Antiamyloidogenic Effects of Ellagic Acid on Human Serum Albumin Fibril Formation Induced by Potassium Sorbate and Glucose.

Oxidative stress has the main role in protein conformational changes and consequent direct involvement in different kind of diseases. Potassium sorbate as a widespread industrial preservative and glucose are two important oxidants that can be involved in oxidative stress. In this study the effect of ellagic acid as a phenolic antioxidant on amyloid fibril formation of human serum albumin upon incubation of potassium sorbate and glucose was studied using thioflavin T assay, surface tension, atomic force microscopy, Amadori product, and carbonyl content assays. The thioflavin T assay and atomic force microscopy micrographs demonstrated the antiamyloidogenic effect of ellagic acid on the human serum albumin fibril formation. This antioxidant also had the repair effect on surface tension of the modified human serum albumin (amyloid intermediates), which was destructed, caused by potassium sorbate and glucose. This mechanism takes place because of potent carbonyl stress suppression effect of ellagic acid, which was strengthening by potassium sorbate in the presence and absence of glucose.

[Tobacco contact dermatitis caused by sensitivity to sorbic acid]. / Eczéma de contact au tabac par sensibilisation à l'acide sorbique.

BACKGROUND: Contact dermatitis caused by tobacco is rare and poorly understood. In this paper, we report what is to our knowledge, the first case of tobacco contact dermatitis with identification of the causative agent. PATIENTS AND METHODS: A 46-year-old man was hospitalised for diffuse dermatitis originating in the left leg. Subsequent epicutaneous tests indicated that this dermatitis was ascribable to sensitisation to the sorbic acid present in Fucidin cream applied around a chronic wound. A persistent plaque of eczema observed on the day of examination opposite the patient's right trouser pocket suggested the implication of tobacco powder with which the pocket was soiled. An epicutaneous test using tobacco (moistened in water) proved positive (++ at 48 and 72 h). This tobacco contained sorbic acid, used as a preservative. DISCUSSION: The positive test for sorbic acid was relevant not only regarding the lesions on the patient's legs (application of a topical cream containing sorbic acid) but also for the lesion on the patient's thigh and for palmar dyshidrosis (through contact with strands of loose rolling tobacco). To our knowledge, this is the first recorded case of contact dermatitis caused by sorbic acid in tobacco.

Inhibition effect of food preservatives on endoproteinases.

The present manuscript proposes a novel approach to assess the impact of food additives on human metabolism by analysing their effect on biomarker enzyme activity. Alterations in the activity of pancreatic enzymes, such as chymotrypsin and trypsin, which are affected by the most common food preservatives, sodium benzoate (E211), potassium sorbate (E202) and sorbic acid (E200), have been evaluated. The proteinase activity was analysed with a bioluminescent method using the light intensity decay constant. Our study revealed that the preservatives reduce proteinase activity by 50% (EC50) at a much lower concentration than their acceptable daily intake (ADI). Thus, sodium benzoate and sorbic acid have an inhibition effect on chymotrypsin at concentrations 14 times lower and 70 times lower than their ADI and this increases with exposure time. Food preservative consumption impacts negatively on protein digestion, which is especially dangerous for patients with pancreatitis.

Potassium sorbate reduces gastric colonization in patients receiving mechanical ventilation.

OBJECTIVES: Tube feeding might increase gastric burden of pathogenic bacteria and predispose patients to ventilator-associated pneumonia. We sought to determine whether a tube feeding formula acidified using potassium sorbate could reduce gastric burden of potentially pathogenic bacteria. DESIGN: Prospective, randomized, double-blind trial. SETTING: RML Specialty Hospital, a facility with expertise in weaning patients from prolonged mechanical ventilation. PATIENTS: Thirty patients recovering from prolonged mechanical ventilation. INTERVENTION: Patients were randomized to receive either a standard tube feeding formula (n=14) or a formula acidified using potassium sorbate to a pH of 4.25 (n=16). MEASUREMENTS AND RESULTS: Weekly quantitative cultures of gastric aspirates. The number of colony-forming units (CFUs) per patient was higher in the control than in the treatment group (53%+/-11% vs 9%+/-3.4%, threshold of >or=100,000 CFU/mL fluid, P=.003). The number of organisms isolated in each patient per week was higher among patients receiving standard tube feeding formula than among patients receiving acidified formula (0.91 +/- 0.20 vs 0.13 +/- 0.05 organisms per patient per week, threshold of >or=100,000 CFU/mL fluid, P=.0014). There was no difference in the incidence of gastrointestinal bleeding or ventilator-associated pneumonia between study groups. CONCLUSION: Tube feeding formula acidified using potassium sorbate was well tolerated and reduced gastric bacterial burden in patients recovering from prolonged mechanical ventilation.

Potassium sorbate as an AGE activator for human serum albumin in the presence and absence of glucose.

Advanced glycation end products (AGEs) are the predominant intermediates of glycation process, and mediate oxidative stress and complications of diabetes. Potassium sorbate (PS) as a widespread preservative is an oxidative agent and used in different dairy and drug products, which can readily enter biological matrices. Here we studied the PS interference with glycation of human serum albumin (HSA) in the presence of glucose (Glc) using various techniques. These included TNBSA assay, circular dichroism, fluorescence spectroscopy, differential scanning calorimetry (DSC), Th T assay, and atomic force microscopy. Our results indicated that HSA glycation was accelerated in the presence of PS. Furthermore, PS produced AGEs in the absence of glucose. Secondary and tertiary structural changes were also observed in HSA incubated with glucose in the presence or absence of PS through beta-sheet inducing effects. Th T assay demonstrated the role of PS in HSA fibril formation in the presence or absence of glucose. Atomic force microscopy determined different amyloid fibril formation in HSA incubated with PS in the presence or absence of glucose. Together our results indicated that PS has a stimulatory effect on glycation and fibrillation of HSA in the presence or absence of glucose, and could exacerbate complication of diabetes.

Exposure assessment of food preservatives (sulphites, benzoic and sorbic acid) in Austria.

An exposure assessment was performed to estimate the potential intake of preservatives in the Austrian population. Food consumption data of different population groups, such as preschool children aged 3-6 years, female and male adults aged 19-65 years were used for calculation. Levels of the preservatives in food were derived from analyses conducted from January 2007 to August 2010. Dietary intakes of the preservatives were estimated and compared to the respective acceptable daily intakes (ADIs). In the average-intake scenario, assuming that consumers randomly consume food products that do or do not contain food additives, estimated dietary intakes of all studied preservatives are well below the ADI for all population groups. Sulphite exposure accounted for 34%, 84% and 89% of the ADI in preschool children, females and males, respectively. The mean estimated daily intake of benzoic acid was 32% (preschool children), 31% (males) and 36% (females) of the ADI. Sorbic acid intakes correspond to 7% of the ADI in preschool children and 6% of the ADI in adults. In the high-intake scenario assuming that consumers always consume food products that contain additives and considering a kind of brand loyalty of consumers, the ADI is exceeded for sulphites among adults (119 and 124%, respectively). Major contributors to the total intake of sulphites were wine and dried fruits for adults. Mean estimated dietary intakes of benzoic acid exceeded the ADI in all population groups, 135% in preschool children, 124% in females and 118% of the ADI in males, respectively. Dietary intakes of sorbic acid are well below the ADI, accounting for a maximum of 30% of the ADI in preschool children. The highest contributors to benzoic and sorbic acid exposure were fish and fish products mainly caused by high consumption data of this large food group, including also mayonnaise-containing fish salads. Other important sources of sorbic acid were bread, buns and toast bread and fruit and vegetable juices.

Contact urticaria from synthetic cassia oil and sorbic acid limited to the face.

A patient with contact urticaria with skin and respiratory symptoms was found to be sensitive to both sorbic acid and synthetic oil of cassia. The contact urticaria was only elicitable on intact skin of the face by open testing. The source of the patient's contactants was her shampoo and toothpaste.

Discoloration of hydrogel contact lenses under standard care regimens.

Four types of hydrogel contact lenses (N = 164) were subjected to in vivo and in vitro standard care regimens for a period of six months. Lens care variables included: heat disinfection in Bausch and Lomb Sensitive Eyes saline solution; heat disinfection in Cooper Unisol 4 sterile, nonpreserved saline solution; American Optical/Reichert Lensept disinfection and storage in Sensitive Eyes saline; and Lensept disinfection and storage in Unisol 4 saline. The study was conducted to determine the conditions under which lens discoloration occurs. The 45% Bufilcon A (55% water) lens showed significant discoloration in vivo with both heat and Lensept disinfection when rinsed and soaked in sorbate-preserved saline, and in vitro when heat disinfected in sorbate-preserved saline.

Sorbic acid revisited.

135 patients wearing hydrogel lenses were prescribed a care system of sorbic acid preserved surfactant, Lensept and Bausch and Lomb Sensitive Eyes Saline (sorbic acid 0.10%). Fifteen percent of patients presented with an adverse ocular response to their care system. The etiology was attributed to sorbic acid as the use of nonpreserved saline eliminated the signs and symptoms. This incidence of reaction is similar to those published earlier on thimerosal preserved saline and sorbic acid preserved saline.

Allergy to ingredients of vehicles.

Common ingredients of vehicles such as perfumes, antibacterial agents, emulsifiers and other surface active agents, propylene glycol, lanolin and wool alcohols were tested in eczema patients over a three-year period. Perfume allergy was detected in 3.6% of the cases, sensitivity to thiomersal in 2%, to sorbic acid in 0.8%, to parabens in only 0.3%, and to wool alcohols in 1.2%. Reactions to emulsifiers were seen over 1% of those tested.

Perioral contact urticaria from sorbic acid and benzoic acid in a salad dressing.

Contact urticaria was observed in a kindergarten in 18 of 20 children following the intake and accidental perioral application of a mayonnaise salad cream. In healthy adult controls, stinging tests and closed 20 minute patch test with the salad dressing were positive in 9 out of 12 and 4 out of 10 cases respectively. Twenty minute patch tests with the different components of the salad dressing were positive only so sorbic acid (SA) and benzoic acid (BA). Urticaria was provoked by inunction of the salad dressing periorally in two healthy boys. Serial 20 minute closed patch testing with varying concentrations of SA in 91 patients and BA in 41 patients gave almost identical results: positive reactions in two thirds of the patients with the highest concentrations. The response was only partially blocked by antihistamine applied locally before testing. Non-immunologic mechanisms are probably responsible for the transient reaction, and no restriction in the extensive use of SA or BA as preservatives in food should be considered.

Effects of preservatives in nasal formulations on the mucosal integrity: an electron microscopic study.

The preservatives benzalkonium chloride (BZC) and potassium sorbate (PS) are widely used in the formulation of nasal drops and cosmetics. Recently, a number of side effects that resulted from mucosal irritation caused by BZC and PS have been reported. Therefore, this study was performed to investigate the possible clinical and histological alterations induced by in vivo administration of these preservatives to the nasal mucosa of rats. 0.01% BZC and 0.12% PS were administered to the nostrils of male rats for 1 or 4 weeks. Clinical symptoms were recorded during the treatment, and light and electron microscopic examinations were carried out on samples taken from one third central and lower regions of the noses at the end of the treatment periods. Symptomatic changes such as sneezing and nasal rubbing were observed in almost all groups, starting from the 6th day of administration. Light and electron microscopy showed histological changes and nasal lesions induced by the preservatives. The symptomatic and histological changes were more pronounced with prolonged duration of administration. Therefore, it has been concluded that in vivo administration of the preservatives BZC and PS may be irritant to the respiratory epithelium of rats.