Withanolides from the active extract of Physalis angulate and their anti-hepatic fibrosis effects

ETHNOPHARMACOLOGICAL RELEVANCE

Physalis angulata L., a traditional Chinese medicine called "Kuzhi" in China, was used traditionally to treat liver diseases (eg. icterus, hepatitis) as well as malaria, asthma, and rheumatism.

AIM OF THE STUDY

Our study aimed to investigate the withanolides with anti-hepatic fibrosis effect from P. angulate.

MATERIALS AND METHODS

Withanolides were obtained from the EtOH extract of P. angulate by bioassay-molecular networking analysis-guided isolation using column chromatography and normal/reversed-phase semipreparative HPLC. The structures of new withanolides were elucidated by combinations of spectroscopic techniques with NMR and ECD calculations. MTT cell viability assay, AO/EB staining method, cell wound healing assay, ELISA and Western blot experiments were employed to evaluate the anti-hepatic fibrosis activity and to uncover related mechanism. Molecular docking analysis and cellular thermal shift assay were used to evaluate and verify the interaction between the active withanolides and their potential targets.

RESULTS

Eight unreported withanolides, withagulides A-H (1-8), along with twenty-eight known ones were obtained from P. angulate. Withanolides 6, 9, 10, 24, 27, and 29-32 showed marked anti-hepatic fibrosis effect with COL1A1 expression inhibition above 50 %. Physalin F (9), the main component in the active fraction, significantly decreased the TGF β1-stimulated expressions of collagen I and α-SMA in LX-2 cells. Mechanism study revealed that physalin F exerted its anti-hepatic fibrosis effect via the PI3K/AKT/mTOR signaling pathway.

CONCLUSION

This study suggested that withanolides were an important class of natural products with marked anti-hepatic fibrosis effect. The main withanolide physalin F might be a promising candidate for hepatic fibrosis treatment. The work provided experimental foundation for the use of P. angulate to treat hepatic fibrosis.

Design, synthesis and biological evaluation of indole-2-carboxylic acid derivatives as novel HIV-1 integrase strand transfer inhibitors

Integrase plays an important role in the life cycle of HIV-1, and integrase strand transfer inhibitors (INSTIs) can effectively impair the viral replication. However, drug resistance mutations have been confirmed to decrease the efficacy of INSTI during the antiviral therapy. Herein, indole-2-carboxylic acid (1) was found to inhibit the strand transfer of integrase, and the indole nucleus of compound 1 was observed to chelate with two Mg2+ ions within the active site of integrase. Through optimization of compound 1, a series of indole-2-carboxylic acid derivatives were designed and synthesized, and compound 17a was proved to markedly inhibit the effect of integrase, with IC50 value of 3.11 μM. Binding mode analysis of 17a demonstrated that the introduced C6 halogenated benzene ring could effectively bind with the viral DNA (dC20) through π-π stacking interaction. These results indicated that indole-2-carboxylic acid is a promising scaffold for the development of integrase inhibitors.

Phomopsterone B Alleviates Liver Fibrosis through mTOR-Mediated Autophagy and Apoptosis Pathway

Liver fibrosis is the initial pathological process of many chronic liver diseases. Targeting hepatic stellate cell (HSC) activation is an available strategy for the therapy of liver fibrosis. We aimed to explore the anti-liver fibrosis activity and potential mechanism of phomopsterone B (PB) in human HSCs. The results showed that PB effectively attenuated the proliferation of TGF-β1-stimulated LX-2 cells in a concentration-dependent manner at doses of 1, 2, and 4 μM. Quantitative real-time PCR and Western blot assays displayed that PB significantly reduced the expression levels of α-SMA and collagen I/III. AO/EB and Hoechst33342 staining and flow cytometry assays exhibited that PB promoted the cells' apoptosis. Meanwhile, PB diminished the number of autophagic vesicles and vacuolated structures, and the LC3B fluorescent spots indicated that PB could effectively inhibit the accretion of autophagosomes in LX-2 cells. Moreover, rapamycin and MHY1485 were utilized to further investigate the effect of mTOR in autophagy and apoptosis. The results demonstrated that PB regulated autophagy and apoptosis via the mTOR-dependent pathway in LX-2 cells. In summary, this is the first evidence that PB effectively alleviates liver fibrosis in TGF-β1-stimulated LX-2 cells, and PB may be a promising candidate for the prevention of liver fibrosis.

The Discovery of Indole-2-carboxylic Acid Derivatives as Novel HIV-1 Integrase Strand Transfer Inhibitors

As an important antiviral target, HIV-1 integrase plays a key role in the viral life cycle, and five integrase strand transfer inhibitors (INSTIs) have been approved for the treatment of HIV-1 infections so far. However, similar to other clinically used antiviral drugs, resistance-causing mutations have appeared, which have impaired the efficacy of INSTIs. In the current study, to identify novel integrase inhibitors, a set of molecular docking-based virtual screenings were performed, and indole-2-carboxylic acid was developed as a potent INSTI scaffold. Indole-2-carboxylic acid derivative 3 was proved to effectively inhibit the strand transfer of HIV-1 integrase, and binding conformation analysis showed that the indole core and C2 carboxyl group obviously chelated the two Mg2+ ions within the active site of integrase. Further structural optimizations on compound 3 provided the derivative 20a, which markedly increased the integrase inhibitory effect, with an IC50 value of 0.13 μM. Binding mode analysis revealed that the introduction of a long branch on C3 of the indole core improved the interaction with the hydrophobic cavity near the active site of integrase, indicating that indole-2-carboxylic acid is a promising scaffold for the development of integrase inhibitors.

Chemical constituents of Aspergillus udagawae isolated from the soil of the Xingren coal areas and their antibacterial activities

A new helvolic acid derivative (1), together with nine known compounds (2-10) were isolated from the metabolites of Aspergillus udagawae MST1-10 with the bioassay-guided fractionation method. Their structures were identified on the basis of spectroscopic analysis. The absolute configuration of compound 1 was elucidated through NOESY and ECD spectra. Compound 2 displayed significant antibacterial activities against Stenotrophomonas maltophilia with MIC value of 2 μg/mL (Trimethoprim, MIC = 64 μg/mL), and with biofilm inhibition rates of 96.41%, 87.77%, and 41.70% at 4MIC, 2MIC, and MIC, respectively.

Amelioration effects of α-viniferin on hyperuricemia and hyperuricemia-induced kidney injury in mice

BACKGROUND

α-Viniferin, the major constituent of the roots of Caragana sinica (Buc'hoz) Rehder with a trimeric resveratrol oligostilbenoid skeleton, was demonstrated to possess a strong inhibitory effect on xanthine oxidase in vitro, suggesting it to be a potential anti-hyperuricemia agent. However, the in vivo anti-hyperuricemia effect and its underlying mechanism were still unknown.

PURPOSE

The current study aimed to evaluate the anti-hyperuricemia effect of α-viniferin in a mouse model and to assess its safety profile with emphasis on its protective effect on hyperuricemia-induced renal injury.

METHODS

The effects were assessed in a potassium oxonate (PO)- and hypoxanthine (HX)-induced hyperuricemia mice model by analyzing the levels of serum uric acid (SUA), urine uric acid (UUA), serum creatinine (SCRE), serum urea nitrogen (SBUN), and histological changes. Western blotting and transcriptomic analysis were used to identify the genes, proteins, and signaling pathways involved.

RESULTS

α-Viniferin treatment significantly reduced SUA levels and markedly mitigated hyperuricemia-induced kidney injury in the hyperuricemia mice. Besides, α-viniferin did not show any obvious toxicity in mice. Research into the mechanism of action of α-viniferin revealed that it not only inhibited uric acid formation by acting as an XOD inhibitor, but also reduced uric acid absorption by acting as a GLUT9 and URAT1 dual inhibitor as well as promoted uric acid excretion by acting as a ABCG2 and OAT1 dual activator. Then, 54 differentially expressed (log₂ FPKM ≥ 1.5, p ≤ 0.01) genes (DEGs) repressed by the treatment of α-viniferin in the hyperuricemia mice were identified in the kidney. Finally, gene annotation results revealed that downregulation of S100A9 in the IL-17 pathway, of CCR5 and PIK3R5 in the chemokine signaling pathway, and of TLR2, ITGA4, and PIK3R5 in the PI3K-AKT signaling pathway were involved in the protective effect of α-viniferin on the hyperuricemia-induced renal injury.

CONCLUSIONS

α-Viniferin inhibited the production of uric acid through down-regulation of XOD in hyperuricemia mice. Besides, it also down-regulated the expressions of URAT1 and GLUT9 and up-regulated the expressions of ABCG2 and OAT1 to promote the excretion of uric acid. α-Viniferin could prevent hyperuricemia mice from renal damage by regulating the IL-17, chemokine, and PI3K-AKT signaling pathways. Collectively, α-viniferin was a promising antihyperuricemia agent with desirable safety profile. This is the first report of α-viniferin as an antihyperuricemia agent.

Three New Selaginellin Derivatives from Selaginella pulvinata and Their α-Glucosidase Inhibitory Activity

Three new selaginellin derivatives, selaginpulvilins V-X (1-3), together with seven known analogs (4-10) were isolated from whole plants of Selaginella pulvinata. Their structures were determined by extensive spectroscopic methods including 1D and 2D NMR, HR-ESI-MS and chemical derivatization method. Compound 1 represents a rare example of naturally occurring selaginellin with an alkynylphenol-trimmed skeleton. Biological evaluation showed that compounds 2, 6 and 8 displayed moderate inhibition against α-glucosidase with IC₅₀ values of 3.71, 2.04 and 4.00 μM, respectively.

Insights into the Inhibitory Mechanism of Viniferifuran on Xanthine Oxidase by Multiple Spectroscopic Techniques and Molecular Docking

Viniferifuran was investigated for its potential to inhibit the activity of xanthine oxidase (XO), a key enzyme catalyzing xanthine to uric acid. An enzyme kinetics analysis showed that viniferifuran possessed a strong inhibition on XO in a typical anti-competitive manner with an IC₅₀ value of 12.32 μM (IC₅₀ for the first-line clinical drug allopurinol: 29.72 μM). FT-IR and CD data analyses showed that viniferifuran could induce a conformational change of XO with a decrease in the α-helix and increases in the β-sheet, β-turn, and random coil structures. A molecular docking analysis revealed that viniferifuran bound to the amino acid residues located within the activity cavity of XO by a strong hydrophobic interaction (for Ser1214, Val1011, Phe914, Phe1009, Leu1014, and Phe649) and hydrogen bonding (for Asn768, Ser876, and Tyr735). These findings suggested that viniferifuran might be a promising XO inhibitor with a favorable mechanism of action.

The Fusaric Acid Derivative qy17 Inhibits Staphylococcus haemolyticus by Disrupting Biofilm Formation and the Stress Response via Altered Gene Expression

Staphylococcus haemolyticus (S. haemolyticus) is the second most commonly isolated coagulase-negative staphylococcus (CoNS) in patients with hospital-acquired infections. It can produce phenol-soluble modulin (PSM) toxins and form biofilms. Compared with the wealth of information on Staphylococcus aureus and Staphylococcus epidermidis, very little is known about S. haemolyticus. There is an urgent need to find an effective preparation to combat the harm caused by S. haemolyticus infection. Chinese herbs have been utilized to cure inflammation and infectious diseases and have a long history of anticancer function in China. Here, we modified fusaric acid characterized from the metabolites of Gibberella intermedia, an endophyte previously isolated from Polygonum capitatum. This study shows that fusaric acid analogs (qy17 and qy20) have strong antibacterial activity against S. haemolyticus. In addition, crystal violet analyses and scanning electron microscopy observations demonstrated that qy17 inhibited biofilm formation and disrupted mature biofilms of S. haemolyticus in a dose-dependent manner. Additionally, it reduced the number of live bacteria inside the biofilm. Furthermore, the antibiofilm function of qy17 was achieved by downregulating transcription factors (sigB), transpeptidase genes (srtA), and bacterial surface proteins (ebp, fbp) and upregulating biofilm-related genes and the density-sensing system (agrB). To further elucidate the bacteriostatic mechanism, transcriptomic analysis was carried out. The following antibacterial mechanisms were uncovered: (i) the inhibition of heat shock (clpB, groES, groL, grpE, dnaK, dnaJ)-, oxidative stress (aphC)- and biotin response (bioB)-related gene expression, which resulted in S. haemolyticus being unable to compensate for various stress conditions, thereby affecting bacterial growth; and (ii) a reduction in the expression of PSM-beta (PSMβ1, PSMβ2, PSMβ3) toxin- and Clp protease (clpP, clpX)-related genes. These findings could have major implications for the treatment of diseases caused by S. haemolyticus infections. Our research reveals for the first time that fusaric acid derivatives inhibit the expression of biofilm formation-related effector and virulence genes of S. haemolyticus. These findings provide new potential drug candidates for hospital-acquired infections caused by S. haemolyticus.

[Association between the Controlling Nutritional Status score and long-term outcome in patients with acute heart failure]

Objective: To evaluate the nutritional status by the Controlling Nutritional Status (CONUT) score and its association with the long-term prognosis in patients with acute heart failure (AHF). Methods: This prospective monocentric study consecutively enrolled patients admitted to our hospital for AHF from April 2012 to May 2016. Patients were divided into 3 groups based on the CONUT score at admission: normal (0-1), mild malnutrition (2-4) and moderate-severe malnutrition (5-12) groups. Baseline information was obtained and recorded within 24 hours after admission. All patients were followed up every 3 months by outpatient visit or telephone call until March 2019. The primary endpoint was all-cause mortality. The Kaplan-Meier survival curves and log-rank test were used to compare all-cause mortality between groups. Variables showing statistical significance in the univariate analysis were incorporated into multivariate Cox regression model to analyze the independent risk factors for all-cause mortality after discharge. Results: A total of 396 patients were enrolled in this study, including 114 patients with normal nutritional status, 200 patients with mild malnutrition and 82 patients with moderate-severe malnutrition. One hundred and fifty-eight patients died during a median follow-up of 34 (18, 46) months. The mortality was 32.4% (37/114), 39% (78/200) and 52.4% (43/82) in normal, mild malnutrition and moderate-severe malnutrition groups, respectively. The mortality was significantly higher in the moderate-severe malnutrition group than in normal nutrition group (P<0.05). However, there was no significant difference in mortality between normal and mild malnutrition group as well as between mild and moderate-severe malnutrition group (both P>0.05). Kaplan-Meier curves indicated that patients with high CONUT score group was at higher risk of all-cause mortality compared with those with low CONUT score (P=0.002). Cox proportional hazard analyses showed that the risk of all-cause mortality of moderate-severe malnutrition group was significantly higher than that of normal nutrition group (HR =1.648, 95%CI 1.021-2.660, P=0.041). Conclusions: The CONUT score of patients with AHF at admission is associated with the long-term prognosis. High CONUT score is an independent risk factor for all-cause mortality in AHF patients after discharge.

Antibacterial activities of the chemical constituents of Schizophyllum commune MST7-3 collected from coal area

Two fusidane-type active compounds (6 and 7) and five new ones (1-5), along with other nine known compounds (8-16) were isolated from the metabolites of Schizophyllum commune MST7-3. Their structures were elucidated on the basis of spectroscopic analysis. The absolute configurations of compounds 2 and 3 were established by Mosher's method and optical rotation. Compounds 6 and 7 showed significant antibacterial activities against Stenotrophomonas maltophilia with MIC values of 4 μg/mL and 16 μg/mL, respectively.

Antihyperuricemia and antigouty arthritis effects of Persicaria capitata herba in mice

BACKGROUND

Hyperuricemia (HUA) is an important risk factor for gout, renal dysfunction and cardiovascular diseases. The whole plant of Persicaria capitata (Buch.-Ham. ex D. Don) H. Gross, namely Persicaria capitata herba, is a well-known ethnic herb with potent therapeutic effects on urinary tract infections and urinary calculus, yet previous reports have only focused on its effect on urinary tract infections.

PURPOSE

To evaluate the therapeutic potential of P. capitata herba against gout by investigating its antihyperuricemia and antigouty arthritis effects and possible mechanisms.

METHODS

The ethanol extract (EP) and water extract (WP) of P. capitata herba were prepared by extracting dried and ground whole plants of P. capitata with 75% ethanol and water, respectively, followed by removal of solvents and characterization by UHPLC-Q-TOF/MS. The antihyperuricemia and antigouty arthritis effects of the two extracts were evaluated in a potassium oxonate- and hypoxanthine-induced hyperuricemia mouse model and a monosodium urate crystal (MSUC)-induced acute gouty arthritis mouse model, respectively. The mechanisms were investigated by testing their effects on the expression of correlated proteins (by Western blot) and mRNAs (by RT-PCR).

RESULTS

UHPLC-HRMS fingerprinting and two chemical markers (i.e., quercetin and quercitrin) determination were used for the characterization of the WP and EP extracts. Both WP and EP extracts showed pronounced antihyperuricemia activities, with a remarkable decline in serum uric acid and a marked increase in urine uric acid in hyperuricemic mice. Unlike the clinical xanthine oxidase (XOD) inhibitor allopurinol, WP and EP did not show any distinct renal toxicities. The underlying antihyperuricemia mechanism involves the inhibition of the activity and expression of XOD and the downregulation of the mRNA and protein expression of glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1). The extracts of P. capitata herba also demonstrated remarkable anti-inflammatory activity in MSUC-induced acute gouty arthritis mice. The mechanism might involve inhibitory effects on the expression of proinflammatory factors.

CONCLUSIONS

The extracts of P. capitata herba possessed pronounced antihyperuricemia and antigouty arthritis effects and were, therefore, promising natural medicines for hyperuricemia-related disorders and gouty arthritis. The use of P. capitata herba for the treatment of urinary calculus may be, at least to some degree, related to its potential as an antihyperuricemia and antigouty arthritis drug.

Pseudosterins A-C, Three 1-Ethyl-3-formyl-β-carbolines from Pseudostellaria heterophylla and Their Cardioprotective Effects

Pseudostellaria heterophylla is used in China not only as a functional food but also as an herb to tonify the spleen, enhance immunity, and treat palpitation. Our previous investigation showed that a fraction enriched in glycosides obtained from the roots of P. heterophylla possessed pronounced protective effects on H9c2 cells against CoCl₂-induced hypoxic injury. However, the active compounds responsible for the observed effects were still unknown. In the current investigation, pseudosterins A–C (1–3), three new alkaloids with a 1-ethyl-3-formyl-β-carboline skeleton, together with polydatin, have been isolated from the active fraction. Their structures were elucidated on the basis of spectroscopic analysis and quantum chemical calculations. The four compounds showed cardioprotective effects against sodium hydrosulfite-induced hypoxia-reoxygenation injury in H9c2 cells, with the three alkaloids being more potent. This is also the first report of alkaloids with a β-carboline skeleton isolated from P. heterophylla as cardioprotective agents.

Discovery of β-Carboline Derivatives as a Highly Potent Cardioprotectant against Myocardial Ischemia-Reperfusion Injury

Timely myocardial reperfusion salvages ischemic myocardium from infarction, whereas reperfusion itself induces cardiomyocyte death, which is called myocardial ischemia/reperfusion (MI/R) injury. Herein, β-carboline derivative 17c was designed and synthesized with obvious myocardial protective activity for the first time. Pretreatment of 17c effectively protected the cardiomyocyte H9c2 cells from H₂O₂-induced lactate dehydrogenase leakage and restored the endogenous antioxidants, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Besides, 17c effectively protected the mitochondria through decreasing the reactive oxygen species overproduction and enhancing the mitochondrial membrane potential. As a result, 17c significantly reduced the necrosis of cardiomyocytes in H₂O₂-induced oxidative stress, which was more potent than polydatin. In MI/R injury rats, 17c pretreatment obviously increased the levels of SOD and GSH-Px and inhibited the apoptosis of cardiomyocytes. Through this way, the size of myocardial infarction was significantly reduced after MI/R injury in vivo, better than that of polydatin, suggesting that 17c is a promising cardioprotectant for the prevention of MI/R injury.

Euphorboside A, a cytotoxic meroterpenoid glycoside with an unusual humulene-phloroglucinol skeleton from Euphorbia kansuensis

Euphorboside A (1), an unusual meroterpenoid glycoside featuring the incorporation of an acylphloroglucinol moiety into a humulene skeleton to form a 6/6/11 ring system, was isolated from the roots of Euphorbia kansuensis. Its structure was elucidated by extensive spectroscopic analysis, chemical methods, and ECD calculations. Compound 1 was screened for the cytotoxicity against nine cancer cell lines, and 1 showed marked inhibitory activities against human colon cancer RKO and human breast cancer MDA-MB-231 cell lines with IC₅₀ values of 3.70 and 4.15 μM, respectively.

Design, synthesis, and biological evaluation of 2,4-diamino pyrimidine derivatives as potent FAK inhibitors with anti-cancer and anti-angiogenesis activities

A series of 2,4-diamino pyrimidine (DAPY) derivatives were designed, synthesized, and evaluated as inhibitors of focal adhesion kinase (FAK) with antitumor and anti-angiogenesis activities. Most compounds effectively suppressed the enzymatic activities of FAK, and the IC₅₀s of 11b and 12f were 2.75 and 1.87 nM, respectively. 11b and 12f exhibited strong antiproliferative effects against seven human cancer cells, with IC₅₀ values against two FAK-overexpressing pancreatic cancer cells (PANC-1 and BxPC-3) of 0.98 μM, 0.55 μM, and 0.11 μM, 0.15 μM, respectively. Moreover, 11b and 12f obviously suppressed the colony formation, migration, and invasion of PANC-1 cells in a dose-dependent manner. Meanwhile, these two compounds could induce the apoptosis of PANC-1 cells and arrest the cell cycle in G2/M phase according to the flow cytometry assay. Western blot revealed that 11b and 12f effectively inhibited the FAK/PI3K/Akt signal pathway and significantly decreased the expression of cyclin D1 and Bcl-2. In addition, compounds 11b and 12f potently inhibited the antiproliferative of HUVECs and obviously altered the cell morphology. 11b and 12f also significantly inhibited the migration, tube formation of HUVECs and severely impaired the angiogenesis in the zebrafish model. Overall, these results revealed the potential of compounds 11b and 12f as promising candidates for further preclinical studies.

Mexicanolide-type limonoids from the twigs and leaves of Cipadessa baccifera

Twelve previously undescribed mexicanolide-type limonoids, including two pairs of isomers, together with seven known analogues were isolated from the twigs and leaves of Cipadessa baccifera. Their structures were determined by extensive spectroscopic methods and electronic circular dichroism (ECD) calculations. Structural variations mainly occurred at the attachment of C-3 and the carbon residues linked to C-17. 21-deoxo-23-oxofebrifugin A and 3-O-detigloyl-3-O-isobutyryl-21-deoxo-23-oxofebrifugin A are two rare naturally occurring mexicanolide-type limonoids bearing an α,β-unsaturated-γ-lactone motif at C-17. Moreover, cipaferen R is the first degraded tetranortriterpenoid derivative featuring an unique acetyl group at C-17. Some isolated compounds were evaluated for nematicidal, antifungal, cytotoxic (against five human cancer cell lines), and acetylcholinesterase inhibitory activities. No nematicidal and antifungal activities were observed, yet 3-O-detigloyl-3-O-isobutyrylfebrifugin A, febrifugin A, febrifugin, and khaysin T exhibited moderate cytotoxic activity against the tested cells with IC₅₀ values ranging from 18.56 ± 0.27 to 38.00 ± 0.85 μM, and 3-O-detigloyl-3-O-isobutyrylfebrifugin A, granatumin E, khaysin T, and 2'S-cipadesin A showed moderate inhibitory activities against acetylcholinesterase (AChE) at 50 μM.

Rhizoma Bletillae polysaccharide elicits hemostatic effects in platelet-rich plasma by activating adenosine diphosphate receptor signaling pathway

Rhizoma Bletillae, the tubes of Bletilla striata, has been traditionally used in China as a hemostatic agent. In preliminary studies, the major active fraction responsible for its hemostatic effect have been confirmed to be Rhizoma Bletillae polysaccharide (RBp), but the hemostatic mechanism of action of RBp is still unknown.The main aim of this study was to clarify its mechanism of hemostatic effect. RBp was prepared by 80 % ethanol precipitation of the water extract of Rhizoma Bletillae followed by the Sevag method to remove proteins. The average molecular weight (Mw) of the crude RBp maintained at a range of 30.06-200 KDa. The hemostatic effects of RBp were evaluated by testing its effect on the platelet aggregation of rat platelet-rich plasma (PRP). PRP was dealt with different concentrations of RBp and platelet aggregation was measured by the turbidimetric method. The hemostatic mechanism of RBp was investigated by examining its effect on platelet shape, platelet secretion, and activation of related receptors (P2Y₁, P2Y₁₂ and TXA2) by electron microscopy and the turbidimetric method. RBp significantly enhanced the platelet aggregations at concentrations of 50-200 mg/L in a concentration-dependent manner. The inhibitory rate of platelet aggregation was significantly increased by apyrase and Ro31-8220 in a concentration-dependent manner, while RBp-induced platelet aggregation was completely inhibited by P2Y₁, P2Y₁₂ and the PKC receptor antagonists. However, the aggregation was not sensitive to TXA2. RBp, the active ingredients of Rhizoma Bletillae responsible for its hemostatic effect, could significantly accelerate the platelet aggregation and shape change. The hemostatic mechanism may involve activation of the P2Y₁, P2Y₁₂, and PKC receptors in the adenosine diphosphate (ADP) receptor signaling pathway.

A New Arylnaphthalide Lignan From Oxalis corniculata

A new arylnaphthalide lignan, corniculin (1), was isolated from 75% EtOH extract of Oxalis corniculata. Its chemical structure was determined by mass spectrometric analysis as well as 1D and 2D nuclear magnetic resonance (NMR).

Design, synthesis, and biological evaluation of 2-amino-N-(2-methoxyphenyl)-6-((4-nitrophenyl)sulfonyl)benzamide derivatives as potent HIV-1 Vif inhibitors

Viral infectivity factor (Vif) is one of the accessory protein of human immunodeficiency virus type I (HIV-1) that inhibits host defense factor, APOBEC3G (A3G), mediated viral cDNA hypermutations. Previous work developed a novel Vif inhibitor 2-amino-N-(2-methoxyphenyl)-6-((4-nitrophenyl)thio)benzamide (1) with strong antiviral activity. Through optimizations on the two side branches, a series of compound 1 derivatives (2-18) were designed, synthesized and tested in vitro for their antiviral activities. The biological results showed that compound 5 and 16 inhibited the virus replication efficiently with EC₅₀ values of 9.81 and 4.62 μM. Meanwhile, low cytotoxicities on H9 cells were observed for the generated compounds by the MTT assay. The structure-activity relationship of compound 1 was preliminarily clarified, which gave rise to the development of more potent Vif inhibitors.

Two new dihydroisocoumarins with antimicrobial activities from the fungus Penicillium sp. XR046 collected from Xinren coal area

Two new dihydroisocoumarins (1 and 2), together with six known compounds (3-8), were isolated from the fungus Penicillium sp. XR046 collected from the Xinren coal area of Guizhou province in China. Their structures were elucidated on the basis of spectroscopic analysis. The absolute configurations of C-3 in 1 and 2 were established by comparison of their CD data with those of known compounds. Compounds 1-6 showed anti-microbial activities with MIC values in the range of 50∼100 μg/mL against Candida albicans, Staphylococcus epidermidis, Bacillus subtilis, and Escherichia coli.

Screening and analysis of potentially active components in Shenxiong glucose injection using UHPLC coupled with photodiode array detection and MS/MS

Shenxiong glucose injection, a pharmaceutical preparation containing a water extract of the roots of Salvia miltiorrhizae and ligustrazine hydrochloride, is widely used in clinical to treat cardiovascular diseases in China. The chemical components of the water extract have been reported and the cardioprotective effects of the injection have been evaluated. However, the chemical constituents of the injection and their correlations with its pharmacological effects have not been established. In this study, 13 chemical constituents of the injection have been identified or characterized by ultra-high performance liquid chromatography with diode array detection and electrospray ionization quadrupole time-of-flight tandem mass spectrometry. Besides, the potentially active compounds of this preparation that directly act on cardiac cells have been screened by cell extraction and ultra high performance liquid chromatography targeted multiple reaction monitoring. As a result, eight potentially active compounds, danshensu (1), ligustrazine hydrochloride (4), salvianolic acid I/H (7), lithospermic acid (8), salvianolic acid D (9), rosmarinic acid (10), salvianolic acid B (12), and salvianolic acid C (13), were obtained and structurally characterized from the 11 target compounds used for screening. The liquid chromatography with quadrupole time-of-flight mass spectrometry and liquid chromatography with multiple reaction monitoring tandem mass spectrometry combination method has demonstrated its potency for the screening, detection, and structural identification of bioactive compounds in a complex matrix.

Two Nitrogen-containing Compounds from Pseudostellaria heterophylla

Two new nitrogen-containing compounds, pseudosteheterins A (1) and B (2), were isolated from the glycosides-enriched cardioprotective fraction of the 70% EtOH extract of the roots of Pseudostellaria heterophylla. Their structures were elucidated by spectroscopic methods, and the absolute configuration of 1 was established by quantum chemical TDDFT calculation of the ECD spectrum of its model compound. Pseudosteheterin B showed significant protective effects in H9c2 myocardial cells against CoCl2-induced injury.

Hepatoprotective natural triterpenoids

Liver diseases are one of the leading causes of death in the world. In spite of tremendous advances in modern drug research, effective and safe hepatoprotective agents are still in urgent demand. Natural products are undoubtedly valuable sources for drug leads. A number of natural triterpenoids were reported to possess pronounced hepatoprotective effects, and triterpenoids have become one of the most important classes of natural products for hepatoprotective agents. However, the significance of natural triterpenoids has been underestimated in the hepatoprotective drug discovery, with only very limited triterpenoids being covered in the reviews of hepatoprotective natural products. In this paper, ca 350 natural triterpenoids with reported hepatoprotective effects in ca 120 references between 1975 and 2016 will be reviewed, and the structure-activity relationships of certain types of natural triterpenoids, if available, will be discussed. Patents are not included.

Shengjiang Xiexin Decoction Alters Pharmacokinetics of Irinotecan by Regulating Metabolic Enzymes and Transporters: A Multi-Target Therapy for Alleviating the Gastrointestinal Toxicity

Shengjiang Xiexin decoction (SXD), a classic traditional Chinese medical formula chronicled in Shang Han Lun, is used in modern clinical practice to decrease gastrointestinal toxicity induced by the chemotherapeutic drug irinotecan (CPT-11). In this study, the effect of SXD on the pharmacokinetics of CPT-11 and its active metabolites (SN-38 and SN-38G), and the underlying mechanisms were further examined. An ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the simultaneous quantification of CPT-11, SN-38, and SN-38G in the plasma, bile, liver, intestine, and intestinal contents of control and SXD-pre-treated rats after intravenous administration of CPT-11. SXD pretreatment increased the area under the curve (AUC) and the initial plasma concentration (C₀) of CPT-11 but decreased the plasma clearance (CL). The AUC and the maximum plasma concentration (C_max) of SN-38 decreased, whereas the C_max of SN-38G increased. Compared with that of the control group, the biliary excretion of CPT-11, SN-38, and SN-38G was inhibited. The CPT-11, SN-38, and SN-38G concentrations in the liver, intestine, and intestinal contents were different between the two groups. Furthermore, the hepatic expression of multidrug resistance-associated protein-2 (Mrp-2), P-glycoprotein (P-gp), and carboxylesterase 2 (CES2) was significantly down-regulated by SXD, while the hepatic and jejunal uridine diphosphate (UDP)-glucuronosyltransferase 1A1 (UGT1A1) expression was elevated. The hydrolysis of CPT-11 to SN-38 by CES and the glucuronidation of SN-38 to SN-38G by UGT were affected by liver and jejunum S9 fractions from rats pre-treated with SXD. Therefore, this study demonstrated for the first time that SXD could alter the pharmacokinetics of CPT-11 and its metabolites to alleviate CPT-11-induced diarrhea. And the underlying mechanism of drug interaction between CPT-11 and SXD involves decreasing hepatic Mrp-2 and P-gp expression and altering the activities of CES and UGT.

Buxusoside, a Flavonoid Disaccharide from Buxus sinica

A new flavonoid diglycoside named buxusoside (1), together with its aglycone chrysosplenol-D (2), as well as 4’, 5-dihydroxy-3,6,7-trimethoxyflavone (3) and 3’,4’,5-trihydroxy-3,6,7-trimethoxyflavone (4), were isolated from the 70% EtOH extract of the air-dried plant of Buxus sinica. Its structure was elucidated mainly by 1D and 2D NMR spectra.

Buxusoside, a Flavonoid Disaccharide from Buxus sinica

A new flavonoid diglycoside named buxusoside (1), together with its aglycone chrysosplenol-D (2), as well as 4', 5-dihydroxy-3,6,7-trimethoxyflavone (3) and 3',4',5-tiihydroxy-3,6,7-trimethoxyflavone (4), were isolated from the 70% EtOH extract of the air-dried plant of Buxus sinica. Its structure was elucidated mainly by iD and 2D NMR spectra.

Isolation and characterization of two new 2-isobutylmalates from Bletilla striata

The present study isolated 17 compounds from the tubers of Bletilla striata (Orchidaceae), using various chromatographic techniques. Their structures were identified based on their physical-chemical properties and spectroscopic analyses. Among them, two new 2-isobutylmalates, named bletimalates A (1) and B (2), together with other fifteen known compounds (3-17), were isolated and identified. Additionally, compounds 3, 4, and 8 were isolated from this plant for the first time.

Koumine, Humantenine, and Yohimbane Alkaloids from Gelsemium elegans

Nine new alkaloids of the koumine (1-4), humantenine (5-7), and yohimbane (8, 9) types as well as 12 known analogues were isolated from the leaves and vine stems of Gelsemium elegans. Compound 1 is the first N-4-demethyl alkaloid of the koumine type, compound 7 is the first nor-humantenine alkaloid, and compounds 8 and 9 are the first N-1-oxide and the first seco-E-ring alkaloids, respectively, of the yohimbane type. Compounds 1 and 7 exhibited moderate cytotoxicity against five human tumor cell lines with IC50 values in the range 4.6-9.3 μM.

Identification of anti-inflammatory constituents from Kalimeris indica with UHPLC-ESI-Q-TOF-MS/MS and GC-MS

ETHNOPHARMACOLOGICAL RELEVANCE

Kalimeris indica is a Miao׳s medicinal plant in Guizhou province of China employing to treat various inflammation-related diseases in clinical. The study aims to determine the active fractions of K. indica for its anti-inflammatory activity and to identify their chemical constituents.

MATERIAL AND METHODS

The dried K. indica herb was extracted with 50% aqueous ethanol and then successively separated with macroporous resin and MCI column chromatography to give five fractions (A-E). The anti-inflammatory effects were determined by measuring the NO and TNF-α production in murine macrophage RAW 264.7 cells after exposure to LPS. The chemical constituents of the anti-inflammatory fractions were analyzed by the method of UHPLC-ESI-Q-TOF/MS or GC-MS.

RESULTS

Five fractions (A-E) of different polarities were prepared from the 50% ethanol extract. Factions C and E showed significant inhibition of NO and TNF-α production. Six constituents, namely 3,4-dicaffeoylquinic acid (1), 3,5-dicaffeoylquinic acid (2), 1,5-dicaffeoylquinic acid (3), rutin (4), 1-malonyl-3,5-dicaffeoylquinic acid (5), and 4,5-dicaffeoylquinic acid (6) were identified from the active fraction C by UHPLC-ESI-Q-TOF/MS. Four compounds including 13-tetradecenal (7), (Z,Z)-9,12-octadecadienoic acid (8), (3α)-12-oleanen-3-yl acetate (9), and (+)-3-oxo-urs-12-en-24-oic acid methyl ester (10) were identified from the active fraction E by GC-MS.

CONCLUSION

K. indica possessed pronounced anti-inflammatory effect. Dicaffeoylquinic acids and their dirivatives, rutin, as well as oleanolic and fatty acid derivatives are the major constituents and possibly the anti-inflammatory principles of the active fractions of K. indica. All the compounds were identified in K. indica for the first time. The work provided evidence for further development and utilization of K. indica and formed a basis for the establishment of quality control methods and standards for K. indica and its pharmaceutical preparations.

Evaluation of the impact of Polygonum capitatum, a traditional Chinese herbal medicine, on rat hepatic cytochrome P450 enzymes by using a cocktail of probe drugs

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonum capitatum is a well-known Miao medicinal plant that has been used for many years for its unique therapeutic effects on various urological disorders, including urinary calculus and urinary tract infections. To investigate the effect of Polygonum capitatum on cytochrome P450 (CYP) isoforms (CYP1A2, CYP2C9, CYP2C19, CYP2E1, and CYP3A4) in vivo using a "cocktail" approach by administering five probe drugs to rats. This study assessed the potential of Polygonum capitatum to interact with co-administered drugs.

MATERIALS AND METHODS

An aqueous extract of dried whole Polygonum capitatum was prepared and administered orally to rats at a dose of 0.58g/kg or 1.74g/kg twice daily for 7 or 14 consecutive days. A cocktail of caffeine (1.0mg/kg), tolbutamide (1.0mg/kg), omeprazole (2.0mg/kg), chlorzoxazone (4.0mg/kg) and midazolam (4.0mg/kg) was then administered on the eighth or fifteenth day to evaluate the effects of Polygonum capitatum on CYP1A2, 2C9, 2C19, 2E1, and 3A4, respectively. Blood samples were collected at a range of time-points and the plasma concentrations of the probe drugs were simultaneously quantified using ultra high-performance liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated to evaluate the effects of Polygonum capitatum on the activities of these CYP enzymes in rats.

RESULTS

Polygonum capitatum pre-treatment had no significant effect on the pharmacokinetic parameters of caffeine, omeprazole or chlorzoxazone. However, the pharmacokinetics of tolbutamide and midazolam were affected significantly (P<0.05) by Polygonum capitatum, which induced more rapid metabolism of these probe compounds.

CONCLUSIONS

These results suggested that Polygonum capitatum could induce CYP2C9 and CYP3A4, and did not influence CYP1A2, CYP2C19 or CYP2E1. Therefore, the clinical dose of drugs metabolized by human CYP2C9 or CYP3A4 may need to be adjusted in patients taking Polygonum capitatum, as this herbal medication may result in reduced effective concentrations of these drugs.

[Quality evaluation of bletillae rhizoma based on hemostatic biopotency]

This dissertation is to determine the biopotency of hemostat which processed in different places by establishing a bioassay method of Bletillae Rhizoma based on the thrombin time. Contrast test is the main methodology. Specifically, the reference substance of Bletillae Rhizoma is determined by comparing with the control substance of vitamin K1 using thrombin time, which is calibrated the Bletillae Rhizoma. The hemostatic biopotency is calculated by using the method of "parallel line assay method based on quantitative responses" (3.3) from different processed products. It indicates that there is a strong linear correlation between Bletillae Rhizoma and control drugs (Y = 66.332-23.913X, R2 = 0.995 3). The hemostatic biopotency of Bletillae Rhizoma from different processed products ranged between 821.93-1 187.53 U x g(-1) shown in the paper, and all of them can meet the requirements of the test. The methodology has an appropriate instrument precision (RSD 3.8%), intermediate precision (RSD 4.6%), repeatability (RSD 3.2%) and stability (RSD 3.7%). Therefore, it can be turned out that the methodology which established in the dissertation is good at determinating the hemostatic biopotency of Bletillae Rhizoma and it is reliable, simple and repeatable.

Limonoids from the Leaves and Twigs of Walsura yunnanensis

Nine new cedrelone limonoids, namely, walsuranolide B (1), 11β-hydroxy-23-O-methylwalsuranolide (2), yunnanolide A (3), yunnanol A (4), 11β-hydroxyisowalsuranolide (5), 11β-hydroxy-1,2-dihydroisowalsuranolide (6), 1α,11β-dihydroxy-1,2-dihydroisowalsuranolide (7), 11β-hydroxy-1α-methoxy-1,2-dihydroisowalsuranolide (8), and yunnanolide B (9), together with a new cycloartane triterpenoid, (24S*,25R*)-cycloartane-3β,24,25,26-tetrol (10), were isolated from the leaves and twigs of Walsura yunnanensis. Their structures were elucidated on the basis of spectroscopic analysis and by comparison with literature data. Compounds 3 and 5 exhibited potent cytotoxicity against five human tumor cell lines with IC50 values in the range 2.2-4.2 μM.

[Simultaneous determination of nine chemical markers of bletillae rhizoma by ultra performance liquid chromatography]

A UPLC method has been developed in the current investigation for simultaneous determination of nine chemical markers of Bletilla striata, 4-hydroxymethylphenyl beta-D-glucoside, blestroside, dactylorhin A, militarine, dihydrophenanthrene 5, gymnoside V, dihydrophenanthrene 1, benzylphenanthrene 3 and gymnosides IX. Separation was performed at 45 degrees C on an ACQUITY UPLC BEH C18 column (2.1 mm x 150 mm, 1.7 microm) with a gradient solvent system of acetonitrile-water as the mobile phase. The flow rate was 0.3 mL x min(-1), the detection wavelength was 280 nm. The results showed that the nine chemical markers could be well resolved and that in the selected linear range, all calibration curves of the nine chemical markers showed good linearity (r > or = 0.999 3). The recoveries (n = 6) were in the range of 98.15% - 102.2% and RSDs were between 2.1% - 3.6%. The data suggested that the developed UPLC-UV method had good reproducibility, robustness, and accuracy, which was suitable for the quality control of Bletilla striata. Applications of the method showed that the nine chemical markers had higher contents in the wild B. striata than in the cultivated ones.

Report: structures and hepatocytotoxicity of co-occurring substances in oleanolic acid tablets

Tablets of oleanolic acid (OA) have been approved by SFDA in China as an adjuvant therapy for acute and chronic hepatitis. Co-occurring substances present in the tablets of OA and their hepatocytotoxicity have not yet been reported. In the current investigation, the crude OA drug was separated by repeated column chromatography. The structures of the isolated compounds were characterized by spectral analysis and the cytotoxicity of each compound was evaluated in vitro against the human normal liver cell L02 at concentrations from 0.125 to 1000 μmol/L using the MTT method. As a result, OA and its 11 co-occurring trace compounds including one new triterpenoid, 3-O- (4-oxo-pentanoyl)-olean-12- en-28-oic acid, were isolated and structurally characterized. Cytotoxicity tests indicated that these compounds were all non-toxic at concentrations up to 50μmol/L. Clear structure-activity relationship (SAR) was also observed. The results suggested that OA tablets of similar origin might not cause obvious cytotoxicity to the normal liver cell. The work may facilitate further SAR studies of OA-type triterpenoids.

Limonoids from the fruits of Khaya ivorensis

Two new limonoids, namely 14,15-didehydroruageanin A (1) and 3-O-methyl- butyrylseneganolide A (2), were isolated from the fruits of Khaya ivorensis along with six known limonoids: seneganolide A (3), 1,3-dideacetylkhivorin (4), 7-deacetylkhivorin (5), 3-deacetylkhivorin (6), 1-deacetylkhivorin (7), and 3-deacetyl-7-oxokhivorin (8). All the compounds were evaluated for their cytotoxicity against five tumor cell lines.

Identification and characterisation of phenolics in Polygonum capitatum by ultrahigh-performance liquid chromatography with photodiode array detection and tandem mass spectrometry

INTRODUCTION

Polygonum capitatum is a well-known Chinese medicinal plant widely used by the Miao people for the treatment of various urologic disorders. Previous investigations have shown the presence of various types of phenolics. Our ultrahigh-performance liquid chromatography with photodiode array detection and mass spectrometry (UPLC-PDA-MS) analysis indicated that flavonoid glycosides and polyphenolic glycosides were its major constituents and quite a number of phenolic compounds have not yet been identified. Identification or characterisation of the major compounds of this plant will contribute to the scientific understanding of the medicinal plant and the authentication of the plant material and its pharmaceutical preparations.

OBJECTIVE

To develop an efficient method for the identification and structural characterisation of the major compounds present in P. capitatum.

METHODS

Elution of the 70% ethanol extract of P. capitatum by 80% ethanol on a D101 macroporous resin column afforded a phenolics-enriched fraction, separation of which by Sephadex LH-20 column chromatography eluted with absolute ethanol gave a tannin-free phenolic fraction (TFPF). Compounds present in TFPF were identified and structurally characterised by UPLC-PDA-ESI-MS/MS.

RESULTS

An amino acid and 40 phenolics including a number of flavonoid glycosides and polyphenolic glycosides were identified or structurally characterised in TFPF. Among these compounds, four were new and 19 were described in the plant for the first time.

CONCLUSION

The study showed that TFPF of P. capitatum contained flavonoid glycosides and polyphenolic glycosides as its major principles. Polyphenolic glycosides were perhaps the most typical chemical markers of P. capitatum.

Two new triterpenoids from Gelsemium elegans and Aglaia odorata

Eleganoside A (1) and odoratanone A (15), a triterpenoid trisaccharide glycoside and a nortriterpenoid, together with twelve known compounds (2-13) and a mixture of cerebrosides (14) were isolated from Gelsemium elegans and Aglaia odorata. Their structures were elucidated by extensive spectroscopic and spectrometric analysis. Eleganoside A (1) features a 3-O-alpha-L-rhamnopyranosyl (1-->4)-beta-D-glucopyranosyl (1-->4)-beta-D-glucopyranoside of a peculiar 3,16-dihydroxyl-lanosta-8,24-dien-26-oic acid triterpenoid skeleton, and odoratanone A (15) is a 29-norcycloartane-type triterpenoid bearing an unusual five-membered methyl acetal ring. Anti-acetylcholinesterase/butyrylcholinesterase (AChE/BChE) assay indicated that at 50 microM, ethyl caffeate (5) was promising as a dual inhibitor of AChE and BChE, and paeonol (3) and 24-hydroperoxy-24-vinylcholesterol (9) exhibited BChE-selective inhibition.

Simultaneous determination of human plasma protein binding of bioactive flavonoids in Polygonum orientale by equilibrium dialysis combined with UPLC-MS/MS

A simple and selective ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) assay was developed for the determination of the human plasma protein binding of four bioactive flavonoids (such as orientin and vitexin) in Polygonum orientale. Protein precipitation was used for sample preparation. Equilibrium dialysis technique was applied to determine the plasma protein binding under physiological conditions. The separation was achieved through a Waters C18 column with a mobile phase composed of 0.1% formic acid in acetonitrile and 0.1% aqueous formic acid using step gradient elution at a flow rate of 0.35 mL/min. A Waters ACQUITY™ TQD system was operated under the multiple reaction monitoring (MRM) mode of positive electrospray ionization. All of the recovery, precision, accuracy and stability of the method met the requirements. Good correlations (r>0.99) of the four compounds were found, which suggested that these compounds can be simultaneously determined with acceptable accuracy. Results showed that the plasma protein bindings of the four bioactive flavonoids were in the range of 74-89% over the six concentrations studied. The binding parameters containing protein binding affinity, protein binding dissociation constant, and protein binding site were studied. The maximum ability to bind with protein was also determined in the assay in order to understand the drug-protein binding of each compound better.

Two New Triterpenoids from Gelsemium Elegans and Aglaia odorata

Eleganoside A (1) and odoratanone A (15), a triterpenoid trisaccharide glycoside and a nortriterpenoid, together with twelve known compounds (2–13) and a mixture of cerebrosides (14) were isolated from Gelsemium elegans and Aglaia odorata. Their structures were elucidated by extensive spectroscopic and spectrometric analysis. Eleganoside A (1) features a 3- O-α-L-rhamnopyranosyl (1→4)-β-D-glucopyranosyl (1→4)-β-D-glucopyranoside of a peculiar 3,16-dihydroxyl-lanosta-8,24-dien-26-oic acid triterpenoid skeleton, and odoratanone A (15) is a 29-norcycloartane-type triterpenoid bearing an unusual five-membered methyl acetal ring. Anti-acetylcholinesterase/butyrylcholinesterase (AChE/BChE) assay indicated that at 50 μM, ethyl caffeate (5) was promising as a dual inhibitor of AChE and BChE, and paeonol (3) and 24-hydroperoxy-24-vinylcholesterol (9) exhibited BChE-selective inhibition.

Uncarilic acid and secouncarilic acid, two new triterpenoids from Uucaria sessilifructus

Two new compounds, the 6-oxo oleanane-type triterpenoid uncarilic acid, and its 5,6-secotriterpenoid derivative, secouncarilic acid, were isolated from the hooks and stems of Uucaria sessilifructus together with seven known ursane-type triterpenoids. Uncarilic acid is the second 6-oxo oleanane-type triterpenoid ever reported, while secouncarilic acid is the first oleanane-type 5,6-secotriterpenoid. A plausible biosynthetic pathway from uncarilic acid to secouncarilic acid was also postulated. The inhibitory activities of all the nine compounds against LPS-induced nitric oxide production in RAW264.7 macrophages were evaluated.

Protective effects of fractions from Pseudostellaria heterophylla against cobalt chloride-induced hypoxic injury in H9c2 cell

ETHNOPHARMACOLOGICAL RELEVANCE

Except for as a well-known tonic Chinese herbal medicine for the treatment of splenic asthenia, anorexia, lassitude and weakness, the roots of Pseudostellaria heterophylla was also used in Chinese medicines for the treatment of palpitation.

AIM OF THE STUDY

The study was designed to determine whether fractions from Pseudostellaria heterophylla could provide cardioprotection on hypoxic cardiomyocytes, what structural types of compounds were responsible for the observed effects, and which is the possible mechanism of action.

MATERIALS AND METHODS

The roots of Pseudostellaria heterophylla were extracted successively with 70% aqueous ethanol and water to give a 70% ethanol extract and a water extract. The latter was first precipitated by 80% ethanol and then protein-removed by the Sevag method to give a fraction enriched in polysaccarides (PHP). The former was separated by column chromatography into a fraction enriched in small-molecule sugars and amino acids (PHSSAC), saponins (PHS), cyclopeptides (PHCP), and sapogenins (PHSG). UV spectral or chemical methods were used to confirm the five fractions. The cardioprotective effects of the fractions were evaluated by measuring the viability and the leakage of lactate dehydrogenase (LDH) of the fraction-pretreated cardiomyocyte H9c2 after exposure to CoCl2-induced hypoxia. The mechanism of action was studied by investigating the nature of cell death inhibition (by Annexin V/PI flow cytometric analysis) and their effects on the levels of malonaldehyde (MDA), superoxide dismutase (SOD) and intracellular reactive oxygen species (ROS).

RESULTS

Fractions PHS and PHP could attenuate CoCl2-induced hypoxic damage to an extent higher than or comparable to the effect of the positive control N-acetyl-l-cysteine (NAC). Pretreatment of the cells with 800 μg/mL of PHS or 10mg/mL of PHP markedly decreased the level of MDA, reduced intracellular ROS, increased the activity of SOD, and reduced leakage of LDH to the levels close to or better than that with 326 μg/mL of NAC. Reduction of apoptosis was also observed for both fractions.

CONCLUSIONS

The overall results suggested that the traditional use of this plant for the treatment of palpitation may be attributed to the presence of cardioprotective agents in Pseudostellaria heterophylla. PHP and PHS were the two active fractions responsible for its cardioprotective effect. The mechanism might involve protections of the cell membrane from hypoxic damage and of the cells from oxidative injury via preventing increased oxidative stress. Protection of the cells via inhibition of cellular apoptosis may also be involved.

UPLC-PDA-ESI-MS/MS analysis of compounds extracted by cardiac h9c2 cell from Polygonum orientale

INTRODUCTION

A flavonoid-enriched extract (FEE) of Polygonum orientale was reported to show cardioprotective effect but only very few compounds were reported to contribute to the effect. Identification of compounds interacting with the target cardiac cell is important for the understanding of active compounds.

OBJECTIVE

To develop an efficient method for the screening of potential active compounds directly acting on the target cardiac cell in FEE and to structurally characterise these compounds.

METHODOLOGY

Flavonoid-enriched extract was prepared by extraction of the plant with water, addition of ethanol to the solution to remove polysaccharides and proteins, and removal of tannins by a polyamide column chromatography. Cell extraction was conducted on a cardiac h9c2 cell and the solution containing compounds released from the cell were desalted by solid phase extraction. Compounds present in the cell extract were detected by ultra-performance liquid chromatography (UPLC) and targeted multi-reaction monitoring (MRM), while their structures were characterised by UPLC-photodiodide array (PDA)-electrospray ion source (ESI)-MS/MS investigations of the FEE.

RESULTS

Twenty-three potentially active phenolics including ten flavonoid C-glycosides and six flavonoid O-glycosides have been identified from the 40 compounds screened in the cell extract. Among these compounds, three were new and nine were identified from this plant for the first time. Strategies for the structural characterisation of flavonoid glycosides were also discussed.

CONCLUSION

The study has shown that FEE contains the flavonoid as its major principles and the coupling of UPLC-PDA-ESI-MS/MS and targeted UPLC-MRM with target cell extraction is an efficient method for the screening and structural characterisation of potential active compounds.