Comprehensive separation and identification of chemical constituents from Apocynum venetum leaves by high-performance counter-current chromatography and high performance liquid chromatography coupled with mass spectrometry

Ethnomedical uses, phytochemistry and pharmacology of Apocynum venetum L

ETHNOPHARMACOLOGICAL RELEVANCE

Apocynum venetum L., commonly known as Luobuma, has been widely utilized in East Asia and Southeast Asia for its medicinal properties and health benefits. Its first documented mention is found in the classic Chinese text Divine Farmer's Materia Medica from the Eastern Han Dynasty, in which it is referred to as "Zeqi." In 1977, the leaves of A. venetum were officially included in the Chinese Pharmacopoeia. The 2020 edition of the Chinese Pharmacopoeia attributes various effects to A. venetum, including liver pacification, spirit tranquilization, heat clearance, and water disinhibition.

AIMS OF THE REVIEW

Despite the abundance of recent studies on A. venetum leaves, a comprehensive review of the literature that incorporates the latest research findings is lacking. The primary goal of this article is to provide researchers with a more comprehensive and detailed reference by conducting an in-depth analysis of the traditional medicinal uses, phytochemicals, and pharmacological mechanisms associated with A. venetum leaves.

MATERIALS AND METHODS

This research project includes original articles published from 1957 to 2024 from various databases, including Web of Science, PubMed, and the China National Knowledge Infrastructure (CNKI). Furthermore, data from ancient Chinese herbal texts, doctoral dissertations, and master's theses were examined, encompassing a total of 89 records.

RESULTS

A. venetum, which is widely utilized in traditional ethnic medicine, possesses a diverse botanical chemical composition with 371 chemical constituents, including flavonoids, terpenoids, steroids, phenylpropanoids, organic acids, polysaccharides, and volatile oils. Although the water-soluble components of A. venetum remain incompletely understood, empirical evidence and scholarly literature have demonstrated the beneficial pharmacological effects of its extracts and chemical constituents, particularly the flavonoids, which offer various effects, including cardiovascular protection, anticancer properties, antioxidant activity, and anti-inflammatory effects.

CONCLUSIONS

This review presents a comprehensive review of the traditional and contemporary medicinal applications of A. venetum. These findings indicate that A. venetum is effective in treating hypertension and also shows promise in addressing hyperlipidemia, atherosclerosis, and myocardial damage. This discovery may offer novel perspectives on the prevention and management of cardiovascular diseases associated with hypertension. Additionally, the article outlines a total of 114 nonvolatile phytochemicals and 257 volatile components identified in A. venetum extract, which is a significant increase compared with the previous literature. Drawing upon published data, this paper also employs bioinformatic analysis to anticipate the potential activity of additional components. In conclusion, this article offers the most comprehensive summary to date of the traditional medicinal uses and components of A. venetum, serving as a scientific foundation for the potential expansion of its clinical application.

Comparative genome and metabolome analyses uncover the evolution and flavonoid biosynthesis between Apocynum venetum and Apocynum hendersonii

Apocynum species have great application prospects in textile and phytoremediation of saline soil, are rich in flavonoids, and possess medicinal significance. Here, we report the draft genomes of Apocynum venetum and Apocynum hendersonii, and elucidate their evolutionary relationship. The high synteny and collinearity between the two suggested that they have experienced the same WGD event. Comparative analysis revealed that flavone 3-hydroxylase (ApF3H) and differentially evolved flavonoid 3-O-glucosyl transferase (ApUFGT) genes are critical for determining natural variation in flavonoid biosynthesis between the species. Overexpression of ApF3H-1 enhanced the total flavonoid content and promoted the antioxidant capacity of transformed plants compared to the wild-type. ApUFGT5 and 6 explained the diversification of flavonoids or their derivatives. These data provide biochemical insight and knowledge on the genetic regulation of flavonoid biosynthesis, supporting the adoption of these genes in breeding programs aimed at the multipurpose utilization of the plants.

Solid-state fermentation of Apocynum venetum L. by Aspergillus niger: Effect on phenolic compounds, antioxidant activities and metabolic syndrome-associated enzymes

This study aimed to evaluate the effect of solid-state fermentation (SSF) with Aspergillus niger on the total phenolic content (TPC), the total flavonoid content (TFC), individual phenolic contents, and antioxidant and inhibitory activities against metabolic syndrome-associated enzymes in an ethanol extract from Apocynum venetum L. (AVL). TPC, TFC, and the contents of quercetin and kaempferol during SSF were 1.52-, 1.33-, 3.64-, and 2.22-fold higher than those of native AVL in the ethyl acetate (EA) subfraction of the ethanol extract. The ABTS·⁺, DPPH· scavenging, and inhibitory activities against α-glucosidase and pancreatic lipase were found to be highest in the EA subfraction. Fermentation significantly increased the ABTS radical cation, DPPH radical scavenging, and pancreatic lipase inhibitory activities by 1.33, 1.39, and 1.28 times, respectively. TPC showed a significantly positive correlation with antioxidant activities or inhibition against metabolic syndrome-associated enzymes. This study provides a theoretical basis for producing tea products with enhanced antioxidant, antidiabetic, and antihyperlipidemic activities.

Health Benefits of Avicularin in the Medicine Against Cancerous Disorders and other Complications: Biological Importance, Therapeutic Benefit and Analytical Aspects

Background:

Herbal drugs and their derived phytochemicals have been used in medicine for the preparation of different types of pharmaceutical products. Pure phytochemicals including flavonoids, alkaloids and terpenoids have been used in medicine for the treatment of different types of human disorders including cancerous disorders. Flavonoids have been well known in medicine for their anti-viral, anti-bacterial, anti-inflammatory, anti-diabetic, anti-cancer, anti-aging and cardioprotective potential. Avicularin, also called quercetin-3-α-l-arabino furanoside, is a pure flavonoid, a class of phytochemicals, found to be present in Lindera erythrocarpa and Lespedeza cuneata. Avicularin has been well known in medicine for its anti-cancer properties.

Methods:

In the present work, scientific data of avicularin have been collected from different databases such as Google, PubMed, Science Direct, Google Scholar and Scopus and summarized with reference to medicinal importance, pharmacological activities and analytical aspects of avicularin. The present review summarized the health beneficial properties of avicularin in medicine through data analysis of various scientific research works. Further analytical progress in medicine for the qualitative and quantitative analysis of avicularin in medicine has been also discussed in the present work.

Results:

Scientific data analysis of different literature work revealed the biological importance of flavonoid class of phytochemical ‘avicularin’ in medicine. Scientific data analysis revealed that avicularin was found to be present in the Lindera erythrocarpa, Lespedeza cuneata, Rhododendron schlipenbachii and Psidium guajava. Avicularin has been well known in medicine for its anti-inflammatory, anti-allergic, anti-oxidant, anti-tumor and hepatoprotective activities. Avicularin protects cardiomyocytes and hepatocytes against oxidative stress-induced apoptosis and induces cytotoxicity in cancer lines and tumor tissues. Avicularin has positive influence on human hepatocellular carcinoma and inhibits intracellular lipid accumulation. The role of avicularin in rheumatoid arthritis has been also established with its underlying molecular mechanisms in the scientific work. Recent interest in avicularin has focused on pharmacological investigations for its anti-cancer activity in the medicine.

Conclusion:

The present work signified the biological importance of avicularin in medicine through its medicinal uses, pharmacological activities and analytical aspects in the biological system.

Isoquercitrin from Apocynum venetum L. produces an anti-obesity effect on obese mice by targeting C-1-tetrahydrofolate synthase, carbonyl reductase, and glutathione S-transferase P and modification of the AMPK/SREBP-1c/FAS/CD36 signaling pathway in mice in vivo

In the present study, mice with high-fat-diet-induced obesity were used in investigating the anti-obesity effects of an aqueous extract and isoquercitrin from Apocynum venetum L.

UPLC-ESI-MS/MS Based Characterization of Active Flavonoids from Apocynum spp. and Anti-Bacteria Assay

In the current study, the active flavonoids from Apocynum venetum and Apocynum hendersonii leaf were efficiently characterized using UPLC-ESI-MS/MS, and yielding the highest content of 15.35 mg/g (A. venetum) and 13.28 mg/g (A. hendersonii) respectively. The antioxidant assay in vitro showed that the isolated flavonoid ingredient groups exhibited free radical scavenging activities to DPPH, ABTS and linoleic acid. The antimicrobial assay revealed the isolated flavonoid ingredient from both A. venetum and A. hendorsonii have exerted anti-MRSA and anti-P. aeruginosa effect through disrupting cell integrity and declining ATP. In vivo assay demonstrated that these flavonoid ingredients effectively accelerated MRSA-infected and P. aeruginosa-infected Balb/c mice wound healing. In summary, these results showed that the characterized flavonoid ingredients exhibited great potential as natural antioxidant and antimicrobial agents, and shed light into future potential applications of Apocynum spp.

Transcriptomic and Metabolomic Differences Between Two Saposhnikovia divaricata (Turcz.) Schischk Phenotypes With Single- and Double-Headed Roots

Saposhnikovia divaricata is derived from the dried roots of Saposhnikovia divaricata (Turcz.) Schischk and used as a Chinese herbal medicine for treating respiratory, immune, and nervous system diseases. The continuously increasing market demand for traditional Chinese medicine requires the commercial cultivation of Saposhnikovia divaricata using standardized methods and high yielding genotypes, such as double-headed root plants, for achieving consistent quality and a reliable supply. In this study, we aimed to identify the quantitative differences in chromone, a precursor of flavonoid biosynthesis, between plants with single- and double-headed roots using high-performance liquid chromatography and further explore the two phenotypes at the transcriptomic and metabolomic levels. Our results showed that the chromone content was significantly higher in plants with double-headed roots than in those with single-headed roots. Transcriptomic analysis revealed six significantly differentially expressed genes between the two phenotypes, including five key genes in the flavonoid biosynthesis pathway (4-coumarate-CoA ligase, chalcone synthase 1, vinorine synthase, chalcone-flavonone isomerase 1, and flavanone 3 beta-hydroxylase) and one key gene in the abscisic acid biosynthetic pathway (zeaxanthin epoxidase). Moreover, metabolomic analysis showed that the 126 differentially expressed metabolites were mainly enriched in the biosynthesis of secondary metabolites and phytohormones. Overall, our results suggest that plants with double-headed roots have higher medicinal value than those with single-headed roots, probably due to differences in various biosynthetic pathways. These data might help select the genotypes with superior yield and therapeutic properties.

Application of Linear Gradient Solvent System in Centrifugal Partition Chromatography Facilitating Bioassay-Guided Fractionation of Yongdamsagan-Tang, Traditional Oriental Decoction

As important pharmaceutical resources, traditional herbal medicines retain continuous attention. To do that, isolation and identification of bioactive molecules from traditional herbal decoction are important. However, conventional fractionation through octadecyl silica column faces irreversible sample adsorption that causes a bias in bioactivity assessment. However, liquid-liquid chromatographic system suffers tedious K value calculation as well as insufficient capacity in separation power when crude extract composed of widely ranging polarities. Here, we developed a comprehensive linear gradient solvent system for centrifugal partition chromatography (CPC) to aid bioassay-guided isolation. The lower aqueous phase of the n-hexane-acetonitrile-water (10:2:8, v/v) was used as the stationary, whereas its upper organic phase followed by the upper phase of ethyl acetate-acetonitrile-water and water-saturated n-butanol-acetonitrile-water in the same ratio were eluted in a linear gradient mode, thereby increasing polarity in the mobile phase. The HPLC profiling of CPC fraction showed that proposed gradient CPC was suitable to separate metabolites from Yongdamsagan-Tang, a traditional medicinal decoction made of ten herbal plants. Exhibiting a high recovery yield of 98.3%, antioxidant response element (ARE) luciferase-inducing assay in HepG2 cells indicated that the fractions composed of baicalein and wogonin, the marker natural products of Scutellaria baicalensis, were to be the most effective molecules from Yongdamsagan-Tang. The presented results demonstrated that bioassay-guided separation that assisted with a linear gradient CPC is an incomparable alternative to HPLC and biphasic CPC in terms of higher yield rate and redundant K value calculation, respectively, which led to an unbiased/time-saving separation and identification of bioactive molecules from the complex crude extract of natural products.

Bioassay-Guided Isolation of Two Eudesmane Sesquiterpenes from Lindera strychnifolia Using Centrifugal Partition Chromatography

In this study, a centrifugal partition chromatography (CPC) separation was applied to identify antioxidant-responsive element (ARE) induction molecules from the crude extract of Lindera strychnifolia roots. CPC was operated with a two-phase solvent system composed of n-hexane-methanol-water (10:8.5:1.5, v/v/v) in dual mode (descending to ascending), which provided a high recovery rate (>95.5%) with high resolution. Then, ARE induction activity of obtained CPC fractions was examined in ARE-transfected HepG2 cells according to the weight ratios of the obtained fractions. The fraction exhibiting ARE-inducing activity was further purified by preparative HPLC that led to isolation of two eudesmane type sesquiterpenes as active compounds. The chemical structures were elucidated as linderolide U (1) and a new sesquiterpene named as linderolide V (2) by spectroscopic data. Further bioactivity test demonstrated that compounds 1 and 2 enhanced ARE activity by 22.4-fold and 7.6-fold, respectively, at 100 μM concentration while 5 μM of sulforaphane induced ARE activity 24.8-fold compared to the control.

UPLC-MS/MS Determination of Chlorogenic Acid, Hyperoside and Astragalin in Plasma and its Pharmacokinetic Application in Liver Injury Rats

Background:

Cuscutae Semen (CS) is reported to show a hepatoprotective effect. Chlorogenic acid, hyperoside and astragalin are three major biologically active components from CS.

Objective:

A sensitive method based on ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated to quantify the three components in rat plasma and was successfully used to study pharmacokinetics in liver injury rats.

Methods:

Plasma samples were prepared with protein precipitation by acetonitrile. Chromatographic separation was achieved on ACQUITY-XBridge BEH C18 column with gradient elution using the mobile phase containing 0.05% formic acid in water (A) and acetonitrile (B). The three components were quantified using Electrospray Ionization (ESI) source in the negative multiple Reaction Monitoring (MRM) mode.

Results:

Calibration curves of each analyte showed good linearity with correlation coefficients over 0.99. Accuracies (RE%) and precisions (RSD%) were within 15%. The method was stable. Recovery of the target compounds in plasma samples ranged from 87.00% to 102.29%. No matrix effect was found to influence the quantitative method.

Conclusion:

The UPLC-MS/MS method met the acceptance criteria and was successfully applied to the simultaneous determination of chlorogenic acid, hyperoside and astragalin in rat plasma for the first time. It is suitable for pharmacokinetic application in liver injury rats. It provides the foundation for further development and utilization of the hepatoprotective effect of cuscutae semen.

Antioxidant, Anti-Inflammatory, and Cytotoxic Properties and Chemical Compositions of Filipendula palmata (Pall.) Maxim

Filipendula palmata (Pall.) Maxim. remains unexplored and underutilized resources with a high potential to improve human health. In this study, a new ursane-type triterpenoid, namely, 2α, 3β-dihydroxyurs-12-en-28-aldehyde (compound 10), and other 23 known compounds were isolated. 5 triterpenoids (compounds 6, 8, and 10-12), 11 flavonoids (compounds 13-15 and 17-24), 6 phenolic compounds (compounds 1, 2, 4, 5, 9, and 16), 2 sterols (compounds 3 and 7) were isolated from the aqueous solution extract of the aerial parts of F. palmata. The structures of all compounds were elucidated by the use of extensive spectroscopic methods such as infrared spectroscopy (IR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), ¹H-NMR, and ¹³C-NMR. The solvent extractions of ethyl acetate fraction were evaluated for antioxidant activities using DPPH (2, 2-diphenyl-1-picrylhydrazyl) and ABTS⁺ (2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) methods. The anti-inflammatory effects of the compounds were evaluated in lipopolysaccharide- (LPS-) stimulated RAW 264.7 macrophages. The extract cytotoxicity on the cancer cell lines MCF-7, HeLa, 4T1, and A549 was determined by MTT assay. As a result, compounds 10, 11, and 12 exhibited better antioxidant activity compared to the other compounds. Compounds 8-24 had different inhibitory effects on the release of NO, TNF-α, and IL-6 in LPS-stimulated RAW 264.7 cells. The new compound has shown a significant inhibiting effect on cancer cells, and the cell inhibition rate increased in a dose-dependent manner. Further research to elucidate the chemical compositions and pharmacological effects of F. palmata is of major importance towards the development and foundation of clinical application of the species.

Development of a method to screen and isolate lipoxidase inhibitors from Radix Saposhnikoviae via ultrafiltration liquid chromatography combined with metablism in vitro

INTRODUCTION

Radix Saposhnikoviae is an excellent source of chromones, the consumption of which has been shown to positively affect human health, such as anti-inflammatory and antioxidant activities in vivo, and it also has been used to treat headache, inflammation, and cancer as a herbal medicine or functional soup.

OBJECTIVE

Isolation and screening of lipoxidase (LOX) inhibitors from Radix Saposhnikoviae. As a result, the metabolism of the active ingredients in cytochrome P450 (CYP450) in vitro was identified.

METHODS

Screen and identify the LOX inhibitors from Radix Saposhnikoviae by ultrafiltration-liquid chromatography-mass spectrometry (UF-LC-MS). Then take the isolation and purification of the inhibitors by high-speed counter-current chromatography (HSCCC) and semi-preparative high-performance liquid chromatography (HPLC). Furthermore, the active ingredients were used to study the metabolism in vitro in CYP450.

RESULTS

Subsequently, the specific binding ligands, prim-O-glucosylcimifugin, cimifugin, and 5-O-methylvisamminol (with purities of 95.28, 92.33%, and 97.89, respectively) were separated by HSCCC. Semi-preparative HPLC was applied to separate the four major compounds in Radix Saposhnikoviae and identify them as prim-O-glucosylcimifugin, 5-O-methylvisamminol, sec-O-glucosylhamaudol, and hamaudol, which were obtained with relatively high purity. Furthermore, the three chromone possible metabolism pathways were obtained.

CONCLUSION

The results demonstrated that UF-LC-MS combined with HSCCC and semi-preparative HPLC is not only a powerful tool for screening and isolating LOX inhibitors in complex samples, but also a useful platform for discovering bioactive compounds for anti-inflammatory activity. This study provides information regarding the active ingredients of chromones in Radix Saposhnikoviae and a framework for anti-inflammatory activity treatment.

Bioassay-Guided Separation of Centipeda minima Using Comprehensive Linear Gradient Centrifugal Partition Chromatography

A comprehensive linear gradient solvent system for centrifugal partition chromatography (CPC) was developed for the bioassay-guided isolation of natural compounds. The gradient solvent system consisted of three different ternary biphasic solvents types: n-hexane–acetonitrile–water (10:2:8, v/v), ethyl acetate–acetonitrile–water (10:2:8, v/v), and water-saturated n-butanol–acetonitrile–water (10:2:8, v/v). The lower phase of the n-hexane–acetonitrile–water (10:2:8, v/v) was used as the stationary phase, while its upper phase, as well as ethyl acetate–acetonitrile–water (10:2:8), and water-saturated n-butanol–acetonitrile–water (10:2:8, v/v) were pumped to generate a linear gradient elution, increasing the mobile phase polarity. We used the gradient CPC to identify antioxidant response elements (AREs), inducing compounds from Centipeda minima, using an ARE-luciferase assay in HepG2 cells, which led to the purification of the active molecules 3-methoxyquercetin and brevilin A. The developed CPC solvent systems allow the separation and isolation of compounds with a wide polarity range, allowing active molecule identification in the complex crude extract of natural products.

In Vitro Analysis of Antioxidant, Anticancer, and Bioactive Components of Apocynum venetum Tea Extracts

The dry leaf of Apocynum venetum tea extracts (AVTEs) belonging to the Apocynaceae family is a traditional Chinese medicine. The aim of this study is to identify the bioactive components of AVTE and analyse its antioxidant and anticancer activity in vitro. Method. Flavones and polyphenols in AVTE were determined by high-performance liquid chromatography (HPLC) assay. The scavenging capacity of tea extracts to 1,1-diphenyl-2-picrylhydrazyl (DPPH); 2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS); hydroxyl (OH); and superoxide anion-free radicals were investigated by spectrophotometry. We also detailed the cytotoxicity assay of AVTE (50, 100, and 200 μg/mL) to human embryonic kidney 293T cells, the protective effect of AVTE on 293T cells induced by hydrogen peroxide (0.3 mmol/L), and the anticancer effect against the human hepatoma HepG2 cells via 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. We investigated the antioxidative effects of AVTE in human embryonic kidney 293T cells and the anticancer mechanism in HepG2 human hepatoma cells via quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR) assay. Results. HPLC analysis showed that AVTEs contain neochlorogenic acid, chlorogenic acid, rutin, isoquercetin, isochlorogenic acid B, astragalin, isochlorogenic acid C, rosmarinic acid, quercetin, and trans-cinnamic acid. These extracts have high antioxidant activity and dose-dependent relation through free radical scavenging experiments. The cell viability of 293T cells treated with hydrogen peroxide (0.3 mmol/L) was significantly lower than that of normal cells, and the cell viability of oxidatively stressed 293T cells after AVTE (50, 100, and 200 μg/mL) treatment was significantly improved (P<0.05). Moreover, cytotoxicity experiments showed that the survival rate of 293T cells was over 90%, but the proliferation of HepG2 cells was significantly inhibited in a dose-dependent manner by AVTE. Furthermore, cytoprotective effects in 293T cells were induced via upregulation of glutathione peroxidase (GSH-Px), GSH, superoxide dismutase (SOD), and catalase (CAT) antioxidant-related factors, as well as apoptosis in HepG2 cells was induced via upregulation of caspase-3, caspase-9, p21, and p53 apoptosis-associated factors, as assessed via mRNA expression levels after treatment with AVTE, which were consistent with the results of antioxidant gene detections. As a conclusion, AVTE appears to be an effectively functional drink, due to its rich functional components and antioxidant and anticancer activities.

Integration of in vitro and in silico perspectives to explain chemical characterization, biological potential and anticancer effects of Hypericum salsugineum: A pharmacologically active source for functional drug formulations

The genus Hypericum is one of the most popular genera in both traditional medicine and scientific platform. This study is designed to provide conceptual insights on the biological potential and chemical characterization of H. salsugineum, which is endemic to Turkey. The qualitative and quantitative phenolic content of the extracts was characterized by HPLC-ESI-MSn. Biological efficiency was investigated by enzyme inhibitory assays (cholinesterases, tyrosinase, amylase, and glucosidase) and anti-cancer efficacy tests (anti-proliferative activities with the iCELLigence technology, colony formation and wound healing scratch assays). Phenolic acids (3-O-caffeoylquinic, 5-O-caffeoylquinic, and 4-O-caffeoylquinic acids) were the predominant group in the studied extracts, although several flavonoids were also detected and quantified. The extracts exhibited good inhibitory effects on tyrosinase and glucosidase, while they had weak ability against cholinesterases and amylase. Computational studies were also performed to explain the interactions between the major phenolics and these enzymes. The extracts displayed significant anti-cancer effects on breast carcinoma cell lines. Our findings suggest that Hypericum salsugineum could be valued as a potential source of biologically-active compounds for designing novel products.

Astragalin: A Bioactive Phytochemical with Potential Therapeutic Activities

Natural products, an infinite treasure of bioactive chemical entities, persist as an inexhaustible resource for discovery of drugs. This review article intends to emphasize on one of the naturally occurring flavonoids, astragalin (kaempferol 3-glucoside), which is a bioactive constituent of various traditional medicinal plants such as Cuscuta chinensis. This multifaceted compound is well known for its diversified pharmacological applications such as anti-inflammatory, antioxidant, neuroprotective, cardioprotective, antiobesity, antiosteoporotic, anticancer, antiulcer, and antidiabetic properties. It carries out the aforementioned activities by the regulation and modulation of various molecular targets such as transcription factors (NF-κB, TNF-α, and TGF-β1), enzymes (iNOS, COX-2, PGE2, MMP-1, MMP-3, MIP-1α, COX-2, PGE-2, HK2, AChe, SOD, DRP-1, DDH, PLCγ1, and GPX), kinases (JNK, MAPK, Akt, ERK, SAPK, IκBα, PI3K, and PKCβ2), cell adhesion proteins (E-cadherin, vimentin PAR-2, and NCam), apoptotic and antiapoptotic proteins (Beclin-1, Bcl-2, Bax, Bcl-xL, cytochrome c, LC3A/B, caspase-3, caspase-9, procaspase-3, procaspase-8, and IgE), and inflammatory cytokines (SOCS-3, SOCS-5, IL-1β, IL-4, IL-6, IL-8, IL-13, MCP-1, CXCL-1, CXCL-2, and IFN-γ). Although researchers have reported multiple pharmacological applications of astragalin in various diseased conditions, further experimental investigations are still mandatory to fully understand its mechanism of action. It is contemplated that astragalin could be subjected to structural optimization to ameliorate its chemical accessibility, to optimize its absorption profiles, and to synthesize its more effective analogues which will ultimately lead towards potent drug candidates.

Quality Evaluation of Apocyni Veneti Folium from Different Habitats and Commercial Herbs Based on Simultaneous Determination of Multiple Bioactive Constituents Combined with Multivariate Statistical Analysis

Apocyni Veneti Folium (AVF) is a kind of staple traditional Chinese medicine with vast clinical consumption because of its positive effects. However, due to the habitats and adulterants, its quality is uneven. To control the quality of this medicinal herb, in this study, the quality of AVF was evaluated based on simultaneous determination of multiple bioactive constituents combined with multivariate statistical analysis. A reliable method based on ultra-fast liquid chromatography tandem triple quadrupole mass spectrometry (UFLC-QTRAP-MS/MS) was developed for the simultaneous determination of a total of 43 constituents, including 15 flavonoids, 6 organic acids, 13 amino acids, and 9 nucleosides in 41 Luobumaye samples from different habitats and commercial herbs. Furthermore, according to the contents of these 43 constituents, principal component analysis (PCA) was employed to classify and distinguish between AVF and its adulterants, leaves of Poacynum hendersonii (PHF), and gray relational analysis (GRA) was performed to evaluate the quality of the samples. The proposed method was successfully applied to the comprehensive quality evaluation of AVF, and all results demonstrated that the quality of AVF was higher than the PHF. This study will provide comprehensive information necessary for the quality control of AVF.

Phytochemical characterization,in vitroandin silicoapproaches for threeHypericumspecies

Members of theHypericumgenus are spread throughout the world and have a long history of use in traditional systems of medicines.

Enhanced HPLC-DAD Method for Fast Determination of Quercetin-3-O-β-d-Glucoside in Extracts and Polyherbal Formulations Containing Azadirachta indica-Optimization and Validation

Azadirachta indica has been used for its medicinal properties since time immemorial. Herbal medicines which are prepared using this medicinal tree are utilized to treat various diseases and disorders. No reports are available for marker-based standardization of these herbal medicines prepared from leaves of A. indica. Also existing HPLC methods for determination quercetin-3-O-β-d-glucoside are time consuming. There is an obvious need for development of new HPLC method for quantification of quercetin-3-O-β-d-glucoside which is fast enough to carry out analysis in stipulated time period. This article deals with the development, optimization and validation of fast HPLC-DAD method for the determination of quercetin-3-O-β-d-glucoside in extracts containing A. indica for its successive application for marker-based standardization of herbal formulations containing A. indica. The retention time of quercetin-3-O-β-d-glucoside was 11.213 min. The method was found to be linear in the range of 4.0-60 µg mL-1. Limit of detection and limit of quantitation of the proposed method were found to be 1.33 and 4.0 µg mL-1, respectively. The mean recoveries were found to be within 93.53-103.75%. The method can be used as quality control tool for routine analysis of herbal extracts and formulations containing A. indicia.

Extraction, Preconcentration and Isolation of Flavonoids from Apocynum venetum L. Leaves Using Ionic Liquid-Based Ultrasonic-Assisted Extraction Coupled with an Aqueous Biphasic System

BACKGROUND

Ionic liquids (ILs) are considered as green solvents, and widely applied for the extraction of various compounds.

METHODS

The present research focuses on the extraction of flavonoids from Apocynum venetum L. leaves by ultrasound-assisted extraction (UAE). Several major influencing factors were optimized. Then, an aqueous biphasic system (ABS) was applied for further isolation of flavonoids.

RESULTS

The flavonoids were mainly distributed in the top phase, while impurities were extracted to the bottom phase. The parameters influencing the extraction, namely type and concentration of salt, temperature, and pH, were studied in detail. Under optimized conditions (72.43% IL extract, 28.57% (NH4)2SO4, 25 °C temperature, pH 4.5), the preconcentration factor and extraction efficiency were found to be 3.78% and 93.35%, respectively.

CONCLUSIONS

This simple and efficient methodology is expected to see great use in the extraction and isolation of pharmaceutically active components from medicinal plant resources.

Separation of phenolic acids and flavonoids from Trollius chinensis Bunge by high speed counter-current chromatography

In this work, eleven compounds were successfully separated from Trollius chinensis Bunge by using a two-step high-speed counter-current chromatography (HSCCC) method. NRTL-SAC (nonrandom two-liquid segment activity coefficient) method, a newly developed solvent system selection strategy, was applied to screening the suitable biphasic liquid systems. Hexane/ethyl acetate/ethanol/water (3:7:3:7, v/v) solvent system was used in the first step, while the hexane/ethyl acetate/methanol/water (1:2:1:2, 1:4:1:4, 1:9:1:9, v/v) systems were employed in the second step. The chemical structures of the separated compounds were identified by UV, high resolution ESI-MS and MS/MS data. The separated compounds are 3,4-dihydroxyphenylethanol (1), vanillic acid (2), orientin (3), vitexin (4), veratric acid (5), 2″-O-(3‴, 4‴-dimethoxybenzoyl) orientin (6), 2″-O-feruloylorientin (7), 2″-O-feruloylvitexin (8), 2″-O-(2‴-methylbutyryl) vitexin (9), 2″-O-(2‴-methylbutyryl) isoswertiajaponin (10), 2″-O-(2‴-methylbutyryl) isoswertisin (11). The results demonstrate that HSCCC is a powerful tool for the separation of compounds from extremely complex samples.

Countercurrent Separation of Natural Products: An Update

This work assesses the current instrumentation, method development, and applications in countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC), collectively referred to as countercurrent separation (CCS). The article provides a critical review of the CCS literature from 2007 since our last review (J. Nat. Prod. 2008, 71, 1489-1508), with a special emphasis on the applications of CCS in natural products research. The current state of CCS is reviewed in regard to three continuing topics (instrumentation, solvent system development, theory) and three new topics (optimization of parameters, workflow, bioactivity applications). The goals of this review are to deliver the necessary background with references for an up-to-date perspective of CCS, to point out its potential for the natural product scientist, and thereby to induce new applications in natural product chemistry, metabolome, and drug discovery research involving organisms from terrestrial and marine sources.

UPLC-Q-TOF/MS-based screening and identification of the main flavonoids and their metabolites in rat bile, urine and feces after oral administration of Scutellaria baicalensis extract

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese Medicines (TCMs) are increasingly used in combination with Western medicine. Scutellaria baicalensis Georgi (Lamiaceae) is a widely used TCM in treating various diseases. However, the in vivo metabolism of its main bioactive flavonoids, baicalin, baicalein, wogonoside and wogonin, needs further study.

MATERIALS AND METHODS

A systematic method based on ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS) technique combined with Metabolynx(TM) software was developed to speculate the metabolites and excretion profiles of the main flavonoids in S. baicalensis extract in rats bile, urine and feces samples after oral administration of the extract.

RESULTS

Four parent components and a total of 15 metabolites were tentatively detected in vivo. All metabolites were detected including sulfate and glucuronide conjugates, hydroxylated, methylated, acetylated and deoxygenated products. Twelve metabolites were from the rat urine, five from the feces and two from the bile. Among them, several products were reported firstly.

CONCLUSION

The research provided useful information for further study of the pharmacology and mechanism of action of S. baicalensis extract in vivo and a proposed method which could develop an integrated template approach to analyze screening and identification of biological samples after oral administration of TCMs.

Apocynum venetum Attenuates Acetaminophen-Induced Liver Injury in Mice

Apocynum venetum L. (A. venetum) has long been used in oriental folk medicine for the treatment of some liver diseases; however, the underlying mechanisms remain to be fully elucidated. Acetaminphen (APAP) is a widely used analgesic drug that can cause acute liver injury in overdose situations. In this study, we investigated the potential protective effect of A. venetum leaf extract (ALE) against APAP-induced hepatotoxicity. Mice were intragastrically administered with ALE once daily for 3 consecutive days prior to receiving a single intraperitoneal injection of APAP. The APAP group showed severe liver injury characterized by the noticeable fluctuations in the following parameters: serum aminotransferases; hepatic malondialdehyde (MDA), 3-nitrotyrosine (3-NT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione (GSH). These liver damages induced by APAP were significantly attenuated by ALE pretreatments. A collective analysis of histopathological examination, DNA laddering and western blot for caspase-3 and cytochrome c indicated that the ALE is also capable of preventing APAP-induced hepatocyte death. Hyperoside, isoquercitrin and their derivatives have been identified as the major components of ALE using HPLC-MS/MS. Taken together, the A. venetum possesses hepatoprotective effects partially due to its anti-oxidant action.

Discrimination between Leave of Apocynum venetum and Its Adulterant, A. pictum Based on Antioxidant Assay and Chemical Profiles Combined with Multivariate Statistical Analysis

An integrated approach including chemical and biological assessments was developed to investigate the differences between Apocynum venetum L. (AV) and its adulterant, Apocynum pictum Schrenk (AP). Ten flavonoids were tentatively identified by ultra-visible and mass spectra data. The chemical component, hyperoside, was identified as a critical parameter for discrimination of two species from the results of principal component analysis (PCA) and quantitative analysis. The anti-oxidative power of the herbal extracts were determined using 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) assay and H₂O₂-induced cell damage on LO2 cells. The results of the biological assays suggested that the chemical differences between AV and AP do lead to difference in activity and AV is demonstrated to have higher anti-oxidant activity.

Development of a method to screen and isolate potential xanthine oxidase inhibitors from Panax japlcus var via ultrafiltration liquid chromatography combined with counter-current chromatography

Panax japlcus var is a typical Chinese herb with a large number of saponins existing in all parts of it. The common methods of screening and isolating saponins are mostly labor-intensive and time-consuming. In this study, a new assay based on ultrafiltration-liquid chromatography-mass spectrometry (UF-LC-MS) was developed for the rapid screening and identifying of the ligands for xanthine oxidase from the extract of P. japlcus. Six saponins were identified as xanthine oxidase inhibitors from the extract. Subsequently, the specific binding ligands, namely, 24 (R)-majoroside R1, chikusetsusaponin IVa, oleanolic acid-28-O-β-D-glucopyranoside, notoginsenoside Fe, ginsenoside Rb2 and ginsenoside Rd (the purities of them were 95.74%, 96.12%, 93.19%, 94.83%, 95.07% and 94.62%, respectively) were separated by high-speed counter-current chromatography (HSCCC). The component ratio of the solvent system of HSCCC was calculated with the help of a multiexponential function model was optimized. The partition coefficient (K) values of the target compounds and resolutions of peaks were employed as the research indicators, and exponential function and binomial formulas were used to optimize the solvent system and flow rate of the mobile phases in a two-stage separation. An optimized two-phase solvent system composed of ethyl acetate, isopropanol, 0.1% aqueous formic acid (1.9:1.0:1.3, v/v/v, for the first-stage) and that composed of methylene chloride, acetonitrile, isopropanol, 0.1% aqueous formic acid (5.6:1.0:2.4:5.2, v/v/v/v, for the second-stage) were used to isolate the six compounds from P. japlcus. The targeted compounds isolated, collected and purified by HSCCC were analyzed by high performance liquid chromatography (UPLC), and the chemical structures of all the six compounds were identified by UV, MS and NMR. The results demonstrate that UF-LC-MS combined with HSCCC might provide not only a powerful tool for screening and isolating xanthine oxidase inhibitors in complex samples but also a useful platform for discovering bioactive compounds for the prevention and treatment of gout.

UPLC-MS/MS method for determination of avicularin in rat plasma and its application to a pharmacokinetic study

A rapid, sensitive and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of avicularin in rat plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2 mL of acetonitrile-methanol (9:1, v/v) to a 0.1 mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 1.60 min and the elution of avicularin was at 1.20 min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring (MRM) mode using the respective transitions m/z 434.1→301.3 for avicularin and m/z 237.2→194.3 for carbamazepine (IS), respectively. The calibration curve was linear over the range of 10-3000 ng/mL with a lower limit of quantitation (LLOQ) of 10 ng/mL. Mean recovery of avicularin in plasma was in the range of 84.2-89.5%. Intra-day and inter-day precision were both <12%. This method was successfully applied in pharmacokinetic study after intravenous administration of 5.0mg/kg avicularin in rats.

Simultaneous qualitative and quantitative analysis of phenolic acids and flavonoids for the quality control of Apocynum venetum L. leaves by HPLC-DAD-ESI-IT-TOF-MS and HPLC-DAD

A reliable method based on high performance liquid chromatography-diode array detector-electrospray ionization-ion trap-time of flight-mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS) was developed for the identification of phenolic acids and flavonoids in Apocynum venetum L. leaves and its adulterant, Pocynum hendersonii (Hook. f.) Woodson leaves. A total of 21 compounds were identified or tentatively identified, including 4 phenolic acids and 17 flavonoids. 3-O-caffeoylquinic acid (3-CQA) and caffeic acid were detected for the first time in A. venetum leaves; 4-O-caffeoylquinic acid (4-CQA), 3-CQA, caffeic acid, quercetin-3-O-(6"-O-malonyl)-galactoside, quercetin-3-O-(6"-O-malonyl)-glucoside, kaempferol-3-O-(6"-O-malonyl)-glucoside, kaempferol-3-O-(6"-O-acetyl)-glucoside, and kaempferol-3-O-dihexoside were detected for the first time in P. hendersonii leaves. Cluster analysis was employed to analyze 24 batches of A. venetum leaves and 5 batches of P. hendersonii leaves collected from various regions in China. The analysis, which was based on the 21 compounds, indicated that profiles of these compounds were distinct between the two species, and among A. venetum leaf samples from different origins. 18 of these 21 compounds were selected as the markers and simultaneously analyzed by HPLC-DAD for the first time. The quantitative analytical method was validated and subsequently applied to the comprehensive quality evaluation of 24 batches of A. venetum leaves.

Application of microdialysis for elucidating the existing form of hyperoside in rat brain: comparison between intragastric and intraperitoneal administration

ETHNOPHARMACOLOGICAL RELEVANCE

Hypericum perforatum (St. John's wort) is an important anti-depressant herb used in clinic and commonly prescribed for mild depression. Hyperoside is one of the major components of H. perforatum and is also detected in many plant species such as Abelmoschus manihot, Black Currant, Rosa agrestis, Apocynum venetum and Nelumbo nucifera.

AIM OF THE STUDY

As the hyperoside showed CNS (central nervous system) protective activity (e.g. anti-depressant-like effect), the possibility of hyperoside or its metabolites to reach CNS should be investigated. Moreover, the pharmacokinetics profile of hyperoside or its metabolites in rat brain should be studied for further elucidating the mechanism of hyperoside action on CNS.

MATERIAL AND METHODS

A simple method for simultaneous determination of unbound hyperoside and its metabolite 3'-O-methyl-hyperoside in rat brain was developed by using ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) and microdialysis technique. This method was applied for pharmacokinetics study of hyperoside and 3'-O-methyl-hyperoside in rat brain after intragastric (i.g.) and intraperitoneally (i.p.) administration of hyperoside in vivo.

RESULTS

Results showed that neither hyperoside nor its metabolites were detected in rat brain after i.g. administration but both compounds could be detected after i.p. administration. Considering the activity of hyperoside through both i.g. and i.p. administration, our results imply that the active components of hyperoside in vivo might be different. Therefore, further studies are needed to identify the active components of hyperoside in vivo through these two different routes. Moreover, non-oral administration route (e.g., i.p.) should be further investigated and be explored to obtain higher bioavailability and better activity for hyperoside. Our results also showed that the real existing form of hyperoside in rat brain were hyperoside and its methylated metabolite with maximum concentration to be 63.78 ng/mL and 24.66 ng/mL after 20mg/kg i.p. administration, respectively. Therefore, a more reasonable concentration of hyperoside should be considered in in vitro assay to reflect the real situation of hyperoside concentration in vivo.

CONCLUSION

Due to the wide use of herbal remedies containing hyperoside, our investigation will contribute to further clarifying the action of this substance. Moreover, this method will be applied for clinical pharmacokinetics study of hyperoside and its metabolite as well as herbs that contain hyperoside.

Botany, traditional uses, phytochemistry and pharmacology of Apocynum venetum L. (Luobuma): A review

ETHNOPHARMACOLOGICAL RELEVANCE

Apocynum venetum L. (Apocynaceae, Luobuma ) has a long history as a Chinese traditional medicine with uses to calm the liver, soothe the nerves, dissipate heat, and promote diuresis. Recently, Luobuma tea has been commercialized as a sedative and anti-aging supplement that has become increasingly popular in North American and East Asian health food markets.

AIMS OF THE REVIEW

The aim of this review is to provide an up-to-date and comprehensive overview of the botany, chemical constituents, traditional uses, pharmacological activities and safety aspects of Apocynum venetum in order to assess its ethnopharmacological use and to explore its therapeutic potentials and future opportunities for research.

BACKGROUND AND METHODS

The accessible literature on Apocynum venetum written in English, Chinese and Japanese were collected and analyzed. The literatures included ancient Chinese herbal classics, pharmacopoeias and articles that included in Pubmed, Web of Science, Google Scholar and Wanfang.

KEY FINDINGS

Modern pharmacological studies demonstrated that Apocynum venetum possess wide pharmacological activities that include antihypertensive, cardiotonic, hepatoprotective, antioxidant, lipid-lowering, antidepressant and anxiolytic effects, which can be explained by the presence of various flavonoid compounds in this plant. The traditional (Lop Nor region) use of Apocynum venetum with tobacco as an agent to detoxify nicotine may receive interest as a possible therapeutic option to detoxify the body from smoking. Based on animal studies and clinical trials, Apocynum venetum causes no severe side effects, even in a stable daily dosage (50mg/person/day) for more than three years.

CONCLUSIONS

Apocynum venetum potentially has therapeutic potential in the prevention and treatment for the cardiovascular and neurological diseases, especially for high blood pressure, high cholesterol, neurasthenia, depression and anxiety. Further investigations are needed to explore individual bioactive compounds responsible for these in vitro and in vivo pharmacological effects and the mode of actions. Further safety assessments and clinical trials should be performed before it can be integrated into medicinal practices.

The potential of metabolic fingerprinting as a tool for the modernisation of TCM preparations

A vast majority Chinese herbal medicines (CHM) are traditionally administered as individually prepared water decoctions (tang) which are rather complicated in practice and their dry extracts show technological problems that hamper straight production of more convenient application forms. Modernised extraction procedures may overcome these difficulties but there is lack of clinical evidence supporting their therapeutic equivalence to traditional decoctions and their quality can often not solely be attributed to the single marker compounds that are usually used for chemical extract optimisation. As demonstrated by the example of the rather simple traditional TCM formula Danggui Buxue Tang, both the chemical composition and the biological activity of extracts resulting from traditional water decoction are influenced by details of the extraction procedure and especially involve pharmacokinetic synergism based on co-extraction. Hence, a more detailed knowledge about the traditional extracts' chemical profiles and their impact on biological activity is desirable in order to allow the development of modernised extracts that factually contain the whole range of compounds relevant for the efficacy of the traditional application. We propose that these compounds can be identified by metabolomics based on comprehensive fingerprint analysis of different extracts with known biological activity. TCM offers a huge variety of traditional products of the same botanical origin but with distinct therapeutic properties, like differentially processed drugs and special daodi qualities. Through this variety, TCM gives an ideal field for the application of metabolomic techniques aiming at the identification of active constituents.

Antidepressant-like effect of hyperoside isolated from Apocynum venetum leaves: possible cellular mechanisms

In the present work, we studied the possible cellular mechanisms of hyperoside isolated from Apocynum venetum leaves in corticosterone-induced neurotoxicity, using PC12 cells as a suitable in vitro model of depression. Cell viability was quantitated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The release amount of lactic dehydrogenase (LDH) and intracellular Ca(2+) concentration were measured using kit and transcript abundances of brain-derived neurotrophic factor (BDNF) and cAMP response element binding protein (CREB) were determined by real-time RT-PCR. The results of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and lactic dehydrogenase (LDH) assays showed that 2.5, 5 and 10 μg/ml hyperoside or 10 μM fluoxetine (FLU) protected PC12 cells from the lesion induced by a 48 h treatment with 10 μM corticosterone. Fura-2/AM (acetoxymethyl ester) assays showed that 2.5, 5 and 10 μg/ml hyperoside or 10 μM FLU attenuated the intracellular Ca(2+) overloading in PC12 cells induced by corticosterone. The transcript abundance of BDNF and CREB in PC12 cells was elevated upon hyperoside treatment. These results suggest that the possible cellular mechanisms of hyperoside antidepressant-like effect is a cytoprotective action related to elevation the expression of BDNF and CREB through the signal pathway AC-cAMP-CREB.

Isolation and structural elucidation of indole alkaloids from Geissospermum vellosii by mass spectrometry

Alkaloids from the stem bark of Geissospermum vellosii possess a variety of therapeutic properties including antimalarial activities, activity as a sexual stimulant and inhibition of the proliferation of HIV and herpes viruses. Methods currently used to isolate the active components from G. vellosii are time-consuming, labor intensive, and result in low recovery. In addition, there is a lack of sensitive and accurate analytical methods for the structural characterization and identification of alkaloid components in minor quantities. A combination of high performance counter-current chromatography and ESI tandem mass spectrometry (MS(n)) was established to isolate alkaloids from the stem bark of G. vellosii, and study their electrospray ionization mass spectrometry fragmentation behavior. Five indole alkaloids were successfully isolated and identified by nuclear magnetic resonance and mass spectrometry. The multi-stage tandem mass spectrometric data were used to study their fragmentation pattern and set a model for detailed structure characterization of related indole alkaloids. The presence of the even mass fragment ion suggestive of an odd number of nitrogen at m/z 144 corresponding to C(10)H(9)N was characteristic to indole alkaloids. The results of the experiments demonstrated that the combination of high performance counter current chromatography and ESI-MS(n) is a sensitive, selective and effective approach for rapid isolation and characterization of alkaloids from G. vellosii.