Authors:W. N. Zhou, J. Ouyang, Z. H. Wang, X. Y. Wang, Y. R. Suo, Z. Zhang, and H. L. Wang
Elsholtzia densa Benth. var. densa (Lamiaceae) is a famous medicinal herb which has been widely used for treatment of colds, headaches, pharyngitis, fever, diarrhea, digestion disorder, rheumatic arthritis, nephritises, and nyctalopia in China. In this study, fraction of the ethyl alcohol extract of E. densa (aerial part) by different polarity solvents indicated that the ethyl acetate soluble fraction exhibited a potent 1,1-diphenyl-2-picryhydrazyl (DPPH) radical scavenging activity with the IC50 value of 148.2 μg/mL. Under the target guidance of DPPH experiment, isoquercitrin, trachelogenin, ethyl caffeate, and arctigenin were separated with purities 95.98%, 92.98%, 96.07%, and 88.83%, respectively, by a dual-mode high-speed counter-current chromatography (HSCCC) method using n-hexane–ethyl acetate–methanol–water (4.5:5:3:4, v/v/v/v) as the solvent system. In order to evaluate the scientific basis, antioxidant activity of four isolated compounds was assessed by the radical scavenging effect on DPPH radical; isoquercitrin and ethyl caffeate showed stronger antioxidant activities with IC50 values of 9.4 μg/mL and 9.2 μg/mL, respectively, while trachelogenin and arctigenin showed weak antioxidant activities with IC50 values of >500 μg/mL and 72.8 μg/mL, respectively. Results of the present study indicated that the combinative method using DPPH antioxidant assay and dual-mode HSCCC could be widely applied for rapid screening and isolating of antioxidants from complex traditional Chinese medicine extract.
Authors:W. J. Duan, Q. Liu, R. X. Zhao, Y. Mu, L. P. Guo, D. P. Li, and X. Wang
A method was developed for the preparative separation of two alkaloids from the crude extract of the radix of Rauvolfia verticillata (Lour.) Baill. in a single run. The two-phase solvent system composed of petroleum ether–ethyl acetate–methanol–water (5:5:2:8, v/v), where triethylamine (40 mmol/L) was added to the upper organic phase as the stationary phase and hydrochloric acid (10 mmol/L) was added to the lower aqueous phase as the mobile phase, was selected for this separation by pH-zone-refining counter-current chromatography (PZRCCC). For the preparative separation, the apparatus was rotated at a speed 850 rpm, while the mobile phase was pumped into the column at 2 mL/min. As a result, 112 mg of reserpine and 21 mg of yohimbine were obtained from 3 g of crude extract in a single run. The analysis of the isolated compounds was determined by high-performance liquid chromatography (HPLC) at 230 nm with purities of over 91.0%, and the chemical identification was carried out by the data of electrospray ionization–mass spectrometry (ESI–MS) and nuclear magnetic resonance (NMR) spectroscopy. The technique introduced in this paper is an efficient method for preparative separation of reserpine and yohimbine from devil pepper radix. It will be beneficial to utilize medicinal materials and also useful for the separation, purification, and pharmacological study of Chinese herbal ingredients.
Authors:J. Wang, M. Liu, X. Tong, W. Peng, H. Cao, and W. Su
Shenqi Fuzheng Injection (SFI) is a traditional Chinese medicine injection, widely used to enhance immune function of clinical cancer patients undergoing chemotherapy. In this study, a high-performance liquid chromatography-diode array detection-evaporative light scattering detection (HPLC-DAD-ELSD) method was established for quality control of SFI, which could simultaneously semiquantitatively reflect the constituents displayed in the chromatographic profile of SFI. The relative retention time and relative peak areas of the 21 common peaks related to the reference peak were calculated. The validity and advantage of this method were validated by systematically comparing chromatograms of 10 batches of SFI samples with the analytical methods of principal component analysis and angle cosine method recommended by the State Food and Drug Administration of China. Moreover, a total of 21 constituents of SFI were identified or tentatively characterized in the fingerprint via ultrafast liquid chromatography-diode array detection-quadrupole time-of-flight (UFLC-DAD-Q-TOF) tandem mass spectrometry technique on the basis of the retention time, ultraviolet spectra, fragmentation patterns, and reported literatures. All the results proved that the technique was useful in comprehensive quality evaluation of SFI and further study.
Authors:J. Wang, L. Jia, W. Wei, S. Lang, P. Shao, and X. Fan
This paper develops an instrumental analytical approach for detection of fourteen polycyclic aromatic hydrocarbons (PAHs) in edible oil samples using gel permeation chromatography (GPC) and ultra-high performance liquid chromatography (UHPLC) coupled with diode array detector (DAD), and fluorescence detector (FLD). The GPC was used to remove triglycerides from edible oil samples. The extracted samples were then detected using UHPLC—DAD—FLD. In order to obtain good separation and high reproducibility, the UHPLC—DAD—FLD experimental condition was optimized. The PAHs including three groups of isomeric PAHs can be separated completely in 12 min using BEH Shield RP 18 column with a suitable gradient elution program. The mean recoveries were in the range of 73–110% with an acceptable reproducibility (RSD < 10%, n = 3). During real sample analysis, the method can decrease the chance of false positives with both DAD and FLD being used simultaneously. The results indicate that the approach is simple, easy, and acceptably reproducible, thereby showing great potential as a method for detection of fourteen PAHs contained in edible oil samples.
Authors:X. Wang, Y. Wu, Q. Wu, Y. Qian, W. Yue, and Q. Liang
The rhizome of Sparganium stoloniferum Buch.-Ham has been used as a traditional Chinese folk medicine for thousands of years. Phenolic compounds are the main bioactive ingredients of the plant. In order to determine the content of phenolic compounds from different major cultivations, a reliable method has been developed using ultra-high performance liquid chromatography coupled with a triple quadrupole electrospray tandem mass spectrometry. Seven compounds, including rutin, kaempferol, p-hydroxybenzaldehyde, formononetin, ferulic acid, vanillic acid, and p-coumaric acid, were simultaneously measured in 10 min. The established approach was fully validated in terms of linearity, sensitivity, precision, repeatability as well as recovery, and successfully applied to determine seven phenolic compounds of Rhizoma Sparganii. This study may be helpful in the quality control of Rhizoma Sparganii and can offer technical support for the pharmacological and clinical study of related drugs.
Authors:C. Wen, Q. Zhang, Y. He, M. Deng, X. Wang, and J. Ma
A sensitive and simple liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method for determination of dasatinib in rat plasma using one-step protein precipitation was developed. After addition of carbamazepine as internal standard (IS), protein precipitation by acetonitrile was used as sample preparation. Chromatographic separation was achieved on an SB-C18 (2.1 mm × 150 mm, 5 μm) column with methanol-0.1% formic acid as mobile phase with gradient elution. Electrospray ionization (ESI) source was applied and operated in positive ion mode; selective ion monitoring (SIM) mode was used to quantification using target fragment ions m/z 488.2 for dasatinib and m/z 338.7 for the IS. Calibration plots were linear over the range of 10–1000 ng mL−1 for dasatinib in rat plasma. Lower limit of quantification (LLOQ) for dasatinib was 10 ng mL−1. Mean recovery of dasatinib from plasma was in the range 82.2%–93.6%. Relative standard deviation (RSD) of intra-day and inter-day precision were both less than 8%. This developed method is successfully used in pharmacokinetic study of dasatinib in rats.
Authors:S.-Y. Shao, Y. Ting, J. Wang, J. Sun, and X.-F. Guo
Phyllostachys edulis (PES), the most important bamboo species in China, is widely distributed in East Asia. Flavonoids, which are important bioactive natural compounds, often have similar structures, making their structural elucidation difficult. The aim of this study was to represent valuable, reliable mass spectral data for the identification of flavonoids in plant leaves. Ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC–Q-TOF-MS/MS) method was established for characterization and identification of the major flavonoids in PES leaf extract. A total of 13 flavonoids were simultaneously characterized, and their proposed characteristic product ions and fragmentation pathways were investigated. Thirteen compounds were separated on an Agilent Zorbax RRHD SB-C18 column (150 mm × 2.1 mm, 1.8 μm). On the basis of comparing with the 4 reference standards and the literature data, the other 9 flavonoids were identified by tandem mass spectrometry (MS/MS). Eight compounds (compounds 1, 4, 5, 8, 9, 10, 11, and 12) were found in PES leaves for the first time. An efficient UPLC–QTOF-MS/MS method was successfully applied for the structural identification of flavonoids in PES leaves. These results have practical applications for the rapid identification and structural characterization of these compounds in crude bioactive extracts or mixtures.
Authors:G.-F. Shi, Z.-J. Wang, G.-Y. Wang, R.-X. Yao, F.-W. Chen, and Z.-R. Shi
High-performance liquid chromatography-mass spectrometry (HPLC-MS) method coupled with radical reaction for screening active ingredients from perennial fujimoto bean whole herb was established. The active ingredients, present in perennial fujimoto bean whole herb, possess scavenging effects towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide, peroxy radical, and hydroxyl radical. The radical scavenging abilities of these active ingredients were evaluated based on the relative peak areas in the HPLC chromatogram. The results indicate that potent antioxidants are present in the anhydrous methanol extract of perennial fujimoto bean whole herb. Based on HPLC-MS analysis, it was found that the scavenging ability can be mostly attributed to the presence of three compounds: cyanidin-3-o-β-d-glucopyranoside, troxerutin, and rutin. The structures were identified based on the MS and nuclear magnetic resonance (NMR) data. Free radical scavenging activity decreased in the following order: troxerutin > rutin > cyanidin-3-o-β-d-glucopyranoside.
Authors:Y. C. Xiao, L. T. Liu, J. J. Bian, C. Q. Yan, L. Ye, M. X. Zhao, Q. S. Huang, W. Wang, K. Liang, Z. F. Shi, and X. Ke
Shuganjieyu (SGJY) capsule is a classical formula widely used in Chinese clinical application. In this paper, an ultra-performance liquid chromatography coupled with electrospray ionization and ion trap mass spectrometry has been established to separate and identify the chemical constituents of SGJY and the multiple constituents of SGJY in rats. The chromatographic separation was performed on a C18 RRHD column (150 × 2.1 mm, 1.8 μm), while 0.1% formic acid–water and 0.1% formic acid–acetonitrile was used as mobile phase. Mass spectral data were acquired in both positive and negative modes. On the basis of the characteristic retention time (Rt) and mass spectral data with those of reference standards and relevant references, 73 constituents from the SGJY and 15 ingredients including 10 original constituents and 5 metabolites from the rat plasma after oral administration of SGJY were identified or tentatively characterized. This study provided helpful chemical information for further pharmacology and active mechanism research on SGJY.