Seven new chemical constituents from the roots of Gentiana macrophylla pall

A simple and sensitive LC-MS/MS method for the determination of loganic acid in rat plasma and its pharmacokinetic analysis

Loganic acid is an iridoid compound extracted from Gentianaceae plant Gentiana macrophylla Pall. It can effectively inhibit inflammation and tumor migration and has antioxidant activity. In this paper, we establish a simple, fast, sensitive and validated LC-MS method with the purpose of quantification of loganic acid in rat plasma with gliclazide as an internal standard (IS). Methanol was used to precipitate the protein in the plasma sample, and a C18 column (2.1 × 50 mm, 1.7 μm) was used for the separation of the target compound. Meanwhile, 0.1% formic acid water-methanol was employed as the mobile phase. Multiple reaction monitoring detection mode was adopted in detection with m/z 375.1 > 213.2 for loganic acid and m/z 322.1 > 169.9 for the IS, respectively, in negative ion scan mode. The linear range of calibration curve was 5.77-11,540.00 ng/ml, and the lower limit of detedtion was 2.89 ng/ml. The inter-day and intra-day precision and accuracy were <15% for lower limit of quantitation, low, middle and high quality control samples. This method was successfully used for the pharmacokinetic study of loganic acid in rat plasma at a dose range of 50-150 mg/kg for oral administration and 2 mg/kg for intravenous administration. The pharmacokinetic results showed that the oral bioavailability of loganic acid was low (2.71-5.58%).

Lignan glucosides from Gentiana macrophylla with potential anti-arthritis and hepatoprotective activities

Ten lignans, including six previously undescribed phenolic ester glycosyl lignans (1-6), were isolated from a well-known traditional Chinese medicine, Qin-Jiao, which is the dry root of Gentiana macrophylla Pall. (Gentianaceae). Their structures were determined by spectroscopic and chemical methods, especially 2D NMR techniques. Quantum chemical calculations of theoretical ECD spectra allowed the determination of their absolute configurations. Refer to its traditional applications for the treatment of rheumatic arthralgia and hepatopathy, these compounds were evaluated on a TNF-α induced MH7A human synoviocyte inflammation model and a D-GalN induced AML12 hepatocyte injury model. Compounds 1, 2, 5, and 6 significantly reduced the release of proinflammatory cytokine IL-1β in MH7A cells at 15 μM and they also could strongly protect AML12 cells against D-GalN injury at 30 μM. Flow cytometry and Western blot analysis showed that compound 5 ameliorated D-GalN induced AML12 cell apoptosis by upregulating the expression of anti-apoptotic Bcl-2 protein and down-regulating the expression of pro-apoptotic Bax protein.

A comprehensive review of phytochemistry, pharmacology and clinical application of Gentianae Macrophyllae Radix

Gentianae Macrophyllae Radix (GMR) is a traditional Chinese herb with the function of dispelling wind and dampness, and removing damp heat. Currently, it is reported in the literature that GMR mainly contains iridoids and secoiridoids, in addition to triterpenoids, flavonoids, lignans, steroids, alkaloids and other chemical components. Among them, iridoids and secoiridoids are the main active ingredients of GMR. Modern pharmacological studies have shown that GMR has pharmacological effects such as anti-inflammatory, anti-tumor, hepatoprotective, immunomodulatory and cardioprotective. In clinical practice, GMR is mainly used to treat rheumatoid arthritis, ulcerative colitis, stroke and other related diseases with good therapeutic effects. Currently, there are few literature reports on the GMR research progress. Therefore, this paper provides a review of the chemical composition, pharmacological activity and clinical applications of GMR to provide some scientific basis for the further development of plant resources.

Terpenoid Glucosides from Gentiana macrophylla That Attenuate TNF-α Induced Pulmonary Inflammation in A549 Cells

Four previously undescribed terpenoid glucosides, including one sesquiterpenoid di-glucoside (1), two new iridoid glucosides (2, 3), and a new triterpenoid tri-glucoside (4), were isolated from a 70% ethanol extract of the root of Gentiana macrophylla (Gentianaceae), along with eight known terpenoids. Their structures were determined by spectroscopic techniques, including 1D, 2D NMR, and HRMS (ESI), as well as chemical methods. The absolute configuration of compound 1 was determined by quantum chemical calculation of its theoretical electronic circular dichroism (ECD) spectrum. The sugar moieties of all the new compounds were confirmed to be D-glucose by GC analysis after acid hydrolysis and acetylation. Anti-pulmonary inflammation activity of the iridoids were evaluated on a TNF-α induced inflammation model in A549 cells. Compound 2 could significantly alleviate the release of proinflammatory cytokines IL-1β and IL-8 and increase the expression of anti-inflammatory cytokine IL-10.

Five New Glycoside Constituents from the Roots of Gentiana crassicaulis Duthie ex Burk

Three undescribed glycoside constituents, macrophyllosides E-G and a pair of iridoid glycosides genticrasides A/B, together with eleven known glycoside compounds were isolated from the roots of Gentiana crassicaulis Duthie ex Burk. Their structures were identified by means of spectra analysis and data comparison with previous literatures. Interestingly, the glucose moieties in macrophylloside E and F possess free anomeric hydroxy groups. Genticrasides A/B, identified as a pair of iridoid originated lactones, have not been reported from Gentianaceae family up to now. The anti-inflammatory effects of selected compounds were also evaluated through the nitric oxide (NO) production inhibition in lipopolysaccharides (LPS)-induced RAW264.7 macrophage cells. In which, macrophyllosides G and D showed NO inhibitory activities with rates of 76.14±4.02 % and 52.44±8.29 % at 100 μg/mL.

An integrated strategy for quality control of the multi-origins herb medicine of Gentianae Macrophyllae Radix based on UPLC-Orbitrap-MS/MS and HPLC-DAD

Gentianae Macrophyllae Radix, the dried root of Gentiana macrophylla Pall., Gentiana crassicaulis Duthie ex Burk., Gentiana straminea Maxim., or Gentiana dahurica Fisch., is a traditional Chinese medicine with multi-origins and some adulterants. Liquid chromatography coupled to electrostatic orbitrap high-resolution mass spectrometry (LC-Orbitrap-MS) was used to search the different components of Gentianae Macrophyllae Radix of the four species. High-performance liquid chromatography (HPLC) combined with fingerprint analysis, principal components analysis (PCA), and partial least-squares discrimination analysis (PLS-DA) was also utilized to distinguish them and their adulterants based on the critical components identified by LC-MS. A single standard to determine the multi-components (SSDMC) method was established for the determination of the critical markers. A total of 93 compounds were identified from Gentianae Macrophyllae Radix, including 58 common ones. Their HPLC fingerprints show a significant difference with the adulterants. In addition, PCA and PLS-DA could make a distinction among the four species. Loganic acid, 6'-O-β-d-glucosylgentiopicroside, swertiamarine, gentiopicroside, and sweroside were identified as the critical markers and then quantified by the SSDMC method. The developed strategy is powerful for the quality control and authentication of Gentianae Macrophyllae Radix.

Inhibitory effect of roburic acid in combination with docetaxel on human prostate cancer cells

Roburic acid (ROB) is a naturally occurred tetracyclic triterpenoid, and the anticancer activity of this compound has not been reported. Docetaxel (DOC) is the first-line chemotherapeutic agent for advanced stage prostate cancer but toxic side effects and drug resistance limit its clinical success. In this study, the potential synergistic anticancer effect and the underlying mechanisms of ROB in combination with DOC on prostate cancer were investigated. The results showed that ROB and DOC in combination synergistically inhibited the growth of prostate cancer cells. The combination also strongly induced apoptosis, and suppressed cell migration, invasion and sphere formation. Mechanistic study showed that the combined effects of ROB and DOC on prostate cancer cells were associated with inhibition of NF-κB activation, down regulation of Bcl-2 and up regulation of Bax. Knockdown of NF-κB by small interfering RNA (siRNA) significantly decreased the combined effect of ROB and DOC. Moreover, we found that esomeprazole (ESOM), a proton pump inhibitor (PPI), strongly enhanced the effectiveness of ROB and DOC on prostate cancer cells in acidic culture medium. Since acidic micro environment is known to impair the efficacy of current anticancer therapies, ESOM combined with ROB and DOC may be an effective approach for improving the treatment of prostate cancer patients.

Secoiridoids and triterpenoids from the traditional Tibetan medicine Gentiana veitchiorum and their immunosuppressive activity

Two undescribed secoiridoids (dehydroxyl-swerimilegenin H and 9-oxo-swerimuslactone A) with eight known ones, and two undescribed triterpenoids [28-O-(3,4-dihydroxyl-benzyl)-lupeol and 17-hydroperoxide-28-norurs-12-en-3-one] with seven known ones, were isolated from the aerial parts of Gentiana veitchiorum, a traditional Tibetan medicine. The structures of these compounds were elucidated by detailed spectroscopic analyses (including 1D and 2D NMR, HRMS, IR, and specific rotation) and comparison with structurally related known compounds. The isolates were selected to evaluate for their immunosuppressive activity via inhibiting the proliferation of T cells and cytokine IFN-γ production in T cells. Among them, 28-O-(3,4-dihydroxyl-benzyl)-lupeol exhibited significant effect by inhibiting the proliferation of T cells (IC₅₀, 20.08 μM) and T cell IFN-γ production (IC₅₀, 7.29 μM).

A new and effective evaluation method for Radix Gentianae Macrophyllae herbs based on 2-phenylethyl β-d-glucopyranoside, 2-methoxyanofinic acid and gentioxepine by UPLC-QTOF-MS exploring and HPLC-DAD quantification

Radix Gentianae Macrophyllae (RGM) is a traditional Chinese medicine belonging to the Gentiana genus and including four species of herbs. Owing to the lack of characteristic constituents, it is difficult to discriminate RGMs of different origins or even differentiate between herbs in the same genus. The current research aimed to explore the characteristic aromatic compounds, verify their significance in distinguishing different origins of RGM herbs and provide a simple and effective quality evaluation method. A selective extraction method was developed for noniridoid compounds and the extract was then subjected to UPLC-QTOF-MS analysis to obtain the RGM-MS ion pair database for noniridoid components. An HPLC-DAD quantitative analysis method was further developed based on characteristic aromatic compounds (2-phenylethyl β-d-glucopyranoside, 2-methoxyanofinic acid and gentioxepine) after the ion screening in the MS database. By means of principal component analysis and hierarchical clustering analysis analysis, the significant relationship between aromatic compounds contents and different species of RGM was revealed. As a result, the significance of 2-phenylethyl β-d-glucopyranoside, 2-methoxyanofinic acid and gentioxepine in distinguishing four species of RGM herbs was verified and a sensitive and reproducible HPLC-DAD method was established using these markers, which can be used for the classification and quantitative analysis of RGMs.

Discrimination of Gentiana and Its Related Species Using IR Spectroscopy Combined with Feature Selection and Stacked Generalization

Gentiana, which is one of the largest genera of Gentianoideae, most of which had potential pharmaceutical value, and applied to local traditional medical treatment. Because of the phytochemical diversity and difference of bioactive compounds among species, which makes it crucial to accurately identify authentic Gentiana species. In this paper, the feasibility of using the infrared spectroscopy technique combined with chemometrics analysis to identify Gentiana and its related species was studied. A total of 180 batches of raw spectral fingerprints were obtained from 18 species of Gentiana and Tripterospermum by near-infrared (NIR: 10,000-4000 cm^-1) and Fourier transform mid-infrared (MIR: 4000-600 cm^-1) spectrum. Firstly, principal component analysis (PCA) was utilized to explore the natural grouping of the 180 samples. Secondly, random forests (RF), support vector machine (SVM), and K-nearest neighbors (KNN) models were built while using full spectra (including 1487 NIR variables and 1214 FT-MIR variables, respectively). The MIR-SVM model had a higher classification accuracy rate than the other models that were based on the results of the calibration sets and prediction sets. The five feature selection strategies, VIP (variable importance in the projection), Boruta, GARF (genetic algorithm combined with random forest), GASVM (genetic algorithm combined with support vector machine), and Venn diagram calculation, were used to reduce the dimensions of the data variable in order to further reduce numbers of variables for modeling. Finally, 101 NIR and 73 FT-MIR bands were selected as the feature variables, respectively. Thirdly, stacking models were built based on the optimal spectral dataset. Most of the stacking models performed better than the full spectra-based models. RF and SVM (as base learners), combined with the SVM meta-classifier, was the optimal stacked generalization strategy. For the SG-Ven-MIR-SVM model, the accuracy (ACC) of the calibration set and validation set were both 100%. Sensitivity (SE), specificity (SP), efficiency (EFF), Matthews correlation coefficient (MCC), and Cohen's kappa coefficient (K) were all 1, which showed that the model had the optimal authenticity identification performance. Those parameters indicated that stacked generalization combined with feature selection is probably an important technique for improving the classification model predictive accuracy and avoid overfitting. The study result can provide a valuable reference for the safety and effectiveness of the clinical application of medicinal Gentiana.