The latest studies show that the active principles of tomatoes, sea buckthorn, and pumpkin oil ha... more The latest studies show that the active principles of tomatoes, sea buckthorn, and pumpkin oil have beneficial effects on prostate disease.The purpose of this study was to encapsulate the bioactive compounds of seabuckthorn juice, tomato juice and pumpkin oil, to obtain a functional product. Microencapsulation was performed using natural polymers such as sodium alginate to provide stability, bioavailability and bioactive compounds controlled release.The CaCl 2 gelation technique was used to obtain microcapsules with or without chitosan coatings like microspheres and mononuclear microcapsules. Bioactive compounds in microcapsules, microspheres, and ingredients were analyzed using UV-Vis and FT-IR analysis. Total polyphenols and total carotenoids concentration was between (40.90-283.75 mgGAE / 100 g sample;9.16-19.71 mg carotenoids/100g sample) in the case of the ingredients while total polyphenols and carotenoids content of microcapsules/microspheres was between (14.09-133.93mgGAE / ...
Liposomes and b-cyclodextrin (b-CD) have been used as carriers for the incorporation of three die... more Liposomes and b-cyclodextrin (b-CD) have been used as carriers for the incorporation of three dietary carotenoids (b-carotene (BC), lutein (LUT) and canthaxanthin (CTX)) into plasma, mitochondrial, microsomal and nuclear membrane fractions from pig liver cells or the retinal epithelial cell line D407. The uptake dynamics of the carotenoids from the carriers to the organelle membranes and their incorporation yield (IY) was followed by incubations at pH 7.4 for up to 3 h. The mean IYs saturated between 0.1 and 0.9 after 10 -30 min of incubation, depending on membrane characteristics (cholesterol to phospholipid ratio) and carotenoid specificity. Mitochondrial membranes (more fluid) favour the incorporation of BC (non-polar), while plasma membranes (more rigid) facilitate the incorporation of lutein, the most polar carotenoid. A high susceptibility of BC to degradation in the microsomal suspension was observed by parallel incubations with/without 2,6-di-t-butyl-p-cresol (BHT) as antioxidant additive. The b-CD carrier showed to be more effective for the incorporation of lutein while BC was incorporated equally into natural membranes either from liposomes or from cyclodextrins. The presence of cytosol in the incubation mixture had no significant effects on the carotenoid incorporations.
European Journal of Lipid Science and Technology, 2009
High-accuracy photopyroelectric measurements, in the thermal-wave-resonator-cavity configuration,... more High-accuracy photopyroelectric measurements, in the thermal-wave-resonator-cavity configuration, were performed in order to measure the thermal diffusivity of some vegetable oils. The high resolution (relative error ±0.5%) of the above method allows for the detection of small changes in the values of this dynamic thermal parameter. The accuracy of the results is mainly due to the possibility to precisely control the variation (30-nm step) of sample thickness, a proper selection of the range of the thickness scan (2 µm < Lm < 4 µm ˜ 5 µm), and an iterative procedure of data analysis. A correlation between thermal diffusivity and the fatty acid composition (obtained via gas chromatography) is suggested for some fresh (sunflower, hemp, flax, and soybean) oils and for hemp oil exposed to a microwave field: Thermal diffusivity appears to be determined by the overall content of polyunsaturated fatty acids.
ABSTRACTThe main focus of our study was to implement a rapid, inexpensive and reliable method tha... more ABSTRACTThe main focus of our study was to implement a rapid, inexpensive and reliable method that could be utilized to check the cereals for safety (i.e., screening for total aflatoxins, as well as individual B1, B2, G1, G2 aflatoxins and ochratoxin A). We developed a protocol by which we were able to isolate mycotoxins from cereals collected from different regions of Romania. After extraction in chloroform, the mycotoxins were separated by thin-layer chromatography (TLC) and quantified using densitometry.Forty-three samples of different cereals (wheat, maize, rye and Triticale) were analyzed. Twenty-five of the 43 samples (58.14% of the total number) were found to be contaminated with different mycotoxins in various concentrations: aflatoxin B1 (1.6–5.7 µg/kg), aflatoxin B2 (0.89–4 µg/kg), aflatoxin G1 (1.2–5.76 µg/kg), aflatoxin G2 (0.96–3.4 µg/kg) and/or 4.3–30 µg/kg ochratoxin A. The concentration of total aflatoxin contamination ranged from 11.2 to 10.8 µg/kg. Among the different cereals, the highest number of contaminated samples was found to be in the wheat samples (62.5%). The method outlined in this study has been adopted already by our laboratory for current analyses of mycotoxins. The results obtained using this method is in compliance with the strict regulatory guidelines developed both in Romania, as well as in the European Union.The main focus of our study was to implement a rapid, inexpensive and reliable method that could be utilized to check the cereals for safety (i.e., screening for total aflatoxins, as well as individual B1, B2, G1, G2 aflatoxins and ochratoxin A). We developed a protocol by which we were able to isolate mycotoxins from cereals collected from different regions of Romania. After extraction in chloroform, the mycotoxins were separated by thin-layer chromatography (TLC) and quantified using densitometry.Forty-three samples of different cereals (wheat, maize, rye and Triticale) were analyzed. Twenty-five of the 43 samples (58.14% of the total number) were found to be contaminated with different mycotoxins in various concentrations: aflatoxin B1 (1.6–5.7 µg/kg), aflatoxin B2 (0.89–4 µg/kg), aflatoxin G1 (1.2–5.76 µg/kg), aflatoxin G2 (0.96–3.4 µg/kg) and/or 4.3–30 µg/kg ochratoxin A. The concentration of total aflatoxin contamination ranged from 11.2 to 10.8 µg/kg. Among the different cereals, the highest number of contaminated samples was found to be in the wheat samples (62.5%). The method outlined in this study has been adopted already by our laboratory for current analyses of mycotoxins. The results obtained using this method is in compliance with the strict regulatory guidelines developed both in Romania, as well as in the European Union.PRACTICAL APPLICATIONSThin-layer chromatography (TLC) is a rapid, inexpensive and convenient method that can be used routinely to screen for mycotoxins. This article describes the detailed procedures for the extraction, purification and quantification of aflatoxins and ochratoxin A, using TLC. Using this method one can identify concomitantly five different mycotoxins and by coupling it with densitometry a quantitative determination is also possible. Therefore, this could become a routine technique in regional laboratories responsible for checking agrifood safety.Thin-layer chromatography (TLC) is a rapid, inexpensive and convenient method that can be used routinely to screen for mycotoxins. This article describes the detailed procedures for the extraction, purification and quantification of aflatoxins and ochratoxin A, using TLC. Using this method one can identify concomitantly five different mycotoxins and by coupling it with densitometry a quantitative determination is also possible. Therefore, this could become a routine technique in regional laboratories responsible for checking agrifood safety.
We investigated the time-dependence of apoptotic events in EL4 cells by monitoring plasma membran... more We investigated the time-dependence of apoptotic events in EL4 cells by monitoring plasma membrane changes in correlation to DNA fragmentation and cell shrinkage. We applied three apoptosis inducers (staurosporine, tubericidine and X-rays) and we looked at various markers to follow the early-to-late apoptotic events: phospholipid translocation (identified through annexin V-fluorescein assay and propidium iodide), lipid package (via merocyanine assay), membrane fluidity and anisotropy (via fluorescent measurements), DNA fragmentation by the fluorescence-labeling test and cell size measurements. The different apoptotic inducers caused different reactions of the cells: staurosporine induced apoptosis most rapidly in a high number of cells, tubercidine triggered apoptosis only in the S phase cells, while X-rays caused a G2/M arrest and subsequently apoptosis. Loss of lipid asymmetry is promptly detectable after one hour of incubation time. The phosphatidylserine translocation, decrease of lipid package and anisotropy, and the increase of membrane fluidity appeared to be based on the same process of lipid asymmetry loss. Therefore, the DNA fragmentation and the cell shrinkage appear to be parallel and independent processes running on different time scales but which are kinetically inter-related. The results indicate different signal steps to apoptosis dependent on inducer characteristics but the kinetics of “early-to-late” apoptosis appears to be a fixed program.
The total content of phenolic compounds (TAP) in 29 different monocultivar olive oil samples from... more The total content of phenolic compounds (TAP) in 29 different monocultivar olive oil samples from France (Aglandau and Tanche) and Spain (Cornicabra, Picual, and Verdial) was assessed by the colorimetric Folin-Ciocalteu method. Also, individual phenolic compounds were determined and quantified by liquid chromatography coupled to mass spectrometry (LC-MS). The French olive oil samples had a lower TAP compared to Spanish samples. The quantity of individual phenolics was similar except for pinoresinol, which was lower in the French olive oil samples. TAP moderately correlated to the sum of quantified compounds (r ) 0.64 and p < 0.01) Partial least-squares (PLS) regression analysis emphasized the importance of hydroxytyrosol and the total amount of quantified phenolic compounds by LC-MS in the prediction of the total amount of phenolic compounds as determined by the Folin-Ciocalteu method. The amount of R-tocopherol was generally different among the cultivars (Tanche > Picual > Verdial > Aglandau > Cornicabra). Of all quantified phenolic compounds in French olive oil samples, only luteolin correlated well to the altitude of the olive orchards (r ) 0.76, p < 0.01).
1University of Agriculture Science and Veterinary Medicine, 3-5 Mãnãstur Str., 400372 Cluj-Napoca... more 1University of Agriculture Science and Veterinary Medicine, 3-5 Mãnãstur Str., 400372 Cluj-Napoca, Romania (e-mail: [email protected]) 2Technical University of Cluj-Napoca, 26-28 Baritiu Str., 400027 Cluj-Napoca, Romania,
Calendula officinalis L. is a medicinal plant that accumulates large amounts of carotenoids in it... more Calendula officinalis L. is a medicinal plant that accumulates large amounts of carotenoids in its inflorescences. The yellow-to-orange colour of inflorescences is mostly due to carotenoids and the shade is dependent on pigments content and profile.We investigated the carotenoid content and profile in four selected varieties of Calendula: Double Esterel Orange, Radio Extra Selected, Bonbon Abricot and Double Esterel Jaune. The total carotenoid content was evaluated spectrophotometrically and pigments were separated using chromatographic methods (CC, TLC, HPLC). An HPLC gradient system with a Nucleosil C 18 column and a Waters PDA detector was used for separation and identification of carotenoids. The carotenoid content was higher in orange varieties: 276 mg/100 g fresh flowers for Double Esterel Orange and 111 mg/100 g fresh flowers for Radio variety. All varieties contain the same pigments but there are significant differences for the ratio between individual pigments. Orange varieties contain higher amounts of hydrocarbons: 44.5% of total carotenoid in Double Esterel Orange; while yellow varieties contain mostly oxygenated derivatives: 97% of total carotenoids in Double Esterel Jaune. The main pigments identified were: flavoxanthin, lutein, rubixanthin, β-carotene, γ-carotene and lycopene. The cultivation of orange varieties is recommended especially when the pharmacological products for skin protection are envisaged.
The carotenoid and phenolic acid contents in fresh, stored and processed (blanched, frozen and bo... more The carotenoid and phenolic acid contents in fresh, stored and processed (blanched, frozen and boiled) spinach were comparatively determined by spectrophotometric and HPLC analyses. The major carotenoids identified after HPLC analysis in saponified samples were lutein (37-53 lg/kg), b-carotene (18-31 lg/kg), violaxanthin (9-23 lg/kg) and neoxanthin (10-22 lg/kg). These carotenoids were all affected by storage and/or heating. The content of carotenoids was best preserved after storage for one day at 4°C.
ABSTRACTThe kinetic patterns of pure soy lipoxygenase LOX-1 and crude or defatted soybean extract... more ABSTRACTThe kinetic patterns of pure soy lipoxygenase LOX-1 and crude or defatted soybean extracts containing LOX isoenzymes (LOX-1, LOX-2 and LOX-3) were studied by UV spectrometry at 234 and 280 nm, depending on their extraction and measurement conditions. Different pHs (from 6.0 to 9.0), corresponding to specific activation of LOX isoenzymes and the ratios of enzyme protein per substrate were used in order to evaluate the enzyme rates, as indicators of its affinity for substrate in different environments. The crude soy extract contained mainly LOX-1 activity (measured at 234 nm, at pH 9.0) and LOX-3, in an approximate ratio of 3:1. The LOX-2 activity was very low. The defatted extracts buffered at pH 6.8 and 7.1 showed a low LOX-1 and LOX 2 activity, but mostly LOX-3 activity (measured at 280 nm, at pH 7.1), with a mirror-type relation between the enzyme/substrate ratio and their enzymatic specific activity. The results suggest that defatting inhibits specifically the LOX-1 activity and indicate the possibility to modulate LOX activity by modifications of enzyme/substrate ratios and modifications of pH in the enzyme environment.The kinetic patterns of pure soy lipoxygenase LOX-1 and crude or defatted soybean extracts containing LOX isoenzymes (LOX-1, LOX-2 and LOX-3) were studied by UV spectrometry at 234 and 280 nm, depending on their extraction and measurement conditions. Different pHs (from 6.0 to 9.0), corresponding to specific activation of LOX isoenzymes and the ratios of enzyme protein per substrate were used in order to evaluate the enzyme rates, as indicators of its affinity for substrate in different environments. The crude soy extract contained mainly LOX-1 activity (measured at 234 nm, at pH 9.0) and LOX-3, in an approximate ratio of 3:1. The LOX-2 activity was very low. The defatted extracts buffered at pH 6.8 and 7.1 showed a low LOX-1 and LOX 2 activity, but mostly LOX-3 activity (measured at 280 nm, at pH 7.1), with a mirror-type relation between the enzyme/substrate ratio and their enzymatic specific activity. The results suggest that defatting inhibits specifically the LOX-1 activity and indicate the possibility to modulate LOX activity by modifications of enzyme/substrate ratios and modifications of pH in the enzyme environment.PRACTICAL APPLICATIONSBecause of the specific kinetic behaviors of the three different LOXs found in crude soy extracts involved in off-flavor generation, one can modulate the inhibition of these isoenzymes during soybean processing. Our experiments showed that pH variation could be a simple solution to inhibit the LOX isoenzymes, and therefore, the off-flavor generation.From the analytical point of view, the techniques described in this article are designed to be as simple as possible, and easy to use at large-scale level in food industry (food chain control). The idea is to minimize the number of separate chemical manipulations and, thereby, minimize errors.These studies can offer the background of further inhibition experiments in vitro using natural extracts. The LOX inhibition by natural antioxidants is related as well to pH and other factors influencing the enzyme's activity; this idea can be also valorized practically in the future.Because of the specific kinetic behaviors of the three different LOXs found in crude soy extracts involved in off-flavor generation, one can modulate the inhibition of these isoenzymes during soybean processing. Our experiments showed that pH variation could be a simple solution to inhibit the LOX isoenzymes, and therefore, the off-flavor generation.From the analytical point of view, the techniques described in this article are designed to be as simple as possible, and easy to use at large-scale level in food industry (food chain control). The idea is to minimize the number of separate chemical manipulations and, thereby, minimize errors.These studies can offer the background of further inhibition experiments in vitro using natural extracts. The LOX inhibition by natural antioxidants is related as well to pH and other factors influencing the enzyme's activity; this idea can be also valorized practically in the future.
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 1999
Incorporation of carotenoids into membranes is supposed to change their physical properties with ... more Incorporation of carotenoids into membranes is supposed to change their physical properties with consequences to signal transduction and membrane protein activities. Here the physical parameters membrane fluidity, micropolarity and anisotropy are considered ...
Pure 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine (DPPC) or mixed DPPC:1,2-dipalmitoyl phosphat... more Pure 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine (DPPC) or mixed DPPC:1,2-dipalmitoyl phosphatidyletanolamine (DPPE):1,2-dipalmitoyl diphosphatidylserine (DPPS) (17:5:3) liposomes were incorporated with 5 mol% dietary carotenoids (b-carotene, lutein and zeaxanthin) or with cholesterol (16 and 48 mol%) in the absence or presence of 15 mol% carotenoids, respectively. The carotenoid incorporation yields ranged from 0.42 in pure to 0.72 in mixed phospholipid liposomes. They decreased significantly, from 3 to 14%, in the corresponding cholesterol-doped liposomes, respectively. Highest incorporation yields were achieved by zeaxanthin and lutein in phospholipid liposomes while in cholesterol-containing liposomes, lutein was highest incorporated. The effects on membrane structure and dynamics were determined by differential scanning calorimetry, steady-state fluorescence and anisotropy measurements. Polar carotenoids and cholesterol cause similar, dose-dependent effects: ordering and rigidification revealed by broadening of the transition peak, and increase of anisotropy. Membrane hydrophobicity is determined by cholesterol content and carotenoid polarity. In cholesterol-doped liposomes, b-carotene is less incorporated than in cholesterol-free liposomes. Our observations suggest effects of carotenoids, even at much lower effective concentrations than cholesterol (8 to 80-fold), on membrane structure and dynamics. Although they are minor constituents of animal membranes, carotenoids may act as modulators of membrane phase transition, fluidity, polarity and permeability, and therefore, can influence the membrane physiology and pathology.
The oxidative potential of a polyphenolic grape seed extract, with the idea of using this extract... more The oxidative potential of a polyphenolic grape seed extract, with the idea of using this extract as a nutritive supplement, was evaluated. Data presented in this work provide in vitro (primary leukocyte culture) UV-Vis spectral evidence, indicating that quinones, as oxidation products, are involved in the modulation of the antioxidant/prooxidant balance at cellular level in the case of catechin-type compounds (pure catechin (CS) and polyphenolic extract (PE)), in the absence or presence of lipoxygenase (pure (LS) or in raw soybean extract (LE)) as oxidative stress inducers. The study shows, to some extent, the grape seed extract tested, considered as an antioxidant nutritive supplement, may have prooxidant activity as well, depending on the dose, duration of administration, and other dietary components. The UV-Vis analysis confirms that the antioxidant activity of this extract might be mediated by prooxidant quinones and oxidation products of the polyphenols from grape seeds.
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2000
The carotenoids beta-carotene (BC), lycopene (LYC), lutein (LUT), zeaxanthin (ZEA), canthaxanthin... more The carotenoids beta-carotene (BC), lycopene (LYC), lutein (LUT), zeaxanthin (ZEA), canthaxanthin (CTX) and astaxanthin (ASTA) have been incorporated into pig liver microsomes. Effective incorporation concentrations in the range of about 1-6 nmol/mg microsomal protein were obtained. A stability test at room temperature revealed that after 3 h BC and LYC had decayed totally whereas, gradually, CTX (46%), LUT (21%), ASTA (17%) and ZEA (5%) decayed. Biophysical parameters of the microsomal membrane were changed hardly by the incorporation of carotenoids. A small rigidification may occur. Membrane anisotropy seems to offer only a small tolerance for incorporation of carotenoids and seems to limit the achievable incorporation concentrations of the carotenoids into microsomes. Microsomes instead of liposomes should be preferred as a membrane model to study mutual effects of carotenoids and membrane dynamics.
The latest studies show that the active principles of tomatoes, sea buckthorn, and pumpkin oil ha... more The latest studies show that the active principles of tomatoes, sea buckthorn, and pumpkin oil have beneficial effects on prostate disease.The purpose of this study was to encapsulate the bioactive compounds of seabuckthorn juice, tomato juice and pumpkin oil, to obtain a functional product. Microencapsulation was performed using natural polymers such as sodium alginate to provide stability, bioavailability and bioactive compounds controlled release.The CaCl 2 gelation technique was used to obtain microcapsules with or without chitosan coatings like microspheres and mononuclear microcapsules. Bioactive compounds in microcapsules, microspheres, and ingredients were analyzed using UV-Vis and FT-IR analysis. Total polyphenols and total carotenoids concentration was between (40.90-283.75 mgGAE / 100 g sample;9.16-19.71 mg carotenoids/100g sample) in the case of the ingredients while total polyphenols and carotenoids content of microcapsules/microspheres was between (14.09-133.93mgGAE / ...
Liposomes and b-cyclodextrin (b-CD) have been used as carriers for the incorporation of three die... more Liposomes and b-cyclodextrin (b-CD) have been used as carriers for the incorporation of three dietary carotenoids (b-carotene (BC), lutein (LUT) and canthaxanthin (CTX)) into plasma, mitochondrial, microsomal and nuclear membrane fractions from pig liver cells or the retinal epithelial cell line D407. The uptake dynamics of the carotenoids from the carriers to the organelle membranes and their incorporation yield (IY) was followed by incubations at pH 7.4 for up to 3 h. The mean IYs saturated between 0.1 and 0.9 after 10 -30 min of incubation, depending on membrane characteristics (cholesterol to phospholipid ratio) and carotenoid specificity. Mitochondrial membranes (more fluid) favour the incorporation of BC (non-polar), while plasma membranes (more rigid) facilitate the incorporation of lutein, the most polar carotenoid. A high susceptibility of BC to degradation in the microsomal suspension was observed by parallel incubations with/without 2,6-di-t-butyl-p-cresol (BHT) as antioxidant additive. The b-CD carrier showed to be more effective for the incorporation of lutein while BC was incorporated equally into natural membranes either from liposomes or from cyclodextrins. The presence of cytosol in the incubation mixture had no significant effects on the carotenoid incorporations.
European Journal of Lipid Science and Technology, 2009
High-accuracy photopyroelectric measurements, in the thermal-wave-resonator-cavity configuration,... more High-accuracy photopyroelectric measurements, in the thermal-wave-resonator-cavity configuration, were performed in order to measure the thermal diffusivity of some vegetable oils. The high resolution (relative error ±0.5%) of the above method allows for the detection of small changes in the values of this dynamic thermal parameter. The accuracy of the results is mainly due to the possibility to precisely control the variation (30-nm step) of sample thickness, a proper selection of the range of the thickness scan (2 µm < Lm < 4 µm ˜ 5 µm), and an iterative procedure of data analysis. A correlation between thermal diffusivity and the fatty acid composition (obtained via gas chromatography) is suggested for some fresh (sunflower, hemp, flax, and soybean) oils and for hemp oil exposed to a microwave field: Thermal diffusivity appears to be determined by the overall content of polyunsaturated fatty acids.
ABSTRACTThe main focus of our study was to implement a rapid, inexpensive and reliable method tha... more ABSTRACTThe main focus of our study was to implement a rapid, inexpensive and reliable method that could be utilized to check the cereals for safety (i.e., screening for total aflatoxins, as well as individual B1, B2, G1, G2 aflatoxins and ochratoxin A). We developed a protocol by which we were able to isolate mycotoxins from cereals collected from different regions of Romania. After extraction in chloroform, the mycotoxins were separated by thin-layer chromatography (TLC) and quantified using densitometry.Forty-three samples of different cereals (wheat, maize, rye and Triticale) were analyzed. Twenty-five of the 43 samples (58.14% of the total number) were found to be contaminated with different mycotoxins in various concentrations: aflatoxin B1 (1.6–5.7 µg/kg), aflatoxin B2 (0.89–4 µg/kg), aflatoxin G1 (1.2–5.76 µg/kg), aflatoxin G2 (0.96–3.4 µg/kg) and/or 4.3–30 µg/kg ochratoxin A. The concentration of total aflatoxin contamination ranged from 11.2 to 10.8 µg/kg. Among the different cereals, the highest number of contaminated samples was found to be in the wheat samples (62.5%). The method outlined in this study has been adopted already by our laboratory for current analyses of mycotoxins. The results obtained using this method is in compliance with the strict regulatory guidelines developed both in Romania, as well as in the European Union.The main focus of our study was to implement a rapid, inexpensive and reliable method that could be utilized to check the cereals for safety (i.e., screening for total aflatoxins, as well as individual B1, B2, G1, G2 aflatoxins and ochratoxin A). We developed a protocol by which we were able to isolate mycotoxins from cereals collected from different regions of Romania. After extraction in chloroform, the mycotoxins were separated by thin-layer chromatography (TLC) and quantified using densitometry.Forty-three samples of different cereals (wheat, maize, rye and Triticale) were analyzed. Twenty-five of the 43 samples (58.14% of the total number) were found to be contaminated with different mycotoxins in various concentrations: aflatoxin B1 (1.6–5.7 µg/kg), aflatoxin B2 (0.89–4 µg/kg), aflatoxin G1 (1.2–5.76 µg/kg), aflatoxin G2 (0.96–3.4 µg/kg) and/or 4.3–30 µg/kg ochratoxin A. The concentration of total aflatoxin contamination ranged from 11.2 to 10.8 µg/kg. Among the different cereals, the highest number of contaminated samples was found to be in the wheat samples (62.5%). The method outlined in this study has been adopted already by our laboratory for current analyses of mycotoxins. The results obtained using this method is in compliance with the strict regulatory guidelines developed both in Romania, as well as in the European Union.PRACTICAL APPLICATIONSThin-layer chromatography (TLC) is a rapid, inexpensive and convenient method that can be used routinely to screen for mycotoxins. This article describes the detailed procedures for the extraction, purification and quantification of aflatoxins and ochratoxin A, using TLC. Using this method one can identify concomitantly five different mycotoxins and by coupling it with densitometry a quantitative determination is also possible. Therefore, this could become a routine technique in regional laboratories responsible for checking agrifood safety.Thin-layer chromatography (TLC) is a rapid, inexpensive and convenient method that can be used routinely to screen for mycotoxins. This article describes the detailed procedures for the extraction, purification and quantification of aflatoxins and ochratoxin A, using TLC. Using this method one can identify concomitantly five different mycotoxins and by coupling it with densitometry a quantitative determination is also possible. Therefore, this could become a routine technique in regional laboratories responsible for checking agrifood safety.
We investigated the time-dependence of apoptotic events in EL4 cells by monitoring plasma membran... more We investigated the time-dependence of apoptotic events in EL4 cells by monitoring plasma membrane changes in correlation to DNA fragmentation and cell shrinkage. We applied three apoptosis inducers (staurosporine, tubericidine and X-rays) and we looked at various markers to follow the early-to-late apoptotic events: phospholipid translocation (identified through annexin V-fluorescein assay and propidium iodide), lipid package (via merocyanine assay), membrane fluidity and anisotropy (via fluorescent measurements), DNA fragmentation by the fluorescence-labeling test and cell size measurements. The different apoptotic inducers caused different reactions of the cells: staurosporine induced apoptosis most rapidly in a high number of cells, tubercidine triggered apoptosis only in the S phase cells, while X-rays caused a G2/M arrest and subsequently apoptosis. Loss of lipid asymmetry is promptly detectable after one hour of incubation time. The phosphatidylserine translocation, decrease of lipid package and anisotropy, and the increase of membrane fluidity appeared to be based on the same process of lipid asymmetry loss. Therefore, the DNA fragmentation and the cell shrinkage appear to be parallel and independent processes running on different time scales but which are kinetically inter-related. The results indicate different signal steps to apoptosis dependent on inducer characteristics but the kinetics of “early-to-late” apoptosis appears to be a fixed program.
The total content of phenolic compounds (TAP) in 29 different monocultivar olive oil samples from... more The total content of phenolic compounds (TAP) in 29 different monocultivar olive oil samples from France (Aglandau and Tanche) and Spain (Cornicabra, Picual, and Verdial) was assessed by the colorimetric Folin-Ciocalteu method. Also, individual phenolic compounds were determined and quantified by liquid chromatography coupled to mass spectrometry (LC-MS). The French olive oil samples had a lower TAP compared to Spanish samples. The quantity of individual phenolics was similar except for pinoresinol, which was lower in the French olive oil samples. TAP moderately correlated to the sum of quantified compounds (r ) 0.64 and p < 0.01) Partial least-squares (PLS) regression analysis emphasized the importance of hydroxytyrosol and the total amount of quantified phenolic compounds by LC-MS in the prediction of the total amount of phenolic compounds as determined by the Folin-Ciocalteu method. The amount of R-tocopherol was generally different among the cultivars (Tanche > Picual > Verdial > Aglandau > Cornicabra). Of all quantified phenolic compounds in French olive oil samples, only luteolin correlated well to the altitude of the olive orchards (r ) 0.76, p < 0.01).
1University of Agriculture Science and Veterinary Medicine, 3-5 Mãnãstur Str., 400372 Cluj-Napoca... more 1University of Agriculture Science and Veterinary Medicine, 3-5 Mãnãstur Str., 400372 Cluj-Napoca, Romania (e-mail: [email protected]) 2Technical University of Cluj-Napoca, 26-28 Baritiu Str., 400027 Cluj-Napoca, Romania,
Calendula officinalis L. is a medicinal plant that accumulates large amounts of carotenoids in it... more Calendula officinalis L. is a medicinal plant that accumulates large amounts of carotenoids in its inflorescences. The yellow-to-orange colour of inflorescences is mostly due to carotenoids and the shade is dependent on pigments content and profile.We investigated the carotenoid content and profile in four selected varieties of Calendula: Double Esterel Orange, Radio Extra Selected, Bonbon Abricot and Double Esterel Jaune. The total carotenoid content was evaluated spectrophotometrically and pigments were separated using chromatographic methods (CC, TLC, HPLC). An HPLC gradient system with a Nucleosil C 18 column and a Waters PDA detector was used for separation and identification of carotenoids. The carotenoid content was higher in orange varieties: 276 mg/100 g fresh flowers for Double Esterel Orange and 111 mg/100 g fresh flowers for Radio variety. All varieties contain the same pigments but there are significant differences for the ratio between individual pigments. Orange varieties contain higher amounts of hydrocarbons: 44.5% of total carotenoid in Double Esterel Orange; while yellow varieties contain mostly oxygenated derivatives: 97% of total carotenoids in Double Esterel Jaune. The main pigments identified were: flavoxanthin, lutein, rubixanthin, β-carotene, γ-carotene and lycopene. The cultivation of orange varieties is recommended especially when the pharmacological products for skin protection are envisaged.
The carotenoid and phenolic acid contents in fresh, stored and processed (blanched, frozen and bo... more The carotenoid and phenolic acid contents in fresh, stored and processed (blanched, frozen and boiled) spinach were comparatively determined by spectrophotometric and HPLC analyses. The major carotenoids identified after HPLC analysis in saponified samples were lutein (37-53 lg/kg), b-carotene (18-31 lg/kg), violaxanthin (9-23 lg/kg) and neoxanthin (10-22 lg/kg). These carotenoids were all affected by storage and/or heating. The content of carotenoids was best preserved after storage for one day at 4°C.
ABSTRACTThe kinetic patterns of pure soy lipoxygenase LOX-1 and crude or defatted soybean extract... more ABSTRACTThe kinetic patterns of pure soy lipoxygenase LOX-1 and crude or defatted soybean extracts containing LOX isoenzymes (LOX-1, LOX-2 and LOX-3) were studied by UV spectrometry at 234 and 280 nm, depending on their extraction and measurement conditions. Different pHs (from 6.0 to 9.0), corresponding to specific activation of LOX isoenzymes and the ratios of enzyme protein per substrate were used in order to evaluate the enzyme rates, as indicators of its affinity for substrate in different environments. The crude soy extract contained mainly LOX-1 activity (measured at 234 nm, at pH 9.0) and LOX-3, in an approximate ratio of 3:1. The LOX-2 activity was very low. The defatted extracts buffered at pH 6.8 and 7.1 showed a low LOX-1 and LOX 2 activity, but mostly LOX-3 activity (measured at 280 nm, at pH 7.1), with a mirror-type relation between the enzyme/substrate ratio and their enzymatic specific activity. The results suggest that defatting inhibits specifically the LOX-1 activity and indicate the possibility to modulate LOX activity by modifications of enzyme/substrate ratios and modifications of pH in the enzyme environment.The kinetic patterns of pure soy lipoxygenase LOX-1 and crude or defatted soybean extracts containing LOX isoenzymes (LOX-1, LOX-2 and LOX-3) were studied by UV spectrometry at 234 and 280 nm, depending on their extraction and measurement conditions. Different pHs (from 6.0 to 9.0), corresponding to specific activation of LOX isoenzymes and the ratios of enzyme protein per substrate were used in order to evaluate the enzyme rates, as indicators of its affinity for substrate in different environments. The crude soy extract contained mainly LOX-1 activity (measured at 234 nm, at pH 9.0) and LOX-3, in an approximate ratio of 3:1. The LOX-2 activity was very low. The defatted extracts buffered at pH 6.8 and 7.1 showed a low LOX-1 and LOX 2 activity, but mostly LOX-3 activity (measured at 280 nm, at pH 7.1), with a mirror-type relation between the enzyme/substrate ratio and their enzymatic specific activity. The results suggest that defatting inhibits specifically the LOX-1 activity and indicate the possibility to modulate LOX activity by modifications of enzyme/substrate ratios and modifications of pH in the enzyme environment.PRACTICAL APPLICATIONSBecause of the specific kinetic behaviors of the three different LOXs found in crude soy extracts involved in off-flavor generation, one can modulate the inhibition of these isoenzymes during soybean processing. Our experiments showed that pH variation could be a simple solution to inhibit the LOX isoenzymes, and therefore, the off-flavor generation.From the analytical point of view, the techniques described in this article are designed to be as simple as possible, and easy to use at large-scale level in food industry (food chain control). The idea is to minimize the number of separate chemical manipulations and, thereby, minimize errors.These studies can offer the background of further inhibition experiments in vitro using natural extracts. The LOX inhibition by natural antioxidants is related as well to pH and other factors influencing the enzyme's activity; this idea can be also valorized practically in the future.Because of the specific kinetic behaviors of the three different LOXs found in crude soy extracts involved in off-flavor generation, one can modulate the inhibition of these isoenzymes during soybean processing. Our experiments showed that pH variation could be a simple solution to inhibit the LOX isoenzymes, and therefore, the off-flavor generation.From the analytical point of view, the techniques described in this article are designed to be as simple as possible, and easy to use at large-scale level in food industry (food chain control). The idea is to minimize the number of separate chemical manipulations and, thereby, minimize errors.These studies can offer the background of further inhibition experiments in vitro using natural extracts. The LOX inhibition by natural antioxidants is related as well to pH and other factors influencing the enzyme's activity; this idea can be also valorized practically in the future.
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 1999
Incorporation of carotenoids into membranes is supposed to change their physical properties with ... more Incorporation of carotenoids into membranes is supposed to change their physical properties with consequences to signal transduction and membrane protein activities. Here the physical parameters membrane fluidity, micropolarity and anisotropy are considered ...
Pure 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine (DPPC) or mixed DPPC:1,2-dipalmitoyl phosphat... more Pure 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine (DPPC) or mixed DPPC:1,2-dipalmitoyl phosphatidyletanolamine (DPPE):1,2-dipalmitoyl diphosphatidylserine (DPPS) (17:5:3) liposomes were incorporated with 5 mol% dietary carotenoids (b-carotene, lutein and zeaxanthin) or with cholesterol (16 and 48 mol%) in the absence or presence of 15 mol% carotenoids, respectively. The carotenoid incorporation yields ranged from 0.42 in pure to 0.72 in mixed phospholipid liposomes. They decreased significantly, from 3 to 14%, in the corresponding cholesterol-doped liposomes, respectively. Highest incorporation yields were achieved by zeaxanthin and lutein in phospholipid liposomes while in cholesterol-containing liposomes, lutein was highest incorporated. The effects on membrane structure and dynamics were determined by differential scanning calorimetry, steady-state fluorescence and anisotropy measurements. Polar carotenoids and cholesterol cause similar, dose-dependent effects: ordering and rigidification revealed by broadening of the transition peak, and increase of anisotropy. Membrane hydrophobicity is determined by cholesterol content and carotenoid polarity. In cholesterol-doped liposomes, b-carotene is less incorporated than in cholesterol-free liposomes. Our observations suggest effects of carotenoids, even at much lower effective concentrations than cholesterol (8 to 80-fold), on membrane structure and dynamics. Although they are minor constituents of animal membranes, carotenoids may act as modulators of membrane phase transition, fluidity, polarity and permeability, and therefore, can influence the membrane physiology and pathology.
The oxidative potential of a polyphenolic grape seed extract, with the idea of using this extract... more The oxidative potential of a polyphenolic grape seed extract, with the idea of using this extract as a nutritive supplement, was evaluated. Data presented in this work provide in vitro (primary leukocyte culture) UV-Vis spectral evidence, indicating that quinones, as oxidation products, are involved in the modulation of the antioxidant/prooxidant balance at cellular level in the case of catechin-type compounds (pure catechin (CS) and polyphenolic extract (PE)), in the absence or presence of lipoxygenase (pure (LS) or in raw soybean extract (LE)) as oxidative stress inducers. The study shows, to some extent, the grape seed extract tested, considered as an antioxidant nutritive supplement, may have prooxidant activity as well, depending on the dose, duration of administration, and other dietary components. The UV-Vis analysis confirms that the antioxidant activity of this extract might be mediated by prooxidant quinones and oxidation products of the polyphenols from grape seeds.
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2000
The carotenoids beta-carotene (BC), lycopene (LYC), lutein (LUT), zeaxanthin (ZEA), canthaxanthin... more The carotenoids beta-carotene (BC), lycopene (LYC), lutein (LUT), zeaxanthin (ZEA), canthaxanthin (CTX) and astaxanthin (ASTA) have been incorporated into pig liver microsomes. Effective incorporation concentrations in the range of about 1-6 nmol/mg microsomal protein were obtained. A stability test at room temperature revealed that after 3 h BC and LYC had decayed totally whereas, gradually, CTX (46%), LUT (21%), ASTA (17%) and ZEA (5%) decayed. Biophysical parameters of the microsomal membrane were changed hardly by the incorporation of carotenoids. A small rigidification may occur. Membrane anisotropy seems to offer only a small tolerance for incorporation of carotenoids and seems to limit the achievable incorporation concentrations of the carotenoids into microsomes. Microsomes instead of liposomes should be preferred as a membrane model to study mutual effects of carotenoids and membrane dynamics.
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Papers by Carmen Socaciu