Beneficial effects of danshensu, an active component of Salvia miltiorrhiza, on homocysteine metabolism via the trans-sulphuration pathway in rats

Challenges and strategies in progress of drug delivery system for traditional Chinese medicine Salviae Miltiorrhizae Radix et Rhizoma (Danshen)

Traditional Chinese medicines (TCMs), with a history of thousands of years, are widely used clinically with effective treatment. However, the drug delivery systems (DDSs) for TCMs remains major challenges due to the characteristics of multi-components including alkaloids, flavones, anthraquinones, glycosides, proteins, volatile oils and other types. Therefore, the novel preparations and technology of modern pharmaceutics is introduced to improve TCM therapeutic effects due to instability and low bioavailability of active ingredients. Salviae Miltiorrhizae Radix et Rhizoma, the radix and rhizomes of Salvia miltiorrhiza Bunge (Danshen in Chinese), is a well known Chinese herbal medicine for protecting the cardiovascular system, with active ingredients mainly including lipophilic tanshinones and hydrophilic salvianolic acids. In this review, this drug is taken as an example to present challenges and strategies in progress of DDSs for TCMs. This review would also summary the characteristics of active ingredients in it including physicochemical properties and pharmacological effects. The purpose of this review is to provide inspirations and ideas for the DDSs designed from TCMs by summarizing the advances on DDSs for both single- and multi-component from Danshen.

Inhibition of nuclear factor kappa B as a mechanism of Danshensu during Toll-like receptor 2-triggered inflammation in macrophages

Danshensu (DSS) is a water-soluble phenolic compound in Danshen (Salvia Miltiorrhiza Radix et Rhizoma). Although various pharmacological activities have been recognized, little is known regarding its anti-inflammatory effect and related molecular mode of action. In the current study, bone marrow-derived macrophages (BMMs) were activated by a Toll-like receptor 2 (TLR2) agonist Pam3CSK4 with or without DSS intervention. Production of pro-inflammatory cytokines interleukin-6 (IL-6) and interleukin-12 (IL-12) was detected by both enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (RT-qPCR). Activation of signaling pathways involving nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) was assessed by Western blot. Additionally, RNA sequencing (RNA-seq) combined with bioinformatics analyses was applied to investigate the molecular mechanisms of DSS. Emphasis was placed on the construction of the protein-protein interaction (PPI) network and transcription factor (TF) enrichment analysis of data including co-regulated differentially expressed genes (DEGs) in the Pam3CSK4 vs. control and DSS vs. Pam3CSK4 groups. The RT-qPCR and ELISA results showed that DSS effectively inhibited the expressions of IL-6 and IL-12, indicating a significant anti-inflammatory effect. Western blot verified that DSS suppressed the phosphorylation of p65, which was in accordance with the results of the TF enrichment analysis. Additionally, the PPI network analysis showed several key molecules, including lactoferrin (Ltf), CC-chemokine receptor 7 (Ccr7), interferon-gamma (IFN-γ) and C-X-C motif chemokine ligand 9 (Cxcl9), to be regulatory genes that responded to DSS treatment. Overall, our study revealed that DSS has a pronounced anti-inflammatory effect involving TLR2 and macrophages through the NF-κB signaling pathway, which supports the novel application of DSS in the treatment of relevant diseases including atherosclerosis and ischemic or ischemic/perfusion injury of the heart and brain.

Salvia miltiorrhiza in diabetes: A review of its pharmacology, phytochemistry, and safety

BACKGROUND

Salvia miltiorrhiza (SM), one of the frequently used herbs in traditional Chinese medicine (TCM), has now attracted rising interests for a possible alternative in the management of diabetes. This review is aimed to providing a comprehensive perspective of SM in phytochemical constituents, pharmacological activities against diabetes and its complications, and safety.

METHODS

A comprehensive search of published literatures was conducted to locate original publications pertaining to SM and diabetes till the end of 2017 using PubMed, China National Knowledge Infrastructure, National Science and Technology Library, China Science and Technology Journal Database, and Web of Science database. The main inquiry was used for the presence of the following keywords in various combinations in the titles and abstracts: Salvia miltiorrhiza, diabetes, obesity, phytochemistry, pharmacology, and safety. About 200 research papers and reviews were consulted.

RESULTS

SM exhibited anti-diabetic activities by treating macro- and micro-vascular diseases in preclinical experiments and clinical trials through an improvement of redox homeostasis and inhibition of apoptosis and inflammation via the regulation of Wnt/β-catenin, TSP-1/TGF-β1/STAT3, JNK/PI3K/Akt, kinin B2 receptor-Akt-GSK-3β, AMPKβ/PGC-1α/Sirt3, Akt/AMPK, TXNIP/NLRP3, TGF-β1/NF-κB, mineralocorticoid receptor/Na⁺/K⁺-ATPase, AGEs/RAGE, Nrf2/Keap1, CaMKKβ/AMPK, AMPK/ACC, IRS-1/PI3K signaling pathways, and modulation of K⁺-Ca²⁺ channels, as well as influence of VEGF, NOS, AGEs, PPAR expression and hIAPP aggregation. The antidiabetic effects of this herb may be related to its TCM characters of improving blood circulation and reliving blood stasis. The main ingredients of SM included salvianolic acids and diterpenoid tanshinones, which have been well studied in the diabetic animals. Acute and subacute toxicity studies supported the notion that SM is well tolerated.

CONCLUSION

SM may offer a new strategy for prevention and treatment of diabetes and its complications that stimulates extensive research into identifying potential anti-diabetic compounds and fractions as well as exploring the underlying mechanisms of this herb. Further scientific evidences are still required from well-designed preclinical experiments and clinical trials on its anti-diabetic effects and safety.

Reducing 3,4-dihydroxyphenylpyruvic acid to d-3,4-dihydroxyphenyllactic acid via a coenzyme nonspecific d-lactate dehydrogenase from Lactobacillus reuteri

AIMS

The purpose of this work was to find an efficient enzyme to synthesize d-3,4-dihydroxyphenyllactic acid (d-DSS).

METHODS AND RESULTS

Nineteen lactic acid bacteria strains were screened for production of d-DSS using 3,4-dihydroxyphenylpyruvic acid (DPA) as a substrate. Lactobacillus reuteri JN516 exhibited the highest d-DSS yield. A nonspecific coenzyme, d-lactate dehydrogenase (d-LDH82319), from L. reuteri JN516 with high DPA reducing activity was identified. This enzyme reduced DPA to form d-DSS with excellent optical purity (enantioselectivity >99%). Its molecular weight was 35 kDa based on SDS-PAGE migration. The Michaelis-Menten constant (Km ), turnover number (kcat ), and catalytic efficiency (kcat /Km ) of d-LDH82319 for DPA were 0·09 mmol l-1 , 2·17 s-1 and 24·07 (mmol l-1 )-1  s-1 , respectively, with NADH as the coenzyme. The (Km ), (kcat ) and (kcat /Km ) of d-LDH82319 for DPA were 0·10 mmol l-1 , 0·13 s-1 and 1·30 (mmol l-1 )-1  s-1 , respectively, with NADPH as the coenzyme. The optimum temperature and pH of d-LDH82319 were 25°C and pH 8 respectively. Additionally, d-LDH82319 had a broad substrate range for alpha-keto acids, among which the activity of reducing pyruvate was the strongest; therefore, it belongs to the group of d-lactate dehydrogenases. d-LDH82319 and glucose dehydrogenase (GDH) were coexpressed to produce d-DSS from DPA.

CONCLUSIONS

d-LDH82319 from L. reuteri JN516 with high DPA reducing activity has the characteristics of a nonspecific coenzyme.

SIGNIFICANCE AND IMPACT OF THE STUDY

d-LDH82319 is the first reported coenzyme nonspecific d-lactate dehydrogenase with DPA-reducing activity. The coexpression system provided an effective method to produce d-DSS.

Cardiovascular Protective Effects of Salvianic Acid A on db/db Mice with Elevated Homocysteine Level

The onsets of left ventricular hypertrophy (LVH) and endothelial dysfunction (ED) in diabetics, especially in those with elevated homocysteine (Hcy), precede the development of cardiovascular (CV) events. Salvianic acid A (SAA) is a renowned Traditional Chinese Medicine (TCM) that has been applied in the treatment of cardiovascular disease for many decades. In this study, we aimed (1) to investigate the CV protective effects of SAA on ameliorating LVH and ED in db/db mice with elevated blood Hcy level and (2) to decipher whether the observed CV protective effects of SAA are associated with Hcy metabolism by modulating the methylation potential and redox status in the liver of the db/db mice with elevated blood Hcy level. Our results found that the administration of SAA could significantly slow down the build-up of left ventricular mass and ameliorate ED. Immunological assay analysis on the mouse liver tissue also indicated that SAA treatment on db/db mice with elevated Hcy was associated with reduced methylation potential but improved redox status. In conclusion, we revealed that SAA has the potential to protect against the hyperglycemia- and hyperhomocysteinemia-induced oxidative stress on diabetic mice via modulation in Hcy metabolism.

Danshensu attenuates aldosterone-induced cardiomyocytes injury through interfering p53 pathway

Heart failure, characterized by impaired systolic and/or diastolic function, is a common cardiovascular disease. The loss of cardiomyocytes due to various factors, including through necrosis or apoptosis can result in heart failure. Previous studies have indicated that excessive aldosterone (ALD) serves an essential role in the process of heart failure, and the heart is also one of the direct targets of ALD, which can provoke hypertrophy and the apoptosis of cardiomyocytes. The aim of the present study was to investigate the protective effect of danshensu (DSS) on ALD‑induced cardiomyocytes injury. The present results demonstrated that DSS increased cell viability and decreased the leakage of lactate dehydrogenase in cardiomyocytes exposed to ALD. In addition, DSS decreased the apoptotic rate of ALD‑stimulated cells. Further research indicated that DSS‑ and cellular tumor antigen p53 (p53)‑alone or combination treatment was able to decrease the expression levels of apoptosis regulator BAX and caspase‑3, and increase the expression of apoptosis regulator B‑cell lymphoma (Bcl)‑2 in ALD‑stimulated cardiomyocytes. Taken together, the results of the present study suggest that DSS inhibits the harmful effects of ALD on cardiomyocytes via interfering with the p53 signaling pathway. These results provide novel evidence for the potential protective effects of DSS.

The Effects of Subchronic Methionine Overload Administered Alone or Simultaneously with L-cysteine or N-acetyl-L-cysteine on Body Weight, Homocysteine Levels and Biochemical Parameters in the Blood of Male Wistar Rats

Hyperhomocysteinemia (HHC), both basal and after methionine load, may occur due to genetic disorders or deficiencies of nutrients that affect the remethylation or trans-sulphuration pathways during methionine metabolism. HHC is involved in the pathogenesis of many illnesses as a result of its prooxidative effect and its impairment of antioxidative protection. The aim was to examine the effects of subchronic methionine overload on the body weight and standard biochemical parameters in rat serum and to examine whether simultaneous subchronic intraperotoneal administration of methionine alone or together with L-cysteine or N-acetyl-cysteine resulted in a change in the body weight and biochemical parameters in the rat serum. The research was conducted during a three-week period (male Wistar albino rats, n=36, body weight of approximately 160 g, age of 15-20 days), and the animals were divided into a control group and three experimental groups of 8-10 animals each: a) control group (0.9% sodium chloride 0.1-0.2 ml/day); b) methionine (0.8 mmol/kg/bw/day) (MET group); c) methionine (0.8 mmol/kg/bw/day) + L-cysteine (7 mg/kg/bw/day) (L-cys+MET group); and d) methionine (0.8 mmol/kg/bw/day) + N-acetyl-L-cysteine (50 mg/kg/bw/day) (NAC+MET group). In addition to the body weight monitoring, the levels of total homocysteine and the standard biochemical parameters in blood samples (plasma or serum) were determined. The results indicated that monitoring the homocysteine levels and standard biochemical parameters in blood could be used for analysis and could provide an excellent guideline for distinguishing between toxic and non-toxic doses of methionine intake, which may be meaningful for clinical applications.

Homocysteine-Induced Endothelial Dysfunction

This review discussed and in particular emphasis the potential cellular pathways and the biological processes involved that lead to homocysteine-induced endothelial dysfunction, in particular in the impaired endothelial dependent dilatation aspect. Hyperhomocysteinemia is an independent cardiovascular risk factor that has been associated with atherosclerotic vascular diseases and ischemic heart attacks. The potential mechanisms by which elevated plasma homocysteine level leads to reduction in nitric oxide bioavailability include the disruptive uncoupling of nitric oxide synthase activity and quenching of nitric oxide by oxidative stress, the enzymatic inhibition by asymmetric dimethylarginine, endoplasmic reticulum stress with eventual endothelial cell apoptosis, and chronic inflammation/prothrombotic conditions. Homocysteine-induced endothelial dysfunction presumably affecting the bioavailability of the potent vasodilator ‘nitric oxide', and such dysfunction can easily be monitor by flow-mediated dilation method using ultrasound. Understanding the mechanisms by which plasma homocysteine alter endothelial nitric oxide production is therefore essential in the comprehension of homocysteine-induced impairment of endothelial dependent dilatation, and its association of cardiovascular risk and its pathophysiology.

Methylation and its role in the disposition of tanshinol, a cardiovascular carboxylic catechol from Salvia miltiorrhiza roots (Danshen)

AIM

Tanshinol is an important catechol in the antianginal herb Salvia miltiorrhiza roots (Danshen). This study aimed to characterize tanshinol methylation.

METHODS

Metabolites of tanshinol were analyzed by liquid chromatography/mass spectrometry. Metabolism was assessed in vitro with rat and human enzymes. The major metabolites were synthesized for studying their interactions with drug metabolizing enzymes and transporters and their vasodilatory properties. Dose-related tanshinol methylation and its influences on tanshinol pharmacokinetics were also studied in rats.

RESULTS

Methylation, preferentially in the 3-hydroxyl group, was the major metabolic pathway of tanshinol. In rats, tanshinol also underwent considerable 3-O-sulfation, which appeared to be poor in human liver. These metabolites were mainly eliminated via renal excretion, which involved tubular secretion mainly by organic anion transporter (OAT) 1. The methylated metabolites had no vasodilatory activity. Entacapone-impaired methylation did not considerably increase systemic exposure to tanshinol in rats. The saturation of tanshinol methylation in rat liver could be predicted from the Michaelis constant of tanshinol for catechol-O-methyltransferase (COMT). Tanshinol had low affinity for human COMT and OATs; its methylated metabolites also had low affinity for the transporters. Tanshinol and its major human metabolite (3-O-methyltanshinol) exhibited negligible inhibitory activities against human cytochrome P450 enzymes, organic anion transporting polypeptides 1B1/1B3, multidrug resistance protein 1, multidrug resistance-associated protein 2, and breast cancer resistance protein.

CONCLUSION

Tanshinol is mainly metabolized via methylation. Tanshinol and its major human metabolite have low potential for pharmacokinetic interactions with synthetic antianginal agents. This study will help define the risk of hyperhomocysteinemia related to tanshinol methylation.

Danshen (Salvia miltiorrhiza) water extract inhibits paracetamol-induced toxicity in primary rat hepatocytes via reducing CYP2E1 activity and oxidative stress

OBJECTIVES

This study aimed to investigate the protective effects of Danshen (Salvia miltiorrhiza) water extract (DSE) and its major phenolic acid components against CYP2E1-mediated paracetamol (APAP)-induced hepatic toxicity.

METHODS

The protection and underlying mechanisms were detected in CYP2E1 overexpression primary rat hepatocytes by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, alamar blue assay, CYP2E1 inhibition assay and glutathione assay.

KEY FINDINGS

After APAP treatment, DSE (0.06-1 mg/ml) significantly increased cell viability in MTT assay. Two major components danshensu (8.2-130.5 μm) and salvianolic acid B (Sal B; 3.3-53.5 μm) mainly contributed to this protection, but rosmarinic acid, protocatechuic aldehyde and Sal A did not. Alamar blue assay showed that DSE, danshensu and Sal B maintained mitochondrial metabolic activity. DSE inhibited CYP2E1 (Ki = 1.46 mg/ml) in a mixed mode in rat liver microsomes in vitro; DSE decreased APAP-induced total glutathione depletion and preserved redox status (GSH/GSSG ratio) in hepatocytes. Danshensu and Sal B did not inhibit CYP2E1 or decrease total glutathione depletion, but preserved redox status.

CONCLUSIONS

DSE protected hepatocytes against APAP-induced injury via maintenance of mitochondrial metabolic activity, CYP2E1 inhibition, reduction of total glutathione depletion and preservation of redox status. Danshensu and Sal B were mainly responsible for this protection.

Effects of Danshensu and Salvianolic Acid B from Salvia miltiorrhiza Bunge (Lamiaceae) on cell proliferation and collagen and melanin production

Danshensu (DSU) and salvianolic acid B (SAB) are the primary water-soluble compounds of Salvia miltiorrhiza Bunge (Lamiaceae). In this study, we analyzed the effects of DSU, SAB and a S. miltiorrhiza extract (SME) on cell proliferation. Additionally, the effects of DSU and SAB on collagen synthesis in Detroit 551 human normal fibroblast cells and on melanin production in B16 melanoma cells were verified. The results demonstrated that SME can enhance the proliferation of Detroit 551 cells and that this boost may be caused by DSU and SAB. This research showed that SME, DSU and SAB all have the ability to increase the production of collagen in Detroit 551 cells. The results also confirmed that DSU and SAB can attenuate the α-MSH-stimulated melanin production of B16 cells by inhibiting tyrosinase activity. Therefore, SME, DSU and SAB each have the potential to be utilized as active ingredients in wound healing or cosmetic treatments. In the future, DSU and SAB could also be used as functional components for treating hyperpigmentation.

Activation of transsulfuration pathway by salvianolic acid a treatment: a homocysteine-lowering approach with beneficial effects on redox homeostasis in high-fat diet-induced hyperlipidemic rats

Background

Elevated homocysteine is a cardiovascular risk factor in hyperlipidemia. Transsulfuration pathway provides an endogenous pathway for homocysteine conversion to antioxidant glutathione (GSH). Salvianolic acid A (Sal A) contains two molecules of caffeic acid and one molecule of danshensu that is capable of enhancing homocysteine transsulfuration, which led to the hypothesis that Sal A has activatory effect on transsulfuration pathway and this effect may have beneficial effects on both homocysteine and redox status in hyperlipidemia.

Methods and results

To test this hypothesis, we developed a rat model of hyperlipidemia induced by high-fat diet for 16 weeks, during which rats were treated with 1 mg/kg salvianolic acid A (Sal A) for the final 4 weeks. Activities of key enzymes and metabolite profiling in the transsulfuration pathway revealed that hyperlipidemia led to elevated plasma homocysteine levels after 16-week dietary treatment, which was associated with reduced activities of homocysteine transsulfuration enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE). The impaired transsulfuration pathway prevented homocysteine transsulfuration to cysteine, resulting in cysteine deficiency and subsequent reduction in GSH pool size. The redox status was altered in the setting of hyperlipidemia as indicated by GSH/GSSG ratio. Sal A treatment increased hepatic CBS and CSE activities, which was associated with reduced accumulation in circulating homocysteine levels and attenuated decline in hepatic cysteine content in hyperlipidemic rats. Sal A also led to an increase in GSH pool size, which subsequently caused a restored GSH/GSSG ratio. The activatory effect of Sal A on CBS was also observed in normal rats and in in vitro experiment.

Conclusion

Our results suggest that activation of transsulfuration pathway by Sal A is a promising homocysteine-lowering approach that has beneficial effects on redox homeostasis in hyperlipidemic settings.

A novel metabolic balance model for describing the metabolic disruption of and interactions between cardiovascular-related markers during acute myocardial infarction

OBJECTIVE

After acute myocardial infarction (AMI), an integral evaluation of risk using multimarker approach and the understanding of the pathophysiological processes involved have recently received much attention. This study aimed to develop a model to integrally evaluate the metabolic disruption of cardiovascular-related markers and unveil their interactions after AMI.

METHODS

AMI was induced in rats by coronary artery ligation. Several cardiovascular-related markers in plasma and the heart were determined during AMI. A metabolic balance model was developed using matrix equations to assess the metabolic disturbance of, and interactions between, these markers.

RESULTS

Metabolic balance maps intuitively depicted the metabolic disruption of cardiovascular-related markers after AMI. The deviation and magnitude of the disruption were quantitatively and integrally described by φ and k (the dynamic parameter of metabolic balance disruption), respectively. The metabolic balance was disturbed in both the circulatory system and the heart post-AMI. All of the measured markers appeared to be interactional. Among these markers, kidney function and dimethylarginine dimethylaminohydrolase (DDAH) activity in the heart showed a potent effect on the other markers, whereas asymmetric dimethylarginine (ADMA) levels in plasma and adenosine triphosphate (ATP) contents in the heart were susceptible to the effects of the other markers.

CONCLUSION

A metabolic balance model was developed to integrally evaluate the disruption of cardiovascular-related markers after AMI, which proposes a new method for evaluating the disease state post-AMI using a multimarker approach. The unveiled interactions between these cardiovascular-related markers are helpful in understanding the pathophysiological processes.

Mechanism and cellular kinetic studies of the enhancement of antioxidant activity by using surface-functionalized gold nanoparticles

The enhanced antioxidant activity of surface-functionalized gold nanoparticles (AuNPs) synthesized by self-assembly has attracted great attention, but little is known about the mechanism behind the enhanced activity. To address this challenge, the antioxidant activity of Au@PEG3SA (i.e., surface-functionalization of spherical AuNPs with the antioxidant salvianic acid A) was used as an example to illustrate the mechanism of the enhanced activity. Evaluation of the antioxidant activity was performed in a radical-scavenging reaction between Au@PEG3SA and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. As expected, the rate constant for the reaction of Au@PEG3SA with DPPH was about nine times greater than that for the salvianic acid A monomer. A comparative analysis of the spectral characteristics of Au@PEG3SA and the salvianic acid A monomer further imply that the enhancement of the antioxidative reaction kinetics may be ascribed to the variation in the transition state for the DPPH-radical scavenging reaction through π-π stacking interactions between and among adjacent groups on the surface of Au@PEG3SA. On the other hand, the kinetic enhancement of Au@PEG3SA on reactive-oxygen-species (ROS) scavenging can be observed in living cells and in vivo, which possibly provides new insight for the bioapplication of self-assembly of surface-functionalized AuNPs.

Preventive effect of danshensu on selenite-induced cataractogenesis in cultured rat lens

BACKGROUND

To investigate the preventive effect of danshensu on the selenite-induced opacification of cultured rat lenses.

METHODS

Isolated lens were divided into three groups with eight lenses in each group. Group I: lenses were incubated with M199 medium alone; Group II: incubated in M199 containing 200 µmol/L sodium selenite; Group III: incubated in M199 containing 200 µmol/L sodium selenite and 500 µmol/L danshensu. Selenite was administered on the third day, and danshensu treatment was from the second to the fifth day. Cataracts development was observed using an inverted microscope, and the lenses were analysed for total anti-oxidative capabilities, mean activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase; levels of reduced glutathione; malondialdehyde; and total sulfhydryl content.

RESULTS

All lenses in Group I were clear, whereas all lenses in Group II developed dense vacuolization and opacification. In Group III, 25% lenses revealed minimal vacuolization, and 75% showed no opacification or vacuolization. Total anti-oxidative capabilities and the mean activities of anti-oxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase; levels of glutathione; and total sulfhydryl content were elevated, and the level of malondialdehyde was decreased following treatment with danshensu compared with Group II.

CONCLUSION

The anti-oxidative properties of danshensu may play a major role in its contribution to the anticataract effect.

Using neural networks to determine the contribution of danshensu to its multiple cardiovascular activities in acute myocardial infarction rats

ETHNOPHARMACOLOGICAL RELEVANCE

Danshensu is an active water-soluble component from Salvia Miltiorrhiza, which has been demonstrated holding multiple mechanisms for the regulation of cardiovascular system. However, the relative contribution of danshensu to its multiple cardiovascular activities remains largely unknown.

AIM OF THE STUDY

To develop an artificial neural network (NN) model simultaneously characterizing danshensu pharmacokinetics and multiple cardiovascular activities in acute myocardial infarction (AMI) rats. The relationship between danshensu pharmacokinetics (PK) and pharmacodynamics (PD) were evaluated using contribution values.

MATERIALS AND METHODS

Danshensu was intraperitoneally injected at a single dose of 20mg/kg to AMI rats induced by coronary artery ligation. Plasma levels of danshensu, cardiac troponin T (cTnT), total homocysteine (Hcy) and reduced glutathione (GSH) were quantified. A back-propagation NN model was developed to characterize the PK and PD profiles of danshensu, in which the input variables contained time, area under plasma concentration-time curve (AUC) of danshensu and rat weights (covariate). Relative contribution of input variable to the output neurons was evaluated using neuron connection weights according to Garson's algorithm. The kinetics of contribution values was also compared and was validated using bootstrap resampling method.

RESULTS

Danshensu exerted significant cTnT-lowering, Hcy- and GSH-elevating effect, and these marker profiles were well captured by the trained NN model. The calculation of relative contributions revealed that the effect of danshensu on the PD marker could be ranked as cTnT>GSH>Hcy, while the effect of AMI disease on the PD marker could be ranked in the following order: cTnT>Hcy>GSH. The activity of transsulfuration pathway was quite obvious under the AMI state.

CONCLUSION

NN is a powerful tool linking PK and PD profiles of danshensu with multiple cardioprotective mechanisms, it provides a simple method for identifying and ranking relative contribution to the multiple therapeutic effects of the drug.

Danshensu protects vascular endothelia in a rat model of hyperhomocysteinemia

AIM

To examine whether danshensu could protect vascular endothelia in a rat model of hyperhomocysteinemia.

METHODS

The model was established by feeding rats with a methionine-rich diet (1 g·kg⁻¹·d⁻¹) for 3 months. Immediately following the discontinuation of methionine-rich diet, rats were treated with danshensu (67.5 mg·kg⁻¹·d⁻¹, po) or saline for 3 additional months. One group of rats receiving vitamin mixture (folic acid, vitamin B12 and vitamin B6) was included as a positive control. One group of rats not exposed to methionine-rich diet was also included as a blank control. The expression of tumor necrosis factor-alpha (TNF-alpha) and intercellular adhesion molecule-1 (ICAM-1) protein in the descending aorta was examined using immunohistochemistry and Western blot. Homocysteine and blood concentration of endothelin and nitric oxide (NO) was also examined.

RESULTS

Methionine-rich diet resulted in accumulation of "foam cells", up-regulated expression of TNF-alpha and ICAM-1 in the descending aorta, and significantly increased serum homocysteine. Plasma endothelin concentration was significantly increased; NO was decreased. Danshensu treatment, either simultaneous to methionine-rich diet or afterwards, attenuated the above mentioned changes.

CONCLUSION

Chronic treatment with danshensu could prevent/attenuate the formation of atherosclerosis. Potential mechanisms include inhibited expression of representative proinflammatory cytokines and adhesion molecules in arterial endothelia. Changes in homocysteine and circulating molecules that control vascular contraction/relaxation via endothelial cells (eg, endothelin and NO) were also implicated.

Effects of the aqueous extract of Salvia Miltiorrhiza (danshen) and its magnesium tanshinoate B-enriched form on blood pressure

Danshen is the dried root and rhizome of the Chinese medicinal plant Salvia miltiorrhiza Bunge (Labiatae), which has been used to treat hypertension and myocardial infarction. One of its water-soluble active components is magnesium tanshinoate B (MTB). The present study examined and compared the cardiovascular effects of the water-soluble extract of danshen (SME) and its MTB-enriched form (containing 70% of MTB (MTB70)). Anaesthetized rats were infused intravenously with saline or phenylephrine to achieve a normal or elevated blood pressure, respectively. Different doses of SME, MTB70 or vehicle were then injected intravenously and their effect on blood pressure was monitored. The results indicate that SME and MTB70 reduce blood pressure dose-dependently. Independently of the initial blood pressure, SME caused a smaller reduction in blood pressure than MTB70. In rats infused with phenylephrine, MTB70 caused greater decreases in blood pressure than in rats infused with saline, while the responses to SME did not differ between the two groups. From these findings, it appears that MTB is one of the major components responsible for the cardiovascular effects of danshen, and that the beneficial cardiovascular effect of the extract is more prominent under conditions of elevated blood pressure.