Structure-function relationship of phenolic antioxidants in topical skin health products.

OBJECTIVES: The present work analysed the antioxidative activity of phenol-based antioxidants using an electron spin resonance method to predict the activity and stability of these antioxidants in cosmetic products. METHODS: The antioxidative power (AP) method was chosen to measure both the capacity and kinetics of an antioxidative reaction by detecting the DPPH (diphenylpicrylhydrazyl) radical. The antioxidative capacity (wc ) relates to the amount of free radicals that can be reduced, whereas the antioxidative reactivity (tr ) relates to the reaction speed and offers a fingerprinting of the redox state of the antioxidant molecules. Fifteen phenolic molecules have been analysed. They differed in the position of the hydroxyl groups and substituents on the aromatic ring. The AP of two distinct formulations containing hydroxytyrosol is presented as well as three phenol-based antioxidants within the same formulation vehicle. RESULTS: The rate at which phenol (ArOH) reacts with DPPH radicals, defined by the term reactivity (tr ) in this paper, was dependent upon the bond dissociation enthalpy (BDE) of the OH bond. Molecules having weak OH bonds and consequently low BDE values showed high antioxidant reactivity. On the other hand, the capacity factor (wc ), which is the concentration of phenol required to reduce a fixed concentration of DPPH radical, depends on the number and position of hydroxyl groups. The results showed that ortho and para positions of the two hydroxyl groups are important for higher capacity. If one of the two hydroxyl groups is blocked by methylation, both the antioxidative capacity and reactivity are reduced, mainly for ortho disubstituted compounds. The presence of a vinylic side chain improved reactivity and capacity tremendously. AP values may be useful in formulation design when identifying antioxidants that are likely to be physically and chemically stable. The importance of optimization of the formulation vehicle itself for a given antioxidant is also illustrated. CONCLUSION: Based on the presented findings, it is possible to predict the antioxidative performance of a phenol-based molecule and its stability and oxidation resistance within a cosmetic formulation. This is essential for antioxidant containing dermal formulations designed to combat skin ageing.

Effects of storage conditions and hemolysis on vitamin E concentrations in porcine serum and liver.

Vitamin E (alpha-tocopherol) is an antioxidant vitamin important in protecting unsaturated fatty acids in lipid membranes from peroxidation. Variation in collection, storage, and shipping conditions of samples can potentially lead to breakdown of vitamin E prior to analysis. Therefore, the purposes of this project were 1) to determine the stability of vitamin E in refrigerated and frozen porcine liver and serum and 2) to evaluate the effects of red blood cell (RBC) hemolysis on porcine serum vitamin E concentrations. Porcine liver and nonhemolyzed serum were collected and stored refrigerated or frozen. Samples were analyzed for vitamin E immediately or on days 2, 3, 7, or 14. In addition, porcine RBCs were added to normal serum at concentrations from 1 x 10(6) to 1 X 10(9) RBC/ml and hemolyzed by freeze-thaw prior to analysis for vitamin E or products of lipid peroxidation.

Comparison of hepatic lesions in veal calves with concentrations of copper, iron and zinc in liver and kidney.

Veal calf producers in Indiana have reported condemnation of carcasses due to icterus as well as condemnation of livers because of yellow discoloration, hepatomegaly and fibrosis. This study assessed the degree of hepatic injury in affected veal calves and correlated it with copper, iron and zinc concentrations in the liver and kidney. Tissues examined histopathologically were from slaughtered and necropsied veal calves. Hepatic lesions were divided into histopathologic categories of severity (minimal, moderate, marked or severe) based upon the degree of fibrosis, biliary epithelial hyperplasia, and inflammation. Hepatic copper levels decreased as the severity of lesions increased. The clinical observations and morphologic changes suggested initial hepatic damage before 9 w-of-age. The affected calves either died of acute copper toxicosis or survived to develop hepatomegaly, hepatic discoloration and/or fibrosis at the time of slaughter.

Suspected ethanol toxicosis in two wild cedar waxwings.

Several wild cedar waxwings (Bombycilla cedrorum) fell from a rooftop following ingestion of overwintered hawthorn (Crataegus sp.) pommes. At necropsy, there was pericardial hemorrhage, although no microscopic abnormalities were found. Ethanol was present in crop contents (380 ppm) and in the livers (238 and 989 ppm). The cause of death was attributed to hemorrhage following a fall precipitated by ethanol intoxication.

Age related susceptibility of newborn pigs to the cutaneous application of chlorpyrifos.

An aerosol preparation containing 2.5% chlorpyrifos was applied to the tail and umbilicus of newborn pigs. Mortality was 7/7 pigs treated 0-3 hr after birth, 3/5 pigs treated at 24-30 hr, and 0/3 pigs treated 30-36 hr after birth. Clinical signs consistent with organophosphate (OP) toxicosis were demonstrated by pigs that subsequently died or were euthanatized in extremis. Blood and brain cholinesterase (ChE) activities were depressed in affected pigs compared to controls. Only 1/3 pigs treated 30-36 hr after birth had a diagnostically significant depression in blood ChE. These results indicate that piglets one day or less of age are susceptible to OP toxicosis by cutaneous absorption of chlorpyrifos.

In utero exposure of bovine fetuses to polychlorinated biphenyls.

Pregnant mature beef cows more than 6 mo from parturition were fed whole plant corn silage from either a silo (contaminated) that had been coated with a plastic containing polychlorinated biphenyls (Aroclor 1254) or from a silo (clean) that had not been coated with the plastic. In addition, a third group of cows was fed silage from the clean silo plus 200 mg Aroclor 1254 per head daily (added polychlorinated biphenyls). After 30 days on treatment, one cow from each of the three treatments had her fetus removed by Caesarean section for assay of liver, thyroid, and fat for polychlorinated biphenyls content. Tissue content of polychlorinated biphenyls for fetuses from cows fed clean silage, contaminated silage, or added polychlorinated biphenyls was (microgram/g): liver, 3.6, 4.7, and 54.1; thyroid, 2.3, 19.4, and 121.1; fat, .65, 18.1, and 130.6, indicating polychlorinated biphenyls cross the placenta readily. Cow milk (colostrum) contents of polychlorinated biphenyls on the 1st day following parturition for the three respective treatments were .54, 8.5, and 96.4 micrograms/g (clean silage, contaminated silage, and added polychlorinated biphenyls). Fetuses taken from cows that had been removed from polychlorinated biphenyl exposure for 6 mo reflected previous treatments of dams by increased fetal fat stores of polychlorinated biphenyls.

Dietary Aroclor 1254 in the milk fat of lactating beef cattle.

Excretion in milk fat of Aroclor 1254 (a mixture of polychlorinated biphenyl) by mature beef cows (Hereford and Hereford cross) was studied. Three groups of 6 cows each were fed primarily a corn silage diet characterized by 1) clean silage (stored in an uncontaminated silo), 2) silage stored in a silo coated with a sealant containing Aroclor 1254, and 3) clean silage to which 200 mg Aroclor 1254 per head daily was added (approximately 2 to 3 mg/kg body weight per day). Treatments were started approximately 3 mo prior to parturition and extended 1 mo after parturition, at which time treatments were discontinued, and cows and nursing calves were placed on pasture. Milk was sampled in the period between parturition and 132 days after discontinuance of treatments. Fat from the milk of cows fed silage from the silo which had not been sealed with the Aroclor 1254 product contained .69 to 1.59 ppm Aroclor 1254 throughout the 164-day lactation. Fat from cows fed silage from the silo treated with the Aroclor 1254 sealant contained more than ten times as much Aroclor 1254 (15.7 to 18.4 ppm) for 32 days as compared with the controls and then dropped to one-half that figure through the 164th day. Fat from the milk of cows fed 200 mg Aroclor 1254 per day contained from 119 to 150 ppm through the first 32 days and then dropped to 39 to 51 ppm through day 164.

Inorganic arsenic toxicosis in cattle.

In 4 occurrences of arsenic poisoning in cattle, the principal clinical sign was acute hemorrhagic diarrhea attributable to hemorrhagic gastroenteritis. Arsenic concentrations in the liver, kidney and rumen contents varied. In one occurrence, arsenic in the hair of affected survivors was assayed at 0.8-3.40 ppm, vs 0.09-0.10 ppm in randomly selected control samples of hair. Sudden death was the only clinical sign in another occurrence in which gastric contents contained arsenic at 671 ppm. In another occurrence, arsenic poisoning caused lesions similar to those of salmonellosis.