A rapid and simple determination of protoberberine alkaloids in Rhizoma Coptidis by 1H NMR and its application for quality control of commercial prescriptions

A rapid localization and analysis method for isoquinoline alkaloids with fluorescence in Coptis chinensis Franch. By fabricating the nano-silver sol as a substrate for surface-enhanced Raman spectroscopy

BACKGROUND

The quality of traditional Chinese medicines (TCMs) directly impacts their clinical efficacy and drug safety, making standardization a critical component of modern TCMs. Surface-enhanced Raman spectroscopy (SERS) is an effective physical detection method with speed, sensitivity, and suitability for large sample analyses. In this study, a SERS analysis method was developed using a nano-silver sol as the matrix to address the interference of fluorescence components in TCMs and overcome the limitations of traditional detection methods.

RESULTS

The higher sensitivity and efficiency of SERS was used, enabling detection of a single sample within 30 s. Coptis chinensis Franch. (CCF) was chosen as the model medicine, the nano-silver sol was used as the matrix, and CCF's fourteen main fluorescent alkaloids were tested as index components. Typical signal peaks of the main components in CCF corresponded to the bending deformation of the nitrogen-containing ring plane outer ring system, methoxy stretching vibration, and isoquinoline ring deformation vibration. Through SERS detection of different parts, the distribution content of the main active components in the cortex of CCF was found to be lower than that in the xylem and phloem. Additionally, rapid quality control analyses indicated that among the nine batches of original medicinal materials purchased from Emei and Guangxi, the main active ingredient showed a higher content.

SIGNIFICANCE

A SERS-based method for the rapid localization and analysis of multiple components of TCMs was established. The findings highlight the potential of SERS as a valuable tool for the analysis and quality control of TCMs, especially for fluorescent components.

Tian-Huang Formula, a Traditional Chinese Medicinal Prescription, Improves Hepatosteatosis and Glucose Intolerance Targeting AKT-SREBP Nexus in Diet-Induced Obese Rats

The progressive increase of metabolic diseases underscores the necessity for developing effective therapies. Although we found Tian-Huang formula (THF) could alleviate metabolic disorders, the underlying mechanism remains to be fully understood. In the present study, firstly, male Sprague-Dawley rats were fed with high-fat diet plus high-fructose drink (HFF, the diet is about 60% of calories from fat and the drink is 12.5% fructose solution) for 14 weeks to induce hepatosteatosis and glucose intolerance and then treated with THF (200 mg/kg) for 4 weeks. Then, metabolomics analysis was performed with rat liver samples and following the clues illustrated by Ingenuity Pathway Analysis (IPA) with the metabolomics discoveries, RT-qPCR and Western blotting were carried out to validate the putative pathways. Our results showed that THF treatment reduced the body weight from 735.1 ± 81.29 to 616.3 ± 52.81 g and plasma triglyceride from 1.5 ± 0.42 to 0.88 ± 0.33 mmol/L; meanwhile, histological examinations of hepatic tissue and epididymis adipose tissue showed obvious alleviation. Compared with the HFF group, the fasting serum insulin and blood glucose level of the THF group were improved from 20.77 ± 6.58 to 9.65 ± 5.48 mIU/L and from 8.96 ± 0.56 to 7.66 ± 1.25 mmol/L, respectively, so did the serum aspartate aminotransferase, insulin resistance index, and oral glucose tolerance (p = 0.0019, 0.0053, and 0.0066, respectively). Furthermore, based on a list of 32 key differential endogenous metabolites, the molecular networks generated by IPA suggested that THF alleviated glucose intolerance and hepatosteatosis by activating phosphatidylinositol-3 kinase (PI3K) and low-density lipoprotein receptor (LDL-R) involved pathways. RT-qPCR and Western blotting results confirmed that THF alleviated hepatic steatosis and glucose intolerance partly through protein kinase B- (AKT-) sterol regulatory element-binding protein (SREBP) nexus. Our findings shed light on molecular mechanisms of THF on alleviating metabolic diseases and provided further evidence for developing its therapeutic potential.

Full-length transcriptome analysis of Coptis deltoidea and identification of putative genes involved in benzylisoquinoline alkaloids biosynthesis based on combined sequencing platforms

The study carry out comprehensive transcriptome analysis of C. deltoidea and exploration of BIAs biosynthesis and accumulation based on UHPLC-MS/MS and combined sequencing platforms. Coptis deltoidea is an important medicinal plant with a long history of medicinal use, which is rich in benzylisoquinoline alkaloids (BIAs). In this study, Ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) and combined sequencing platforms were performed for exploration of BIAs biosynthesis, accumulation and comprehensive transcriptome analysis of C. deltoidea. By metabolism profiling, the accumulation of ten BIAs was analyzed using UHPLC-MS/MS and different contents were observed in different organs. From transcriptome sequencing result, we applied single-molecule real-time (SMRT) sequencing to C. deltoidea and generated a total of 75,438 full-length transcripts. We proposed the candidate biosynthetic pathway of tyrosine, precursor of BIAs, and identified 64 full length-transcripts encoding enzymes putatively involved in BIAs biosynthesis. RNA-Seq data indicated that the majority of genes exhibited relatively high expression level in roots. Transport of BIAs was also important for their accumulation. Here, 9 ABC transporters and 2 MATE transporters highly homologous to known alkaloid transporters related with BIAs transport in roots and rhizomes were identified. These findings based on the combined sequencing platforms provide valuable genetic information for C. deltoidea and the results of transcriptome combined with metabolome analysis can help us better understand BIAs biosynthesis and transport in this medicinal plant. The information will be critical for further characterization of C. deltoidea transcriptome and molecular-assisted breeding for this medicinal plant with scarce resources.

Anti-Diabetic Effect of a Shihunine-Rich Extract of Dendrobium loddigesii on 3T3-L1 Cells and db/db Mice by Up-Regulating AMPK-GLUT4-PPARα

The stems of Dendrobium loddigesii, a Chinese herb, are often used to treat diabetes and its polar extract is rich in shihunine, a water-soluble Orchidaceae alkaloid, but little is known about the anti-diabetes effects and mechanism of shihunine. This study investigated the anti-diabetic effect of a shihunine-rich extract of D. loddigesii (DLS) based on 3T3-L1 cells and db/db mice. The underlying mechanisms were primarily explored using Western blot analysis and immunohistochemical staining. The 3T3-L1 cell experiments showed that DLS can reduce the intracellular accumulation of oil droplets as well as triglycerides (p < 0.001) and promote the 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2deoxyglucose (2-NBDG) uptake of 3T3-L1 cells (p < 0.001). The animal experiments confirmed that after 8 weeks of DLS treatment, the body weight, fasting blood sugar, and serum lipid levels of mice were significantly lowered, and the oral glucose tolerance test and serum insulin level were significantly improved compared to the no-treatment diabetes mellitus group. Further histomorphology observation led to the conclusion that the quantities of islet cells were significantly increased and the increase in adipose cell size was significantly suppressed. The immunohistochemical test of pancreatic tissue revealed that DLS inhibited the expression of cleaved cysteine aspartic acid-specific protease 3 (cleaved caspase-3). Western blot experiments showed that DLS had agonistic effects on adenosine monophosphate (AMP)-activated protein kinase phosphorylation (p-AMPK) and increased the expression levels of peroxisome proliferator-activated receptor α (PPARα) and glucose transporter 4 (GLUT4) in liver or adipose tissues. These data suggest that the shihunine-rich extract of D. loddigesii is an anti-diabetic fraction of D. loddigesii. Under our experimental condition, DLS at a dose of 50 mg/kg has good anti-diabetic efficacy.

Study on the Polar Extracts of Dendrobium nobile, D. officinale, D. loddigesii, and Flickingeria fimbriata: Metabolite Identification, Content Evaluation, and Bioactivity Assay

The polar extract of the Dendrobium species or F. fimbriata (a substitute of Dendrobium), between the fat-soluble extract and polysaccharide has barely been researched. This report worked on the qualitative and quantitative studies of polar extracts from D. nobile, D. officinale, D. loddigesii, and F. fimbriata. Eight water-soluble metabolites containing a new diglucoside, flifimdioside A (1), and a rare imidazolium-type alkaloid, anosmine (4), were identified using chromatography as well as spectroscopic techniques. Their contents in the four herbs were high, approximately 0.9–3.7 mg/g based on the analysis of quantitative nuclear magnetic resonance (qNMR) spectroscopy. Biological activity evaluation showed that the polar extract of F. fimbriata or its pure component had good antioxidant and neuroprotective activity; compounds 1‒4 and shihunine (8) showed weak α-glucosidase inhibitory activity; 4 and 8 had weak anti-inflammatory activity. Under trial conditions, all samples had no cytotoxic activity.

A feasible and practical 1H NMR analytical method for the quality control and quantification of bioactive principles in Lycii Fructus

Lycii Fructus, a solanaceous drug, is widely used as functional foods and in Traditional Chinese Medicine. Samples collected from different regions of China have been found to be not identical in chemical compositions which might affect the biological activities. Although many chromatographic and spectrometric methods have been reported to determine the concentration of betaine and other bioactive amino acids, disturbance resulted from other polar substances with low UV-absorbance and expensive mass facilities reduced the applicability of these techniques. In the present study, the strong cation exchange solid phase extraction procedure incorporated with ¹H NMR was successfully developed as a rapid and reliable method that can simultaneously determine betaine, citric acid, threonine, alanine, and proline in various Lycii Fructus. In addition, ERETIC 2 method based on PULCON principle was also applied and compared with conventional method. This feasible and practical method offers a very powerful tool for the quality control of commercial Lycii Fructus from different sources.

Species evolution and quality evaluation of four Coptis herbal medicinal materials in Southwest China

Coptis herbs, which are important herbal medicinal materials, are the dried rhizomes of various plants. In China's herbal market, drying herbs can severely influence morphological markers such as shape, color, and odor, which make consumers difficult to precisely identify the herbs and effectively evaluate the quality. Here, we present the phylogenetic analysis of four Coptis herbal medicinal materials based on internal transcribed spacer sequences. C. chinensis, C. omeiensis, C. deltoidea and C. teeta constituted a monophyletic group. In this group, C. omeiensis and C. deltoidea cluster together, and they form the sister group with C. teeta, and C. chinensis locate the outermost of C. omeiensis, C. deltoidea and C. teeta. At the same time, the HPLC-DAD method was applied to simultaneously analyze main alkaloids from seventeen different samples. On the basis of the robust phylogenetic topology, the parsimony reconstructions of six effective medicinal constituents were implemented to elucidate the evolutionary history in Coptis herbs, and thus evaluate the herbal quality. The results showed that C. chinensis had been considered to be the best herb, not only the high content in single constituent but also in total alkaloids. In addition, all the samples from seventeen habitats were considered as qualified herbs, and they could meet the requirements of national quality standards for Coptis herbs in China.

Pharmacokinetics and tissue distribution of coptisine in rats after oral administration by liquid chromatography-mass spectrometry

Coptisine, one of the main components isolated from Coptidis rhizoma, has been reported to have many beneficial pharmacological effects including anti-inflammatory, anti-hypercholesterolemia, neuroprotective and cardioprotective properties. However, to date the information related to the in vivo pharmacokinetics (PK) of coptisine is very limited. The purposes of our study are to establish a fast and sensitive quantification method of coptisine using liquid chromatography-mass spectrometry (LC-MS) and evaluate the PK profile of coptisine in rats. The calibration curve for coptisine was linear from 0.78 to 50 ng/mL. After single-dose oral administration of coptisine, the mean peak plasma concentration values for groups treated with 30, 75 and 150 mg/kg doses ranged from 44.15 to 66.89 ng/mL, and the mean area under the concentration-time curve values ranged from 63.24 to 87.97 mg/L h. The absolute bioavailability was calculated to range from 1.87 to 0.52%. Coptisine remained in all analyzed samples at low concentrations after oral administration of 30 mg/kg.

The First Comprehensive Phylogeny of Coptis (Ranunculaceae) and Its Implications for Character Evolution and Classification

Coptis (Ranunculaceae) contains 15 species and is one of the pharmaceutically most important plant genera in eastern Asia. Understanding of the evolution of morphological characters and phylogenetic relationships within the genus is very limited. Here, we present the first comprehensive phylogenetic analysis of the genus based on two plastid and one nuclear markers. The phylogeny was reconstructed using Bayesian inference, as well as maximum parsimony and maximum likelihood methods. The Swofford-Olsen-Waddell-Hillis and Bayesian tests were used to assess the strength of the conflicts between traditional taxonomic units and those suggested by the phylogenetic inferences. Evolution of morphological characters was inferred using Bayesian method to identify synapomorphies for the infrageneric lineages. Our data recognize two strongly supported clades within Coptis. The first clade contains subgenus Coptis and section Japonocoptis of subgenus Metacoptis, supported by morphological characters, such as traits of the central leaflet base, petal color, and petal shape. The second clade consists of section Japonocoptis of subgenus Metacoptis. Coptis morii is not united with C. quinquefolia, in contrast with the view that C. morii is a synonym of C. quinquefolia. Two varieties of C. chinensis do not cluster together. Coptis groenlandica and C. lutescens are reduced to C. trifolia and C. japonica, respectively. Central leaflet base, sepal shape, and petal blade carry a strong phylogenetic signal in Coptis, while leaf type, sepal and petal color, and petal shape exhibit relatively higher levels of evolutionary flexibility.

Rational quality assessment procedure for less-investigated herbal medicines: Case of a Congolese antimalarial drug with an analytical report

Herbal medicines are the most globally used type of medical drugs. Their high cultural acceptability is due to the experienced safety and efficiency over centuries of use. Many of them are still phytochemically less-investigated, and are used without standardization or quality control. Choosing SIROP KILMA, an authorized Congolese antimalarial phytomedicine, as a model case, our study describes an interdisciplinary approach for a rational quality assessment of herbal drugs in general. It combines an authentication step of the herbal remedy prior to any fingerprinting, the isolation of the major constituents, the development and validation of an HPLC-DAD analytical method with internal markers, and the application of the method to several batches of the herbal medicine (here KILMA) thus permitting the establishment of a quantitative fingerprint. From the constitutive plants of KILMA, acteoside, isoacteoside, stachannin A, and pectolinarigenin-7-O-glucoside were isolated, and acteoside was used as the prime marker for the validation of an analytical method. This study contributes to the efforts of the WHO for the establishment of standards enabling the analytical evaluation of herbal materials. Moreover, the paper describes the first phytochemical and analytical report on a marketed Congolese phytomedicine.

Protein tyrosine phosphatase 1B inhibitory activity of alkaloids from Rhizoma Coptidis and their molecular docking studies

ETHNOPHARMACOLOGIC RELEVANCE

Rhizoma Coptidis (the rhizome of Coptis chinensis Franch) has commonly been used for treatment of diabetes mellitus in traditional Chinese medicine due to its blood sugar-lowering properties and therapeutic benefits which highly related to the alkaloids therein. However, a limited number of studies focused on the Coptis alkaloids other than berberine.

MATERIALS AND METHODS

In the present study, we investigated the anti-diabetic potential of Coptis alkaloids, including berberine (1), epiberberine (2), magnoflorine (3), and coptisine (4), by evaluating the ability of these compounds to inhibit protein tyrosine phosphatase 1B (PTP1B), and ONOO(-)-mediated protein tyrosine nitration. We scrutinized the potentials of Coptis alkaloids as PTP1B inhibitors via enzyme kinetics and molecular docking simulation.

RESULTS

The Coptis alkaloids 1-4 exhibited remarkable inhibitory activities against PTP1B with the IC50 values of 16.43, 24.19, 28.14, and 51.04 μM, respectively, when compared to the positive control ursolic acid. These alkaloids also suppressed ONOO(-)-mediated tyrosine nitration effectively in a dose dependent manner. In addition, our kinetic study using the Lineweaver-Burk and Dixon plots revealed that 1 and 2 showed a mixed-type inhibition against PTP1B, while 3 and 4 noncompetitively inhibited PTP1B. Moreover, molecular docking simulation of these compounds demonstrated negative binding energies (Autodock 4.0=-6.7 to -7.8 kcal/mol; Fred 2.0=-59.4 to -68.2 kcal/mol) and a high proximity to PTP1B residues, including Phe182 and Asp181 in the WPD loop, Cys215 in the active sites and Tyr46, Arg47, Asp48, Val49, Ser216, Ala217, Gly218, Ile219, Gly220, Arg221 and Gln262 in the pocket site, indicating a higher affinity and tighter binding capacity of these alkaloids for the active site of the enzyme.

CONCLUSION

Our results clearly indicate the promising anti-diabetic potential of Coptis alkaloids as inhibitors on PTP1B as well as suppressors of ONOO(-)-mediated protein tyrosine nitration, and thus hold promise as therapeutic agents for the treatment of diabetes and related disease.

Histochemical evaluation of alkaloids in rhizome of Coptis chinensis using laser microdissection and liquid chromatography/mass spectrometry

Traditional macroscopic and microscopic identification methods of medicinal materials are economical and practical, but usually experience-based due to few chemical supports. Here histochemical evaluation on bioactive components of Coptidis Rhizoma (CR) in anatomic sections using laser microdissection and liquid chromatography-mass spectrometry (LMD-LC-MS) was developed to correlate the inner quality and outer features of materials from different growing areas. Results of a total 33 peaks representing potential different alkaloids were detected and 8 common peaks were identified as the major alkaloids, namely magnoflorine, thalifendine, columbamine, epiberberine, jatrorrhizine, coptisine, palmatine, and berberine. Six major alkaloids were quantified in the top and middle sections of raw materials and in their tissues and cells at the same time. Histochemical analyses showed consistent results with direct determination in raw materials and explained the reason why top sections of all samples contained higher contents of alkaloids by giving out attributions of each alkaloid in different anatomic sections. Besides, results manifested the distribution and accumulation rules of alkaloids in diverse tissues and cells of CR. This study demonstrates an effective and scientific way to correlate bioactive components and morphological features of medicinal materials, which is beneficial to future research, agriculture and application.

Coptis chinensis alkaloids exert anti-adipogenic activity on 3T3-L1 adipocytes by downregulating C/EBP-α and PPAR-γ

Obesity is a complex, multifactorial, and chronic disease that increases the risk for type 2 diabetes, coronary heart disease and hypertension, and has become a major worldwide health problem. Developing novel anti-obesity drugs from natural products is a promising solution to the global health problem of obesity. While screening anti-obesity potentials of natural products, the methanol extract of the rhizome of Coptis chinensis (Coptidis Rhizoma) was found to significantly inhibit adipocyte differentiation and lipid contents in 3T3-L1 cells, as assessed by Oil-Red O staining. Five known alkaloids, berberine, epiberberine, coptisine, palmatine, and magnoflorine, were isolated from the n-BuOH fraction of the methanol extract of Coptidis Rhizoma. We determined the chemical structure of these alkaloids through comparisons of published nuclear magnetic resonance (NMR) spectral data. Furthermore, we screened these alkaloids for their ability to inhibit adipogenesis over a range of concentrations (12.5-50 μM). All five Coptidis Rhizoma alkaloids significantly inhibited lipid accumulation in 3T3-L1 cells without affecting cell viability in a concentration dependent manner. In addition, the five alkaloids significantly reduced the expression levels of several adipocyte marker genes including proliferator activated receptor-γ (PPAR-γ) and CCAAT/enhancer-binding protein-α (C/EBP-α). In the present study, we found that the isolated alkaloids inhibited adipogenesis in a dose-dependent manner in 3T3-L1 cells; this inhibition was attributed to their abilities to downregulate the protein levels of the adipocyte marker proteins PPAR-γ and C/EBP-α. Thus, these results suggest that Coptidis Rhizoma extract and its isolated alkaloids may be of therapeutic interest with respect to the treatment of obesity.

Integrated pharmacokinetics of five protoberberine-type alkaloids in normal and insomnic rats after single and multiple oral administration of Jiao-Tai-Wan

ETHNOPHARMACOLOGICAL RELEVANCE

Jiao-Tai-Wan (JTW), an important herbal formula consists of Rhizoma coptidis and Cortex cinnamomi powder, is a famous prescription which has been used for centuries to treat insomnia in Traditional Chinese Medicine. The purpose of this study is to compare the pharmacokinetic properties of five protoberberine-type alkaloids (i.e. berberine, palmatine, coptisine, epiberberine and jatrorrhizine), the main bioactive constituents in JTW, between normal and insomnic rats. We also investigate the differences between single-dose and multiple-dose pharmacokinetics of five protoberberine-type alkaloids.

MATERIALS AND METHODS

The insomnic rat models were induced by intraperitoneal injection of one-dose para-chlorophenylalanine acid (PCPA). Quantification of five protoberberine-type alkaloids in rat plasma was achieved by using a rapid LC-MS/MS method. Plasma samples were collected at different time points to construct pharmacokinetic profiles by plotting drug concentration versus time and estimate pharmacokinetic parameters. An unpaired Student׳s t test was used for comparisons with SPSS 17.0.

RESULTS

The five protoberberine-type alkaloids of single-dose normal groups had slow absorption and low bioavailability, as well as a delay of peak time. In the single-dose oral administration, the Cmax and Tmax of five ingredients in insomnic rats had significant differences compared with those of normal rats. In the multiple-dose oral administration, the pharmacokinetic parameters of five protoberberine-type alkaloids varied greatly in insomnic rats. In the normal rats, there were significant differences (P<0.05) in the principal pharmacokinetic parameters such as Cmax and Tmax between single-dose and multiple-dose oral administration. In the insomnic rats, the five ingredients of multiple-dose groups showed better absorption than the single-dose groups. Particularly, three peaks were observed in multiple-dose model group of plasma-concentration curves.

CONCLUSIONS

The pharmacokinetic behavior of five protoberberine-type alkaloids was described in this paper. In both normal groups and model groups, the pharmacokinetic behavior of multiple-dose had significant differences comparing with the single-dose; either single-dose or multiple-dose, the pharmacokinetic behavior of insomnic rats had significant differences comparing the normal rats. Multiple dosing may improve the absorption of JTW in insomnic rats, which will increase the bioavailability and bring into active role in therapeutical effect.

Application of quantitative 1H NMR for the calibration of protoberberine alkaloid reference standards

Quantitative nuclear magnetic resonance spectroscopy (qNMR) has been developed into an important tool in the drug analysis, biomacromolecule detection, and metabolism study. Compared with mass balance method, qNMR method bears some advantages in the calibration of reference standard (RS): it determines the absolute amount of a sample; other chemical compound and its certified reference material (CRM) can be used as internal standard (IS) to obtain the purity of the sample. Protoberberine alkaloids have many biological activities and have been used as reference standards for the control of many herbal drugs. In present study, the qNMR methods were developed for the calibration of berberine hydrochloride, palmatine hydrochloride, tetrahydropalmatine, and phellodendrine hydrochloride with potassium hydrogen phthalate as IS. Method validation was carried out according to the guidelines for the method validation of Chinese Pharmacopoeia. The results of qNMR were compared with those of mass balance method and the differences between the results of two methods were acceptable based on the analysis of estimated measurement uncertainties. Therefore, qNMR is an effective and reliable analysis method for the calibration of RS and can be used as a good complementarity to the mass balance method.

Jiao tai wan attenuates hepatic lipid accumulation in type 2 diabetes mellitus

Jiao Tai Wan (JTW), a Chinese herbal formula containing Rhizoma Coptidis and Cortex Cinnamomi, has been used for diabetic treatment for many years. The aim of this study was to determine the main components in JTW and to investigate the effects of JTW on hepatic lipid accumulation in diabetic rats and humans. JTW extract was prepared and the main components were assayed by HPLC. An animal model of diabetes mellitus was established and JTW was administered intragastrically. In the clinical study, diabetic patients with poor glycemic control were treated with JTW. Blood glucose and lipid parameters, liver histology, hepatic triglyceride content and lipogenic gene expression were examined. Our data demonstrated that JTW significantly improved hyperglycemia, hyperlipidemia and hepatic lipid accumulation in diabetic rats. This was accompanied by the down-regulation of acetyl coenzyme A carboxylase (ACC) and fatty acid synthase (FAS) protein expressions, and the up-regulation of AMP-activated protein kinase (AMPK) and phosphorylated-ACC (pACC) protein expressions in the liver tissues. Diabetic patients also exhibited decreases in their hepatic triglyceride content. The results suggest that JTW attenuates hepatic lipid accumulation in diabetic rats and humans. These beneficial effects are possibly associated with the inhibition of lipogenic gene expression in the liver.

Developmental changes in the composition of five anthraquinones from Rheum palmatum as quantified by (1) H-NMR

INTRODUCTION

Rheum palmatum is an important traditional Chinese medicine featuring anthraquinones with several activities. Generally, rhein, emodin, aloe-emodin, physcion and chrysophanol are used as chemical markers for the quality control of rhubarb products.

OBJECTIVE

To develop a simple protocol for the quantification of rhein, emodin, aloe-emodin, physcion and chrysophanol in R. palmatum collected at different developmental stages.

METHODS

(1) H-NMR spectra were measured on samples dissolved in acetone-d6 , quantification was carried out using the signals of H-4 of rhein (δH 8.36), H-7 of emodin (δH 6.68), CH2 OH of aloe-emodin (δH 4.81), OCH3 of physcion (δH 4.02) and CH3 of chrysophanol (δH 2.50), which were well separated from other signals. Quantitative analysis was based on the relative ratio of the intensity of each compound to the known amount of internal standard maleic acid.

RESULTS

The quantitative (1) H-NMR (qHNMR) method developed showed good precision, trueness, linearity, repeatability and stability for the quantification of rhein, emodin, aloe-emodin, physcion and chrysophanol. This method was applied successfully to explore the seasonal variations of the five major anthraquinones in R. palmatum, and provided quantitative results in reasonable agreement with those obtained by the HPLC-UV method.

CONCLUSION

Compared with the conventional HPLC-based methods, the qHNMR analysis is rapid, reference-free and convenient with less sample pre-treatment. This technique should be a feasible choice for the quality control of R. palmatum.

Characterization of protoberberine alkaloids in Coptidis Rhizoma (Huanglian) by HPLC with ESI-MS/MS

This study aims to qualitatively analyze protoberberine alkaloids in crude extract of Coptidis Rhizoma using HPLC with ESI-MS/MS. Possible specific molecular weights of protoberberine alkaloids were firstly deduced according to literatures and were adopted to screen the alkaloids in the HPLC with ESI-MS of crude extract of Coptidis Rhizoma. As a result, 21 protoberberine alkaloids were found, including compounds of very low concentration and compounds coeluted in one peak. Among these, two compounds were positively identified and verified by comparison with standards. Ten of these compounds were first reported in this study for Coptidis Rhizoma. In addition, chromatographic retention parameters a and c of all compounds were obtained using their retention times under five gradient conditions and were applied to confirm the deduction about the structures of protoberberine alkaloids by tandem mass data.

Quantitative 1H NMR. Development and potential of an analytical method: an update

Covering the literature from mid-2004 until the end of 2011, this review continues a previous literature overview on quantitative (1)H NMR (qHNMR) methodology and its applications in the analysis of natural products. Among the foremost advantages of qHNMR is its accurate function with external calibration, the lack of any requirement for identical reference materials, a high precision and accuracy when properly validated, and an ability to quantitate multiple analytes simultaneously. As a result of the inclusion of over 170 new references, this updated review summarizes a wealth of detailed experiential evidence and newly developed methodology that supports qHNMR as a valuable and unbiased analytical tool for natural product and other areas of research.

Relative determination of dehydroevodiamine in rat plasma by LC-MS and study on its pharmacokinetics

The lack of purified standards is a bottleneck on assaying herbs in vitro and in vivo. This present work proposed a strategy of relative quantification that used a herb extract as a relative standard. A rapid and selective liquid chromatography tandem mass spectrometry method was similarly developed and validated for the relative determination of dehydroevodiamine in rat plasma according to the absolute quantification. Protein precipitation was used for the pretreatment of plasma samples. Chromatographic separation was achieved on a Diamonsil C18 column with an isocratic mobile phase of a 70:30 (v/v) acetonitrile-0.3% formic acid mixture at a flow rate of 0.45 mL/min. The assay was validated in the range 100.0 ≈ 50,000.0 ngH/mL (r(2) = 0.9804), the lowest level of this range being the lower limit of quantification based on 50 µL of plasma. The precision and accuracy were within recommended limits of nominal values. The method was applied to evaluate the comparative pharmacokinetics of dehydroevodiamine in rats following oral administration of Evodia rutaecarpa and Rhizoma coptidis-Evodia rutaecarpa couple. This approach was found to be capable of providing complete pharmacokinetic parameters as well as the typical pharmacokinetic assay calibrated by authentic standards, except for the absolute plasma concentrations.

Properties of sesame oil by detailed 1H and 13C NMR assignments before and after ozonation and their correlation with iodine value, peroxide value, and viscosity measurements

Gaseous ozone chemically reacts with unsaturated triglyceride substrates leading to ozonated derivatives with a wide potential applications, ranging from the petrochemical to the pharmaceutical industry. To date, an ultimate understanding of the ozone reactivity during sesame oil ozonation process as well as detailed (1)H and (13)C NMR assignments are lacking. A practical advantage of NMR is that a single NMR sample measurement can explain many issues, while similar analysis by traditional methods may require several independent and time-consuming measurements. Moreover, significant relationships among NMR spectra and both conventional chemical analysis and viscosity measurements have been found. Eventually, NMR could play an important role for quality attributes of ozonated oil derivatives.