Effective substances and molecular mechanisms guided by network pharmacology: An example study of Scrophulariae Radix treatment of hyperthyroidism and thyroid hormone-induced liver and kidney injuries

ETHNOPHARMACOLOGICAL RELEVANCE

Scrophulariae Radix (Xuanshen [XS]) has been used for several years to treat hyperthyroidism. However, its effective substances and pharmacological mechanisms in the treatment of hyperthyroidism and thyroid hormone-induced liver and kidney injuries have not yet been elucidated.

AIM OF THE STUDY

This study aimed to explore the pharmacological material basis and potential mechanism of XS therapy for hyperthyroidism and thyroid hormone-induced liver and kidney injuries based on network pharmacology prediction and experimental validation.

MATERIALS AND METHODS

Based on 31 in vivo XS compounds identified using ultra-performance liquid chromatography tandem quadruple exactive orbitrap high-resolution accurate-mass spectrometry (UPLC-QE-HRMS), a network pharmacology approach was used for mechanism prediction. Systematic networks were constructed to identify the potential molecular targets, biological processes (BP), and signaling pathways. A component-target-pathway network was established. Mice were administered levothyroxine sodium through gavage for 30 d and then treated with different doses of XS extract with or without propylthiouracil (PTU) for 30 d. Blood, liver, and kidney samples were analyzed using an enzyme-linked immunosorbent assay (ELISA) and western blotting.

RESULTS

A total of 31 prototypes, 60 Phase I metabolites, and 23 Phase II metabolites were tentatively identified in the plasma of rats following the oral administration of XS extract. Ninety-six potential common targets between the 31 in vivo compounds and the diseases were identified. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that Bcl-2, BAD, JNK, p38, and ERK1/2 were the top targets. XS extract with or without PTU had the following effects: inhibition of T3/T4/fT3/fT4 caused by levothyroxine; increase of TSH levels in serum; restoration of thyroid structure; improvement of liver and kidney structure and function by elevating the activities of anti-oxidant enzymes catalase (CAT),superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px); activation anti-apoptotic proteins Bcl-2; inhibition the apoptotic protein p-BAD; downregulation inflammation-related proteins p-ERK1/2, p-JNK, and p-p38; and inhibition of the aggregation of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6, as well as immune cells in the liver.

CONCLUSION

XS can be used to treat hyperthyroidism and liver and kidney injuries caused by thyroid hormones through its anti-oxidant, anti-inflammatory, and anti-apoptotic properties. In addition, serum pharmacochemical analysis revealed that five active compounds, namely 4-methylcatechol, sugiol, eugenol, acetovanillone, and oleic acid, have diverse metabolic pathways in vivo and exhibit potential as effective therapeutic agents.

Targeted characterization and guided isolation of chemical components in Scrophulariae Radix based on LC-MS

How to achieve rapid characterization and efficient isolation of chemical components from traditional Chinese medicines (TCMs) is what the researchers have been exploring. Herein, a strategy integrated diagnostic ion filtering (DIF) and selected ion recording (SIR)-based screen was firstly proposed and successfully applied for targeted characterization and guided isolation of the chemical components from Scrophulariae Radix, one of TCMs. After acquiring the Q-TOF-MS/MS untargeted data, 128 compounds were characterized based on DIF, a self-built database and comparison of the related literatures, in which 38 compounds were reported for the first time. Subsequently, the SIR method of UPLC-QqQ-MS/MS was adopted to guide the isolation of potential new compounds. Finally, three new compounds together with one known compound with the same skeleton were isolated, and unambiguously elucidated by NMR and acid hydrolysis. These results indicated that this integrated analytical approach is effective and reliable in targeted characterizing chemical components and isolating new compounds from the extract of Scrophulariae Radix.

Comprehensive quality evaluation of processed Scrophulariae Radix from different regions of China using HPLC coupled with chemometrics methods

INTRODUCTION

Scrophulariae Radix (SR) has been extensively used in traditional Chinese medicine (TCM) for thousands of years. However, the processing methods and production areas of Scrophularia ningpoensis have undergone notable historic changes. Thus, their effects on the bioactive constituents of SR still need to be studied further.

OBJECTIVES

This study aimed to establish an objective and comprehensive method to identify the correlation of bioactive constituents of SR with variety, place of origin and processing method for evaluating their qualities.

METHODOLOGY

An accurate and rapid high-performance liquid chromatography-diode array detector (HPLC-DAD) method for the simultaneous determination of 11 marker components (aucubin, harpagide, 6-O-methyl-catalpol, harpagoside, verbascoside, isoverbascoside, angoroside C, cinnamic acid, l-tyrosine, l-phenylalanine, and l-tryptophan) was established to evaluate the quality of SR for the first time. In addition, the effects of different production areas and processed methods on the target compounds were studied by analysing 66 batches of SR samples with chemometrics methods, including similarity evaluation of chromatographic fingerprints of TCM, principal component analysis (PCA), and partial least squares-discriminant analysis (PLS-DA).

RESULTS

Compared with "sweating", short-term "steaming" and "slice-drying" could largely preserve the bioactive constituents of SR. When using the model established through PLS-DA, five components were identified as the most significant variables for discrimination. Furthermore, the score plots of PCA and the similarity evaluation revealed that variety had a more notable influence on the quality of SR than the place of origin.

CONCLUSION

An objective approach of HPLC fingerprint coupled with chemometrics analysis and quantitative assessment could be applied to discriminate different processed SR and evaluate the qualities of SR rapidly.

[Chemical constituents, pharmacological activities, processing and clinical application of traditional Chinese medicine Scrophulariae Radix: a review]

Traditional Chinese medicine Scrophulariae Radix, which is also called Yuan Shen, black Shen, is the dried root of Scrophularia ningpoensis of the Scrophulariaceae family. Research has indicated that the chemical constituents of Scrophulariae Radix mainly include terpenoids, phenylpropanoids, organic acids, volatile oils, steroids, sugars, flavonoids, alkaloids and phenols, among which iridoids and phenylpropanoids were the main active constituents. It has been reported that extracts of Scrophulariae Radix or its active substances have anti-inflammatory, antioxidant, hepatoprotective, anti-tumor, anti-fatigue, uric acid-lowering, anti-depression, myocardial cell-protective and other pharmacological activities, and can regulate cardiovascular system, central nervous system and immune system. This paper reviewed the present research achievements of Scrophulariae Radix in chemical constituents, pharmacological activities, processing methods, toxicity and other aspects, and the clinical application of Scrophulariae Radix in ancient and modern times was illustrated. This paper aimed to provide reference for further research of Scrophulariae Radix and facilitated its clinical application.

Scrophulariae Radix-Atractylodes sinensis pair and metformin inhibit inflammation by modulating gut microbiota of high-fat diet/streptozotocin-induced diabetes in rats

INTRODUCTION

Type 2 mellitus (T2DM), a chronic metabolic disorder, causes severe impairment of patients' quality of life and has attracted global attention. Many studies have suggested the importance of the gut microbiota in the occurrence of T2DM. The Scrophulariae Radix and Atractylodes sinensis (XC) pair, recommended in traditional Chinese medicine (TCM), have been used for treating diabetes for many years. However, research on the role of the XC pair in modulating gut microbial communities is lacking, but it is important to elucidate the underlying mechanism.

METHODS

In this study, we detected bacterial communities by high-throughput 16S rRNA gene sequencing.

RESULTS

The results showed that XC + MET reduced postprandial hyperglycemia and inflammatory response in diabetic rats more effectively than metformin (MET) alone. The XC + MET treatment reshaped the intestinal microbial composition of diabetic rats. XC can help MET regulate carbohydrate, amino acid, and lipid metabolism, particularly the insulin signaling pathway.

DISCUSSION

This research would help elucidate potential mechanisms and the treatment methods.

[Chemical constituents of Scrophulariae Radix and their antitumor activities in vitro]

The present study investigated the chemical constituents of Scrophulariae Radix and their antitumor activities in vitro. The compounds in the ethyl acetate extract were separated and purified by conventional column chromatographies(such as silica gel, Sephadex LH-20, and ODS column) and semi-preparative high-performance liquid chromatography(HPLC), and their structures were identified by various spectral techniques such as nuclear magnetic resonance(NMR) and mass spectrometry(MS). Twenty-three compounds were isolated and identified as benzyl-β-D-(3',6'-di-O-acetyl) glucoside(1), 5-O-p-methoxybenzoyl kojic acid(2), 5-O-methoxybenzoyl kojic acid(3), 7-O-methylbenzoyl kojic acid(4), 5-O-benzoyl kojic acid(5), methyl ferulate ethyl ether(6), trans-ferulic acid(7), trans-isoferulic acid(8), trans-caffeic acid(9), trans-caffeic acid methyl ester(10), caffeic acid ethyl ester(11), trans-cinnamic acid(12), trans-p-methoxycinnamic acid(13), trans-p-hydroxycinnamic acid(14), trans-p-hydroxycinnamic acid methyl ester(15), 2-(3,4-dihydroxyphenethyl) alcohol(16),(p-hydroxyphenyl) propanoic acid(17), coniferaldehyde(18), sinapaldehyde(19), benzyl β-primeveroside(20), 5-(hydroxymethyl) furfural(21), furan-2-carboxylic acid(22), and decanedioic acid(23). Among them, compound 1 is a new benzyl glucoside, compounds 2-4 are new pyranone compounds, compound 5 is a new natural product of pyranone. The NMR data of compounds 5 and 6 are reported for the first time. Compounds 6 and 20 were isolated from the Scrophularia plant for the first time. Compounds 8, 11, 14, 16, 18, 19, 22, and 23 were isolated from this plant for the first time. The in vitro cytotoxic activities of these compounds against three tumor cell lines(HepG2, A549, and 4 T1) were evaluated. The results showed that compounds 10 and 15 showed cytotoxic activities against HepG2 cells with IC_(50) values of(19.46±0.48) μmol·L~(-1) and(46.10±1.21) μmol·L~(-1).

Scrophulariae Radix: An Overview of Its Biological Activities and Nutraceutical and Pharmaceutical Applications

Scrophulariae Radix (SR) has an important role as a medicinal plant, the roots of which are recorded used to cure fever, swelling, constipation, pharyngitis, laryngitis, neuritis, sore throat, rheumatism, and arthritis in Asia for more than two thousand years. In this paper, the studies published on Scrophularia buergeriana (SB) and Scrophularia ningpoensis (SN) in the latest 20 years were reviewed, and the biological activities of SB and SN were evaluated based on in vitro and in vivo studies. SB presented anti-inflammatory activities, immune-enhancing effects, bone disorder prevention activity, neuroprotective effect, anti-amnesic effect, and anti-allergic effect; SN showed a neuroprotective effect, anti-apoptotic effect, anti-amnesic effect, and anti-depressant effect; and SR exhibited an immune-enhancing effect and cardioprotective effects through in vitro and in vivo experiments. SB and SN are both known to exert neuroprotective and anti-amensice effects. This review investigated their applicability in the nutraceutical, functional foods, and pharmaceutical industries. Further studies, such as toxicological studies and clinical trials, on the efficacy and safety of SR, including SB and SN, need to be conducted.

[Study on scrophulariaceae radix reference extract and its application in quality control of Scrophulariae Radix]

By establishing the preparation process of Scrophulariaceae Radix reference extract(SRRE) and calibrating it, we discussed its feasibility as a substitute for single reference substance in the quality control of Scrophulariae Radix. The SRREs were prepared by solvent extraction method and chromatographic separation technology, and then calibrated with the reference substances of harpagide, angoroside C and harpagoside. The HPLC content determination method of Scrophulariae Radixl was established with SRREs of the known content and the reference substances of harpagide, angoroside C and harpagoside respectively as the control ones. Then the content of three components in Scrophulariae Radix was determined, and the t-test method was used to compare the results of the two methods. With SRRE as references, harpagide, angoroside C and harpagoside were in a good linear relationship(r≥0.999 8) within each range, and the average recovery rate was 98.55% to 100.6%. The t-test results showed that the P values of two determination methods were 0.493, 0.155 and 0.171 for harpagide, angoroside C and harpagoside respectively, indicating no significant diffe-rence between the two methods of content determination. The SRRE can be used as a substitute for the reference in the quality control of Scrophulariaceae Radix. The SRRE can replace the corresponding reference substance for the quality control of Scrophulariae Radix. The results of this study provide new methods and new ideas for the quality evaluation of Scrophulariae Radix, and provide a scientific basis for the application of reference extracts in the quality research of traditional Chinese medicine.

[Establishment of quality control model for high performance liquid chromatography fingerprint based on ultraviolet full-wavelength scanning spectrum: case study on different grades of Scrophulariae Radix]

High performance liquid chromatography-ultraviolet(HPLC-UV) fingerprint is one of the most important methods for the quality control of Chinese medicines in Chinese Pharmacopoeia. However, certain subjectivity is present in selection of specific band of UV, and the inherent quality differences of Chinese medicine can't be well characterized by this method. Therefore, with different grades of Scrophulariae Radix were taken as the research object in this study, a new quality control model of HPLC-UV was established in this study based on the ultraviolet full-wavelength scanning spectrum. Firstly, different grades of Scrophulariae Radix samples were collected, and the full-wavelength ultraviolet absorption spectra of all the samples were established at the bands of 200-400 nm. In order to analyze the differences among samples, the analysis model was built following multivariate statistical analysis methods such as principal component analysis(PCA) and partial least squares discrimination analysis(PLS-DA) after the pretreatment of spectral data. The result showed that the ultraviolet band at 251 nm may contribute most to distinguish the quality differences among different grades of samples. Then, the HPLC fingerprints of samples were established with the band at 251 nm. The multivariate statistical analysis showed that there was a more significant classification trend in HPLC fingerprints than that in the original UV fingerprints, which could be used to distinguish different grades of samples, and could better reflect the differences among different grades. The method reported in this study can be of a great guidance and reference for the establishment of specific fingerprints of Chinese medicines as well as for the quality control of Chinese medicine.

[Grades evaluation of Scrophulariae Radix pieces based on quality constant]

The quality constant evaluation method was applied in the grade evaluation of Scrophulariae Radix pieces. Nineteen batches of Scrophulariae Radix were measured for the appearance index. Harpagide and harpagoside were taken as index components for the content determination. The traditional grading standard and the modern quality control index were combined to calculate the quality constant and grade Scrophulariae Radix pieces. The results showed that the quality constants ranged between 156. 75 and 491. 65; according to the percentage mass constants,more than 80% were graded as first-class pieces,50%-80% were graded as second-class pieces,and the rest were graded as third-class pieces. The quality constants of first-class Scrophulariae Radix were >393. 32,that of second-class Scrophulariae Radix was between 245. 83 and 393. 32,and that of third-class Scrophulariae Radix was < 245. 83. The study shows that this method can objectively,reasonably and effectively classify Scrophulariae Radix pieces,and further promote and apply the evaluation method of slice model quality constant to prove the rationality,scientificity and practicability.

Investigation of the In Vivo Metabolism of Sibirioside A and Angoroside C in Rats by HPLC-ESI-IT-TOF-MSn

Sibirioside A and angoroside C are two important phenylpropanoid glycosides of the traditional Chinese medicine Scrophulariae Radix. High performance liquid chromatography, coupled with an ion trap time-of-flight multistage mass spectrometry equipped with electrospray ionization source (HPLC-ESI-IT-TOF-MSⁿ), was applied to the profile and we identified the metabolites of sibirioside A and angoroside C in vivo in rats. A total of four metabolites of sibirioside A were identified: SM1, SM2 and SM3 which were known as new compounds. A total of 25 metabolites were detected for angoroside C: AM4, AM5, AM6, AM7, AM16, AM17, AM20, AM21, AM22, AM23 and AM25 which were identified to be new compounds. The main metabolic reactions were hydrolysis, reduction, hydroxylation, methylation, sulfation, and gluconylation. The prototype of sibirioside A was widely distributed in tissues found in the heart, liver, spleen, lung, kidney, stomach and small intestine of rats, and mainly distributed in the stomach, small intestine, kidney and liver. But for angoroside C, nothing was found in the viscera except the stomach and small intestine. The metabolites of sibirioside A were mainly eliminated from feces, while it was urine for the metabolites of angoroside C. Furthermore, 19 metabolites were likely to have bioactivities based on the ‘PharmMapper’ analysis, which roughly matched the known pharmacological activities of Scrophulariae Radix (SR) and the prototypes. One of the main pharmacological activities of SR in traditional Chinese medicine is anti-diabetes, and the predicted results showed that SM1, SM2, SM3, AM2, AM4, AM5, AM6, AM9, AM10, AM11, AM12, AM13, AM15, AM18, AM19, AM24, and AM25 might be used to cure diabetes. These findings provide a reference for studying the metabolism, distribution and pharmacological actions of phenylpropanoid glycosides in vivo.

[Identification of chemical constituents in Scrophulariae Radix by HPLC-IT-TOF-MS]

This experiment was performed to establish a qualitative analysis on chemical constituents of Scrophulariae Radix by HPLC-ESI-IT-TOF-MS．The analysis was conducted on a C₁₈ column (Kromasil 100-5, 4.6 mm×250 mm, 5 μm) with 0.1% formic acid-acetonitrile as the mobile phase for gradient elution; ESI ion source was used for mass spectra, and data were collected innegative and positive modes. The results showed that 64 compounds from Scrophulariae Radix had been identified by analyzing negative ion mass data including element composition and by comparing with data from literature. Two new compounds (4-hydroxy-6-O-methylcatalpol and acetylangoroside C) and seventeen known compounds were detected from Scrophulariae Radix for the first time. Seventeen known compounds included twelve iridoid glycosides, three phenylpropanoid glycosides and two other kind compounds. This study will provide chemical basis for elucidation of the effective substance in the Scrophulariae Radix.

Quality Evaluation of Scrophulariae Radix Processed by Different 'Sweating' Methods Based on Simultaneous Determination of Multiple Bioactive Constituents Combined with Grey Relational Analysis

Scrophulariae Radix is one of the most popular traditional Chinese medicines (TCMs), which needs to be processed by ‘sweating’ methods. Primary processing of Scrophulariae Radix is an important link which closely relates to the quality of products in this TCM. To facilitate selection of the suitable ‘sweating’ processing method for Scrophulariae Radix, in this study the quality of Scrophulariae Radix processed by different ‘sweating’ methods was evaluated based on simultaneous determination of multiple bioactive constituents combined with grey relational analysis. The contents of iridoid glycosides, phenylpropanoid glycosides, and organic acids in Scrophulariae Radix processed by different ‘sweating’ methods were simultaneously determined using ultra high performance liquid chromatography coupled with triple quadrupole-linear ion trap mass spectrometry (UPLC-QTRAP-MS/MS). Furthermore, grey relational analysis (GRA) was performed to evaluate the ‘sweating’ processed samples according to the contents of twelve constituents. All of the results demonstrated that the quality of Scrophulariae Radix processed by oven drying at 35 °C and ‘sweating’ for three days was better. The developed method was useful for the overall assessment on quality of Scrophulariae Radix, and this study may provide the foundation and support for ‘sweating’ processing of Scrophulariae Radix in normalization and standardization.