Determination of 30 Free Fatty Acids in Two Famous Tibetan Medicines by HPLC with Fluorescence Detection and Mass Spectrometric Identification

A simple and sensitive high-performance liquid chromatographic (HPLC) method with fluorescence detection and mass spectrometric identification has been developed for analysis of 30 long-chain and short-chain free fatty acids (FFAs). The fatty acids were derivatized to their esters with 1-[2-(p-toluenesulfonate)ethyl]-2-phenylimidazole-[4,5-f]-9,10-phenanthrene (TSPP) in N,N-dimethylformamide (DMF) at 90 °C with anhydrous K₂CO₃ as catalyst. A mixture of C₁–C₃₀ fatty acids was completely separated within 60 min by gradient elution on a reversed-phase C₈ column. Qualitative identification of the acids was performed by atmospheric-pressure chemical ionization mass spectrometry (APCI–MS) in positive-ion mode. The fluorescence excitation and emission wavelengths were 260 and 380 nm, respectively. Quantitative determination of the 30 acids in two Tibetan medicines Gentiana straminea and G. dahurica was performed. The results indicated that the medicines contained many FFAs. Linear correlation coefficients for the FFA derivatives were >0.9991. Relative standard deviations (RSDs, n = 6) for the fatty acid derivatives were <3%. Detection limits (at a signal-to-noise ratio of 3:1) were 3.1–38 fmol. When the fatty acid derivatives were determined in the two real samples results were satisfactory and the sensitivity and reproducibility of the method were good.     

Biological Activities and Chemical Profile of Gentiana asclepiadea and Inula helenium Ethanolic Extracts

This study aimed to investigate the antioxidant, antimicrobial, and cytotoxic potential of ethanolic extracts obtained from Gentiana asclepiadea L. and Inula helenium L. roots, in relation to their chemical composition. The total polyphenols, flavonoids, and phenolic acids were determined by spectrophotometric methods, while LC-MS analysis was used to evaluate the individual constituents. The antioxidant properties were tested using the FRAP and DPPH methods. The standard well diffusion and broth microdilution assays were carried out to establish in vitro antimicrobial efficacy and minimum inhibitory and bactericidal concentrations. The cytotoxicity was tested on rat intestinal epithelial cells using the MTT assay. The results pointed out important constituents such as secoiridoid glycoside (amarogentin), phenolic acids (caffeic acid, chlorogenic acid, trans-p-coumaric acid, salicylic acid), and flavonoids (apigenin, chrysin, luteolin, luteolin-7-O-glucoside, quercetin, rutoside, and naringenin) and promising antioxidant properties. The in vitro antimicrobial effect was noticed towards several pathogens (Bacillus cereus > Staphylococcus aureus > Enterococcus faecalis > Salmonella typhimurium and Salmonella enteritidis > Escherichia coli), with a pronounced bactericidal activity. Rat intestinal epithelial cell viability was not affected by the selected concentrations of these two extracts. These data support the ethnomedicinal recommendations of these species and highlight them as valuable sources of bioactive compounds.     

Authentication of Gentiana straminea Maxim. and its substitutes based on chemical profiling of iridoids using liquid chromatography with mass spectrometry

A liquid chromatography–electrospray ionization–ion‐trap mass spectrometry (MSⁿ) method was established and applied for authentication of Gentiana straminea from the four substitutes, G. tibetica, G. lhassica, G. waltonii and G. robusta, based on chemical profiling of the principal iridoid glucosides aided by a quadrupole time‐of‐flight mass spectrometry. The fragmentation pathways of the three representative iridoid glucosides, loganic acid, gentiopicroside and sweroside, were investigated by MSⁿ analysis in negative ion mode, which assisted the characterization of analogs detected in the chromatographic profiling of the tested Gentiana species. In total, 25 iridoids were identified or tentatively characterized from G. straminea and four substitutes, in which 7‐O‐(4′′‐O‐glucosyl)coumaroyl‐loganic acid and 7‐O‐coumaroyl‐loganic acid are diagnostic in G. straminea and can serve as the proposed chemical markers to discriminate it from morphologically similar substitutes.     

青藏高原3种秦艽组植物微量元素比较分析

利用全谱直读等离子体发射光谱法(ICP-AES)测定了3种秦艽组植物10种微量元素(Cu,Zn,Fe,Mn,Ni,Co,Sn,V,Al,Ti)的含量,并进行了比较分析。结果表明,所测定元素在3个不同物种内的含量排列顺序基本一致,显示了三者在元素富集方面的相似性。就同一种元素在3个物种内的富集水平而言,以麻花艽根部具有较高含量的元素Cu,Zn,Co,Al和Ti,管花秦艽根部则大量富集了其余5种微量元素,达乌里秦艽对元素的吸收积累能力居中,揭示了不同物种对同一元素富集能力的差异。该研究可为秦艽类植物资源的深入开发利用提供参考。     

高速逆流色谱法从秦艽地上部分制备分离龙胆苦苷

采用高速逆流色谱法分离纯化秦艽地上部分中的龙胆苦苷。溶剂系统为V(氯仿)∶V(甲醇)∶V(水)=4∶4∶2,上相为固定相,下相为流动相,转速为800r/min,流速为2mL/min。所得产物经LC-MS分析为龙胆苦苷,纯度经高效液相色谱分析为94.0%(峰面积归一化法)。在保证分离效果的前提下,增大进样量,摸索制备分离龙胆苦苷的高速逆流色谱条件,为用高速逆流色谱法大量制备龙胆苦苷提供了一个可行方法。     

FAAS测定提宗龙胆花中的7种矿质元素

采用火焰原子吸收光谱法对藏药提宗龙胆花中Cu、Zn、Fe、Mg、Ca、K、Na 7种矿质元素进行了测定。在选定的测定条件下,提宗龙胆花中各元素间相互干扰小,对测定结果无明显影响。方法的校准曲线线性关系良好(r=0.9944—0.9999),方法的回收率(n=6)在94.5%—107.7%之间。提宗龙胆花中K、Ca、Mg、Fe等元素含量均较高,研究结果为提宗龙胆这一传统藏药的合理开发与利用提供了可靠依据。     

Characterization of Gentiana rigescens by Ultraviolet–Visible and Infrared Spectroscopies with Chemometrics

Gentiana rigescens is a medicinal plant for treatment of rheumatism, convulsions, and jaundice. The present paper reports the potential for chemometric characterization of G. rigescens using ultraviolet–visible and infrared spectroscopies, individually and together. Low- and mid-level data fusions were considered in this study. Partial least square discriminant analysis and support vector machine were used to analyze single and fused spectral data, respectively. The data fusion strategy improved the classification capacity. In particular, the mid-level data fusion provided the best results by selecting important variance from the data matrixes, with 100% correct classification of test samples by partial least square discriminant analysis and support vector machine characterization. The results demonstrated that the combined use of ultraviolet–visible and infrared spectroscopies is more suitable for the discrimination of G. rigescens than the individual methods.     

Rapid Identification of Wild Gentiana Genus in Different Geographical Locations Based on FT-IR and an Improved Neural Network Structure Double-Net

Gentiana Genus, a herb mainly distributed in Asia and Europe, has been used to treat the damp heat disease of the liver for over 2000 years in China. Previous studies have shown significant differences in the compositional contents of wild Gentiana Genus samples from different geographical origins. Therefore, the traceable geographic locations of the wild Gentiana Genus samples are essential to ensure practical medicinal value. Over the last few years, the developments in chemometrics have facilitated the analysis of the composition of medicinal herbs via spectroscopy. Notably, FT-IR spectroscopy is widely used because of its benefit of allowing rapid, nondestructive measurements. In this paper, we collected wild Gentiana Genus samples from seven different provinces (222 samples in total). Twenty-one different FT-IR spectral pre-processing methods that were used in our experiments. Meanwhile, we also designed a neural network, Double-Net, to predict the geographical locations of wild Gentiana Genus plants via FT-IR spectroscopy. The experiments showed that the accuracy of the neural network structure Double-Net we designed can reach 100%, and the F1_score can reach 1.0.     

Separation and determination of gentiopicroside and swertiamarin in Tibetan medicines by micellar electrokinetic electrophoresis

Micellar electrokinetic electrophoresis was employed to determine two active components, gentiopicroside (GE) and swertiamarin (SW) in one Tibetan preparation medicine named shiweilongdankeli, two Tibetan herbal medicines named Gentiana rhodantha and Gentiana kitag and three other Chinese Gentiana medicines named Gentiana scabra, Gentiana rigescens and Gentiana macrophylla. The dissociation constants of gentiopicroside and swertiamarin determined by MEKC were 7.71 and 6.25. The optimum buffer system was 70 mm borate-10 mm sodium dodecylsulfate (SDS) -6% (v/v) ispropanol (pH 9.0). The voltage was 15 kV and detection was at 254 nm. The lower limits of detection (defined as a signal-to-noise ratio of about 3) were approximately 3.86 mg L(-1) for GE and 5.88 mg L(-1) for SW. The relative standard deviation of the migration time and peak area of the GE and SW were 2.33, 2.47 and 1.27, 2.19%, respectively and the recoveries of the two compounds were 96-104% for GE and 92-102% for SW.