Improvement of performance for flexible film dosimeter by incorporating additive agents.

Objective.To evaluate the reduction in energy dependence and aging effect of the lithium salt of pentacosa-10,-12-diynoic acid (LiPCDA) films with additives including aluminum oxide (Al2O3), propyl gallate (PG), and disodium ethylenediaminetetracetate (EDTA).Approach. LiPCDA films exhibited energy dependence on kilovoltage (kV) and megavoltage (MV) photon energies and experienced deterioration over time. Evaluations were conducted with added Al2O3and antioxidants to mitigate these issues, and films were produced with and without Al2O3to assess energy dependence. The films were irradiated at doses of 0, 3, 6, and 12 cGy at photon energies of 75 kV, 105 kV, 6 MV, 10 MV, and 15 MV. For the energy range of 75 kV to 15 MV, the mean and standard deviation (std) were calculated and compared for the values normalized to the net optical density (netOD) at 6 MV, corresponding to identical dose levels. To evaluate the aging effect, PG and disodium EDTA were incorporated into the films: sample C with 1% PG, sample D with 2% PG, sample E with 0.62% disodium EDTA added to sample D, and sample F with 1.23% disodium EDTA added to sample D.Main results. Films containing Al2O3demonstrated a maximum 15.8% increase in mean normalized values and a 15.1% reduction in std, reflecting a greater netOD reduction at kV than MV energies, which indicates less energy dependence in these films. When the OD of sample 1-4 depending on the addition of PG and disodium EDTA, was observed for 20 weeks, the transmission mode decreased by 8.7%, 8.3%, 29.3%, and 27.3%, respectively, while the reflection mode was 5.4%, 3.0%, 37.0%, and 34.5%, respectively.Significance. Al2O3effectively reduced the voltage and MV energy dependence. PG was more effective than disodium EDTA in preventing the deterioration of film performance owing to the aging effect.

Preparation and structural characterization of epoxidized soybean oils-based pressure sensitive adhesive grafted with tea polyphenol palmitate.

Vegetable oils-based pressure sensitive adhesives (PSAs) are green and sustainable but face unsatisfactory adhesion strengths and are prone to aging during storage and application due to the existence of residual double bonds and massive ester bonds. Nine common antioxidants (tea polyphenol palmitate (TPP), caffeic acid, ferulic acid, gallic acid, butylated hydroxytoluene, tertiary butylhydroquinone, butylated hydroxyanisole, propyl gallate, and tea polyphenols) were grafted into epoxidized soybean oils-PSA (ESO-PSA) system to enhance antiaging properties and adhesion strengths. Results showed ESO-PSAs grafted with caffeic acid, tertiary butylhydroquinone, butylated hydroxyanisole, propyl gallate, tea polyphenols, or TPP didn't occur failure with TPP having best performance. The optimal conditions were ESO reacted with 0.9 % TPP, 70 % rosin ester, and 7.0 % phosphoric acid at 50 °C for 5 min, under which peel strength and loop tack increased to 2.460 N/cm and 1.66 N, respectively, but peel strength residue reduced to 138.09 %, compared with control (0.407 N/cm, 0.43 N, and 1669.99 %). Differential scanning calorimetry and thermogravimetric results showed TPP grafting increased the glass transition temperature of ESO-PSA slightly but improved its thermal stability significantly. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance results showed TPP, phosphoric acid, and rosin ester all partially participated in the covalently crosslinking polymerization of ESO-PSAs and the rest existed in the network structures in the free form.

Investigation of the pectin grafting with gallic acid and propyl gallate and their antioxidant activities, antibacterial activities and fresh keeping performance.

In this paper, a method for the enzymatic modification of pectin, in which gallic acid (GA) and propyl gallate (PG) were grafted onto pectin molecules in an aqueous/organic two-phase system catalyzed by lipase, was proposed. The potential reaction mechanism was explored through UV-Vis, FTIR and 1H NMR spectroscopic methods and density functional theory. Results suggested that the lipase played a dual role during the modification by catalyzing the hydrolysis of methyl ester bonds of pectin in the aqueous phase and the esterification between the 4-OH of GA and PG and the -COOH of pectin in the organic phase. Moreover, the effects of GA and PG on the antioxidant and the antibacterial activities of pectin were evaluated, and results showed that the antioxidant and the antibacterial activities of modified pectin were better than those of native pectin. The effect of modified pectin on the quality of fresh bass (Lateolabrax maculatus) was further studied. Results suggested that, compared to control group, the total viable count, histamine level, malondialdehyde content and acid value of bass fillets treated with modified pectin were significantly reduced, whereas the sensory score was significantly increased.

Protein Cohabitation: Improving the Photochemical Stability of R-Phycoerythrin in the Solid State.

The poor photochemical stability of R-phycoerythrin (R-PE) has been a bottleneck for its broad-spectrum applications. Inspired by nature, we studied a sustainable strategy of protein cohabitation to enhance R-PE stability by embedding it in a solid matrix of gelatin. Both pure R-PE and fresh phycobiliprotein (PBP) extracts recovered from Gracilaria gracilis were studied. The incorporation of R-PE in the gelatin-based films (gelatin-RPE and gelatin-PBPs) has improved its photochemical stability for at least 8 months, the longest time period reported so far. These results were evidenced by not only absorption but also emission quantum yield measurements (Φ). Moreover, the photostability of gelatin-RPE films upon continuous excitation with an AM1.5G solar simulator was tested and found to remain stable for 23 h after initial decreasing up to 250 min. In the end, another approach was established to allow 100% photostability for a 3 h exposure to an AM1.5G solar simulator by doping the gelatin-based film including R-Phycoerythrin with n-propyl gallate stabilized with Tween 80, allowing their use as naturally based optically active centers in photovoltaic applications.

Adsorption of gallic acid, propyl gallate and polyphenols from Bryophyllum extracts on activated carbon.

The adsorption of gallic acid (GA) and propyl gallate (PG) on activated carbon (AC) was studied as a function of the AC mass and temperature. Clean first order behavior was obtained for at least three half-lives and the equilibrium was reached after ∼4 h contact time. An increase in the temperature (T = 20-40 °C) increases their adsorption rate constant values (k1) by 2.5 fold but has a negligible effect on the amount of antioxidant adsorbed per mass of AC at equilibrium. We also analyzed the adsorption process of polyphenols from Bryophyllum extracts and ca 100% of the total amount of the polyphenols in the extract were adsorbed when using 7 mg of AC. Results can be explained on the basis of the Freundlich isotherm but do not fit the Langmuir model. Results suggest that the combination of emerging in vitro plant culture technologies with adsorption on activated carbon can be successfully employed to remove important amounts of bioactive compounds from plant extracts by employing effective, sustainable and environmental friendly procedures.

Dietary antioxidants as a source of hydrogen peroxide.

Studies of 54 antioxidants revealed that 27 of them, mainly polyphenols, generated hydrogen peroxide (H2O2) when added to Dulbecco's modified Eagle's medium (DMEM), other media used for culture of mammalian and yeast cells and phosphate-buffered saline. The most active antioxidants were: propyl gallate (PG), (-)-epigallocatechin gallate (EGCG) and quercetin (Q). Chelex treatment and iron chelators decreased H2O2 generation suggesting that transition metal ions catalyze antioxidant autoxidation and H2O2 production. Green tea also generated H2O2; tea prepared on tap water generated significantly more H2O2 than tea prepared on deionized water. Ascorbic acid decreased H2O2 production although it generated H2O2 itself, in the absence of other additives. Lemon added to the tea significantly reduced generation of H2O2. Hydrogen peroxide generated in the medium contributed to the cytotoxicity of PG, EGCG and Q to human prostate carcinoma DU-145 cells, since catalase increased the survival of the cells subjected to these compounds in vitro.

Determination of the antioxidant propyl gallate in meat by using a screen-printed electrode modified with CoSe2 nanoparticles and reduced graphene oxide.

A voltammetric sensor is described for the quantitation of propyl gallate (PG). A screen-printed carbon electrode (SPCE) was modified with reduced graphene sheets that were decorated with cobalt diselenide nanoparticles (CoSe2@rGO). The material was hydrothermally prepared and characterized by several spectroscopic techniques. The modified SPCE displays excellent electrocatalytic ability towards PG. Differential pulse voltammetry, with a peak voltage at 0.34 V (vs. Ag/AgCl) has a sensitivity of 12.84 µA·µM-1·cm-2 and a detection limit as low as 16 nM. The method is reproducible, selective, and practical. This method was applied to the determination of PG in spiked meat samples, and the result showed an adequate recovery. Graphical abstract Schematic of a new method for fast and sensitive electrochemical determination of the food additive propyl gallate in meat.

Method validation and measurement uncertainty for the simultaneous determination of synthetic phenolic antioxidants in edible oils commonly consumed in Korea.

This study investigated a method for the validation and determination of measurement uncertainty for the simultaneous determination of synthetic phenolic antioxidants (SPAs) such as propyl gallate (PG), octyl gallate (OG), dodecyl gallate (DG), 2,4,5-trihydroxy butyrophenone (THBP), tert-butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) in edible oils commonly consumed in Korea. The validated method was able to extract SPA residues under the optimized HPLC-UV and LC-MS/MS conditions. Furthermore, the measurement of uncertainty was evaluated based on the precision study. For HPLC-UV analysis, the recoveries of SPAs ranged from 91.4% to 115.9% with relative standard deviations between 0.3% and 11.4%. In addition, the expanded uncertainties of the SPAs ranged from 0.15 to 5.91. These results indicate that the validated method is appropriate for the extraction and determination of SPAs and can be used to verify the safety of edible oil products containing SPAs residues.

Effect of the structure of gallic acid and its derivatives on their interaction with plant ferritin.

Gallic acid and its derivatives co-exist with protein components in foodstuffs, but there is few report on their interaction with proteins. On the other hand, plant ferritin represents not only a novel class of iron supplement, but also a new nanocarrier for encapsulation of bioactive nutrients. However, plant ferritin is easy to be degraded by pepsin in the stomach, thereby limiting its application. Herein, we investigated the interaction of gallic acid and its derivatives with recombinant soybean seed H-2 ferritin (rH-2). We found that these phenolic acids interacted with rH-2 in a structure-dependent manner; namely, gallic acid (GA), methyl gallate (MEGA) and propyl gallate (PG) having three HO groups can bind to rH-2, while their analogues with two HO groups cannot. Consequently, such binding largely inhibited ferritin degradation by pepsin. These findings advance our understanding of the relationship between the structure and function of phenolic acids.

Protective effect of propyl gallate against oxidized low-density lipoprotein-induced injury of endothelial cells.

OBJECTIVE: To evaluate the protective effect of propyl gallate (PG), an alkyl ester of gallic acid which is an active ingredient of Radix Paeoniae, against oxidized low-density lipoprotein (ox-LDL)-induced apoptosis and death in endothelial cells (ECs) and to find out its preliminary mechanism. METHODS: The cultured endothelial cells were divided into normal, model (ox-LDL), control (fetal bovine serum), PG high dose (20 µg/mL), PG middle dose (10 µg/mL), and PG low dose (5 µg/mL) groups, each derived from three different pools of umbilical cords. The model of injured human umbilical vein endothelial cells (HUVECs) was induced by ox-LDL. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, Hoechst 33258 staining, flow cytometry and measurement of nitrogen monoxidum (NO) release were used to evaluate the protective effect of PG against ox-LDL-induced apoptosis and death in HUVECs. To find out the mechanism of this protective effect, the expression of endothelial nitric oxide synthase (eNOS) mRNA, eNOS protein expression, immunofluorescence of intracellular reactive oxygen species (ROS) and activities of malondialdehyde (MDA), superoxidedismutase (SOD) and glutathione peroxidase (GPx) were observed. RESULTS: PG significantly reduced ox-LDL-induced apoptosis and cell death. The percentage of cells death and apoptosis was significantly higher in the ox-LDL group than that in the control group (P<0.05). Compared with the control group, the cells death and apoptosis of PG group was no different (P>0.05). As compared with the ox-LDL group, results of the PG high dose group showed that cell viability was significantly increased (P<0.05), the level of NO release, expression of eNOS mRNA, densitometric value of eNOS protein expression, as well as the activities of SOD and GPx were all significantly higher (all P<0.05). CONCLUSION: PG could potentially serve as a novel endothelial protective agent against ox-LDL-induced injury of endothelial cell.

Effects of a dietary antioxidant blend and vitamin E on fatty acid profile, liver function, and inflammatory response in broiler chickens fed a diet high in oxidants.

The aim of the current study was to determine the effects of a dietary antioxidant blend and vitamin E on fatty acid profile, inflammatory response, and liver function. Cobb 500 male broilers (n = 1,200, d 0) were randomly distributed into 6 treatments with 10 replicate floor pens. Treatments included (1) a high-oxidant diet, with vitamin E at 10 IU/kg, 3% oxidized oil, 3% polyunsaturated fatty acids (PUFA) source (HO); (2) the HO diet with vitamin E at 200 IU/kg (VE); (3) the HO diet with an antioxidant blend at 135 mg/kg (AOX); (4) the HO diet with both vitamin E at 200 IU/kg and an antioxidant blend at 135 mg/kg (VE+AOX); (5) standard control (SC); and (6) a positive control, which was the SC diet with an antioxidant blend at 135 mg/kg. The concentrations of 20:4, 20:5, 22:5, 22:6, and all the n-3 fatty acids were greater in the abdominal fat of HO, VE, AOX, and VE+AOX birds than SC and positive control birds on d 21 and 42 (P < 0.001). Compared with HO treatment, AOX and VE+AOX preserved the deposition of PUFA better (P < 0.001). The HO birds had greater concentrations of aspartate aminotransferase on d 21 and 42, and γ-glutamyl transferase on d 21, whereas AOX and VE+AOX chickens had restored γ-glutamyl transferase concentration (P < 0.01). The inflammation scores of abdominal fat of AOX and VE+AOX birds were lower than the HO on d 21 (P < 0.001). Compared with SC, the VE and VE+AOX birds exhibited greater vacuole scores on d 21 and 42 (P < 0.01). The lower vacuoles score in SC was associated with a greater expression of peroxisome proliferator activated receptor -γ and -α (P < 0.05). The expression of inflammatory genes in the liver did not differ among treatments. In conclusion, the AOX and AOX+VE diets were effective in preserving PUFA in the abdominal fat, moderately improved liver function, and reduced inflammation in fat.

Effects of a dietary antioxidant blend and vitamin E on growth performance, oxidative status, and meat quality in broiler chickens fed a diet high in oxidants.

The aim of the study was to determine the effects of a dietary antioxidant blend (AB) and vitamin E on performance, oxidative status, and meat quality. Cobb 500 male broilers (n = 1,200, d 0) were randomly distributed into 6 treatments with 10 replicate pens. Treatments included 1) HO: high oxidant diet, vitamin E at 10 IU/kg, 3% oxidized soybean oil, 3% polyunsaturated fatty acid (PUFA) source; 2) VE: the HO diet with vitamin E at 200 IU/kg; 3) AOX: the HO diet with AB at 135 mg/kg; 4) VE+AOX: the HO diet with vitamin E at 200 IU/kg and AB at 135 mg/kg; 5) SC: standard control; and 6) PC: positive control, the SC diet with AB at 135 mg/kg. From d 0 through d 21, high oxidant diet treatment birds had greater BW, ADG, and ADFI than the SC birds; the AOX birds had better G:F on d 10 and 42, and from d 0 to 42 than SC birds (P < 0.05). The plasma TBA reactive substance level was lower in the AOX birds than the VE treatment birds in all phases (P < 0.05). High oxidant diet treatment birds had greater α-1-acid glycoprotein levels on d 10 than SC and PC birds (P < 0.05). The AOX, PC, and SC birds had a greater level of uric acid than the HO and VE+AOX birds on d 10. Superoxide dismutase expression in the liver was less with the HO treatment compared with the SC treatment on d 7 (P < 0.05). The vitamin E concentration in the breast muscle was greatest in the VE birds, whereas vitamin A concentration was greater in the PC birds compared with the SC birds on d 21 (P < 0.05). Compared with VE and AOX, the HO treatment had greater drip loss (P < 0.05). In conclusion, dietary addition of AOX was effective in improving growth, moderately restored the whole body antioxidant capability, and reduced drip loss.

Sensitized chemiluminescence of 2-phenyl-4,5-di(2-furyl)-1H-imidazole/K3Fe(CN)6/propyl gallate system combining with solid-phase extraction for the determination of propyl gallate in edible oil.

In this paper, a novel chemiluminescence (CL) method has been developed for the determination of propyl gallate (PG). The proposed method was based on the enhancing effect of PG on the CL signal of 2-phenyl-4,5-di(2-furyl)-1H-imidazole (PDFI) and K3Fe(CN)6 reaction in an alkaline solution. Under the optimum conditions, the enhanced CL intensity was linearly related to the concentration of PG. The linear range of the calibration curve was 0.05-8 µg/mL, and the corresponding detection limit (3σ) was 0.036 µg/mL. The relative standard deviation for determining 1.0 µg/mL PG was 2.8% (n=11). The proposed method has been successfully applied to the determination of PG in edible oil. The edible oil samples were prepared by the solid-phase extraction (SPE) with a C18 column served as the stationary phase. Furthermore, the possible CL mechanism was also discussed briefly based on the photoluminescence (PL) and CL spectra.

Effects of emulsifier hydrophile-lipophile balance and emulsifier concentration on the distributions of gallic acid, propyl gallate, and α-tocopherol in corn oil emulsions.

We evaluated the effects of the hydrophile-lipophile balance (HLB) and emulsifier concentration on the distribution of the antioxidants gallic acid (GA), propyl gallate (PG), and α-tocopherol (TOC) between the aqueous, interfacial, and oil regions of food-grade emulsions composed of stripped corn oil, acidic water, and a mixture of the non-ionic surfactants Tween 20, 40, 80, and Span 20. The distribution of the antioxidants (AOs) is described by two partition constants, that between the oil-interfacial region, P(O)(I), and that between the aqueous and interfacial region, P(W)(I), of the emulsions. The partition constants were determined from the kinetic analyses of the variation in the observed rate constant, k(obs), for the reaction between the AOs and the hydrophobic 4-hexadecylbenzenediazonium ions, 16-ArN(2)(+), with the emulsifier volume fraction. The effects of emulsifier HLB on the second-order rate constants in the interfacial region k(I) were also evaluated for each antioxidant. Results show that an increase in emulsifier concentration promotes the incorporation of AOs to the interfacial region of the emulsions, so that at surfactant volume fractions of 0.04, more than 90% of GA and PG and more than 50% of TOC are located in that region. A decrease in the HLB favors the incorporation of PG and TOC to the interfacial region of the emulsions but has a negligible effect on the fraction of GA in that region. The %AOs in the interfacial region of the emulsions does not correlate with the polarity of the antioxidant, so that GA and PG are predominantly located in the aqueous-interfacial regions of the emulsion rather that in the oil droplet interior; meanwhile, TOC is mostly located in the oil-interfacial regions. Results should aid to understand how antioxidants are distributed in food-grade emulsions and their relative efficiency in inhibiting lipid oxidation.

Differential role of ethylene and hydrogen peroxide in dark-induced stomatal closure.

Regulation of stomatal aperture is crucial in terrestrial plants for controlling water loss and gaseous exchange with environment. While much is known of signaling for stomatal opening induced by blue light and the role of hormones, little is known about the regulation of stomatal closing in darkness. The present study was aimed to verify their role in stomatal regulation in darkness. Epidermal peelings from the leaves of Commelina benghalensis were incubated in a defined medium in darkness for 1 h followed by a 1 h incubation in different test solutions [H2O2, propyl gallate, ethrel (ethylene), AgNO3, sodium orthovanadate, tetraethyl ammonium chloride, CaCl2, LaCl3, separately and in combination] before stomatal apertures were measured under the microscope. In the dark stomata remained closed under treatments with ethylene and propyl gallate but opened widely in the presence of H2O2 and AgNO3. The opening effect was largely unaffected by supplementing the treatment with Na-vanadate (PM H+ ATPase inhibitor) and tetraethyl ammonium chloride (K(+)-channel inhibitor) except that opening was significantly inhibited by the latter in presence of H2O2. On the other hand, H2O2 could not override the closing effect of ethylene at any concentrations while a marginal opening of stomata was found when Ag NO3 treatment was given together with propyl gallate. CaCl2 treatment opened stomata in the darkness while LaCl3 maintained stomata closed. A combination of LaCl3 and propyl gallate strongly promoted stomatal opening. A probable action of ethylene in closing stomata of Commelina benghalensis in dark has been proposed.

[Metabolite profiling of propyl gallate in rat plasma and urine by HPLC-DAD-ESI-IT-TOF-MS(n) technique].

To make a clear understanding of the in vivo metabolism of propyl gallate in rats and determine the original compounds of the metabolites of Paeoniae Radix Rubra (PRR), the urine and plasma of the rats administrated with propyl gallate were collected, and then the HPLC-DAD-ESI-IT-TOF-MS(n) technique was applied to screen and identify the metabolites of propyl gallate from these bio-samples. By comparing the collected LC-MS data, the origin of the metabolites of PRR were confirmed. Finally, 33 metabolites of propyl gallate were identified from urine sample, and 20 metabolites of propyl gallate were identified from the plasma sample. In total, 37 metabolites of propyl gallate were identified, and 17 of them were identical to the metabolites of PRR. They are mainly the phase II metabolites of propyl gallate, 3-hydroxypropyl 3,4,5-trihydroxybenzoate, gallic acid and pyrogallol. Phase I reactions (decarboxylation, hydroxylation) and phase II reactions (sulfation, glucuronidation and methylation) were observed as the main metabolic pathways of propyl gallate. In this research, the in vivo metabolism of proply gallate was reported for the first time and 37 metabolites were identified, among which 35 were new metabolites of propyl gallate, and 20 were new compounds. The results demonstrated that 17 metabolites of PRR can be formed from propyl gallate. This will enhance our understanding of the metabolism and Effective forms (the truly active structures) of propyl gallate and PRR.

Metabolite profiling of propyl gallate in rat plasma and urine by HPLC-DAD-ESI-IT-TOF-MS(n) technique / 中国中药杂志

To make a clear understanding of the in vivo metabolism of propyl gallate in rats and determine the original compounds of the metabolites of Paeoniae Radix Rubra (PRR), the urine and plasma of the rats administrated with propyl gallate were collected, and then the HPLC-DAD-ESI-IT-TOF-MS(n) technique was applied to screen and identify the metabolites of propyl gallate from these bio-samples. By comparing the collected LC-MS data, the origin of the metabolites of PRR were confirmed. Finally, 33 metabolites of propyl gallate were identified from urine sample, and 20 metabolites of propyl gallate were identified from the plasma sample. In total, 37 metabolites of propyl gallate were identified, and 17 of them were identical to the metabolites of PRR. They are mainly the phase II metabolites of propyl gallate, 3-hydroxypropyl 3,4,5-trihydroxybenzoate, gallic acid and pyrogallol. Phase I reactions (decarboxylation, hydroxylation) and phase II reactions (sulfation, glucuronidation and methylation) were observed as the main metabolic pathways of propyl gallate. In this research, the in vivo metabolism of proply gallate was reported for the first time and 37 metabolites were identified, among which 35 were new metabolites of propyl gallate, and 20 were new compounds. The results demonstrated that 17 metabolites of PRR can be formed from propyl gallate. This will enhance our understanding of the metabolism and Effective forms (the truly active structures) of propyl gallate and PRR.

Utility of 4-chloro-7-nitrobenzofurazan for the spectrofluorimetric determination of butylated hydroxyanisole and propyl gallate in foodstuffs.

UNLABELLED: A spectrofluorimetric method is presented for the determination of 2 synthetic phenolic antioxidants (SPAs), butylated hydroxyanisole (BHA), and propyl gallate (PG) in foodstuffs. The proposed method is based on the derivatization of SPAs with 4-chloro-7-nitrobenzofurazan (NBD-Cl) in phosphate buffer of pH 9.0 to yield a highly fluorescent brown product. The optimum experimental conditions have been studied carefully. Linear calibration curves were obtained over the concentration range of 0.20 to 40 µg mL⁻¹ for BHA, and 0.80 to 50 µg mL⁻¹ for PG, using NBD-Cl reagent. The detection limits were 18 ng mL⁻¹ for BHA, 55 ng mL⁻¹ for PG. Intra-day and inter-day relative standard deviations at 3 different concentrations were determined. The high recovery values indicate the accuracy of the proposed methods, and low relative standard deviation values indicate good precision. The results presented in this report show that the applied spectrofluorimetric method is acceptable for the determination of the 2 SPAs in the foodstuffs. Other SPAs, tertiary butyl hydroquinone and butylated hydroxytoluene in foodstuffs do not interfere with the proposed method. PRACTICAL APPLICATIONS: In this spectrofluorimetric method, NBD-Cl as a derivation agent is used to detect synthetic phenolic antioxidants. The method specificity has been greatly improved; there was no interference from other commonly used phenolic substances.

A target analogue imprinted polymer for the recognition of antiplatelet active ingredients in Radix Salviae Miltiorrhizae by LC/MS/MS.

The purpose of this study was to prepare a propyl gallate (PrG) molecular imprinted polymer as a cartridge stuffing material to isolate antiplatelet active ingredients. A macroporous polymer was synthesized utilizing ethylene glycol dimethacrylate (EDMA) as the crosslinking agent, PrG as the template molecule and 4-vinylpyridine (4-Vpy) as the functional monomer. Subsequently, PrG was removed by washing with methanol-glacial acetic acid (9:1, v/v). The molecular imprinted polymer recognized an active ingredient, protocatechuic acid, from a crude extract of the Chinese herbal medicine, Radix Salviae Miltiorrhizae (Danshen), using an on-line column switching solid phase extraction process. Pharmacological experiments showed that protocatechuic acid inhibits arachidonic acid (10 mg/kg) induced aggregation of rat platelets in vivo. This study provides an example of an application of separation-analysis technique for screening potentially bioactive compounds.

Cloud-point extraction and reversed-phase high-performance liquid chromatography for the determination of synthetic phenolic antioxidants in edible oils.

A cloud-point extraction (CPE) method using Triton X-114 (TX-114) nonionic surfactant was developed for the extraction and preconcentration of propyl gallate (PG), tertiary butyl hydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) from edible oils. The optimum conditions of CPE were 2.5% (v/v) TX-114, 0.5% (w/v) NaCl and 40 min equilibration time at 50 °C. The surfactant-rich phase was then analyzed by reversed-phase high-performance liquid chromatography with ultraviolet detection at 280 nm, using a gradient mobile phase consisting of methanol and 1.5% (v/v) acetic acid. Under the studied conditions, 4 synthetic phenolic antioxidants (SPAs) were successfully separated within 24 min. The limits of detection (LOD) were 1.9 ng mL(-1) for PG, 11 ng mL(-1) for TBHQ, 2.3 ng mL(-1) for BHA, and 5.9 ng mL(-1) for BHT. Recoveries of the SPAs spiked into edible oil were in the range 81% to 88%. The CPE method was shown to be potentially useful for the preconcentration of the target analytes, with a preconcentration factor of 14. Moreover, the method is simple, has high sensitivity, consumes much less solvent than traditional methods, and is environment-friendly. Practical Application: The method established in this article uses less organic solvent to extract SPAs from edible oils; it is simple, highly sensitive and results in no pollution to the environment.