Salvianolic acid A protects against vascular endothelial dysfunction in high-fat diet fed and streptozotocin-induced diabetic rats

Treatment of diabetic retinopathy with herbs for tonifying kidney and activating blood circulation: A review of pharmacological studies

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic retinopathy (DR) is a prevalent microvascular complication of diabetes. Chinese medicine believes that kidney deficiency and blood stasis are significant pathogenesis of DR. A characteristic therapeutic approach for this pathogenesis is the kidney-tonifying and blood-activating method. By literature retrieval from several databases, we methodically summarized the commonly used kidney-tonifying and blood-activating herbs for treating DR, including Lycii Fructus, Rehmanniane Radix Praeparata, and Corni Fructus with the function of nourishing kidney; Salvia Miltiorrhizae Radix et Rhizoma with the function of enhancing blood circulation; Rehmanniae Radix with the function of nourishing kidney yin; and Astragali Radix with the function of tonifying qi. It has been demonstrated that these Chinese herbs described above, by tonifying the kidney and activating blood circulation, significantly improve the course of DR.

AIM OF THE STUDY

Through literature research, to gain a thorough comprehension of the pathogenesis of DR. Simultaneously, through the traditional application analysis, modern pharmacology research and network pharmacology analysis of kidney-tonifying and blood-activating herbs, to review the effectiveness and advantages of kidney-tonifying and blood-activating herbs in treating DR comprehensively.

MATERIALS AND METHODS

PubMed, the China National Knowledge Infrastructure (CNKI), and Wanfang Data were used to filter the most popular herbs for tonifying kidney and activating blood in the treatment of DR. The search terms were "diabetic retinopathy" and "tonifying kidney and activating blood". Mostly from 2000 to 2023. Network pharmacology was applied to examine the key active components and forecast the mechanisms of kidney-tonifying and blood-activating herbs in the treatment of DR.

RESULTS

Kidney deficiency and blood stasis are the pathogenesis of DR, and the pathogenesis is linked to oxidative stress, inflammation, hypoxia, and hyperglycemia. Scientific data and network pharmacology analysis have demonstrated the benefit of tonifying kidney and activating blood herbs in treating DR through several channels, multiple components, and multiple targets.

CONCLUSIONS

This review first presents useful information for subsequent research into the material foundation and pharmacodynamics of herbs for tonifying kidney and activating blood, and offers fresh insights into the treatment of DR.

Mechanistic exploration of the shenlian formula in the suppression of atherosclerosis progression via network pharmacology and in vivo experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

The Shenlian formula (SL) is a Chinese medicine formula used to curb the development of atherosclerosis (AS) and cardiovascular disease in clinical practice. However, owing to the complexity of compounds and their related multiple targets in traditional Chinese medicine (TCM), it remains difficult and urgent to elucidate the underlying mechanisms at a holistic level.

AIM

To investigate the intrinsic mechanisms by which SL suppresses AS progression and to gain new insight into its clinical use.

METHODS

We proposed a network pharmacology-based workflow to evaluate the mechanism by which SL affects AS via data analysis, target prediction, PPI network construction, GO and KEGG analyses, and a "drug-core ingredient-potential target-key pathway" network. Then, non-targeted lipidomic analysis was performed to explore the differential lipid metabolites in AS rats, revealing the possible mechanism by which SL affects atherosclerotic progression. Moreover, an AS rabbit model was constructed and gavaged for SL intervention. Serum lipid profiles and inflammatory cytokine indices were tested as an indication of the mitigating effect of SL on AS.

RESULTS

A total of 89 bioactive compounds and 298 targets related to SL and AS, which play essential roles in this process, were identified, and a component-target-disease network was constructed. GO and KEGG analyses revealed that SL regulated metabolic pathway, lipids and atherosclerosis, the PI3K-Akt pathway, the MAPK pathway and so on. In vivo experimental validation revealed that a total of 43 different lipid metabolites regulated by SL were identified by non-targeted lipidomics, and glycerophospholipid metabolism was found to be an important mechanism for SL to interfere with AS. SL reduced the plaque area and decreased the levels of inflammatory cytokines (TNF-α and IL-4) and blood lipids (TC, TG, LDL-C, and ApoB) in HFD-induced AS models. In addition, HDL and ApoA1 levels are increased. PLA2 and Lipin1 are highly expressed in AS model, indicating their role in destabilizing glycerophosphatidylcholine metabolism and contributing to the onset and progression of ankylosing spondylitis. Moreover, SL intervention significantly reduced the level of pro-inflammatory cytokines; significantly down-regulated NF-kB/p65 expression, exhibiting anti-inflammatory activity.

CONCLUSION

The Shenlian formula (SL) plays a pivotal role in the suppression of AS progression by targeting multiple pathways and mechanisms. This study provides novel insights into the essential genes and pathways associated with the prognosis and pathogenesis of AS.

Systematic investigation of Radix Salviae for treating diabetic peripheral neuropathy disease based on network Pharmacology

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a debilitating complication of diabetes mellitus with limited available treatment options. Radix Salviae, a traditional Chinese herb, has shown promise in treating DPN, but its therapeutic mech-anisms have not been systematically investigated.

AIM

Radix Salviae (Danshen in pinin), a traditional Chinese medicine (TCM), is widely used to treat DPN in China. However, the mechanism through which Radix Salviae treats DPN remains unclear. Therefore, we aimed to explore the mechanism of action of Radix Salviae against DPN using network pharmacology.

METHODS

The active ingredients and target genes of Radix Salviae were screened using the TCM pharmacology database and analysis platform. The genes associated with DPN were obtained from the Gene Cards and OMIM databases, a drug-com-position-target-disease network was constructed, and a protein-protein inter-action network was subsequently constructed to screen the main targets. Gene Ontology (GO) functional annotation and pathway enrichment analysis were performed via the Kyoto Encyclopedia of Genes and Genomes (KEGG) using Bioconductor.

RESULTS

A total of 56 effective components, 108 targets and 4581 DPN-related target genes of Radix Salviae were screened. Intervention with Radix Salviae for DPN mainly involved 81 target genes. The top 30 major targets were selected for enrichment analysis of GO and KEGG pathways.

CONCLUSION

These results suggested that Radix Salviae could treat DPN by regulating the AGE-RAGE signaling pathway and the PI3K-Akt signaling pathway. Therefore, Danshen may affect DPN by regulating inflammation and apoptosis.

Salvianolic acid A attenuates inflammation-mediated atherosclerosis by suppressing GRP78 secretion of endothelial cells

ETHNOPHARMACOLOGICAL RELEVANCE

Salvianolic acid A (SAA) is the main active component of the classic anti-atherosclerotic drug Salvia miltiorrhiza Bunge. Inflammation-induced infiltration of monocyte/macrophages into the vascular wall is the initiating step in atherogenesis, and targeted blocking of this step may provide a promising avenue for the precise treatment of atherosclerosis. However, the effect of salvianolic acid A on macrophages is still unknown.

AIM OF THE STUDY

To evaluate the effect of SAA on macrophage infiltration and the underlying mechanism of SAA against atherosclerosis.

MATERIALS AND METHODS

Vascular endothelial cells were stimulated with lipopolysaccharide (LPS) to simulate the inflammatory environment, and its effect on monocyte/macrophages was evaluated. Mass spectrometry was used to identify the proteins that play a key role and further validated them. LncRNA sequencing, western blot analysis, RNA immunoprecipitation, and RNA pulldown were used to elucidate the mechanism of SAA against atherosclerosis. Finally, ApoE^-/- mice were fed a high-fat diet to creat an in vivo atherosclerosis model. Secretory GRP78 content, lipid levels, plaque area, macrophage infiltration, and degree of inflammation were assessed by standard assays after 16 weeks of intragastric administration of SAA or biweekly tail vein injections of GRP78 antibody.

RESULTS

After LPS stimulation, the increased secretion of GRP78 recruits circulating monocyte/macrophages and drives monocyte/macrophage adhesion and invasion into the vascular intima to promote atherosclerosis progression. Interestingly, SAA exerts anti-atherosclerosis effects by inhibiting the secretion of GRP78. Further mechanistic studies indicated that SAA upregulates the expression of lncRNA NR2F2-AS1, which reverses the abnormal localization of the KDEL receptor (KDELR) caused by inflammation. It promotes the homing of GRP78 from the Golgi apparatus to the endoplasmic reticulum rather than secreting outside the cell.

CONCLUSION

SAA alleviates atherosclerosis by inhibiting GRP78 secretion via the lncRNA NR2F2-AS1-KDELR axis. The findings not only provide a new direction for the precise therapy of atherosclerosis based on secretory GRP78 but also elucidate the pharmacological mechanism of SAA against atherosclerosis, putting the foundation for further development and clinical application of SAA drugs.

Isolation and Comprehensive in Silico Characterisation of a New 3-Hydroxy-3-Methylglutaryl-Coenzyme A Reductase 4 (HMGR4) Gene Promoter from Salvia miltiorrhiza: Comparative Analyses of Plant HMGR Promoters

Salvia miltiorrhiza synthesises tanshinones with multidirectional therapeutic effects. These compounds have a complex biosynthetic pathway, whose first rate limiting enzyme is 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR). In the present study, a new 1646 bp fragment of the S. miltiorrhiza HMGR4 gene consisting of a promoter, 5′ untranslated region and part of a coding sequence was isolated and characterised in silico using bioinformatics tools. The results indicate the presence of a TATA box, tandem repeat and pyrimidine-rich sequence, and the absence of CpG islands. The sequence was rich in motifs recognised by specific transcription factors sensitive mainly to light, salicylic acid, bacterial infection and auxins; it also demonstrated many binding sites for microRNAs. Moreover, our results suggest that HMGR4 expression is possibly regulated during flowering, embryogenesis, organogenesis and the circadian rhythm. The obtained data were verified by comparison with microarray co-expression results obtained for Arabidopsis thaliana. Alignment of the isolated HMGR4 sequence with other plant HMGRs indicated the presence of many common binding sites for transcription factors, including conserved ones. Our findings provide valuable information for understanding the mechanisms that direct transcription of the S. miltiorrhiza HMGR4 gene.

Bioactive Components of Salvia and Their Potential Antidiabetic Properties: A Review

The utilization of therapeutic plants is expanding around the globe, coupled with the tremendous expansion of alternative medicine and growing demand in health treatment. Plants are applied in pharmaceuticals to preserve and expand health—physically, mentally and as well as to treat particular health conditions and afflictions. There are more than 600 families of plants identified so far. Among the plants that are often studied for their health benefit include the genus of Salvia in the mint family, Lamiaceae. This review aims to determine the bioactive components of Salvia and their potential as antidiabetic agents. The search was conducted using three databases (PubMed, EMBASE and Scopus), and all relevant articles that are freely available in the English language were extracted within 10 years (2011–2021). Salvia spp. comprises many biologically active components that can be divided into monoterpenes, diterpenes, triterpenes, and phenolic components, but only a few of these have been studied in-depth for their health benefit claims. The most commonly studied bioactive component was salvianolic acids. Interestingly, S. miltiorrhiza is undoubtedly the most widely studied Salvia species in terms of its effectiveness as an antidiabetic agent. In conclusion, we hope that this review stimulates more studies on bioactive components from medicinal plants, not only on their potential as antidiabetic agents but also for other possible health benefits.

Salvianolic acid A prevented cerebrovascular endothelial injury caused by acute ischemic stroke through inhibiting the Src signaling pathway

Stroke is an acute cerebrovascular disease caused by ruptured or blocked blood vessels. For the prevention of ischemic stroke, the coagulation state of blood and cerebrovascular protection should be considered. Our previous study has shown that salvianolic acid A (SAA), which is a water-soluble component from the root of Salvia Miltiorrhiza Bge, prevents thrombosis with a mild inhibitory effect on platelet aggregation. In this study we investigated the preventive effects of SAA on cerebrovascular endothelial injury caused by ischemia in vivo and oxygen-glucose deprivation (OGD) in vitro, and explored the underlying mechanisms. An autologous thrombus stroke model was established in SD rats by electrocoagulation. SAA (10 mg/kg) was orally administered twice a day for 5 days before the operation. The rats were sacrificed at 24 h after the operation. We showed that pretreatment with SAA significantly improved the neurological deficits, intracerebral hemorrhage, BBB disruption, and vascular endothelial dysfunction as compared with model group. In human brain microvascular endothelial cells (HBMECs), pretreatment with SAA (10 μM) significantly inhibited OGD-induced cell viability reduction and degradation of tight junction proteins (ZO-1, occludin, claudin-5). Furthermore, we found that SAA inhibited the upregulation of Src signaling pathway in vivo and vitro and reversed the increased expression of matrix metalloproteinases (MMPs) after ischemic stroke. In conclusion, our results suggest that SAA protects cerebrovascular endothelial cells against ischemia and OGD injury via suppressing Src signaling pathway. These findings show that pretreatment with SAA is a potential therapeutic strategy for the prevention of ischemic stroke.

The Effect of Salvianolic Acid on Vascular Protection and Possible Mechanisms

Salvia miltiorrhiza (Danshen), as an important traditional Chinese medicinal plant, has been used in China for the treatment of cardiovascular diseases for hundreds of years. Salvianolic acids (salvianolic acid A and salvianolic acid B) as the most abundant water-soluble component extracted from Salvia miltiorrhiza have attracted more and more attention from cardiovascular scientists due to its comprehensive cardiovascular actions. In vivo and in vitro studies have rendered salvianolic acid an excellent drug candidate for the treatment and prevention of cardiovascular diseases. In this review, we surveyed the protective effects of salvianolic acid A and salvianolic acid B against cardiovascular diseases and the pharmacological basis, providing a strong scientific rationale for elucidating the important role of Salvia miltiorrhiza in cardiovascular therapy. More importantly, we also hope to provide new inspiration and perspectives on the development and innovation of small-molecule cardiovascular drugs based on salvianolic acid.

Network Pharmacology-Based Identification of the Mechanisms of Shen-Qi Compound Formula in Treating Diabetes Mellitus

Aim

The purpose of this research is to identify the mechanisms of Shen-Qi compound formula (SQC), a traditional Chinese medicine (TCM), for treating diabetes mellitus (DM) using system pharmacology.

Methods

The active components and therapeutic targets were identified, and these targets were analyzed using gene ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and protein-protein interaction (PPI) analysis. Finally, an integrated pathway was constructed to show the mechanisms of SQC.

Results

A total of 282 active components and 195 targets were identified through a database search. The component-target network was constructed, and the key components were screened out according to their degree. Through the GO, PPI, and KEGG analyses, the mechanism network of SQC treating DM was constructed.

Conclusions

This study shows that the mechanisms of SQC treating DM are related to various pathways and targets. This study provides a good foundation and basis for further in-depth verification and clinical application.

Pharmacological management of vascular endothelial dysfunction in diabetes: TCM and western medicine compared based on biomarkers and biochemical parameters

Diabetes, a worldwide health concern while burdening significant populace of countries with time due to a hefty increase in both incidence and prevalence rates. Hyperglycemia has been buttressed both in clinical and experimental studies to modulate widespread molecular actions that effect macro and microvascular dysfunctions. Endothelial dysfunction, activation, inflammation, and endothelial barrier leakage are key factors contributing to vascular complications in diabetes, plus the development of diabetes-induced cardiovascular diseases. The recent increase in molecular, transcriptional, and clinical studies has brought a new scope to the understanding of molecular mechanisms and the therapeutic targets for endothelial dysfunction in diabetes. In this review, an attempt made to discuss up to date critical and emerging molecular signaling pathways involved in the pathophysiology of endothelial dysfunction and viable pharmacological management targets. Importantly, we exploit some Traditional Chinese Medicines (TCM)/TCM isolated bioactive compounds modulating effects on endothelial dysfunction in diabetes. Finally, clinical studies data on biomarkers and biochemical parameters involved in the assessment of the efficacy of treatment in vascular endothelial dysfunction in diabetes was compared between clinically used western hypoglycemic drugs and TCM formulas.

Chemical and pharmacological research on the polyphenol acids isolated from Danshen: A review of salvianolic acids

Danshen, the dried root of Salvia miltiorrhiza Bge, is a common medicinal herb in Traditional Chinese Medicine, which has been used for the treatment of a number of diseases for thousands of years. More than 2000 years ago, the Chinese early pharmacy monograph "Shennong Materia Medica" recorded that Danshen could be used for the treatment of gastrointestinal diseases, cardiovascular diseases, certain gynecological diseases, etc. Since then, Danshen has been widely used clinically in many different prescriptions for many different diseases, especially for the treatment of cardiovascular diseases. Nowadays, many pharmacological studies about the water-soluble components from Danshen have been reported, especially salvianolic acids. It turned out that salvianolic acids showed strong anti-lipid peroxidation and anti-thrombic activities, and among them, SalAA and SalAB were the most potent. This review focused on the achievements in research of salvianolic acids regarding their bioactivities and pharmacological effects. These studies not only shed light on the water-soluble active components of Danshen and their mechanisms at the molecular level, but also provided theoretical information for the development of new medicines from Danshen for the treatment of cardiovascular and cerebrovascular diseases, inflammatory diseases, metabolic diseases, etc.

The protective effects of salvianolic acid A against hepatic ischemia-reperfusion injury via inhibiting expression of toll-like receptor 4 in rats

INTRODUCTION

Ischemia-reperfusion injury (IRI) is a serious complication of hepatectomy and liver transplantation. The aim of this study was to evaluate the protective effects of salvianolic acid-A (Sal-A) against IRI-induced hepatocellular injury.

MATERIAL AND METHODS

Forty rats were randomly divided into the following four groups: (1) sham group, (2) IR group, (3) Sal-A(10) group and (4) Sal-A(20) group. After 90 min of ischemia and 6 h of reperfusion, serum alanine aminotransferease (ALT) and apartate aminotransferase (AST) levels were measured; the amounts of malondialdehyde (MDA) and superoxide dismutase (SOD) in the liver tissue were determined; the expression of Bcl-2 and caspase-3 was detected and the severity of apoptosis, inflammation and pathological alterations were evaluated. Also apoptosis and mRNA and protein levels of TLR4 (toll-like receptor 4) were tested.

RESULTS

The serum aminotransferases, hepatic MDA concentration, and apoptotic cells in the IR group were significantly higher than in the sham group (p < 0.01), whereas the Sal-A group values were lower than in the IR group (p < 0.05). Compared with the IR group, the Sal-A groups had significantly higher Bcl-2 expression and downregulated cleaved caspase-3 expression in liver tissue. Moreover, increased mRNA and protein levels of TLR4 in IR rats and Sal-A could improve the increased mRNA and protein levels of TLR4.

CONCLUSIONS

Sal-A had a synergistically protective effect on the liver tissue against IRI that might be due to decreased oxidative stress, inflammation, hepatocellular apoptosis and include, at least in part, the regulation of TLR4.

A Novel UPLC-MS/MS Method for the Determination of Salvianolic Acid A in Rat Urine, Feces, and Bile and its Application to Excretion Study

Background:

Salvianolic acid A (SAA) is a polyphenolic acid extracted from Salvia miltiorrhiza Bunge. It showed protective effect against diabetic complications after oral administration with a low bioavailability of 1.42%. Attempts have been made to develop it into a new medication. Intracorporal process of SAA is indistinct and no report regarding the excretion is available. Our preliminary experiment revealed that previous reported methods were unsuitable for the excretion study due to the serious matrix effect.

Methods:

To better clarify its pharmacokinetics and avoid the interference of complex endogenous substances, a sensitive UPLC-MS/MS method with a better resolution was developed for the excretion study of SAA for the first time. The analytes were separated by reversed-phase chromatography with acetonitrile-water (containing 0.1% formic acid) gradient elution. The mass spectrometer was operated in the negative ESI mode and multiple reaction monitoring mode.

Results:

This method was linear over the concentration range of 2.5-100, 5-100 and 5-100 ng/mL in urine, feces and bile, respectively. The accuracy, precision, stability, recovery and matrix effect were satisfactory in all matrices examined. The validated method was successfully applied to an excretion study in rats. After oral administration of 20 mg/kg, the average accumulated excretion amount of SAA in urine, feces and bile were 99.80, 32046.30 and 161.03 ng, respectively.

Conclusion:

A quick but low elimination was observed. The date is useful for the clinical trial design of SAA.

Some pharmacokinetic parameters of salvianolic acid A following single-dose oral administration to rats

CONTEXT

Salvianolic acid A (Sal A) is a hydrophilic bioactive compound isolated from Salvia miltiorrhiza Bunge (Lamiaceae). It exerts beneficial effects after oral administration on diabetic complications.

OBJECTIVE

To systematically study the absorption, distribution and excretion of Sal A after single-dose oral administration.

MATERIALS AND METHODS

Animal experiments were conducted in Sprague-Dawley rats. Plasma was sampled at designated times after oral doses of 5, 10 and 20 mg/kg, and an intravenous dose of 50 μg/kg. Tissues were harvested at 10, 60 and 120 min postdosing. Bile, urine and feces were collected at specified intervals before and after dosing. Absorption and distribution characteristics were analyzed by LC-MS, and excretion characteristics were analyzed by UPLC-MS/MS. The Caco-2 cell model was applied to investigate potential mechanisms.

RESULTS

The C_max (5 mg/kg: 31.53 μg/L; 10 mg/kg: 57.39 μg/L; 20 mg/kg: 111.91 μg/L) of Sal A increased linearly with doses (r> 0.99). The calculated absolute bioavailability was 0.39-0.52%. Transport experiment showed poor permeability and the ratio of P_B-A to P_A-B was 3.13-3.97. The highest concentration of Sal A was achieved in stomach followed by small intestine and liver, and it could also be detected in brain homogenate. Approximately 0.775% of its administered dose was excreted via feces, followed by bile (0.00373%) and urine (0.00252%).

DISCUSSION AND CONCLUSIONS

These results support the future development of Sal A as an oral drug for the treatment of diabetic complications. Future research should be conducted to investigate the reason for its poor bioavailability and improve this situation.

Salvia miltiorrhizaBurge (Danshen): a golden herbal medicine in cardiovascular therapeutics

Salvia miltiorrhiza Burge (Danshen) is an eminent medicinal herb that possesses broad cardiovascular and cerebrovascular protective actions and has been used in Asian countries for many centuries. Accumulating evidence suggests that Danshen and its components prevent vascular diseases, in particular, atherosclerosis and cardiac diseases, including myocardial infarction, myocardial ischemia/reperfusion injury, arrhythmia, cardiac hypertrophy and cardiac fibrosis. The published literature indicates that lipophilic constituents (tanshinone I, tanshinone IIa, tanshinone IIb, cryptotanshinone, dihydrotanshinone, etc) as well as hydrophilic constituents (danshensu, salvianolic acid A and B, protocatechuic aldehyde, etc) contribute to the cardiovascular protective actions of Danshen, suggesting a potential synergism among these constituents. Herein, we provide a systematic up-to-date review on the cardiovascular actions and therapeutic potential of major pharmacologically active constituents of Danshen. These bioactive compounds will serve as excellent drug candidates in small-molecule cardiovascular drug discovery. This article also provides a scientific rationale for understanding the traditional use of Danshen in cardiovascular therapeutics.

Salvianolic acid A improves intestinal motility in diabetic rats through antioxidant capacity and upregulation of nNOS

OBJECTIVE

This study aimed to detect the effect of a new herbal extract salvianolic acid A (SalA) on gastrointestinal complications in diabetic rats.

METHODS

Altogether 80 rats were divided randomly into five groups, including normal control (NC) group, high-fat (HF) diet group, diabetes mellitus (DM) control group, and DM treated with SalA (0.1 mg/kg and 0.3 mg/kg) groups, respectively. DM was induced by feeding the rats with HF diet and the administration of streptozotocin (30 mg/kg). Four weeks after the establishment of the DM model, the rats received SalA or double distilled water for 8 weeks. After the evaluation of intestinal motility, the animals were sacrificed and their intestines were isolated and collected. The levels of advanced glycation end-products (AGE) and malondialdehyde (MDA) were detected. Protein gene product 9.5 (PGP9.5) and neuronal nitric oxide synthase (nNOS) expressions in the intestine were also detected.

RESULTS

Compared with the NC and HF rats, the DM control rats showed significantly increased blood glucose level and decreased weight. Compared with the DM control group, SalA did not influence their weight and blood glucose level, but significantly reduced the levels of AGE and MDA. Intestinal transit was promoted by SalA in diabetic rats, and the expressions of PGP9.5 and nNOS in the intestine were both upregulated.

CONCLUSION

The effect of SalA on the intestinal motility of diabetic rats might be due to its antioxidant capacity and restoring nNOS expression.

Polyphenols: Potential source of drugs for the treatment of ischaemic heart disease

Polyphenols, which are naturally present in plants, have been studied for their chemical and pharmacological properties. Polyphenols have been found to exhibit various bioactivities such as antioxidant, free radical scavenging and anti-inflammatory effects, in addition to regulating the intracellular free calcium levels. These bioactivities are related to the underlying mechanisms of ischaemic heart diseases. Pharmacological studies have proven polyphenols to be effective in treating cardiovascular diseases in various ways, particularly ischaemic heart diseases. Based on their mode of action, we propose that some polyphenols can be developed as drugs to treat ischaemic heart diseases. For this purpose, a strategy to evaluate the therapeutic value of drugs for ischaemic heart diseases is needed. Despite several advances in percutaneous coronary intervention (PCI), the incidence of myocardial infarction and deaths due to cardiovascular diseases has not decreased markedly in China. Due to their pleiotropic properties and structural diversity, polyphenols have been of great interest in pharmacology. In the present review, we summarize the pharmacological effects and mechanisms of polyphenols reported after 2000, and we analyse the benefits or druggability of these compounds for ischaemic heart diseases.

Salvia miltiorrhiza: Traditional medicinal uses, chemistry, and pharmacology

Salvia miltiorrhiza Bunge (SM) is a very popular medicinal plant that has been extensively applied for many years to treat various diseases, especially coronary heart diseases and cerebrovascular diseases, either alone or in combination with other Chinese plant-based medicines. Although a large number of studies on SM have been performed, they are scattered across a variety of publications. The present review is an up-to-date summary of the published scientific information about the traditional uses, chemical constituents, pharmacological effects, side effects, and drug interactions with SM, in order to lay the foundation for further investigations and better utilization of SM. SM contains diverse chemical components including diterpenoid quinones, hydrophilic phenolic acids, and essential oils. Many pharmacological studies have been done on SM during the last 30 years, focusing on the cardiovascular and cerebrovascular effects, and the antioxidative, neuroprotective, antifibrotic, anti-inflammatory, and antineoplastic activities. The research results strongly support the notion that SM has beneficial therapeutic properties and has a potential of being an effective adaptogenic remedy.

Salvianolic acid A suppresses CCL-20 expression in TNF-α-treated macrophages and ApoE-deficient mice

OBJECTIVES

The CC chemokine ligand-20 (CCL-20)/macrophage inflammatory protein-3α has been seen as one of the most important chemokines and played a key role in atherogenesis, but the mechanism that underlies the regulation of CCL-20 has not been established clearly yet. The aim of this study was to investigate the influence of salvianolic acid A (SAA) on the expression of CCL-20 in macrophages and ApoE-deficient (ApoE) mice.

METHODS

The expression of CCL-20 was detected both at protein and messenger RNA levels in RAW264.7 cells. We validated the result in ApoE mice that were intraperitoneally injected with SAA. Phosphorylation of p38 mitogen-activated protein kinase was detected with Western blot, and inhibitor of p38 was used to investigate the mechanism of regulation of CCL-20. Hematoxylin and eosin and Oil-Red-O staining were used to evaluate the atherosclerotic lesions and lipid accumulation in ApoE mice. Immunohistochemical analysis was used to detect the expressions of CCL-20 and CCR6 in the atherosclerotic lesions. Immunofluorescent analysis was used to certify the origination of CCL-20.

RESULTS

Recombinant tumor necrosis factor-α (TNF-α) upregulated CCL-20 production in dose- and time-dependent manners in RAW264.7 cells. The activity of TNF-α-induced CCL-20 production seemed to be significantly suppressed by SAA. Using p38 mitogen-activated protein kinase inhibitor, we found that p38 mediated the effects of TNF-α- and SAA-induced CCL-20 expression changes. In addition, immunohistochemical analysis of aortic root of ApoE mice also demonstrated that the expressions of CCL-20 and CCR6 were both downregulated significantly with SAA treatment. Furthermore, treatment of SAA inhibited the progression of the atherosclerotic plaques and lipid accumulation.

CONCLUSIONS

These results demonstrate that TNF-α increased but SAA suppressed CCL-20 production significantly via a novel mechanism.

Prevention of pulmonary fibrosis with salvianolic acid a by inducing fibroblast cell cycle arrest and promoting apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Danshen (Salvia miltiorrhiza Bunge) is widely used in traditional Chinese medicine (TCM), often in combination with other herbs, to treat a diversity of ailments. More recent studies have focused on its possible roles in the treatment of respiratory diseases (pneumonia and pulmonary fibrosis) and found that it has pharmacological activity that protects pulmonary morphology and function. However, the mechanism underlying this activity has not yet been clarified.

MATERIALS AND METHODS

The purpose of this study was to investigate the anti-pulmonary fibrosis effects exerted by salvianolic acid A (SAA), the ingredient responsible for the pharmacological activity of Danshen, and the underlying mechanisms. Bleomycin (BLM)-induced rat pulmonary fibrosis was used to evaluate the antifibrotic role of SAA, and fibroblast cells were used to study the mechanism involved.

RESULTS

BLM-treated rats exhibited increased alveolar wall thickness and collagen deposition in lung tissues, but these pathologies were greatly attenuated by daily administration of SAA. We also found that SAA significantly inhibited the proliferation, adhesion and migration of fibroblasts in vitro. This was partly due to a strong induction of cell cycle arrest and apoptosis upon SAA treatment. Consistent with these phenotypes, we observed decreased expression of the cell cycle-related proteins cyclin D1, cyclin E1, and cyclin B1, and increased expression of p53 and p21 in SAA-treated cells. In addition, the anti-apoptotic Bcl-2 protein decreased in a dose-dependent manner, while cleaved caspase-3 protein increased upon SAA treatment.

CONCLUSIONS

These results suggest that the alleviation of rat pulmonary fibrosis by SAA is due to the inhibition of fibroblast proliferation and induction of apoptosis, which occurs mainly through p53-dependent growth arrest and apoptosis. We suggest that SAA should be considered as a potential novel therapeutic agent for the treatment of fibrotic lung diseases.

Protective effects of Salvia miltiorrhiza injection against learning and memory impairments in streptozotocin-induced diabetic rats

The aim of this study was to explore the protective effects of Salvia miltiorrhiza injection against learning and memory impairment in streptozotocin (STZ)-induced diabetic rats and the possible mechanism involved. Sprague Dawley male rats (n=30) were randomized into three groups: Diabetes, diabetes treated with S. miltiorrhiza injection and normal control. Diabetes was induced by an intraperitoneal injection of STZ (65 mg/kg). The S. miltiorrhiza injection-treated rats received an intraperitoneal injection of S. miltiorrhiza (5 ml/kg/day) while the rats of the other two groups were administered an intraperitoneal injection of the same volume of 0.9% saline for four weeks. After four weeks of treatment, the escape latency and search strategies in the rats were assessed by the Morris water maze test. The protein levels of mitogen-activated protein kinase phosphatase-1 (MKP-1) were also assessed by immunohistochemistry. Four weeks after the induction of diabetes, the body weight of the diabetic rats was significantly lower and the blood glucose concentration was significantly higher than that of the control rats. S. miltiorrhiza injection was observed to improve the blood glucose and learning ability (P<0.05). Compared with the control group, the expression of MKP-1 was significantly decreased in the hippocampal area of the diabetes group; S. miltiorrhiza injection-treated rats showed an increased expression compared with the diabetic rats, but the expression remained lower than that of the normal control group (P<0.05). In conclusion, S. miltiorrhiza injection can improve the learning and memory decline of diabetic rats. The changes in expression of MKP-1 under hyperglycemia may play a role in the protective effects of S. miltiorrhiza against dementia in diabetic rats.

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.

Pharmacokinetic study of salvianolic acid A in beagle dog after oral administration by a liquid chromatography-mass spectrometry method: a study on bioavailability and dose proportionality

ETHNOPHARMACOLOGICAL RELEVANCE

Salvianolic acid A (SAA) is one of the main water-soluble components isolated from Salvia miltiorrhiza Bunge. Pharmacological researches revealed that it had various curative activities after oral and intravenous administration, including beneficial effects on diabetes and its complications, cardioprotective effect, anti-platelet aggregation, and so on. However, there is no report regarding the pharmacokinetics of SAA in beagle dogs after oral administration up to now.

AIM OF THE STUDY

To study the pharmacokinetics of different doses of SAA in beagle dogs and figure out the absolute bioavailability and dose proportionality of SAA after oral administration.

MATERIALS AND METHODS

Male and female beagle dogs were orally administered SAA 5, 10 and 20mg/kg randomly. The plasma drug concentration was detected by a rapid, sensitive and reproducible liquid chromatography-mass spectrometry (LC-MS) method. The pharmacokinetic parameters were calculated from plasma concentration-time data using the DAS pharmacokinetic software Data Analysis System Version 3.0 program.

RESULTS

After single-dose oral administration of SAA, the mean peak plasma concentration (Cmax) values for groups treated with 5, 10 and 20 mg/kg doses ranged from 14.38 to 38.18 µg/L, and the mean area under the concentration-time curve (AUC(0-t)) values ranged from 38.77 to 130.33 (µg/L·h). SAA showed lack of dose proportionality over the dose range 5-20mg/kg, based on the power model. However, the increase in systemic exposure with dose appeared linear. The absolute bioavailability was calculated to range from 1.47% to 1.84%.

CONCLUSION

The pharmacokinetic properties of SAA in beagle dogs after oral administration were characterized as rapid oral absorption, quick clearance, and poor absolute bioavailability. Systemic exposure exhibited lack of dose proportionality over the dose range 5-20mg/kg. Furthermore, a readily preparative LC-MS method was demonstrated in this study for the research of traditional Chinese medicine.

Salvianolic acid A protects the peripheral nerve function in diabetic rats through regulation of the AMPK-PGC1α-Sirt3 axis

Salvianolic acid A (SalA) is one of the main efficacious, water-soluble constituents of Salvia miltiorrhiza Bunge. This study investigated the protective effects of SalA on peripheral nerve in diabetic rats. Administration of SalA (0.3, 1 and 3 mg/kg, ig) was started from the 5th week after strepotozotocin (STZ60 mg/kg) intraperitoneal injection and continued for 8 weeks. Paw withdrawal mechanical threshold (PWMT) and motor nerve conduction velocity (MNCV) were used to assess peripheral nerve function. The western blot methods were employed to test the expression levels of serine-threonine liver kinase B1 (LKB1), AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1α), silent information regulator protein3 (sirtuin 3/Sirt3) and neuronal nitric oxide synthase (nNOS) in sciatic nerve. Results showed that SalA administration could increase PWMT and MNCV in diabetic rats; reduce the deterioration of sciatic nerve pathology; increase AMPK phosphorylation level, up-regulate PGC-1α, Sirt3 and nNOS expression, but had no influence on LKB1. These results suggest that SalA has protective effects against diabetic neuropathy. The beneficial effects of SalA on peripheral nerve function in diabetic rats might be attributed to improvements in glucose metabolism through regulation of the AMPK-PGC1α-Sirt3 axis.

Ischemia/reperfusion-induced MKP-3 impairs endothelial NO formation via inactivation of ERK1/2 pathway

Mitogen-activated protein kinase phosphatases (MKPs) are a family of dual-specificity phosphatases. Endothelial cells express multiple MKP family members, such as MKP-3. However, the effects of MKP-3 on endothelial biological processes have not yet been fully elucidated. Here, we address the association between MKP-3 and endothelial Nitric oxide (NO) formation under ischemia/reperfusion (IS/RP) condition. Human umbilical vein endothelial cells (HUVECs) were subjected to IS/RP treatment. The MKP-3 expression and NO formation were examined. IS/RP induced endothelial MKP-3 expression and inhibited eNOS expression and NO formation, accompanied by an increase of endothelial apoptosis. The siRNA experiments showed that MKP-3 was an important mediator in impairing eNOS expression and NO production in endothelial cells. Transfection of HUVECs with constitutively active ERK plasmids suggested that the above mentioned effect of MKP-3 was via inactivation of ERK1/2 pathway. Furthermore, impairment of eNOS expression was restored by treatment of histone deacetylase (HDAC) inhibitor and related to histone deacetylation and recruitment of HDAC1 to the eNOS promoter. Finally, Salvianolic acid A (SalA) markedly attenuated induction of MKP-3 and inhibition of eNOS expression and NO formation under endothelial IS/RP condition. Overall, these results for the first time demonstrated that IS/RP inhibited eNOS expression by inactivation of ERK1/2 and recruitment of HDAC1 to the gene promoter, leading to decreased NO formation through a MKP-3-dependent mechanism in endothelial cells, and SalA has therapeutic significance in protecting endothelial cells from impaired NO formation in response to IS/RP.