Retention and distribution of polyphenols after pan-frying of French fries in oils enriched with olive leaf extract.

Palm oil, olive oil, and sunflower oil were supplemented with an extract rich in polyphenols obtained from olive tree (Olea europaea) leaves at levels of 120 and 240 mg total polyphenols per kilogram of oil. Pan-frying of potatoes was performed in both the enriched and the nonsupplemented oils under domestic frying conditions. Total polyphenol content was estimated by the Folin-Ciocalteau assay, oleuropein was determined by HPLC analysis, while other individual polyphenols by GC/MS analysis. Fourteen polyphenol species were identified in the olive leaf extract, among which oleuropein predominated (1.25 g/kg olive leaves). All the enriched oils contained oleuropein before and after frying. Oleuropein as well as other polyphenol species were detected in all French fries cooked in enriched oils. Polyphenol intake by consuming French fries pan-fried in the enriched oils was calculated to be 6 to 31 times higher than that in the case of French fries fried in commercial oils, being dependent on the frying oil type.

Bioavailability of the phenolic compounds of the fruits (drupes) of Olea europaea (olives): impact on plasma antioxidant status in humans.

To examine the bioavailability of olive polyphenols and to correlate it with their antioxidant efficacy, plasma and urine from healthy volunteers who had consumed 20 olives were subjected to (a) GC-MS analysis for individual phenolics, (b) estimation of plasma total polyphenol content and (c) estimation of plasma total antioxidant potential. Olive polyphenols were absorbed and metabolized within the body, occurring in plasma mainly in the conjugated form with glucuronic acid and reaching C(max) in 1-2h. Excretion rates were maximum at 0-4h. Tyrosol and hydroxytyrosol increased in plasma after intervention. Total antioxidant potential increased (p<0.05). The results indicate that olive polyphenols possess good bioavailability, which is in accordance with their antioxidant efficacy.

Glutathione depletion restores the susceptibility of cisplatin-resistant chronic myelogenous leukemia cell lines to Natural Killer cell-mediated cell death via necrosis rather than apoptosis.

We investigated the effect of intracellular glutathione (GSH) levels on Natural Killer-mediated apoptosis in cisplatin-resistant K562 cells. K562/B6 and K562/C9 are cisplatin-resistant K562 cells less susceptible to lysis by natural killer cells. Cisplatin-resistant K562 cells did not present the apoptotic pattern of DNA fragmentation as it was observed for their maternal counterparts. K562/B6 and K562/C9 cell lines produce 1.6- and 1.9-times more GSH than K562 cells. Treatment of both cell lines with D,L-buthionine-(S,R)-sulfoximine (BSO, a gamma-glutamyl cysteine synthetase inhibitor) decreased GSH levels and augmented cell death induced by NK cells via a necrotic rather than an apoptotic process. Proliferating cell nuclear antigen (PCNA) expression was elevated in cisplatin-resistant K562 subclones, and the reduction of GSH levels after treatment with BSO decreased the expression of PCNA. These results suggest that the GSH level affects the NK cell-mediated cell death of cisplatin-resistant K562 cells by inducing necrosis rather than apoptosis.

Analysis of olive oil and seed oil triglycerides by capillary gas chromatography as a tool for the detection of the adulteration of olive oil.

Individual triglyceride (TG) species of olive oil and several seed oils (corn, cottonseed, palm, peanut, soybean, and sunflower) are baseline separated on a WCOT TAP CB fused-silica capillary column by capillary gas chromatography (CGC) with a flame-ionization detector (FID) and either cold on-column or split injection. An adulteration of olive oil with a low content (< 5%) of these seed oils (except peanut oil) can be verified by the detection of the increasing levels of trilinolein or tripalmitin in olive oil in which these TG species are normally absent or present at very low levels (< 0.5%). An adulteration with over 20% peanut oil can be detected by the increasing levels of palmitodilinolein. TG species that can be coeluted with trilinolein in the reversed-phase high-performance liquid chromatographic (RP-HPLC) mode are baseline separated by the CGC technique, and their structures are identified by selective ion monitoring mass spectrometry. The following comparisons--the CGC-FID and RP-HPLC methods for detection of adulteration, cold on-column and split-injection modes for CGC-FID, and silylation or thin-layer chromatography pretreatment and simple dilution of one or more of the oil samples--are also presented. The normalized percentage area of the TG species is sufficient for the method limits used in this study. Mixtures of virgin olive oil with refined or residue olive oil could not be distinguished from the virgin type by the method used in this study.

The influence of parathyroid hormone on platelet-activating factor (PAF) blood levels in hemodialysis patients.

PAF represents a new family of glycerophospholipids and possesses multiple biological activities including platelet aggregation. Production of PAF has been demonstrated in a number of different cell types and in response to various stimuli. In this work an attempt is made to study the effect of parathyroid hormone (PTH) on PAF production. In 13 hemodialysis patients with severe secondary hyperparathyroidism, PAF levels in blood as well as intact PTH (iPTH) and total calcium in serum (tCa), before and 10 days after parathyroidectomy (PTHx), were measured. Our results indicate that PAF levels in blood as well as iPTH and tCa were higher before PTHx than after [a) PAF before 1.10 x 10(-4) +/- 9 x 10(-5) gamma/ml and after 2 x 10(-5) +/- 1 x 10(-5) gamma/ml, p < 0.001; b) iPTH before 880 +/- 392.9 pm/ml and after 121.6 +/- 61.9 pm/ml, p < 0.001; c) tCa before 9.96 +/- 0.35 mg/dl and after 8.38 +/- 0.30 mg/dl, p < 0.001]. Using stepwise regression analysis it seems that PAF is dependent on calcium which is dependent mainly on iPTH. Since a) platelet dysfunction is among the factors which are incriminated for bleeding in uremia and b) PAF which induces platelet aggregation acts via specific receptors, we checked the response of platelets in terms of their ability to aggregate in vitro following increasing doses of exogenous PAF in 5 of the above patients in order to investigate whether the high levels of PAF before PTHx may desensitize platelets.(ABSTRACT TRUNCATED AT 250 WORDS)

A simple and precise method for the routine determination of platelet-activating factor in blood and urine.

A simple and precise method is described for the measurement of platelet-activating factor (PAF) in blood and urine. The method involves the isolation of PAF from blood samples by two successive steps. In the first step, blood proteins are precipitated with ethanol and the "free" PAF, i.e., the PAF which is extractable with ethanol, is recovered. In the second step, "bound" PAF, i.e., PAF not extractable with ethanol, is extracted from the protein precipitate with chloroform/methanol/water. The extraction of PAF from urine samples requires only the ethanol extraction step. "Free" and "bound" PAF are then each fractionated by silicic acid column chromatography, and the methanol/water eluent containing PAF is then further fractionated by high-performance liquid chromatography using an isocratic solvent system of acetonitrile/methanol/water. PAF is then quantitated by measuring its ability to induce platelet aggregation in an aggregometer. Application of the method to blood and urine samples from twenty-three healthy volunteers revealed PAF levels in blood of 140-480 pg/mL (630-254.4 pg "free" PAF/mL and 64-225.6 pg "bound" PAF/mL), and of 1.2-4.0 pg PAF/mL in urine. The method overcomes various technical problems and was shown to be very precise. It should prove useful for monitoring PAF levels in various disease conditions.

Abnormal platelet response to PAF and ADP in beta-thalassaemia.

1. AGEPC (2 microM) caused a noticeable increment in platelet aggregation, in increasing order, in 9 heterozygous beta-thalassaemic subjects, 18 homozygous beta-thalassaemics and 12 splenectomized homozygous beta-thalassaemics. 2. Recombination experiments with "patient" platelets and "normal" plasma or the reverse, as well as hydrolysis of labelled AGEPC from "normal" and "patient" serum, suggested that the observed abnormalities were due to platelets rather than to the plasma PAF hydrolase. 3. A normal splenectomized subject showed also hyperaggregability and PAF serum levels in a splenectomized patient were found twice as high in a non-splenectomized patient. 4. ADP (5 microM) caused decreased or normal platelet aggregation in the homozygous patients, approximately normal in the heterozygous subjects and increased in the splenectomized patients.

Detection of olive oil adulteration with linoleic acid-rich oils by reversed-phase high-performance liquid chromatography.

Adulteration of olive oil with very low levels (1-2%) of linoleic acid-rich oils can be unequivocally detected by reversed-phase high-performance liquid chromatography on columns packed with C18 alkyl bonded-phase particles. Triglyceride fractionation according to their equivalent carbon numbers is effected in 22-25 min by eluting the column with a non-aqueous mobile phase (acetonitrile-absolute ethanol-isopropanol, 72:18:10), compatible with UV-detector systems.

Biological activity of lipids of pine pollen on platelet aggregation in correlation with the platelet activating factor.

Pollen lipids of a pine species were separated by thin layer chromatography systems. The purified neutral and polar lipid classes were examined for their possible platelet aggregation activity and for their effect on Platelet Activating Factor activity. The lipid fraction comigrating on thin layer chromatography with glycerylether standards was shown to have a remarkable inhibition of Platelet Activating Factor activity on washed rabbit platelets in a concentration of 4.5.10(-6) M. At a ten fold higher concentration these lipids also induced platelet aggregation.