A novel method has been established for the rapid separation and determination of free fatty acids from 37 different varieties of raspberry. In this study, a new fluorescent labeling reagent for fatty acids, 2-(4-amino)-phenyl-1-hydrogen-phenanthrene [9, 10-d] imidazole (PIA), has been synthesized and successfully applied to the high-performance liquid chromatography (HPLC) determination of fatty acids in raspberry. The novel method has been optimized by HPLC with fluorescence detection and online mass spectrometry identification (HPLC-FLD-MS/MS). The 22 main fatty acids (FAs) present in raspberry were derivatized by PIA and separated on a reversed-phase Hypersil GOLD column with gradient elution. The main experimental parameters affecting extraction efficiency and derivatization yield were investigated and optimized by response surface methodology (RSM) combined with Box-Behnken design (BBD). Under the optimum conditions, the method was successfully applied for the analysis of 22 fatty acids in 37 different varieties of raspberry. Good linear correlations were observed for all fatty acids with correlation coefficients of > 0.9978. Limits of detection and quantification (LOD and LOQ) were in the range of 0.12 to 0.49 ng/mL and 1.07 to 2.81 ng/mL, respectively. Furthermore, the results indicated that the raspberries were rich in fatty acids, but the contents of the fatty acids varied among the different varieties.
A new labeling reagent, 1-(2-naphthyl)-3-methyl-5-pyrazolone (NMP), coupling with liquid chromatography (LC) with electrospray ionization mass spectrometry (ESI-MS) for the detection of carbohydrates from a famous Tibetan medicine is reported. Carbohydrates were derivatized to their bis-NMP-labeled derivatives. The method, in conjunction with a gradient elution, offered a baseline resolution of carbohydrate derivatives on a reversed phase Hypersil ODS-2 column. The carbohydrates such as mannose, galacturonic acid, glucuronic acid, rhamnose, glucose, galactose, xylose, arabinose, and fucose could be successfully detected by UV and ESI-MS. Derivatives showed intense protonated molecular ion at m/z [M + H]+ in positive ion mode. The mass to charge ratios of characteristic fragment ions at m/z 473.0 could be used for the accurately qualitative identification of carbohydrates; this characteristic fragment ion was from the cleavage of C2-C3 bond in the carbohydrate chain giving the specific fragment ions at m/z [MH-CmH2m+1Om-H2O]+ for pentose, hexose, and glyceraldehydes, and at m/z [MH-CmH2m-1Om+1-H2O]+ for alduronic acids, such as galacturonic acid and glucuronic acid (m = n - 2, n is carbon atom number of carbohydrate). Compared with the traditional 1-phenyl-3-methyl-5-pyrazolone (PMP) reagent, currently synthesized NMP show the advantage of higher sensitivity to carbohydrate compounds with UV and ESI-MS detection.
Graphical abstract Highlights • Five anthocyanidins are identified in Lycium ruthenicum Murray by UPLC-Q-Orbitrap MS. • Five anthocyanins are identified in Lycium ruthenicum Murray by UPLC-Q-Orbitrap MS. • Anthocyanin extracts hanve the activity of anti-gout. • Petunidin-3-glu has the activity of anti-gout. Abstract Lycium ruthenicum Murray (LR) represents an agricultural cash crop found in Northwest China and has been used in traditional folk medicine for a long time. However, detailed qualitative and quantitative analyses of LR anthocyanins, as well as their pharmacological research, remain scarce. In this work, we established a rapid method for the simultaneous identification and quantification of six anthocyanidins and six anthocyanins from LR via UPLC-quadrupole-Orbitrap mass spectrometry (UPLC-Q-Orbitrap MS) analysis. Finally, five anthocyanidins and five anthocyanins were qualitatively and quantitatively analyzed. Among these, 10 constituents (delphinidin-3-glu, cyanidin-3-glu, petunidin-3-glu, peonidin-3-glu, malvidin-3-glu, delphinidin, cyanidin, petunidin, pelargonidin and malvidin) were detected and petunidin-3-glu proved to be the predominant species in LR. Furthermore, the anti-inflammatory effects of anthocyanin extracts and petunidin-3-glu were investigated using a rat model involving gouty arthritis induced by monosodium urate. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-18 (IL-18), prostaglandin E2 (PE2), cyclooxygenase-1 (COX-1) enzymes in serum, the paw COX-1 mRNA expression and paw volume could be determined to be significantly increased in rats suffering from gouty arthritis induced by monosodium urate. However, these indicators were found to be significantly reduced after treatment with anthocyanin extracts (200 mg/kg b.wt, p.o.) and petunidin-3-glu (40 mg/kg b.wt, p.o.). Taken in concert, our study shows that anthocyanin extracts and petunidin-3-glu may significantly reduce monosodium urate crystal-induced inflammation. Use and administration of these compounds may be potentially valuable for the further development and clinical applicability of the active compounds in this plant.
Lycium ruthenicum Murr. (LR) is a perennial shrub commonly used as a nutritional food and medicine. Herein, we identified 12 anthocyanins from LR, with petunidin derivatives constituting approximately 97% of the total anthocyanin content. Furthermore, the potential mechanism of anthocyanins exerting neuroprotective effects in d-galactose (d-gal)-treated rats was explored. Behavioral results showed that anthocyanins relieved d-gal-induced memory disorder. Additionally, anthocyanins reduced receptor for advanced glycation end products (RAGE) and suppressed oxidative stress caused by d-gal. Anthocyanins suppressed microgliosis and astrocytosis and reduced the overexpression of nuclear factor kappa B (NF-κB), interleukin-1-β (IL-1β), cyclooxygenase-2 (COX-2), and tumor necrosis factor-α (TNF-α). Moreover, anthocyanins lowered C-jun N-terminal kinase ( p-JNK), caspase-3 levels, and the B-cell lymphoma 2-associated X protein/B-cell lymphoma 2 (Bax/Bcl-2) ratio. Thus, anthocyanins from LR attenuated memory disfunction, neuroinflammation, and neurodegeneration caused by d-gal, possibly through the RAGE/NF-κB/JNK pathway, representing a promising, safe candidate for prevention and therapy of neurodegenerative diseases.
A method that involved the combination of pH-zone-refining counter-current chromatography and semipreparative reversed-phase liquid chromatography has been established for the preparative separation of alkaloids from Hypecoum leptocarpum. From 1.2 g of crude sample, 31 mg N-feruloyltyramine, 27 mg oxohydrastinine, 47 mg hydroprotopine, 25 mg leptopidine, and 18 mg hypecocarpine have been obtained. The structure of the new compound, hypecocarpine, is confirmed based on the analysis of spectroscopic data, including NMR, UV, and IR spectroscopy and positive electrospray ionization mass spectrometry. The known chemical structures were characterized on the basis of (1) H and (13) C NMR spectroscopy. The purities of the five alkaloids are all over 92.7% as determined by high-performance liquid chromatography. The alkaloids' cytotoxicity in breast cancer cells is assessed by using a Cell Counting Kit assay and their inhibitory effect on fatty acid synthase expression is assessed by a Western blot assay. These results suggest that leptopidine could suppress growth and induce cytotoxicity in breast cancer cells and that the cytotoxicity of leptopidine may be related to its inhibitory effect on fatty acid synthase expression.
A novel hyphenated method based on ultrasound-assisted dispersive liquid-liquid microextraction coupled to precolumn derivatization has been established for the simultaneous determination of bisphenol A, 4-octylphenol, and 4-nonylphenol by high-performance liquid chromatography with fluorescence detection. Different parameters that influence microextraction and derivatization have been optimized. The quantitative linear range of analytes is 5.0-400.0 ng/L, and the correlation coefficients are more than 0.9998. Limits of detection for soft drinks and dairy products have been obtained in the range of 0.5-1.2 ng/kg and 0.01-0.04 μg/kg, respectively. Relative standard deviations of intra- and inter-day precision for retention time and peak area are in the range of 0.47-2.31 and 2.76-8.79%, respectively. Accuracy is satisfactory in the range of 81.5-118.7%. Relative standard deviations of repeatability are in the range of 0.35-1.43 and 2.36-4.75% for retention time and peak area, respectively. Enrichment factors for bisphenol A, 4-octylphenol, and 4-nonylphenol are 170.5, 240.3, and 283.2, respectively. The results of recovery and matrix effect are in the range of 82.7-114.9 and 92.0-109.0%, respectively. The proposed method has been applied to the determination of bisphenol A, 4-octylphenol, and 4-nonylphenol in soft drinks and dairy products with much higher sensitivity than many other methods.
Abstract This presented study describes a method based on high performance liquid chromatography combined with fluorescence detection (HPLC-FLD) using N-(2-iodoacetyl)-1-pyrenemethylamine (NIPA) as a novel fluorescence labeling reagent for the determination of thyreostats in bovine milk. Five thyreostats, belonging to the group of imidazole and thiouracil, were investigated in this work: tapazole (TAP), thiouracil (TU), methylthiouracil (MTU), propylthiouracil (PTU) and phenylthiouracial (PhTU). Thyreostats were specifically purified by a silver ion solid phase extraction (Ag-SPE) cartridge and then labeled using NIPA. The labeled derivatives showed excellent fluorescence property with maximum excitation and emission wavelengths of 330 nm and 375 nm, respectively. The labeled derivatives were separated on a reversed-phase Eclipse SB-C18 column within 12 min. Excellent linearity (R2 > 0.995) of all thyreostats was achieved with the limits of detection (LODs) and the limits of quantitation (LOQs) in the low micrograms per liter range of 0.21–0.30 μg/L and 0.70–1.00 μg/L, respectively. Satisfactory recoveries in the range of 93.5–98.0% were obtained for all thyreostats. The developed method has been successfully applied to analyze thyreostats in bovine milk with good applicability. Thirty bovine milk samples have been investigated, and varying levels of thiouracil were detected in thirteen of these samples. The highest level in the raw milk reached a value of 4.5 μg/L. To our best knowledge, this study is the first to report the presence of naturally occurring thiouracil in milk by HPLC-FLD analysis. Highlights • A pre-column derivatization HPLC-FLD method was developed for the determination of thyreostats in milk samples. • LOD was in the low micrograms per liter range of 0.21–0.30 μg·L−1. • The proposed method was successfully applied to the determination of thyreostats in milk sample. • This study is the first to report the presence of naturally occurring thiouracil in milk by HPLC-FLD analysis.
In this work, we have developed an efficient method for the rapid extraction and separation of triterpene acids from 37 different varieties of raspberry via ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME). The triterpene acids were then determined by high-performance liquid chromatography (HPLC) with fluorescence detection using benzimidazo-[2,1-b]quinazolin-12(6H)-one-5-ethyl-p-toluenesulfonate (BQETS) as the labeling agent. Five triterpene acids, including asiatic acid (AA), maslinic acid (MA), corosolic acid (CA), oleanolic acid (OA) and betulinic acid (BA), were extracted by UA-DLLME using chloroform and acetone as the extracting and dispersing solvents, respectively. After extraction and nitrogen flushing, the extracts were simultaneously characterized by HPLC based on pre-column derivatization using BQETS, a new labeling agent synthesized in our laboratory. Several key parameters affecting the extraction efficiency and derivatization yields were investigated and optimized by response surface methodology (RSM) combined with Box-Behnken design (BBD). The method was further validated for linearity (correlation coefficient <i>R</i> <sup>2</sup> > 0.9979), precision (RSD = 0.23-2.45 %), and recovery (RSD = 90-106.5 %). The limits of detection (LODs) and the limits of quantification (LOQs) were determined to be within the range of 1.83-7.69 µg/L and 6.06-25.47 µg/L, respectively. This is the first report of the use of BQETS as a pre-column derivatization agent for the determination of triterpene acids in real samples. The proposed method has been applied to the determination of five triterpene acids in 37 different raspberry varieties with significantly increased sensitivity compared to other methods. The results obtained indicate that the contents of triterpene acids vary significantly across different raspberry varieties.
A novel hyphenated technique based on ultrasonic-assisted dispersive liquid-liquid microextraction (UA-DLLME) coupled with derivatization has been established for the determination of brassinolide (BL, a representative of brassinosteroids) by HPLC fluorescence detection. 9-Phenanthreneboronic acid is used as labeling reagent of BL. UA-DLLME parameters containing type and volume of extraction and disperser solvent, pH and ultrasonication time are optimized. Derivatization parameters are optimized included amount of 9-phenanthreneboronic acid, volume ratio of pyridine, derivatization time and temperature. Under optimal conditions, quantitative linear range of BL is 50-1,000 ng L<sup>−1</sup> and excellent linear response is observed with correlation coefficient of 0.9996. Limit of detection and limit of quantification are calculated as 8.0 and 25.0 ng L<sup>−1</sup>, respectively. RSDs of retention time and peak area are in the range of 0.68-0.97 % and 4.61-6.54 % for intra-day precision, 1.32-1.94 % and 7.28-9.75 % for inter-day precision, respectively. Accuracy is satisfactory in the range of 82.3-125.1 %. RSDs’ values of repeatability are in the range of 0.82-1.79 and 3.95-8.53 % for retention time and peak area, respectively. Enrichment factor for BL is 189. The results of recovery and matrix effect are in the range of 82.0-108.6 and 90.0-115.3 %, respectively. The proposed method has been applied for the determination of BL in <i>Arabidopsis thaliana</i>, <i>Daucus carota</i> and <i>Brassica campestris</i> L. leaves with much higher sensitivity than many other methods.
Naturally occurring oligostilbenes are receiving more attention because they exhibit several beneficial effects for health, including hepatoprotective, antitumor, anti-adipogenic, antioxidant, antiaging, anti-inflammatory, anti-microbial, antiviral, immunosuppressive and neuroprotective activities. Thus, they could be of some potentially therapeutic values for several diseases. In this study, we adopted the alkaline extraction-acid precipitation (AEAP) method for extraction of oligostilbenes from the seed kernel of Iris lactea Then, the high-speed counter-current chromatography (HSCCC) was used for preparative isolation and purification of oligostilbenes from the AEAP extracts. Finally, three oligostilbenes, namely vitisin D (73 mg), ampelopsin B (25 mg) and cis-vitisin A (16 mg), were successfully fractionated by HSCCC with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (2:5:3:6, v/v/v/v) from 300 mg of the AEAP extracts in ∼ 190 min. The purities of the three isolated oligostilbenes were all over 95.0% as analyzed by high performance liquid chromatography. They all were isolated from I. lacteal for the first time.The method of AEAP for the preparation of the oligostilbene-enriched crude sample was simple, and the HSCCC technique for the isolation and purification of oligostilbenes was efficient.
Glucose carbon with uniform diameter was successfully anchored by TiO<sub>2</sub> nanoparticles via a facile low-temperature hydrothermal process independent of surfactants or external forces. The resultant TiO<sub>2</sub>@glucose carbon composite (TiO<sub>2</sub>@GCs) was characterized by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The elimination of direct deep blue (DDB) from aqueous solution by adsorption onto TiO<sub>2</sub>@GCs was investigated in the up-flow fixed-bed columns. The effects of the influent concentration (10-30 mg L<sup>−1</sup>), flow rate (3-5 mL min<sup>−1</sup>), bed depth (1.0-2.0 cm) and pH (1.0-9.0) were investigated. Breakthrough time and adsorption capacity of the fixed-bed increased with increasing bed depth, whereas decreased with the increase in initial concentration, bed depth and solution pH values. The experimental data was in good agreement with both Thomas model and Yoon-Nelson model. The employed bed saturated with DDB was readily regenerated through a simple regeneration process with UV irradiation for 1 h. Furthermore, the adsorption-regeneration process was conducted for six cycles and no major decrease of regeneration efficiency was observed for the first three cycles. One possible mechanism for regenerating dye-loaded TiO<sub>2</sub>@GCs was proposed. The verifying experiment found that hydroxyl radicals and superoxide ions significantly affected the regeneration of employed TiO<sub>2</sub>@GCs bed.
<i>Potentilla parvifolia </i>Fisch. (Rosaceae) is a traditional medicinal plant in P. R. China. In this study, seven flavonoids, ayanin (<b>1</b>), tricin (<b>2</b>), quercetin (<b>3</b>), tiliroside (<b>4</b>), miquelianin (<b>5</b>), isoquercitrin (<b>6</b>), and astragalin (<b>7</b>), were separated and purified from ethyl acetate extractive fractions from ethanol extracts of <i>P. parvifolia</i> using a combination of sevaral chromatographic methods. The human neuroblastoma SH-SY5Y cells were differentiated with all trans-retinoic acid and treated with okadaic acid to induce tau protein phosphorylation and synaptic atrophy, which could establish an Alzheimer's disease cell model. The neuroprotective effects of these flavonoids in cellular were evaluated <i>in vitro</i> by this cell model. Results from the Western blot and morphology analysis suggested that compounds <b>3</b> and <b>4</b> had the better neuroprotective effects.
Fatty acids in Herpetospermum seed oil from supercritical CO2 extraction were analyzed by HPLC fluorescence detection (HPLC-FLD) with pre-column derivatization and GC-MS. After derivatizing 39 kinds of saturated and unsaturated fatty acids used 1-[ 2- ( p-toluenesulfonate ) ethyl]-2-phenylimidazole [ 4,5-f] 9,10-phenanthrene ( TSPP ) as pre-column derivatization reagent. All the fatty acid derivatives were separated with a good baseline resolution in conjunction with a gradient elution. The external standard method for the simultaneous quantitative determination of 39 fatty acids was developed and applied for the determination of the free fatty acid contents in Herpetospermum seed oil samples obtained from supercritical CO2 extraction coupled with orthogonal tests, ultrasound-assisted extraction and microwave-assisted reflux extraction. The mass percent of oleic acid, linoleic acid and linolenic acid and the ratio of unsaturated fatty acids and all fatty acids in 9 orthogonal test samples were contrasted. The results indicated that the mass percent of oleic acid, linoleic acid and linolenic acid in Herpetospermum seed oil are up to 34.65% ( 147. 14 mg/g), 22.85% (97.03 mg/g), 20. 86% ( 88. 56 rag/g), respectively, and ratio of unsaturated fatty acids and all fatty acids is 79%. Furthermore, by GC-MS method, the acid catalysis and alkaline catalysis of the methyl esterifying reaction were discussed for the analysis fatty acids in Herpetospermum seed oil, and the optimum GC-MS conditions were obtained. Simultaneously, the characteristics of HPLC and GC-MS methods were discussed about analyzing fatty acids.
<p>A simple and sensitive method for the determination of free fatty acids (FFAs) using acridoné9́ethyĺṕtoluenesulfonate (AETS) as a fluorescence derivatization reagent by high performance liquid chromatography (HPLC) has been developed. Free fatty acid derivatives were separated on an Eclipse XDB́C<sub>8</sub> column with a good baseline resolution and detected with the fluorescence of which excitation and emission wavelengths of derivatives were set at <sub>ex</sub>=404 and <sub>em</sub>=440 nm, respectively. Identification of 19 fatty acid derivatives was carried out by online post́column mass spectrometry with an atmospheric pressure chemical ionization (APCI) source under positivéion detection mode. Nineteen FFAs from the extract of <i>Lomatogonium rotatum</i> are sensitively determined. The results indicate that the plant <i>Lomatogonium rotatum</i> is enriched with an abundance of FFAs and FFAs of higher contents, which mainly focus on even carbon atoms, C<sub>14</sub>, C<sub>16</sub>, and C<sub>18</sub>. The validation of the method including linearity, repeatability, and detection limits was examined. Most linear correlation coefficients for fatty acid derivatives are >0.9989, and detection limits (at signaĺtónoise of 3:1) are 12.3-43.7 fmol. The relative standard deviations (RSDs) of the peak areas and retention times for 19 FFAs standards are <2.24% and 0.45%, respectively. The established method is rapid and reproducible for the separation determination of FFAs from the extract of <i>Lomatogonium rotatum</i> with satisfactory results.</p>
• HPLC-DAD-APCI/MS was set up for analysis of flavonoid aglycones in the RBP. • The method is capable of providing higher sensitivity and repeatability. • Four methods were applied and assessed for extraction of flavonoids from RBP. • The highest extraction efficiency of flavonoids from RBP was achieved by MAE. • MAE is of short extraction time, low solvent consumption and homogeneous conditions.<br>For identification and quantification of flavonoid aglycones in rape bee pollen (RBP) collected from the Qinghai-Tibetan Plateau, a high-performance liquid chromatography (HPLC) separation method with diode array detector (DAD) and atmospheric pressure chemical ionization/mass spectrometric (APCI/MS) detection and four extraction methods (i.e. microwave-assisted extraction, Soxhlet extraction, cold-soaked extraction, and heat reflux extraction) were developed in this study. The identification of flavonoid aglycones was based on retention time and mass spectra by comparison with standards. Results demonstrated that this method showed excellent reproducibility and correlation coefficient, and offered the detection limits of 0.77-15.50 pmol at signal-to-noise ratio of 3. Quercetin and kaempferol were presented in RBP, and microwave-assisted extraction (MAE) was superior to the other three methods in terms of efficiency, convenience and high content of quercetin (1.37 ± 0.059 mg/g) and kaempferol (23.44 ± 0.544 mg/g). Our work indicated that: 1) the proposed HPLC-DAD-APCI/MS was an accurate and precise analysis method to identify and quantify the flavonoid aglycones in RBP; and 2) MAE was efficient to extract flavonoids from RBP with short extraction time, low solvent consumption, and homogeneous extraction conditions.
To alleviate the adverse effects of pesticide residues on the environment, development of a more safe, economical, and reliable usage approach of pesticides is critically urgent. In the present study, a novel pesticide carrier LA-NSM (lauric acid-modified Nitraria seed meal) with controlled release property was prepared through grafting esterification of lauric acid onto Nitraria seed meal substrates. The structure of the obtained samples was characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and contact angle measurements. The results indicated that LA-NSM products had a well-defined hydrophobic surface and irregular holes for efficient loading of pesticide molecules. Deltamethrin (DEL), a representative insoluble pyrethroid insecticide in water, was deliberately selected as the index pesticide to evaluate the loading and releasing efficiency of LA-NSM. The loading capacity of LA-NSM for DEL can reach about 1068 mg/g. pH, humidity of soil, and temperature had a significant influence on controlled release performance of LA-NSM@DEL. Moreover, the releasing kinetics of LA-NSM@DEL composites could be fitted well with the Higuchi model. Overall, the highly hydrophobic property, excellent loading, and controlled release ability of LA-NSM made it a promising candidate in agricultural applications. [ABSTRACT FROM AUTHOR]