Ptehosides A-I: Nine undescribed iridoids with in vitro cytotoxicity from the whole plant of Pterocephalus hookeri (C.B. Clarke) Höeck.

Nine previously undescribed iridoids, ptehosides A-I (1-9), together with 12 known ones (10-21), were isolated from Pterocephalus hookeri (C.B. Clarke) Höeck. Their structures were elucidated using various spectroscopic methods including HR-ESI-MS, NMR, UV, IR and CD, etc. The cytotoxic activities of all isolates were evaluated using MTT method in three human cancer cell lines (Caco2, Huh-7, and SW982). As result, compound 9 exhibited substantial inhibitory activity on Caco2, Huh-7, and SW982 cells with IC50 values of 1.17 ± 0.05, 1.15 ± 0.05 and 1.14 ± 0.04 µM, respectively. A preliminary mechanism study showed that 9 arrested the cell cycle of SW982 cells in the G0/G1 phase and induced apoptosis by upregulating Bax expression and downregulating Bcl-2 expression.

[Mechanism of Tibetan medicine Pterocephalus hookeri extract in treatment of rheumatoid arthritis based on serum metabonomics].

Ultra-high performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry(UPLC-Q-TOF/MS) was used to investigate the effect of Pterocephalus hookeri on serum metabolism of adjuvant arthritis(AA) model rats induced by complete Freund's adjuvant. After the AA model was properly induced, the serum of rats was collected 30 days after treatment. UPLC-Q-TOF-MS chromatograms were collected and analyzed by principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA). The results revealed that compared with the control group, the model group showed increased content of 12 biomarkers in the serum(P<0.05) and reduced content of the other nine biomarkers(P<0.05). P. hookeri extract could recover the above-mentioned 19 biomarkers to a certain range. Pathway enrichment showed that these markers mainly involved eight metabolic pathways, including valine, leucine, and isoleucine degradation, arachidonic acid metabolism, arginine and proline metabolism, glycerol phospholipid metabolism, primary bile acid biosynthesis, bile acid biosynthesis, tryptophan metabolism, and unsaturated fatty acid biosynthesis. The findings of this study demonstrate that P. hookeri extract can regulate metabolic disorders and promote the regression of metabolic phenotype to the normal level to exert the therapeutic effect on AA rats. This study is expected to provide a certain scientific basis for the biological research on the treatment of rheumatoid arthritis by P. hookeri.

Bis-Iridoids from Pterocephalus hookeri and Evaluation of Their Anti-Inflammatory Activity.

Four new secoiridoid-iridoid heterodimers, pterocenoids E-H (1-4), together with a known analog (5), were separated from the whole plants of Pterocephalus hookeri. Their structures were characterized by detailed spectroscopic analyses and NMR comparison with reported data for known analogs. Pterocenoid E (1) represents the first bis-iridoid example incorporating a rare trans-fused monomeric unit, and the C(8) configuration in 5 was corrected to be reversed to the original assignment. Among all the isolates, compound 5 not only showed moderate inhibition against the nitric oxide production (IC50 =36.0±4.3 µM) but also dose-dependently suppressed the secretion of an important pro-inflammatory cytokine TNF-α, in lipopolysaccharide-induced RAW264.7 cells.

Bioactive pentacyclic triterpenoids from the whole plants of Pterocephalus hookeri.

Eight undescribed triterpenoids (pterohoonoids A-H) including four oleananes, one nor-oleanane and three nor-ursanes, along with seven known analogues, were isolated from the whole plants of Pterocephalus hookeri (Dipsacaceae). The structures with relative stereochemistries of these molecules were elucidated mainly by spectroscopic analyses, and the absolute configurations of the undescribed ones were assigned by a variety of methods, including time-dependent density functional theory (TD-DFT) based electronic circular dichroism (ECD) calculation, Rh2(OCOCF3)4-induced ECD experiment and chemical transformation. The inhibitory effects toward the diabetes target α-glucosidase of all the isolates were assessed, and four of them exhibited pronounced activity with IC50 values ranging from 6.8 to 55.8 µM. In addition, four compounds also showed inhibition against the nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 macrophage cells (IC50 = 12.4-63.7 µM). Further assays demonstrated that the most active compound pterohoonoid A inhibited the release of two key pro-inflammatory cytokines TNF-α and IL-6 in a dose-dependent manner.

Mechanism of Tibetan medicine Pterocephalus hookeri extract in treatment of rheumatoid arthritis based on serum metabonomics / 中国中药杂志

Ultra-high performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry(UPLC-Q-TOF/MS) was used to investigate the effect of Pterocephalus hookeri on serum metabolism of adjuvant arthritis(AA) model rats induced by complete Freund's adjuvant. After the AA model was properly induced, the serum of rats was collected 30 days after treatment. UPLC-Q-TOF-MS chromatograms were collected and analyzed by principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA). The results revealed that compared with the control group, the model group showed increased content of 12 biomarkers in the serum(P<0.05) and reduced content of the other nine biomarkers(P<0.05). P. hookeri extract could recover the above-mentioned 19 biomarkers to a certain range. Pathway enrichment showed that these markers mainly involved eight metabolic pathways, including valine, leucine, and isoleucine degradation, arachidonic acid metabolism, arginine and proline metabolism, glycerol phospholipid metabolism, primary bile acid biosynthesis, bile acid biosynthesis, tryptophan metabolism, and unsaturated fatty acid biosynthesis. The findings of this study demonstrate that P. hookeri extract can regulate metabolic disorders and promote the regression of metabolic phenotype to the normal level to exert the therapeutic effect on AA rats. This study is expected to provide a certain scientific basis for the biological research on the treatment of rheumatoid arthritis by P. hookeri.

Targeted Separation of COX-2 Inhibitor from Pterocephalus hookeri Using Preparative High-Performance Liquid Chromatography Directed by the Affinity Solid-Phase Extraction HPLC System.

Pterocephalus hookeri, as a kind of popular traditional Tibetan medicine, is reputed to treat inflammatory related diseases. In the present work, a cyclooxygenase-2 functionalized affinity solid-phase extraction HPLC system was developed and combined with preparative-HPLC for rapidly screening and separating cyclooxygenase-2 ligand from P. hookeri extracts. Firstly, ligands of cyclooxygenase-2 were screened from extracts by affinity solid-phase extraction HPLC system. Then directed by the screening results, the recognized potential active compounds were targeted separated. As a result, the major cyclooxygenase-2 inhibitor of P. hookeri was obtained with a purity of >95%, which was identified as sylvestroside I. To test the accuracy of this method, the anti-inflammatory activity of sylvestroside I was inspected in lipopolysaccharide-induced RAW 264.7 cells. The results show that sylvestroside I significantly suppressed the release of prostaglandin E2 with dose-dependent, which was in good agreement with the screening result of the affinity solid-phase method. This method of integration of screening and targeted separation proved to be very efficient for the recognition and isolation of cyclooxygenase-2 inhibitors from natural products.

Comprehensive screening and separation of cyclooxygenase-2 inhibitors from Pterocephalus hookeri by affinity solid-phase extraction coupled with preparative high-performance liquid chromatography.

Pterocephalus hookeri, a classical Tibetan herb, is mainly used to treat rheumatoid arthritis (RA) and contains various constituents potentially with cyclooxygenase-2 (COX-2) selective inhibition. A novel strategy for screening and target separating COX-2 inhibitors from the extracts of P. hookeri based on affinity solid-phase extraction (ASPE) column combined with preparative high-performance liquid chromatography (pre-HPLC) was successfully developed. The potential COX-2 inhibitors of P. hookeri were screened and recognized by the ASPE-HPLC system, which strategy is to analyze the compounds isolated by the ASPE column. Then, the active compounds were targeted separated by pre-HPLC according to real-time chromatograms. The control drugs celecoxib and glipizide were analyzed to verify the specificity and accuracy of the developed method. As a result, two pure compounds with COX-2 binding affinities were successfully separated from P. hookeri. They were characterized as swertisin and scopoletin using 1H- and 13C NMR spectroscopy, and the in vitro COX-2 inhibitory activities were verified. Compounds with COX-2 inhibitory activities could be screened and targeted separated from crude extracts by this strategy, which indicated that the proposed method was feasible, robust and effective for rapid separation of COX-2 inhibitors from natural products.

Pterocephin A, a novel Triterpenoid Saponin from Pterocephalus hookeri induced liver injury by activation of necroptosis.

BACKGROUND: Pterocephalus hookeri (C. B. Clarke) Höeck, a Tibetan medicine widely used for treatment of rheumatoid arthritis, was recorded in Chinese Pharmacopoeia (2020 version) with slight toxicity. The liver injury was observed in mice with administration of n-butanol extract (BUE) in our previously study. However, the toxic components and the mechanism were still unrevealed. PURPOSE: The present study was aimed to isolate and structural elucidate of the toxic compound pterocephin A (PA), as well as evaluate its liver toxicity and investigate its mechanism. METHODS: PA was isolated from the BUE of P. hookeri. Its structure was determined by analysis of HRMS, NMR and ECD data. L-02 cellular viability, LDH, ALT, AST, ROS, intracellular Ca2+ and the fluidity of cell membrane were assessed by multifunctional microplate reader. The PI staining, cell membrane permeability assessment, and mitochondrial fluorescence staining analysis were determined through the fluorescence microscope. Liver samples for mice were assessed by pathological and immunohistochemistry analysis. Expression levels of indicated proteins were measured by western blotting assays. RESULTS: PA was determined as a previously undescribed oleanolane-type triterpenoid saponin. In vitro study revealed PA significantly induced hepatotoxicity by inhibition of L-02 cell growth, abnormally elevation of ALT and AST. Mechanically, PA induced the damage of cell membrane, fragmentation of mitochondria, and subsequently increase of intracellular Ca2+ and ROS levels, which trigged by necroptosis with the activation of RIP1 and NF-κB signaling pathways. In vivo study confirmed PA could induce liver injury in mice with observation of the body weight loss, increasing of serum ALT and AST, and the histopathological changes in liver tissues. CONCLUSION: Our present study indicated that PA was an undescribed toxic constituent in P. hookeri to induce liver injury in mice by activation of necroptosis and inflammation. And the findings are of great significance for the clinical use safely of this herb.

Ptehoosines A and B: Two new sesamin-type sesquilignans with antiangiogenic activity from Pterocephalus hookeri (C.B. Clarke) Höeck.

Two undescribed sesamin-type sesquilignans ptehoosines A (1) and B (2), together with 4 known lignans (3-6), were isolated from Pterocephalus hookeri (C.B. Clarke) Höeck which was widely used as traditional Tibetan medicine for treatment of rheumatoid arthritis. Their structures were determined by HR-ESI-MS, NMR analysis and CD experiment. The in vitro antiangiogenic effect of all isolated compounds against human umbilical vein endothelial cells (HUVECs) were evaluated by CCK-8 assay. Among them, compound 1 exhibited significant proliferative inhibition on HUVECs with IC50 value of 32.82 ± 0.99 µM. Further in vitro study indicated 1 could arrest cell cycle at G0/G1 phase and reduce the migration of HUVECs. In vivo experiment exhibited 1 could inhibit tail vessels plexus in zebrafish. The above finding suggested that 1 was a promising lead compound against RA by inhibiting of angiogenesis.

Pterocephanoside A, a new iridoid from a traditional Tibetan medicine, Pterocephalus hookeri.

This work obtained and identified pterocephanoside A (1), one new iridoid glucoside derivative with rare structure of three iridoid glycosides linked to cyclopenta[c]pyran-3(1H)-one, and 10 known iridoids (2-11) from Pterocephalus hookeri through silica gel column chromatography and semi-preparative HPLC. The structure of the new compound was confirmed by 1D and 2D NMR and HRMS data analysis. Compounds 1 and 2 were isolated from this plant for the first time. The iridoids mostly possessed seco-iridoid subtype and iridoid subtype skeletons from P. hookeri. Compounds 1, 3, 4, and 6-11 showed weak anti-inflammatory activity.

[Correlation study on Tibetan medicine Pterocephalus hookeri of bitter taste receptors based on molecular docking technology].

In order to study the interaction between Pterocephalus hookeri and bitter taste receptors,three-dimensional structural models of bitter taste receptors TAS2 R16,TAS2 R14 and TAS2 R13 were established by homology modeling in this paper. Maestro software was used for docking the chemical constituents of P. hookeri with bitter taste receptors. The results showed that 25 chemical components of P. hookeri can regulate three bitter taste receptors. And these components were mainly iridoid glycosides and phenolic acids.This research focused on the comprehensive application of homology modeling and molecular docking technology to explore the interaction between bitter chemical constituents of P. hookeri and bitter taste receptors. This study provided assistance in revealing pharmacodynamic basis of bitter Tibetan medicine at molecular level. It also provided new ideas and methods for the study of Tibetan medicine.

Evaluation of the Liver Toxicity of Pterocephalus hookeri Extract via Triggering Necrosis.

Pterocephalus hookeri (C. B. Clarke) Höeck, recorded in the Chinese Pharmacopoeia (2015 version) as a Tibetan medicine for the treatment of various diseases, especially rheumatoid arthritis, was believed to possess a slight toxicity. However, hardly any research has been carried out about it. The present study aimed to evaluate the toxicity in vivo and in vitro. Toxicity was observed by the evaluation of mice weight loss and histopathological changes in the liver. Then, the comparison research between ethyl acetate extract (EAE) and n-butanol extract (BUE) suggested that liver toxicity was mainly induced by BUE. The mechanical study suggested that BUE-induced liver toxicity was closely associated with necrosis detected by MTT and propidium iodide (PI) staining, via releasing lactate dehydrogenase (LDH), reducing the fluidity, and increasing the permeability of the cell membrane. Western blot analysis confirmed that the necrosis occurred molecularly by the up-regulation of receptor-interacting protein kinase 1 (RIP1) and receptor-interacting protein kinase 3 (RIP3), as well as the activation of the nuclear factor-kappa-gene binding (NF-κB) signaling pathway in vivo and in vitro. This finding indicated that the liver toxicity induced by BUE from P. hookeri was mainly caused by necrosis, which provides an important theoretical support for further evaluation of the safety of this folk medicine.

Sweroside Alleviated LPS-Induced Inflammation via SIRT1 Mediating NF-κB and FOXO1 Signaling Pathways in RAW264.7 Cells.

Pterocephalus hookeri was used as a traditional Chinese medicine for the treatment of rheumatoid arthritis. Sweroside was a main iridoid isolated from P. hookeri. The present study aimed to investigate the anti-inflammatory effect mechanism of sweroside. In RAW264.7 cells induced by lipopolysaccharide (LPS), the abnormal proliferation, the NO content increase, and the downregulated Sirtuin1 (SIRT1) expression were observed. Sweroside could alleviate the inflammation by inhibiting cell proliferation through arresting the cell cycle at the G0/G1 phase, by suppressing pro-inflammatory cytokines and by promoting anti-inflammatory cytokines in LPS-induced RAW264.7 cells. Further mechanism research indicated that sweroside could activate the SIRT1, then suppress the nuclear factor-kappa B (NF-κB) and promote the Forkhead transcription factor O1 (FOXO1) signaling pathways. The present study indicated that sweroside may be the main anti-inflammatory constituent of P. hookeri and a promising candidate for anti-inflammation therapy.

Correlation study on Tibetan medicine Pterocephalus hookeri of bitter taste receptors based on molecular docking technology / 中国中药杂志

In order to study the interaction between Pterocephalus hookeri and bitter taste receptors,three-dimensional structural models of bitter taste receptors TAS2 R16,TAS2 R14 and TAS2 R13 were established by homology modeling in this paper. Maestro software was used for docking the chemical constituents of P. hookeri with bitter taste receptors. The results showed that 25 chemical components of P. hookeri can regulate three bitter taste receptors. And these components were mainly iridoid glycosides and phenolic acids.This research focused on the comprehensive application of homology modeling and molecular docking technology to explore the interaction between bitter chemical constituents of P. hookeri and bitter taste receptors. This study provided assistance in revealing pharmacodynamic basis of bitter Tibetan medicine at molecular level. It also provided new ideas and methods for the study of Tibetan medicine.

Antinociceptive and anti-inflammatory activities of a standardizedextract of bis-iridoids from Pterocephalus hookeri.

ETHNOPHARMACOLOGICAL RELEVANCE: Pterocephalus hookeri (C.B. Clarke) Höeck, one of the most popular Tibetan herbs, has been widely applied in Tibetan medicine prescriptions. Chemical investigations have led to the isolation of many bis-iridoids. However, the pharmacological activities of bis-iridoid constituents of this plant have never been reported before. AIM OF THE STUDY: This study evaluated the anti-inflammatory and analgesic activities of afraction of bis-iridoid constituents of P. hookeri (BCPH) in order to provide experimental evidence for its traditional use, such as for cold, flu, and rheumatoid arthritis. MATERIALS AND METHODS: The analgesic effects of BCPH were investigated using the hot-plate test and acetic acid-induced writhing test. The anti-inflammatory activities were observed using the following models: carrageenin-induced edema of the hind paw of rats and xylene-induced ear edema in mice. The effects of dexamethasone administration were also studied. RESULTS: BCPH significantly increased the hot-platepain threshold and reduced acetic acid-induced writhing response in mice. Moreover, BCPH remarkably inhibited xylene-induced ear edema and reduced the carrageenin-induced rat paw edema perimeter. CONCLUSION: The results reveal that BCPH has central, peripheral analgesic activities as well as anti-inflammatory effects, supporting the traditional application of this herb in treating various diseases associated with inflammation and pain.

Chemical constituents from Pterocephalus hookeri and their neuroprotection activities / 中成药

AIM To study the chemical constituents from Pterocephalus hookeri (C.B.Clarke) Hoeck and their neuroprotection activities.METHODS The 95％ ethanol extract from P.hookeri was isolated and purified by Sephadex LH-20,DM-130 macroporous resin,silica and HPLC,then the structures of obtained compounds were identified by physicochemical properties and spectral data.The neuroprotection activities were studied by establishment of Parkinson's disease model of genetically modified zebrafish.RESULTS Nine compounds were isolated and identified as triplostoside A (1),cantleyoside (2),sylvestroside Ⅰ (3),sylvestroside Ⅲ dimethyl acetal (4),sylvestroside Ⅲ (5),laciniatoside Ⅰ-7-dibutyl acetal (6),laciniatoside Ⅰ (7),laciniatoside Ⅱ (8),sylvestroside Ⅳ (9).The n-BuOH fraction of P.hookeri had good performance on neuroprotection in hydrogen peroxide model.CONCLUSION Compound 4 is isolated from this plant for the first time.P.hookeri has neuroprotection activities.

[Potential distribution of the traditional Tibetan herb Pterocephalus hookeri by Maxent model].

In order to study the ecology suitability of Pterocephalus hookeri, and provide a reference for GAP planting location and regional development, the Maxent model and GIS technology were used to investigate ecology suitability regions for P. hookeri based on the distribution points collected from Chinese virtual herbarium, the references and field trips. The potential distribution areas mainly concentrated in the eastern Tibet, western Sichuan, southern Qinghai, northwest Yunnan, and southern Gansu. There were 7 major environmental factors to have obvious influence on ecology suitability distributions of P. hookeri, including altitude (contribution rate of 62%), precipitation of warmest quarter (contribution rate of 14.4%), coefficient of variation of precipitation seasonality (contribution rate of 7.2%), mean temperature of driest quarter (contribution rate of 3.5%), the electrical conductivity of top and sub-soil (contribution rate of 3%), the total exchangeable bases in the top- and subsoil (contribution rate of 2.4%) and SD of temperature seasonality (contribution rate of 2.2%). The study of the ecological suitability regionalization of P. hookeri based on Maxent model can provide scientific basis for the selection of artificial planting base and GAP planting location.

[Simultaneous determination of ten major compounds including iridoid glycosides and phenolic acids in Pterocephalus hookeri by UPLC-PDA].

This study is to develop an UPLC-PDA method for determination of 10 major components in Pterocephalus. The UPLC-PDA assay was performed on a Waters Acquity UPLCR BEH C18（2.1 mm ×100 mm,1.7 µm）, and the column temperature was at 30 ℃. The mobile phase consists of water containing 0.2% phosphoric acid (A) and acetonitrile (B) in gradient elution at a flow rate of 0.4 mL•min⁻¹. The detection wave length was set at 237 and 325 nm, and the injection volume was 1 µL in the UPLC system. The linear range of 10 detected compounds were good (r≥0.999 7), and the overall recoveries ranged from 96.30% to 103.0%, with the RSD ranging from 0.72% to 2.9%. The method was simple, accurate and reproducible, which can be used for the simultaneous determination of the content of ten major components in P. hookeri.

The anti-arthritic activity of total glycosides from Pterocephalus hookeri, a traditional Tibetan herbal medicine.

CONTEXT: Pterocephalus hookeri (C. B. Clarke) Hock., a traditional Tibetan herbal medicine rich in glycosides, has been used to treat several diseases including rheumatoid arthritis. OBJECTIVE: To evaluate the anti-arthritic activity of total glycosides from P. hookeri, and its possible mechanisms of action. MATERIALS AND METHODS: Anti-arthritic activity of total glycosides from P. hookeri (oral administration for 30 days at 14-56 mg/kg) was evaluated using paw swelling, arthritis scores and histopathological measurement in adjuvant-induced arthritis (AA) Sprague-Dawley rats. The NF-κB p65 expression in synovial tissues, and serum superoxide dismutase (SOD) activity, malondialdehyde (MDA) and nitric oxide (NO) levels was measured in AA rats, respectively. Further assessment of anti-inflammatory and analgesic activities of these glycosides were carried out using inflammation and hyperalgesia models induced by xylene, carrageenan, agar and acetic acid, respectively. RESULTS: Total glycosides (56 mg/kg) decreased the paw swelling (38.0%, p < 0.01), arthritis scores (25.3%, p < 0.01) and synovial inflammation in AA rats. The glycosides significantly (p < 0.05-0.01) attenuated the inflammation induced by xylene, carrageenan, acetic acid and agar, increased the pain threshold in acetic acid-induced writhing in mice and mechanical stimuli-induced hyperalgia in AA rats. The glycosides (14, 28, 56 mg/kg) also suppressed the NF-κB p65 expression (33.1-78.2%, p < 0.05-0.01), reduced MDA (21.3-35.9%, p < 0.01) and NO (20.3-32.4%, p < 0.05-0.01) levels, respectively, enhanced the SOD activity (7.8%, p < 0.05) at 56 mg/kg in AA rats. DISCUSSION AND CONCLUSION: Our findings confirmed the anti-arthritic property of the total glycosides from P. hookeri, which may be attributed to its inhibition on NF-κB signalling and oxidative stress.

Study on the Active Components Targets of Tibetan Medicine Pterocephalus hookeri in Anti-rheumatoid Ar-thritis Based on Network Pharmacology / 中国药房

OBJECTIVE:To explore the multi-component,multi-target,multi-channel mechanism of Tibetan medicine Ptero-cephalus hookeri in the treatment of rheumatoid arthritis (RA). METHODS:The selected target compounds (10 chemical struc-tures of P. hookeri)were imported and stored by related software;target prediction and filtering were conducted by PharmMapper and DrugBank databases. The pathways of targets were acquired and analyzed by MAS 3.0 database. Finally P. hookeriactive com-ponent-targeting-pathwaynetwork was constructed by Cytoscape 3.4.0 software. RESULTS:The target information obtained in the PharmMapper database were compared with that of the DrugBank database for inflammation-related drugs,26 potential targets for the treatment of RA were obtained,in which MAPK14,RXRA,ALB,PDE4D,VDR may be the main potential target gene group in the treatment of RA. 57 functional pathways were obtained after 26 functional targets were annotated by pathway. In addition to 27 RA-related pathways,30 other pathways such as endocrine regulation and immune were involved. CONCLUSIONS:Base on the study of network pharmacology,P. hookeri plays the role in the treatment of RA by acting on inflammation,immune,endo-crine and related targets and pathways.