New Glycosyltransferases in Panax notoginseng Perfect Main Ginsenosides Biosynthetic Pathways.

Ginsenosides, the main bioactive ingredients of the Panax genus, are dammarane or oleanane triterpenoids with glycosylated modifications at C3/C6/C20 hydroxyls or C28 carboxyl, and their diverse glycosylation pattern has attracted great attention. However, the biosynthesis of some important saponins is still unclear. In this study, six UGTs were characterized, two of which were novel. PnUGT71A3 catalyzes not only the C6 hydroxyl glycosylation of protopanaxatriol (PPT) and F1 to form Rh1 and Rg1, respectively, but also the C20 hydroxyl glycosylation of protopanaxadiol (PPD)-type Rg3 to generate Rd. Especially, PnUGT94M1 is UDP-ß-l-rhamnose (UDP-Rha)-dependent, regioselectively catalyzing the C2' hydroxyl rhamnosylation of C6 glucose of the PPT-type ginsenosides Rg1 and Rh1 to generate ginsenosides Re and Rg2, respectively. Site-directed mutagenesis showed that His21, Asp120, Ser363, and Pro372 are key residues, and the triple mutant (G344S/G345S/L346T) highly improved the activity toward Rg1 and Rh1. The findings in this study, perfect main ginsenosides biosynthetic pathways in the Panax genus, expand the biocatalyst toolbox for ginsenoside production and show that the PSPG motif is one of the options to modify UGTs to improve their activities.

Zuogui Wan ameliorates high glucose-induced podocyte apoptosis and improves diabetic nephropathy in db/db mice.

Zuogui Wan (ZGW), a well-known traditional Chinese medicine (TCM), has been used to nourish "Kidney-Yin" for a long time in China, implying a protective effect on the kidney. The aim of the present study is to investigate the effect of ZGW on high glucose-induced podocyte apoptosis and diabetic nephropathy (DN) in db/db mice. ZGW (1 g/kg-1/day-1) was administered intragastrically to db/db mice for 8 weeks. HPLC was used for identifying the components of ZGW, biochemical and histopathological approaches were used for evaluating its therapeutic effects, and cultured mouse podocytes were used for further exploring its underlying mechanism in vitro. ZGW improved renal function and podocyte loss and also normalized kidney reactive oxygen species production in db/db mice. The cytotoxicity of ZGW on mouse podocytes was assessed by the LDH assay. The effect of ZGW on podocyte viability and apoptosis was determined with CCK-8 and Annexin-V/PI staining by treatment with high glucose. ZGW attenuated podocyte apoptosis, and oxidative stress was detected by the peroxide-sensitive fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA) staining in a dose-dependent manner. Furthermore, ZGW decreased the expression of caspase-3 and phospho-p38 in both the kidney cortex and high glucose-treated podocytes. Thus, our data from in vivo and in vitro studies demonstrated that ZGW improved renal injury in diabetes by inhibiting oxidative stress and podocyte apoptosis.

A complementary chromatographic strategy for integrated components characterization of Imperatae Rhizoma based on convergence and liquid chromatography combined with mass spectrometry and molecular network.

The complexity of natural ingredients and the diversity of preparations are the major obstacles to the quality evaluation of traditional Chinese medicines (TCMs). A more comprehensive characterization of herbal compounds using different types of chromatographic separation techniques and covering a diverse polarity range can help evaluate the quality of TCMs. In this study, we first proposed a comprehensive method for characterizing compounds derived from Imperatae Rhizoma by combining the complementary strengths of UPCC-QTOF-MS (ultra-performance convergence chromatography coupled with quadrupole-time of flight mass spectrometry) with UPLC-QTOF-MS (ultra-performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry). The method based on the UNIFI scientific platform significantly shortened the analysis time and enabled a more comprehensive characterization of known and unreported compounds. Meanwhile, a feature-based molecular network (FBMN) was established on the Global Natural Product Social (GNPS) to infer potential compounds by rapidly classifying and visualizing these components. A total of 62 compounds in Imperatae Rhizoma were jointly characterizedand classified into six types. In comparison, the UPCC-QTOF-MS technology individually characterized 17 components, including lactones, phenols, aldehydes, phenylpropanoids, and small polar organic acids. The UPLC-QTOF-MS technology characterized 16 compounds mainly phenylpropionic acids, flavonoid glycosides, and chromone glycosides. Furthermore, three types of characteristic compounds could be well aggregated into an FBMN approach. Five possible potential new compounds were detected through the supplementary identification of GNPS and the correlation analysis of vicinal known compounds. The strategy was first applied to Imperatae Rhizoma and facilitated the characterization of a large quantity of data to provide comprehensive chemical composition results. This approach can be easily extended to the study of the material basis of other herbs or preparations in order to improve the accuracy of herb quality evaluation.

Metabolic profiling and pharmacokinetic studies of sinapine thiocyanate by UHPLC-Q/TOF-MS and UHPLC-MS/MS.

Sinapine thiocyanate (ST) is an index component and pharmacological active component of Semen Sinapis and Semen Raphani, and it is widely used to relieving cough and asthma. This study aimed to obtain the metabolic and pharmacokinetic characterization of ST. The metabolic profiles of ST were obtained from rat plasma, urine, and feces via ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UHPLC-Q/TOF-MS). Thirteen metabolites were structurally identified, and the proposed metabolic pathways of ST included deamination, demethylation, hydrogenation, dehydration, and extensive conjugation, including glucuronidation and sulfonation. ST was selected as the plasma marker for the pharmacokinetic study. A simple and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the quantitation of ST in rat plasma. The linear range of ST was 0.1-500 ng/mL (R2 = 0.9976), and the lowest limit of quantification was 0.1 ng/mL. The intra-precision and inter-precision of the assay were 1.31-5.12% and 2.72-7.66%, and the accuracy (RE%) ranged from - 4.88% to 3.82% and - 3.47% to 6.18%. The extraction recovery, matrix effect, and stability of ST were within acceptable limits. The established method was validated and successfully applied to the pharmacokinetic study of ST. For pharmacokinetic experiments, the male Sprague-Dawley rats were administrated with ST solution intravenously (2 mg/kg) or orally (100 mg/kg). The oral absolute bioavailability of ST was calculated as 1.84%, and the apparent volume of distribution of intravenous and intragastric administrations were 107.51 ± 21.16 L/kg and 78.60 ± 14.44 L/kg, respectively. The maximum plasma concentration was 47.82 ± 18.77 nM, and the time to maximum peak was 88.74 ± 20.08 min for the intragastric dosing group. According to the pharmacokinetic and metabolic profiling results, metabolites with high abundance of ST in bio-fluids would be the next object in tissue distribution and pharmacodynamic study.

Notoginsenoside Ft1 acts as a TGR5 agonist but FXR antagonist to alleviate high fat diet-induced obesity and insulin resistance in mice.

Obesity and its associated complications are highly related to a current public health crisis around the world. A growing body of evidence has indicated that G-protein coupled bile acid (BA) receptor TGR5 (also known as Gpbar-1) is a potential drug target to treat obesity and associated metabolic disorders. We have identified notoginsenoside Ft1 (Ft1) from Panax notoginseng as an agonist of TGR5 in vitro. However, the pharmacological effects of Ft1 on diet-induced obese (DIO) mice and the underlying mechanisms are still elusive. Here we show that Ft1 (100 mg/100 diet) increased adipose lipolysis, promoted fat browning in inguinal adipose tissue and induced glucagon-like peptide-1 (GLP-1) secretion in the ileum of wild type but not Tgr5 -/- obese mice. In addition, Ft1 elevated serum free and taurine-conjugated bile acids (BAs) by antagonizing Fxr transcriptional activities in the ileum to activate Tgr5 in the adipose tissues. The metabolic benefits of Ft1 were abolished in Cyp27a1 -/- mice which have much lower BA levels. These results identify Ft1 as a single compound with opposite activities on two key BA receptors to alleviate high fat diet-induced obesity and insulin resistance in mice.

Metabolite profiling of Shuganzhi tablets in rats and pharmacokinetics study of four bioactive compounds with liquid chromatography combined with electrospray ionization tandem mass spectrometry.

Shuganzhi Tablets (SGZT) is developed on the basis of a clinical empirical formula as a hospital preparation for the treatment of fatty liver. In this study, a rapid and highly sensitive LC-MS/MS method was established and validated for simultaneous determination of ginsenoside Re, ginsenoside Rg1, notoginsenoside R1, naringin, specnuezhenide, emodin, polydatin, hesperidin and saikosaponin A in rat plasma. Multiple reaction monitoring mode played an important role in simultaneous quantitative analysis of multiple components. The analytes were separated by the action of an ACQUITY UPLC® BEH C18 column (2.1 × 50 mm, 1.7 µm) in five minutes. The validated LC-MS/MS method was successfully applied to the pharmacokinetic analysis of hesperidin, emodin, polydatin and naringin of SGZT in rat plasma after administration. A UHPLC system couple with a quadrupole combined with time of flight mass spectrometer was used for qualitatively analyzing of the composition of SGZT and its metabolites in serum, urine, bile and feces of rats. The results showed that a total of 65 components were detected in rat biological samples, including 10 prototype components and 55 metabolites. It was speculated that the ingredients of SGZT experienced mainly the following reactions in rats: phase I reaction such as hydrolysis, oxidation, hydroxylation, carboxylation and dehydroxylation and phase Ⅱ reaction such as glucuronidation and sulfation. These results provide useful information for the further study of its active ingredients.

Danning tablets alleviate high fat diet-induced obesity and fatty liver in mice via modulating SREBP pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: The traditional Chinese formula Danning tablets exhibit wide clinical applications in liver and gallbladder diseases, and currently it is reported to be effective on fatty liver disease in clinical trials. However, the underlying mechanisms remain elusive. AIM OF THE STUDY: The purpose of the present study was to assess the effects and potential pharmacological mechanisms of Danning tablet against high fat diet (HFD)-induced obesity, fatty liver, and related metabolic disorders in mice. MATERIALS AND METHODS: C57BL/6 J male mice were treated with HFD for 12 weeks to trigger obesity and fatty liver condition. Then those mice were randomly divided into 5 groups, namely HFD, Danning tablet (0.75, 1.5 or 3 g/kg bodyweight) or lovastatin (30 mg/kg bodyweight) for extra 6 weeks' treatment of HFD. Food intake and bodyweight were recorded each week. In the last week, before the mice were sacrificed, fasting blood glucose levels and insulin levels were measured. Furthermore, insulin and glucose tolerance tests were performed. Blood and hepatic lipid levels were examined, the lipid metabolism-associated gene expressions and protein levels in the liver or adipose tissues were assayed after sacrificing all mice. RESULTS: Our results demonstrated that a high dose of Danning tablet (3 g/kg) treatment mitigated body weight gain, reduced blood and hepatic cholesterol and triglyceride levels. The morphology analysis showed that Danning tablets could reduce lipid accumulation in both liver and brown adipose tissue. Moreover, Danning tablets could improve fasting blood glucose levels and ameliorate glucose and insulin tolerance in HFD-induced obese mice. Furthermore, qRT-PCR analysis revealed that the mRNA expressions of SREBP-1 and SREBP-2 as well as their target genes were remarkedly down-regulated in the liver and adipose tissue of diet-induced obesity (DIO) mice after treating those mice with Danning tablets. CONCLUSION: Our results indicated that Danning tablets could improve the obesity-induced metabolic associated fatty liver disease (MAFLD) and related metabolic disorders. The potential mechanism may probably involve the regulation of the SREBP pathway.

Ginsenoside Ro Ameliorates High-Fat Diet-Induced Obesity and Insulin Resistance in Mice via Activation of the G Protein-Coupled Bile Acid Receptor 5 Pathway.

Obesity, a well known risk factor in multiple metabolic diseases, is dramatically increasing worldwide. Ginsenosides extracted from ginseng have been reported against obesity and the associated metabolic disorders. As a subtype of ginsenoside, ginsenoside Ro is a critical constituent of ginseng. However, its specific effects on obesity remain unknown. G protein-coupled bile acid receptor 5 (TGR5) (also known as GPBAR1) is a bile acid membrane receptor, widely expressed in human tissues contributing to various metabolic processes to confer the regulations of glucose and lipid homeostasis. TGR5 has displayed potential as a therapeutic target for the treatment of metabolic disorders. Here, we explore the antiobesity effect of ginsenoside Ro with TGR5 activation screened by a library of natural products. Our results showed that the ginsenoside Ro (90mg/kg) treatment ameliorated body weight and lipid accumulation in multiple metabolic organs of high-fat diet-induced obese (DIO) mice without affecting food intake and improved oral glucose tolerance tests, intraperitoneal insulin tolerance tests, and fasting serum glucose. We also found that triglyceride and total cholesterol in serum and liver were significantly decreased after ginsenoside Ro treatment. Then we used Tgr5 knockout mice to explore the role of Tgr5 in the antiobesity effect of ginsenoside Ro. Our results further demonstrated that ginsenoside Ro promoted glucagon-like peptide 1 (GLP-1) secretion and energy expenditure in wild-type DIO mice. However, the stimulation of ginsenoside Ro on GLP-1 secretion and energy expenditure were restrained in the Tgr5 knockout mice. In conclusion, our findings demonstrated that ginsenoside Ro ameliorates obesity and insulin resistance in DIO mice via activating TGR5, indicating a potential therapeutic role of ginsenoside Ro to treat obesity and its associated metabolic diseases. SIGNIFICANCE STATEMENT: Obesity is dramatically increasing worldwide, and it contributes to multiple metabolic diseases. G protein-coupled bile acid receptor 5 (TGR5) is a potential therapeutic target for the treatment of metabolic disorders. Ginsenoside Ro, as an oleanane-type ginsenoside, ameliorates obesity and insulin resistance, promotes glucagon-like peptide 1 secretion, and increases energy expenditure via activating TGR5. Ginsenoside Ro could be a potential leading compound for treating obesity and its associated metabolic diseases.

Pharmacokinetic studies of ginsenosides Rk1 and Rg5 in rats by UFLC-MS/MS.

A rapid ultra-fast liquid chromatography tandem mass spectrometry method was developed and validated to determine ginsenosides Rk1 and Rg5, a pair of isomers, in rat plasma, which was successfully applied to their pharmacokinetic studies. Two ginsenosides were given to male Sprague-Dawley rats via intragastrical and intravenous routes, respectively, and the impact of double bond position on the pharmacokinetic features of the two ginsenosides was elucidated in rats. Ginsenoside Rg3 was used as internal standard and ethyl acetate was applied to extract analytes and internal standard. Chromatographic separation was carried out on a reverse-phase UPLC HSS T3 column (100 × 2.1 mm, 1.8 µm). The flow rate was set to 0.4 ml/min. The fragmentation transition was m/z 765.4 → m/z 101.1 for two ginsenosides. The mobile phases were composed of 0.1% formic acid aqueous solution and acetonitrile. The linear range was 2-1,000 ng/ml for the two ginsenosides. Intra- and inter-day precisions were <11.67%, and accuracy fluctuated from -7.44 to 6.78%. The extraction recovery, matrix effect and stability were within acceptable levels. After treatment with ginsenosides Rk1 and Rg5, some differences were found in their pharmacokinetic profiles in rats. The maximum plasma drug concentration and the area under the plasma drug concentration-time curve of ginsenoside Rg5 were about 5 times bigger than those of ginsenoside Rk1 after oral administration, and 3 times higher after intravenous administration. The oral bioavailabilities of ginsenosides Rk1 and Rg5 were 0.67 and 0.97%, respectively. The results indicated that ∆20(22) -ginsenosides showed better pharmacokinetic features than ∆20(21) -ginsenosides with the same glycosylation.

Phytochemical analysis of Panax species: a review.

Panax species have gained numerous attentions because of their various biological effects on cardiovascular, kidney, reproductive diseases known for a long time. Recently, advanced analytical methods including thin layer chromatography, high-performance thin layer chromatography, gas chromatography, high-performance liquid chromatography, ultra-high performance liquid chromatography with tandem ultraviolet, diode array detector, evaporative light scattering detector, and mass detector, two-dimensional high-performance liquid chromatography, high speed counter-current chromatography, high speed centrifugal partition chromatography, micellar electrokinetic chromatography, high-performance anion-exchange chromatography, ambient ionization mass spectrometry, molecularly imprinted polymer, enzyme immunoassay, 1H-NMR, and infrared spectroscopy have been used to identify and evaluate chemical constituents in Panax species. Moreover, Soxhlet extraction, heat reflux extraction, ultrasonic extraction, solid phase extraction, microwave-assisted extraction, pressurized liquid extraction, enzyme-assisted extraction, acceleration solvent extraction, matrix solid phase dispersion extraction, and pulsed electric field are discussed. In this review, a total of 219 articles published from 1980 to 2018 are investigated. Panax species including P. notoginseng, P. quinquefolius, sand P. ginseng in the raw and processed forms from different parts, geographical origins, and growing times are studied. Furthermore, the potential biomarkers are screened through the previous articles. It is expected that the review can provide a fundamental for further studies.

Dynamic changes in chemical compositions and anti-acetylcholinesterase activity associated with steaming process of stem-leaf saponins of Panax notoginseng.

Stem-leaf saponins (SLSs), the total saponins from aerial part of P. notoginseng, are by-products of notoginseng, a famous traditional Chinese medicine. SLSs have been used as a health functional food in China, but its mild effects limited clinical applications in diseases. Inspired by steaming of notoginseng to enhance its pharmacological activity, a steaming protocol was developed to treat SLSs. SLSs were steamed at 100, 120, and 140°C for 1, 2, 3, and 4 h, respectively. The ultra-performance liquid chromatography coupled with quadrupole time-of-flight MS and ultra-performance liquid chromatography-tandem triple quadrupole mass spectrometry were applied to analyze the dynamic changes in chemical compositions. The anti-acetylcholinesterase activity of steamed SLS were assessed in vitro by directly determining the metabolic product of acetylcholine/choline. The components of SLSs were significantly changed by steaming. A total of 117 saponins and aglycones were characterized, and 35 of them were newly generated. The anti-acetylcholinesterase activity of steamed SLSs gradually increased with the extension of steamed time and the increase of steamed temperature and reached the maximum after 140°C for 3 h. Furthermore, ginsenosides Rk1 and Rg5, the main components of steamed SLSs, showed dose-dependent anti-acetylcholinesterase activities with half maximal inhibitory concentration (IC50 ) values of 26.88 ± 0.53 µm and 22.41 ± 1.31 µm that were only 1.8- and 1.5-fold higher than that of donepezil with IC50 values of 14.93 ± 4.17 µM, respectively.

Identification of lusianthridin metabolites in rat liver microsomes by liquid chromatography combined with electrospray ionization time-of-flight mass spectrometry.

Lusianthridin, a bioactive component isolated from Dendrobium venustum, has been demonstrated to have many biological properties such as antioxidant and anticancer activities. However, the metabolic profiles remain unknown. This study was carried out to investigate the metabolic profiles of lusianthridin in liver microsomes. Lusianthridin was co-incubated with liver microsomes in the presence of nicotinamide adenine dinucleotide phosphate and UDP-glucuronic acid or glutathione at 37°C for 1 h. The incubation samples were analyzed by liquid chromatography combined with electrospray ionization high-resolution mass spectrometry. The data were acquired and processed. The structures of the metabolites were proposed by comparing their accurate mass and MS2 spectra with those of the parent compound. A total of 15 metabolites were detected in vitro, including two phase I and 13 phase II metabolites. The phase I metabolic pathways were oxidation, demethylation and dehydrogenation. The phase II metabolic pathways referred to glucuronidation and glutathione conjugation. The present study provides an overview pertaining to the metabolic profiles of lusianthridin in vitro, which is indispensable for understanding the efficacy and safety of lusianthridin, as well as the herbal medicine D. venustum.

Pharmacokinetic, bioavailability, and metabolism studies of lusianthridin, a dihydrophenanthrene compound, in rats by liquid chromatography/electrospray ionization tandem mass spectrometry.

Lusianthridin was reported to possess many biological properties such as anti-oxidant and anti-cancer activities. However, its metabolic profiles and pharmacokinetics in vivo remain unknown. This study was carried out to investigate the metabolic profiles and pharmacokinetics of lusianthridin in rats. The metabolic profiles were obtained by an ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS). A total of eighteen metabolites involved three phase I metabolites and fifteen phase II metabolites were detected and identified. The major metabolic pathways of lusianthridin were demethylation, oxidation, sulfation, glucuronidation and glutathione conjugation. In addition, a simple and sensitive ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established for determination of lusianthridin in rat plasma. After extracted by protein precipitation, lusianthridin was quantitated in positive ion mode. The method was linear over the range of 0.5-500 ng/mL (r ≥ 0.995) with the LLOQ of 0.5 ng/mL. The intra- and inter- precision and accuracy, extraction recovery, matrix effect and stability were within the acceptable limits. The validated method was applied to the pre-clinical pharmacokinetic study of lusianthridin in rats. After oral administration, lusianthridin was quickly absorbed into plasma and reached the max concentration of 236.22 ng/mL at 22.00 min. The elimination half life of lusianthridin from plasma was approximately 83.05-104.47 min and the oral absolute bioavailability was calculated as 30.93 %.

Localization of constituents for determining the age and parts of ginseng through ultraperfomance liquid chromatography quadrupole/time of flight-mass spectrometry combined with desorption electrospray ionization mass spectrometry imaging.

Ginseng has been used for prevention and treatment of disease for thousands of years in China and many other Asian countries. Phytochemical studies have indicated that ginsenosides, polysaccharides, alkaloids, and phenolic acids are the active constituents of ginseng. Main and branch roots of ginseng exhibit distinct bioactive behavior. Furthermore, the bioactive behavior of ginseng depends on its age. Traditional analysis is complex preparation and provides inadequate of chemical information of the original distribution of analytes. Therefore, in this study, ultraperformance liquid chromatography quadrupole/time of flight-mass spectrometry (UPLC-QTOF MS) and desorption electrospray ionization mass spectrometry imaging (DESI-MSI) combined with orthogonal partial least squares discriminant analysis were used to discriminate ginseng in different age and parts of ginseng, and profiled distribution of selected markers. The results indicated that UPLC-QTOF-MS and DESI-MSI could be used to determine the parts and age of ginseng. Fifteen variables including five of protopanaxatriol (PPT), four of protopanaxadiol (PPD), and six of other types were assumed as markers for different parts of ginseng. Moreover, four variables of PPT, four of PPD, and ten of other types were used to determine the age of ginseng samples. An analysis of localization of markers indicated that malonyl ginsenoside, including malonyl-ginsenoside Rb1, Rb2, Rc, and Rd was mainly distributed in the corks. Neutral ginsenoside Rg1, yesanchinoisde D, and chikusetsusaponin Iva were mainly distributed in the cork and phloem. Non-ginsenoside castanoside H, 20(S)-protopanaxatriol, unknown 2, saponin III and cistanoside C were distributed in all tissues. Ethyloleate, unknown 1 and monolinolein were distributed in the cork.

A rapid and sensitive ultra-high-pressure liquid chromatography-tandem mass spectrometry method for the determination of notoginsenoside Ft1 in rat plasma with application to pharmacokinetic study.

Notoginsenoside Ft1 (NGFt1), a dammarane triterpene glycoside isolated from Panax notoginseng, showed potent effective in stimulating platelet aggregation in our previous assay, yet its pharmacokinetic behavior is still unclear. This study describes a rapid and sensitive ultra-high-pressure LC-tandem mass spectrometry assay for determining of NGFt1 in rat plasma. Methanol-mediated precipitation was used for sample pre-treatment. Chromatographic separation was achieved on a C18 column with gradient elution using water and acetonitrile as mobile phase. Determination was obtained using an electrospray ionization source in negative selected reaction monitoring (SRM) mode at the transitions of m/z 915.9 → m/z 783.8 and m/z 799.8 → m/z 637.8 for NGFt1 and internal standard, respectively. The assay was linear over the concentration range 0.25-2500 ng/mL (r > 0.995) with the lower limit of quantification of 0.25 ng/mL. The intra- and inter-day precisions (relative standard deviation, %) ranged 1.65%-9.84% and 2.46%-13.49%, respectively, whereas accuracy (relative recovery, %) ranged from 96.21% to 99.45%, respectively. The recovery ranged from 95.09% to 102.22% and the matrix effect from 98.29% to 100.13%. The analyte was stable under tested storage conditions. The method has been successfully applied to a preclinical pharmacokinetic study in rats after a single intravenous (2 mg/kg) and oral (50 mg/kg) administration.

Acylated iridoid glucosides from Pseudocaryopteris paniculata (C.B.Clarke) P.D.Cantino.

Phytochemical investigation of the ethyl acetate fraction of Pseudocaryopteris paniculata C.B.Clarke P.D.Cantino resulted in the identification of 26 undescribed iridoid glucosides (paniculosides A-Z), along with 7 known iridoid glucosides. Their structures were elucidated via two-dimensional nuclear-magnetic-resonance (2D-NMR) spectroscopy, high-resolution electrospray ionization mass spectroscopy (HR-ESI-MS), and chemical-hydrolysis methods. All isolated substances were analyzed for their cytoprotective effects against t-BHP-induced toxicity in HepG2 cells. Among the tested compounds, paniculoside A, paniculoside I, paniculoside T, and paniculoside U exhibited moderate cytoprotective activities with IC50 values in the range of 11.72-34.22 µM against t-BHP-induced toxicity.

Protein cross-linking in primary cultured mouse hepatocytes by dehydropyrrolizidine alkaloids: Structure-toxicity relationship.

Pyrrolizidine alkaloids (PAs) are natural toxins found in about 3%-5% of flowering plants. Dehydropyrrolizidine alkaloids contain a double bond in 1, 2-position of the necine bases, including retronecine type PAs (RET-PAs) and their N-oxides (RET N-oxide-PAs), and otonecine type PAs (OTO-PAs), and are known for their significant hepatotoxicity. Most dehydropyrrolizidine alkaloids are metabolically activated by cytochrome P450 (CYP450) enzymes to generate active pyrroles, which further bind to proteins to form pyrrole-protein adducts (PPAs). Methods for predicting PA-induced liver injury are generally performed on in vitro models with extremely low activities of CYP450 enzymes, which is different from the situation in vivo. In this regard, primary cultured mouse hepatocytes, which showed comparable CYP450 activity with the in vivo models, were applied to illustrate the structure-toxicity relationship of 13 dehydropyrrolizidine alkaloids, namely, eight RET-PAs, three RET N-oxide-PAs, and two OTO-PAs. PA-induced cytotoxicity and PA-generated PPAs were analyzed in primary mouse hepatocytes treated with different PAs. Results showed that PA-induced toxicity was correlated with the amount of PA-generated PPAs. RET-PAs and OTO-PAs were generally more toxic than RET N-oxide-PAs and generated higher amount of PPAs. PPAs were utilized to evaluate the efficiency of metabolic activation and predict the toxic potencies of dehydropyrrolizidine alkaloids. The proposed model could be a new approach for toxicity evaluation and risk control of exposure to PAs.

[Quantification of hepatotoxic pyrrolizidine alkaloid adonifoline in traditional Chinese medicine preparations containing Senecionis Scandentis Herba].

Pyrrolizidine alkaloids(PAs) are a kind of natural toxins, which can cause severe hepatotoxicity, pulmonary toxicity, genotoxicity, neurotoxicity, embryotoxicity and even death. Therefore, international organizations and countries such as World Health Organization have paid great attention to herbal medicines and preparations containing PAs. PAs are widely distributed in Chinese herb medicines and contained in hundreds of traditional Chinese medicine preparations. The content of adonifoline, the main PAs in Senecionis Scandentis Herba, shall be less than 0.004% in herbal medicines as described in Chinese pharmacopeia. However, there is no guidance in preparations which contain Senecionis Scandentis Herba. In this study, 14 preparations were analyzed by an UPLC-MS method. Among them, 8 preparations were found to contain adonifoline much higher than the content limits of such countries as Germany, Netherlands and New Zealand. And the highest contents of adonifoline were found in Qianbai Biyan Tablets and Qianbai Biyan Capsules, which are officially recorded in Chinese Pharmacopeia. The contents of adonifoline varied in different batches of the same preparations. The highest content was 156.10 µg·g~(-1) Qianbai Biyan Tablets, whose daily intake of adonifoline was up to 1 030.26 µg according to the recommended dosage of the preparation. Our results showed the potential risk of these preparations, and the content limit of adonifoline shall be inspected Chinese medicine preparations containing Senecionis Scandentis Herba.

Dose-dependent exposure profile and metabolic characterization of notoginsenoside R1 in rat plasma by ultra-fast liquid chromatography-electrospray ionization-tandem mass spectrometry.

Notoginsenoside R1 (NGR1 ), a diagnostic protopanaxatriol-type (ppt-type) saponin in Panax notoginseng, possesses potent biological activities including antithrombotic, anti-inflammatory, neuron protection and improvement of microcirculation, yet its pharmacokinetics and metabolic characterization as an individual compound remain unclear. The aim of this study was to investigate the exposure profile of NGR1 in rats after oral and intravenous administration and to explore the metabolic characterization of NGR1 . A simple and sensitive ultra-fast liquid chromatographic-tandem mass spectrometric method was developed and validated for the quantitative determination of NGR1 and its major metabolites, and for characterization of its metabolic profile in rat plasma. The blood samples were precipitated with methanol, quantified in a negative multiple reaction monitoring mode and analyzed within 6.0 min. Validation parameters (linearity, precision and accuracy, recovery and matrix effect, stability) were within acceptable ranges. After oral administration, NGR1 exhibited dose-independent exposure behaviors with t1/2 over 8.0 h and oral bioavailability of 0.25-0.29%. A total of seven metabolites were characterized, including two pairs of epimers, 20(R)-notoginsenoside R2 /20(S)-notoginsenoside R2 and 20(R)-ginsenoside Rh1 /20(S)-ginsenoside Rh1 , with the 20(R) form of saponins identified for the first time in rat plasma. Five deglycometabolites were quantitatively determined, among which 20(S)-notoginsenoside R2 , ginsenoside Rg1 , ginsenoside F1 and protopanaxatriol displayed relatively high exploration, which may partly explain the pharmacodynamic diversity of ginsenosides after oral dose.

Ameliorative effect of deoxyvasicine on scopolamine-induced cognitive dysfunction by restoration of cholinergic function in mice.

BACKGROUND: Aerial parts of Peganum harmala Linn is used as a traditional medical herb for treatment of amnesia in Uighur medicine in China. Deoxyvasicine (DVAS) is one of the chief active ingredients in P. harmala, it possesses strong acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities in vitro, but the therapeutic effect and mechanisms on amnesia in vivo are unclear. PURPOSE: The objective of this study was to investigate the improvement effect of DVAS from P. harmala in learning and memory deficits of scopolamine-induced mice and elucidate the underlying mechanisms involved. METHODS: Mice were pretreated with DVAS (5, 15 and 45 mg/kg) and huperzine-A (0.2 mg/kg) by gavage for 7 days, and subsequently were daily intraperitoneally injected with scopolamine (1 mg/kg) to induce learning and memory deficits and behavioral performance was assessed by Morris water maze. To further evaluate the potential mechanisms of DVAS in improving learning and memory capabilities, pathological change, levels of various biochemical markers and protein expressions related to cholinergic system, oxidative stress, and neuroinflammation were examined. RESULTS: The results showed that DVAS could alleviate learning and memory deficits in scopolamine-treated mice. DVAS could regulate cholinergic function by inhibiting AChE and activating choline acetyltransferase (ChAT) activities and protein expressions. DVAS could induce brain-derived neurotrophic factor and protect hippocampal pyramidal cells against neuronal damage. DVAS also enhanced antioxidant defense via increasing the antioxidant enzyme level and activity of glutathione peroxidase, and anti-inflammatory function through suppressing tumor necrosis factor-α. Additionally, DVAS could regulate the neurotransmitters by elevating acetylcholine, 5-hydroxytryptamine, γ-aminobutyric acid and reducing 5-hydroxyindole-3-acetic acid and glutamic acid. CONCLUSION: Results illustrated that DVAS may be a promising candidate compound against amnesia via restoration of cholinergic function, regulating neurotransmitters, attenuating neuroinflammation and oxidative stress.