Constituent analysis and quality control of anthocyanin constituents of dried Lycium ruthenicum Murray fruits by HPLC–MS and HPLC–DAD

In recent years, many investigations on the anthocyanins of the fresh Lycium ruthenicum Murray fruits have been reported; while few studies about dried fruits have been published. In this study, chemical profile of dried fruits was illustrated by a high-performance liquid chromatography–tandem mass spectrometry method, which provided evidence for the certain identification of the main anthocyanins. Among these compounds, nine of them were selected as marker compounds for the semiquantitative evaluation, using a simple and reliable method by high-performance liquid chromatography–photodiode array detection (HPLC–DAD), with the combination of chromatographic fingerprint analysis. Separation was achieved on a C18 ODS 80TS QA analytical column with linear gradient elution of acetonitrile and 10% formic acid and 0.1% trifluoroacetic acid (TFA) aqueous solution. Our results showed that the contents of anthocyanins of dried L. ruthenicum Murray from different origins were different. We also inferred the anthocyanin compositions of dried L. ruthenicum Murray through analyzing the UV spectrum, retention time, elution order, and MS data. Finally, eight kinds of anthocyanin compositions were identified and different from the anthocyanins in fresh L. ruthenicum Murray. In a word, this study may provide experimental data in further development and utilization of L. ruthenicum Murray.     

Development and validation of a capillary zone electrophoresis method for the quantitative determination of anthocyanins in wine

A capillary zone electrophoresis (CZE) method is proposed for the quantitative determination of anthocyanins in wine as an alternative to high-performance liquid chromatography. The CZE separation was carried out using a 46 cm (effective length)×75 μm I.D. fused-silica capillary at 10 °C and a 50 mM sodium tetraborate buffer at pH 8.4 with 15% of methanol as modifier. A voltage of 25 kV and a hydrodynamic injection of 300 mbar s were used. The electropherograms were recorded at 599 nm. It was found that SO₂ (antibacterial and antioxidant agent added to wine during its production) increased the absorbance of anthocyanins at 599 nm in a basic medium. Therefore, a concentration of 250 mg/l of SO₂ was added to the samples and the calibration solution before the analysis in order to avoid errors by this matrix effect. The analytical response was linear (R=0.998) between 10 and 700 μg/ml of malvidin-3-O-glucoside. The limit of detection and the reproducibility (as a relative standard deviation, n=11) were 1 μg/ml and 1.5%, respectively. Finally, the CZE method was validated by the analysis of synthetic wine samples (errors less than 8%) and by the comparison of the results obtained in the analysis of different monovarietal wines by CZE with those obtained by the standard HPLC method. In this comparison, a good correlation (R=0.998) with a slope of 1.005±0.044 and an intercept of −0.752±6.690 was obtained for malvidin-3-O-glucoside.     

Anthocyanins profile as fingerprint of wines using atmospheric pressure photoionisation coupled to quadrupole time-of-flight mass spectrometry

Present work shows for the first time the suitability of the atmospheric pressure photoionisation (APPI) coupled to quadrupole time-of-flight mass spectrometry (QqTOF) to characterise anthocyanins in wines. Results obtained are satisfactorily compared with the electrospray ionisation (ESI-MS) that has also been used. Parameters concerning the direct infusion-APPI-MS have been studied and optimised to generate information-rich mass spectra for wine fingerprinting.The proposed analytical methodology has been used to obtain a classification rule for unknown samples according to their anthocyanins profiles. In addition, the procedure shows high sample throughput since the time consuming sample treatment required for the extraction of anthocyanins from wines has been drastically reduced in this fingerprint-targeted approach.     

High resolution LC-MS characterization of phenolic compounds and the evaluation of antioxidant properties of a tropical purple radish genotype

This study reports qualitative profiling of the phenolic compounds in an indigenously developed purple radish genotype VRRAD-151 using ultra performance liquid chromatography with quadrupole time of flight mass spectrometry. The root and leaf samples were harvested at the horticultural maturity stage of the genotype. Roots were divided into the periderm, and xylem, and the leaf samples were divided into petiole, and lamina, and these were separately extracted with methanol before the LC-MS analysis. A total of 66 compounds, including 23 flavonols, 1 dihydroflavonols, 4 flavonones, 4 flavones, 28 anthocyanins, 2 isoflavonoids, 3 phenolic acids, and 1 hydroxybenzaldehyde were putatively identified based on high resolution accurate mass analysis with the data processing through UNIFI®, which is a comprehensive compound identification software solution. An in-house developed database comprising the secondary metabolites of polyphenols was used for the screening purpose, and each phenolic compound was identified based on the detection of the precursor ion, and at least one characteristic fragment ion, each with less than 5 ppm of mass error. Anthocyanins were the most abundant type of phenolics exhibiting 59% in leaf petiole, 80% in root periderm, and 90% in root xylem. The relative concentration of anthocyanins was lower (11%) in the leaf lamina. Cyanidins were the most predominant anthocyanins accounting for 54, 100, 90 and 65%, in leaf lamina, leaf petiole, root periderm and root xylem, respectively. Eight anthocyanins and 25 flavonols (except kaempferol-3-O-p-coumaryl-shophoroside-7-O-glucoside) are tentatively new identifications and reported for the first time in radish. Flavonols were found to be the predominant group of phenolic compounds in the leaf lamina, and interestingly, the gradient of antioxidant activity followed the (relative) concentration gradient of flavonols in the samples. The relative antioxidant activity of various fractions when compared with each other, followed the trend: leaf lamina > root periderm > leaf petiole ≈ root xylem. Based on the results it can be reflected that this genotype can be utilized as a functional food for management of various human and animal diseases. Since the detected anthocyanins were mostly present in acylated forms, this genotype can function as a potential source of stable natural colorants.     

Wild strawberry (Arbutus unedo): Phytochemical screening and antioxidant properties of fruits collected in northern Morocco

The aim of this study was to determine the polyphenolic compounds and the antioxidant ability of Arbutus unedo fruits, collected from three regions of northern Morocco, using high-performance liquid chromatography coupled to diode array and electrospray ionization mass spectrometry detection. The proper extraction method has been selected to achieve this objective. After delipidation, the three harvests were extracted by sonication using two solvents with increased polarity ethyl acetate and MeOH:water, 80:20 (v/v). Total polyphenols, flavonoids, tannins and anthocyanins were respectively: 108.41 ± 9.29 mg GAE/g (w/w) dry weight (DW), 101.07 ± 5.6 mg QE/g (w/w) (DW), 0.45 ± 0.48 mg EC/g (w/w) (DW) and 0.35 ± 0.48 mg Pg-3-glu/g (w/w) (DW). EC50 values for reducing power and DPPH radical scavenging activities were between 1.37 ± 0.2 and 17.82 ± 0.12 µg/mL (w/v). A total of 75 compounds were tentatively identified and some of these had never been found until nowadays in Arbutus unedo. The average amount of antioxidant compounds obtained by semi-quantitative analyses was 120.35 ± 32.05 mg/100 g (w/w) (DW). The attained results clearly highlight the potential of A. unedo as a source of healthy compounds, which could be advantageously added to the daily diet, making it a potential candidate for the cure for many emerging diseases.     

亲水相互作用色谱-串联质谱法快速测定葡萄酒中四种花青素

采用亲水相互作用色谱-串联质谱法(HILIC-MS/MS)建立同时测定葡萄酒中矢车菊素-3-O-葡萄糖苷、氯化葡萄糖苷芍药素、飞燕草素葡萄糖苷和氯化锦葵色素-3-O-葡糖苷4种花青素的分析方法。葡萄酒样品用甲醇直接稀释后,采用Merck ZIC HILIC色谱柱(150×2.1mm,3.5μm)分离;以乙腈-20mmol/L乙酸铵溶液作为流动相,梯度洗脱,目标化合物在多反应监测(MRM)模式下进行检测,外标法定量。在优化的条件下,4种花青素在1.0~50.0ng/mL范围内呈良好的线性关系,相关系数均不低于0.9992,方法定量限为0.05~1.0ng/mL。方法平均回收率为93.1%~96.7%,相对标准偏差不大于5.2%。该方法前处理简单、选择性好、灵敏度高,非常适用于葡萄酒中花青素的测定。