of an essential oil extracted from pistachio hulls against a number of standard and clinical strains of Candida sp. METHODS: C. albicans ATCC 64550, C. parapsilosis ATCC 22019, 4 clinical strains of C. albicans, 3 clinical strains of C. parapsilosis and 3 clinical strains of C. glabrata were used. All clinical isolates were identified by species-specific PCR-based methods. Susceptibility studies were performed using pistachio hull essential oil alone or in combination with antifungal compounds. The interactions between pistachio hull essential oil and selected antifungal compounds were also evaluated using the checkerboard method and the mechanisms of interaction investigated by droplet size distribution. RESULTS: Pistachio hull essential oil was fungicidal at the concentrations between 2.50 and 5.0 mg/ml. D-limonene and 3-Carene were the components with major activity. An antagonistic effect was observed with all combinations tested. CONCLUSION: The antifungal activity of pistachio hull essential oil could be used to help control resistance in Candida species. More studies need to be performed to elucidate the mechanisms responsible for the activity of pistachio hull essential oil.

Study of the Lipid Profile of ATCC and Clinical Strains of Staphylococcus aureus in Relation to Their Antibiotic Resistance.

A number of reports have indicated a relationship between bacterial resistance to antibiotics and their lipid composition. In the present study, we characterized the lipid profiles of American Type Culture Collection (ATCC) and clinical strains of Staphylococcus aureus and its correlation with antibiotic resistance and hydrophobicity. The following strains were used: S. aureus ATCC 6538P, S. aureus ATCC 43300 (MRSA), seven clinical strains from the pharynges, two strains from duodenal ulcers, four strains from hip prostheses, and one strain from the conjunctiva. Lipid-related differentiation was observed across the S. aureus strains: the higher abundance of anteiso-pentadecanoic acid (anteiso-C15:0) and anteiso-heptadecanoic acid (anteiso-C17:0), followed by iso-pentadecanoic acid (iso-C15:0), suggested that these were common lipids. Iso-tridecanoic acid (iso-C13:0) and anteiso-tridecanoic acid (anteiso-C13:0), iso-hexadecanoic acid (iso-C16:0) and anteiso-hexadecanoic acid (anteiso-C16:0), and all forms of octadecanoic acid (C18:0) were usually detected in low abundance. Strains isolated from pharynges showed the highest ratio of branched/straight chains. A distinction in two clusters based on the amount and type of bacterial lipids identified was obtained, which correlated to the antibiotic resistance, the strains origin, and the cell-surface hydrophobicity. We report a potential correlation between the lipid profile of S. aureus strains, site of infection, antibiotic resistance, and cell-surface hydrophobicity. These results, which still need further insights, could be a first step to identifying antibiotic resistance in response to environmental adaptation.

Durum wheat particle size affects starch and protein digestion in vitro.

PURPOSE: The term bioaccessibility refers to the proportion of a nutrient released from a complex food matrix during digestion and, therefore, becoming potentially available for absorption in the gastrointestinal tract. In the present study, we assessed the starch and protein bioaccessibility from a range of wheat endosperm products differing in particle size. METHODS: Five porridge meals (size A, flour, mean particle size 0.11 mm, size B, small, mean particle size 0.38 mm, size C, semolina, mean particle size 1.01 mm, size D, medium, mean particle size 1.44 mm, size E, large, mean particle size 1.95 mm) with theoretically different postprandial glycaemic responses were subjected to oral processing in vitro, followed by simulated gastric and duodenal digestion. RESULTS: A significant increase (P < 0.001) in starch degradation was observed in size A (52%) compared with size E (25%). Both sizes C and D gave less, although not significantly, digestible starch (32 and 28%, respectively). The glucose release significantly decreased as the particle size of the meal increased (92.16% detected for size A vs 47.39% for size E). In agreement with starch degradation and glucose release, size A gave the most digestible protein. CONCLUSIONS: This data provide further evidence that, by decreasing the size of wheat endosperm, starch release and glycaemic response are enhanced. We also showed that protein bioaccessibility followed a similar trend as for starch digestion. Finally, these results support the hypothesis that different degrees of starch encapsulation elicit different blood glucose responses.

Phenolic profile and biological properties of the leaves of Ficus vasta Forssk. (Moraceae) growing in Egypt.

BACKGROUND: Ficus vasta Forssk. (Moraceae) is traditionally used for the treatment of various ailments; nonetheless, this species has been poorly studied to date. This work aimed to characterize the phenolic profile and to evaluate the antioxidant and antimicrobial properties of a hydroalcoholic extract obtained from F. vasta leaves collected in Egypt. METHODS: The phenolic profile of the extract was characterized by HPLC-PDA/ESI-MS. The antioxidant properties were examined by different in vitro systems: DPPH test, reducing power and metal chelating activity assays. Moreover, the ability of the extract to protect Escherichia coli growth and survival from H2O2-induced oxidative stress was evaluated. The potential toxicity was investigated using Artemia salina lethality bioassay. Finally, the antimicrobial properties against a representative set of Gram-positive and Gram-negative bacterial strains and the yeast C. albicans were assayed by standard methods. RESULTS: By HPLC-PDA/ESI-MS analysis 12 compounds belonging to the groups of phenolic acids and flavonoids were identified. The extract exhibited strong radical scavenging activity in DPPH test (IC50 = 0.0672 ± 0.0038 mg/mL), reducing power (3.65 ± 0.48 ASE/mL) and chelating activity (IC50 = 0.801 ± 0.007 mg/mL). A total protection against H2O2-induced damage on E. coli was observed. No toxicity against A. salina was found (LC50 > 1000 µg/mL). The extract exhibited bacteriostatic activity against almost all the bacteria tested (MICs: 250-62.5 µg/mL). CONCLUSIONS: The obtained results demonstrate the potential of F. vasta leaves as safe sources of natural antioxidant and antimicrobial compounds.

Antimicrobial Activity of Selected Polyphenols and Capsaicinoids Identified in Pepper (Capsicum annuum L.) and Their Possible Mode of Interaction.

Antimicrobial activity of pepper polyphenols and capsaicinoids (Coumarin, caffeic acid, narangin, kaempferol, rutin, quercetin, capsaicin, and dihydrocapsaicin) against 13 pathogen bacteria and three beneficial strains was studied using the disk diffusion and microdilution methods. In general, phenolic compounds had the most important activity with the highest inhibition zones obtained with caffeic acid (3.5-20.5 mm), quercetin (4.75-3.5 mm), and kaempferol (7-14 mm). In the determination of the minimal inhibitory concentrations, the effects of both quercetin and kaempferol were more important than caffeic acid. The clinical strains Staphylococcus aureus (319, 14, 8, 32, and 550) were more sensitive to quercetin (0.00195-0.0078 mg L-1) whereas kaempferol was more active against the strains S. aureus (ATCC 6538, 26), S. typhimurium ATCC 13311, and Pseudomonas aeruginosa ATCC 27853 (0.0156-0.125 mg L-1). The interaction between these three polyphenols was studied against S. aureus ATCC 6538 and P. aeruginosa ATCC 27853. Different modes of interaction were observed (synergism, additive, and indifferent), but no antagonism was obtained. The best combination was quercetin and caffeic acid for S. aureus with fractional inhibitory concentration index (FICI) of 0.37, and kaempferol with quercetin for P. aeruginosa (FICI = 0.31).

In Vitro Evaluation of the Antioxidant, Cytoprotective, and Antimicrobial Properties of Essential Oil from Pistacia vera L. Variety Bronte Hull.

Although the chemical composition and biological properties of some species of the genus Pistacia has been investigated, studies on hull essential oil of Pistacia vera L. variety Bronte (HEO) are currently lacking. In this work, we have carried out an in-depth phytochemical profile elucidation by Gas Chromatography-Mass Spectrometry (GC-MS) analysis, and an evaluation of antioxidant scavenging properties of HEO, using several different in vitro methods, checking also its cytoprotective potential on lymphocytes treated with tert-butyl hydroperoxide. Moreover, the antimicrobial activity against Gram-positive and Gram-negative strains, both American Type Culture Collection (ATCC) and clinical isolates, was also investigated. GC-MS analysis highlighted the richness of this complex matrix, with the identification of 40 derivatives. The major components identified were 4-Carene (31.743%), α-Pinene (23.584%), d-Limonene (8.002%), and 3-Carene (7.731%). The HEO showed a strong iron chelating activity and was found to be markedly active against hydroxyl radical, while scarce effects were found against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Moreover, pre-treatment with HEO was observed to significantly increase the cell viability, decreasing the lactate dehydrogenase (LDH) release. HEO was bactericidal against all the tested strains at the concentration of 7.11 mg/mL, with the exception of Pseudomonas aeruginosa ATCC 9027. The obtained results demonstrate the strong free-radical scavenging activity of HEO along with remarkable cytoprotective and antimicrobial properties.

Anti-infective potential of Citrus bergamia Risso et Poiteau (bergamot) derivatives: a systematic review.

Infectious diseases remain among the leading causes of morbidity and mortality worldwide, mainly because of the increase of resistance to chemotherapeutic drugs. Nature is the major source of anti-infective drugs and could represent a font of medicines that may help overcome antibiotic resistance. Recently, the potential antimicrobial effect of certain plant extracts has attracted attention within the scientific community as alternatives to synthetic drugs. Here, we present a systematic review on the anti-infective properties of bergamot derivatives that highlight the activity of bergamot essential oil against bacteria, mycetes and larvae, as well as the anti-Helicobacter pylori effect of bergamot juice and the antimicrobial properties of extracts from bergamot peel. Findings presented herein could be used to develop novel and alternative preventive and therapeutic strategies aimed to overcome antibiotic resistance. Copyright © 2016 John Wiley & Sons, Ltd.

In vitro effect of bergamot (Citrus bergamia) juice against cagA-positive and-negative clinical isolates of Helicobacter pylori.

BACKGROUND: Helicobacter pylori infection has been associated with chronic gastritis, peptic ulcer and gastric carcinoma as over half of the world's population is colonized with this gram-negative bacterium. Due to the increasing antibiotic resistance, its eradication rates fails in a great portion of patients. A number of studies showed that molecules largely distributed in commonly consumed fruits and vegetables may have antimicrobial activity. The aim of the present study was to investigate the effect of bergamot juice (BJ) against Helicobacter pylori in vitro. The potential therapeutic combination between BJ and the antibiotics amoxicillin (AMX), clarithromycin (CLA) and metronidazole (MTZ) has also been evaluated. METHODS: The minimum inhibitory concentration (MIC) of BJ, AMX, CLA and MTZ against 2 ATCC and 32 clinical isolates of H. pylori was assayed according to CLSI. The checkerboard method was used to determine the efficacy of the association BJ with the three reference antibiotics. Killing curves were performed on the two cagA-positive ATCC strains of H. pylori (ATCC 43504 and ATCC 49503), on the clinical isolate cagA-positive HP6 strain of H. pylori and on the clinical isolate cagA-negative HP61 strain of H. pylori. RESULTS: BJ (2.5%, v/v) inhibited the growth of 50% of the H. pylori clinical isolates, whereas 5% (v/v) inhibited 90%. AMX was the most effective antibiotic against the reference strains and the clinical isolates, followed by CLA and MTZ. In the combination assays, synergism was observed between BJ and AMX and between BJ and MTZ against both the reference strains and the clinical isolates. Indifference was observed between BJ and CLA. CONCLUSIONS: BJ was effective in vitro against H. pylori and the genotype status of the clinical strains may have an impact on its susceptibility. The synergistic combination of BJ and antibiotics could be used to prevent or treat resistance.

Almond Skin Inhibits HSV-2 Replication in Peripheral Blood Mononuclear Cells by Modulating the Cytokine Network.

We have investigated the effect of almond skin extracts on the production of pro-inflammatory and anti-inflammatory cytokines in human peripheral blood mononuclear cells (PBMCs). PBMCs were either infected or not by herpes simplex virus type 2 (HSV-2), with and without prior treatment with almond skin extracts. Production of IL-17 induced by HSV-2 was inhibited by natural skins (NS) treatment. NS triggered PBMC in releasing IFN-α, IFN-γ and IL-4 in cellular supernatants. These results may explain the antiviral potential of almond skins.

The effects of processing and mastication on almond lipid bioaccessibility using novel methods of in vitro digestion modelling and micro-structural analysis.

A number of studies have demonstrated that consuming almonds increases satiety but does not result in weight gain, despite their high energy and lipid content. To understand the mechanism of almond digestion, in the present study, we investigated the bioaccessibility of lipids from masticated almonds during in vitro simulated human digestion, and determined the associated changes in cell-wall composition and cellular microstructure. The influence of processing on lipid release was assessed by using natural raw almonds (NA) and roasted almonds (RA). Masticated samples from four healthy adults (two females, two males) were exposed to a dynamic gastric model of digestion followed by simulated duodenal digestion. Between 7·8 and 11·1 % of the total lipid was released as a result of mastication, with no significant differences between the NA and RA samples. Significant digestion occurred during the in vitro gastric phase (16·4 and 15·9 %) and the in vitro duodenal phase (32·2 and 32·7 %) for the NA and RA samples, respectively. Roasting produced a smaller average particle size distribution post-mastication; however, this was not significant in terms of lipid release. Light microscopy showed major changes that occurred in the distribution of lipid in all cells after the roasting process. Further changes were observed in the surface cells of almond fragments and in fractured cells after exposure to the duodenal environment. Almond cell walls prevented lipid release from intact cells, providing a mechanism for incomplete nutrient absorption in the gut. The composition of almond cell walls was not affected by processing or simulated digestion.

3,4-DHPEA-EA from Olea Europaea L. is effective against standard and clinical isolates of Staphylococcus sp.

BACKGROUND: The aim of the present work was to evaluate the antibacterial effect of 3,4-DHPEA-EA (methyl-4-(2-(3,4-dihydroxyphenethoxy)-2-oxoethyl)-3-formyl-2-methyl-3,4-dihydro-2H-pyran-5-carboxylate), a derivate of oleuropein, against a range of Gram-positive bacteria, including ATCC strains, food and clinical isolates. METHODS: The minimum inhibitory concentrations (MICs) of 3,4-DHPEA-EA were determined by the broth microdilution method and the Bioscreen C. RESULTS: 3,4-DHPEA-EA was effective against ATCC and clinical isolates of Staphylococcus aureus (MIC values between 125 and 250 µg/ml) and ATCC and clinical isolates of Staphylococcus epidermidis (MIC values between 7.81 and 62.5 µg/ml). No significant differences were observed between the two solvents (methanol and DMSO) used to dissolve 3,4-DHPEA-EA. CONCLUSIONS: The results obtained could be used to develop novel therapies for the treatment of skin infections. Further studies need to be performed to elucidate the formation of 3,4-DHPEA-EA by acid hydrolysis of oleuropein in the human stomach.

Antibacterial activities of almond skins on cagA-positive and-negative clinical isolates of Helicobacter pylori.

BACKGROUND: Helicobacter pylori is known to be a gastric pathogen of humans. Eradication regimens for H. pylori infection have some side effects, compliance problems, relapses, and antibiotic resistance. Therefore, the need for alternative therapies for H. pylori infections is of special interest. We have previously shown that polyphenols from almond skins are active against a range of food-borne pathogens. The aim of this study was to evaluate the antibacterial effects of natural almond skins before and after simulated human digestion and the pure flavonoid compounds epicatechin, naringenin and protocatechuic acid against H. pylori. RESULTS: H. pylori strains were isolated from gastric biopsy samples following standard microbiology procedures. Also, cagA and vacA genes were identified using PCR. Susceptibility studies on 34 strains of H. pylori, including two reference strains (ATCC 43504, ATCC 49503), were performed by the standard agar dilution method. CONCLUSIONS: Polyphenols from almond skins were effective in vitro against H. pylori, irrespective of genotype status and could therefore be used in combination with antibiotics as a novel strategy for antibiotic resistance.

Antioxidant and photoprotective effects of blanch water, a byproduct of the almond processing industry.

The aim of the present work was to evaluate the antioxidant and photoprotective effect of blanch water (BW), a byproduct of the almond processing industry. The polyphenolic content of a BW extract, the level of proanthocyanidins and the vanillin index determination were determined. The antioxidant activity and the radical scavenging activity of the BW were evaluated by a range of in vitro tests. The in vivo photoprotective effect was investigated using a formulation containing 2% of the BW extract on skin erythema induced by acute UV-B exposure in twelve volunteers. Results confirmed the presence of added-value antioxidant compounds in the industrial BW extract, and the most representative compounds were naringenin-7-O-glucoside and kaempferol-7-O-rutinoside. The proanthocyanidin content was 71.84 ± 5.21 cyanidin equivalents/g of BW extract. The good antiradical activity of the BW extract was demonstrated in both the DPPH• test and in the Reducing Power test. The percentage inhibition of erythema obtained using a formulation of BW was 50.48, value clearly demonstrating an effect against photooxidative damage in vivo.

Survival of Lactobacillus rhamnosus strains inoculated in cheese matrix during simulated human digestion.

Survival of probiotic bacteria during transit through the gastrointestinal (GI) tract is influenced by a number of environmental variables including stomach acidity, bile salts, digestive enzymes and food matrix. This study assessed survival of seven selected Lactobacillus rhamnosus strains delivered within a model cheese system to the human upper GI tract using a dynamic gastric model (DGM). Good survival rates for all tested strains were recorded during both simulated gastric and duodenal digestion. Strains H12, H25 and N24 demonstrated higher survival capacities during gastric digestion than L. rhamnosus GG strain used as control, with H12 and N24 continuing to grow during duodenal digestion. Strains L. rhamnosus F17, N24 and R61 showed adhesion properties to both HT-29 and Caco-2 cells. The ability to attach to the cheese matrix during digestion was confirmed by scanning electron microscopy, also indicating production of extracellular polysaccharides as a response to acid stress.

Both IL-1ß and TNF-α regulate NGAL expression in polymorphonuclear granulocytes of chronic hemodialysis patients.

BACKGROUND: NGAL is involved in modulation of the inflammatory response and is found in the sera of uremic patients. We investigated whether hemodiafiltration (HDF) could influence the ability of polymorphonuclear granulocytes (PMGs) to release NGAL. The involvement of interleukin- (IL-)1ß and tumor necrosis factor- (TNF-)α on NGAL release was evaluated. METHODS: We studied end-stage renal disease (ESRD) patients at the start of dialysis (Pre-HDF) and at the end of treatment (Post-HDF) and 18 healthy subjects (HSs). Peripheral venous blood was taken from HDF patients at the start of dialysis and at the end of treatment. RESULTS: PMGs obtained from ESRD patients were hyporesponsive to LPS treatment, with respect to PMG from HS. IL-1ß and TNF-α produced by PMG from post-HDF patients were higher than those obtained by PMG from pre-HDF. Neutralization of IL-1ß, but not of TNF-α, determined a clear-cut production of NGAL in PMG from healthy donors. On the contrary, specific induction of NGAL in PMG from uremic patients was dependent on the presence in supernatants of IL-1ß and TNF-α. CONCLUSION: Our data demonstrate that in PMG from healthy subjects, NGAL production was supported solely by IL-1ß, whereas in PMG from HDF patients, NGAL production was supported by IL-1ß, TNF-α.

Survival of Lactobacillus rhamnosus strains in the upper gastrointestinal tract.

In the present study six probiotic Lactobacillus rhamnosus strains were investigated for their ability to survive in the human upper gastrointestinal tract through a dynamic gastric model of digestion. MRS broth was used as delivery vehicle and survival was investigated during in vitro gastric and gastric plus duodenal digestion. Results highlighted that all tested strains showed good survival rate during both gastric and duodenal digestion. In particular, three strains exhibited a great survival showing a recovery percentage in the range between 117 and 276%. In agreement with survival data, high lactic acid production was detected for all strains, confirming their metabolic activity during digestion.

Involvement of TLR4 and PPAR-α Receptors in Host Response and NLRP3 Inflammasome Activation, Against Pulmonary Infection With Pseudomonas Aeruginosa.

BACKGROUND: Colonization with Pseudomonas aeruginosa (PA), the most common pathogen isolated mainly in patients with cystic fibrosis, is particularly difficult to eradicate and is associated with acceleration of decline in lung function and with poorer prognosis. PA LPS is recognized by Toll-like receptors-4 (TLR4) and has been shown to induce lung inflammation in vivo. In addition, regulation of this process is essential for proper pathogen clearance and to prevent excessive inflammatory response resulting in tissue damage. One potential regulator of these process is the peroxisome proliferator-activated receptors (PPARs), and in particular PPARα. Thus, the purpose of the present study was to evaluate the effects of the absence of TLR4 and PPARα receptors in the pulmonary innate immunity response to PA and in the consequent inflammatory response and in the activation of the macromolecular complex of the NLRP3 inflammosome. METHODS: To evaluate the involvement of TLR4 and PPARα in a PA infection, we used TLR4 KO and PPARα KO mice that received an intratracheal (i.t.) administration of 50 µL of PA strain (106 CFU), thus evaluating if these mice were profoundly susceptible to PA compared with WT mice. RESULTS: The results of the present study showed that administration of PA worsened the pathophysiology of PA lung disease in TLR4 and PPARα KO mice compared with WT mice. CONCLUSIONS: The present study demonstrated that TLR4 and PPARα receptors would mediate the earliest control of bacterial replication as well as proinflammatory responses to PA infections, and in particular that PPARα receptors are needed to prevent an excessive inflammatory response, as in the control of the inflammasome complex NLP3 activation.

Simulated human digestion of N1-aryl-2-arylthioacetamidobenzimidazoles and their activity against Herpes-simplex virus 1 in vitro.

Drug performance in the gastrointestinal tract (GIT) plays a crucial role in determining release and absorption. In the present work, we assessed the in vitro digestion of two synthetic N1-aryl-2-arylthioacetamidobenzimidazoles (NAABs), NAAB-496 and NAAB-503, using bio-relevant models of the human stomach and small intestine. The activity of NAAB-496 and NAAB-503 against herpes simplex virus (HSV-1) replication was also investigated. NAAB-496 was resistant to pepsin in the gastric environment, with a virtual 100% recovery, which decreased to 43.2% in the small intestine. NAAB-503 was sensitive to pepsin, with 65.7% degradation after 120 min gastric phase. 1H Nuclear magnetic resonance (NMR) post in vitro digestion highlighted an alteration of NAAB-496 after the gastric phase, whereas NAAB-503 appeared comparable to the original spectral data. Both NAAB-496 and NAAB-503 revealed some antiviral activity anti-HSV-1. The 50% effective concentration (EC50) of the compounds was 0.058 mg/mL for NAAB-496 and 0.066 for NAAB-503. Future studies will evaluate the behavior of NAAB-496 within pharmaceutical formulations.

Biochemical Characterization of Clinical Strains of Staphylococcus spp. and Their Sensitivity to Polyphenols-Rich Extracts from Pistachio (Pistacia vera L.).

We characterized a number of clinical strains of Staphylococcus spp. and investigated their sensitivity against polyphenols-rich extracts from natural raw and roasted pistachios (NPRE and RPRE, respectively). Out of 31 clinical isolates of Staphylococcus spp., 23 were coagulase-positive and identified as S. aureus, of which 21 were MRSA. Polyphenols-rich extracts from natural pistachios and roasted pistachios were prepared: the total phenols content, expressed as gallic acid equivalent (GAE)/100 g fresh weight (FW), was higher in natural pistachios (359.04 ± 8.124 mg) than roasted pistachios (225.18 ± 5.055 mg). The higher total phenols content in natural pistachios also correlated to the higher free-radical scavenging activity found by DPPH assay: NPRE and RPRE showed IC50 values of 0.85 (C.L. 0.725⁻0.976 mg mL-1) and 1.15 (C.L. 0.920⁻1.275 mg mL-1), respectively. Both NPRE and RPRE were active against S. aureus 6538P and Staph. spp. clinical isolates, with RPRE being the most active (MIC values ranging between 31.25 and 2000 µg mL-1). The antimicrobial potential of pistachios could be used to identify novel treatments for S. aureus skin infections.