In vitro activity of tea-tree oil against clinical skin isolates of meticillin-resistant and -sensitive Staphylococcus aureus and coagulase-negative staphylococci growing planktonically and as biofilms

The susceptibility of Staphylococcus aureus [meticillin-resistant (MRSA) and meticillin-sensitive (MSSA)] and coagulase-negative staphylococci (CoNS), which respectively form part of the transient and commensal skin flora, to tea-tree oil (TTO) was compared using broth microdilution and quantitative in vitro time-kill test methods. MRSA and MSSA isolates were significantly less susceptible than CoNS isolates, as measured by both MIC and minimum bactericidal concentration. A significant decrease in the mean viable count of all isolates in comparison with the control was seen at each time interval in time-kill assays. However, the only significant difference in the overall mean log(10) reduction in viable count between the groups of isolates was between CoNS and MSSA at 3 h, with CoNS isolates demonstrating a significantly lower mean reduction. To provide a better simulation of in vivo conditions on the skin, where bacteria are reported to grow as microcolonies encased in glycocalyx, the bactericidal activity of TTO against isolates grown as biofilms was also compared. Biofilms formed by MSSA and MRSA isolates were completely eradicated following exposure to 5 % TTO for 1 h. In contrast, of the biofilms formed by the nine CoNS isolates tested, only five were completely killed, although a reduction in viable count was apparent for the other four isolates. These results suggest that TTO exerts a greater bactericidal activity against biofilm-grown MRSA and MSSA isolates than against some biofilm-grown CoNS isolates.

Comparison of the cidal activity of tea tree oil and terpinen-4-ol against clinical bacterial skin isolates and human fibroblast cells

Aim: The aim of this study was to compare both the antimicrobial activity of terpinen-4-ol and tea tree oil (TTO) against clinical skin isolates of meticillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (CoNS) and their toxicity against human fibroblast cells.

A randomised interventional trial of ω-3-polyunsaturated fatty acids on endothelial function and disease activity in systemic lupus erythematosus

Objective: To determine the clinical effect of dietary supplementation with low-dose ?-3-polyunsaturated fatty acids on disease activity and endothelial function in patients with systemic lupus erythematosus. Methods: A 24-week randomised double-blind placebo-controlled parallel trial of the effect of 3 g of ?-3-polyunsaturated fatty acids on 60 patients with systemic lupus erythematosus was performed. Serial measurements of disease activity using the revised Systemic Lupus Activity Measure (SLAM-R) and British Isles Lupus Assessment Group index of disease activity for systemic lupus erythematosus (BILAG), endothelial function using flow-mediated dilation (FMD) of the brachial artery, oxidative stress using platelet 8-isoprostanes and analysis of platelet membrane fatty acids were taken at baseline, 12 and 24 weeks. Results: In the fish oil group there was a significant improvement at 24 weeks in SLAM-R (from 9.4 (SD 3.0) to 6.3 (2.5), p

Steam reforming of model compounds and fast pyrolysis bio-oil on supported noble metal catalysts

The production of hydrogen by steam reforming of bio-oils obtained from the fast pyrolysis of biomass requires the development of efficient catalysts able to cope with the complex chemical nature of the reactant. The present work focuses on the use of noble metal-based catalysts for the steam reforming of a few model compounds and that of an actual bio-oil. The steam reforming of the model compounds was investigated in the temperature range 650-950 degrees C over Pt, Pd and Rh supported on alumina and a ceria-zirconia sample. The model compounds used were acetic acid, phenol, acetone and ethanol. The nature of the support appeared to play a significant role in the activity of these catalysts. The use of ceria-zirconia, a redox mixed oxide, lead to higher H-2 yields as compared to the case of the alumina-supported catalysts. The supported Rh and Pt catalysts were the most active for the steam reforming of these compounds, while Pd-based catalysts poorly performed. The activity of the promising Pt and Rh catalysts was also investigated for the steam reforming of a bio-oil obtained from beech wood fast pyrolysis. Temperatures close to, or higher than, 800 degrees C were required to achieve significant conversions to COx and H-2 (e.g., H-2 yields around 70%). The ceria-zirconia materials showed a higher activity than the corresponding alumina samples. A Pt/ceria-zirconia sample used for over 9 h showed essentially constant activity, while extensive carbonaceous deposits were observed on the quartz reactor walls from early time on stream. In the present case, no benefit was observed by adding a small amount of O-2 to the steam/bio-oil feed (autothermal reforming, ATR), probably partly due to the already high concentration of oxygen in the bio-oil composition. (c) 2005 Elsevier B.V. All rights reserved.

CsF and alumina: A mixed homogeneous-heterogeneous catalytic system for the transesterification of sunflower oil with methanol

The activity and nature (i e heterogeneous and/or homogeneous) of catalysts based on CsF supported on alpha-Al2O3 were investigated for the transesterification of vegetable oil with methanol. The effect of the activation temperature, CsF loading and the reusability in a recirculating reactor were first studied CsF/alpha-Al2O3 exhibited the highest activity for a CsF loading of 0 6 mmol/g and when activated at 120 degrees C An important aspect of this study is the effect of CsF leaching into the reaction mixture, which is attributed to the high solubility of CsF in methanol, leading to a complete loss of activity after one run It was Identified that the activity of the catalyst resulted from a synergy between alumina and dissolved CsF, the presence of both compounds being absolutely necessary to observe any conversion The use of an alumina with a higher surface area resulted in a far greater reaction rate, showing that the concentration of surface site on the oxide (probably surface hydroxyl) was rate-limiting in the case of the experiments using the low surface area alpha-Al2O3 This work emphasizes that combined homogeneous-heterogeneous catalytic systems made from the blending of the respective catalysts can be used to obtain high conversion of vegetable oil to biodiesel. Despite the homogeneous/heterogeneous dual character, such a catalytic system may prove valuable in developing a simple and cost-effective continuous catalytic process for biodiesel production (C) 2010 Elsevier B V All rights reserved

Antioxidant Activity of Sesame (Seasamum indicum L.) Cake Extract for the Stabilization of Olein Based Butter

This study investigated the effect of ethanolic sesame cake extract on oxidative stabilization of olein based butter. Fractionation of cream was performed by the dry fractionation technique at 10 °C, ethanolic sesame cake extract (SCE) was incorporated into olein butter at three different concentrations; 50, 100, 150 ppm (T1, T2, T3) and compared with a control. The total phenolic content of SCE was 1.72 (mg gallic acid equivalent g−1 dry weight). The HPLC characterization of ethanolic sesame cake revealed the presence of antioxidant substances viz. sesamol, sesamin and sesamolin in higher extents. The DPPH free radical scavenging activity of SCE was 83 % as compared to 64 and 75 % in BHA and BHT. Fractionation of milk fat at 10 °C significantly (p < 0.05) influenced the fatty acid profile of olein and stearin fractions from the parent milk fat. Concentration of oleic acid and linoleic acid in olein fraction was 29.62 and 33.46 % greater than the parent milk fat. The loss of C18:1 in 90 days stored control and T3 was 24.37 and 3.58 %, respectively, 58 % C18:2 was broken down into oxidation products over 8.55 % loss in T3. The peroxide value of control, T1, T2, BHT and T3 in the Schaal oven test was 8.59, 8.12, 5.34, 4.52 and 2.49 (mequiv O2/kg). The peroxide value and anisidine value of 3 months stored control and T3 were 1.21, 0.42 (mequiv O2/kg) and 27.25, 13.25, respectively. The concentration of conjugated dienes in T3 was substantially less than the control. The induction period of T3 was considerably higher than BHT with no difference in sensory characteristics (p > 0.05). Ethanolic SCE can be used for the long-term preservation of olein butter, with acceptable sensory characteristics.

Virgin Olive Oil: Losses of Antioxidant Polar Phenolic Compounds due to Storage, Packaging, and Culinary Uses

Virgin olive oil is a high quality natural product obtained only by physical means. In addition to triacylglycerols it contains nutritionally important polar and non-polar antioxidant phenols and other bioactive ingredients. The polar fraction is a complex mixture of phenolic acids, simple phenols, derivatives of the glycosides oleuropein and ligstroside, lignans, and flavonoids. These compounds contribute significantly to the stability, flavor, and biological value of virgin olive. In the various stages of production, during storage and in the culinary uses, polar phenols and other valuable bioactive ingredients may be damaged. Oxidation, photo-oxidation, enzymic hydrolysis and heating at frying temperatures have a serious adverse effect. Due to the biological importance of the oil and its unique character, analytical methods have been developed to evaluate antioxidant activity or analyse complex phenol mixtures. These are based on radical scavenging assays and chromatographic techniques. Hyphenated methods are also used including liquid chromatography-mass spectrometry and liquid chromatography-nuclear magnetic resonance spectroscopy.

Hydroprocessing of waste cooking oil over a dispersed nano catalyst: Kinetics study and temperature effect

The kinetics of hydrodeoxygenation of waste cooking oil (WCO) is investigated with unsupported CoMoS catalysts. A kinetic model is established and a comprehensive analysis of each reaction pathway is carried out. The results show that hydrodecarbonylation/decarboxylation (HDC) routes are the predominant reaction pathways in the elimination of oxygen, with the rate constant three times as high as that of hydrodeoxygenation (HDO). However, the HDC activity of the CoMoS catalyst deactivates due to gradual loss of sulfur from the catalyst. HDO process is insensitive to the sulfur deficiency. The kinetic modeling shows that direct hydrodecarbonylation of fatty acids dominates the HDC routes and, in the HDO route, fatty acids are transferred to aldehydes/alcohols and then to C-18 hydrocarbons, a final product, and the reduction of acids is the rate limiting step. The HDO route via alcohols is dominant over aldehydes due to a significantly higher reaction rate constant. The difference of C-18/C-17 ratio in unsupported and supported catalysts show that a support with Lewis acid sites may play an important role in the selectivity for the hydrodeoxygenation pathways and promoting the final product quality