Ursolic acid from the Chinese herb danshen (Salvia miltiorrhiza L.) upregulates eNOS and downregulates Nox4 expression in human endothelial cells

Ursolic acid enhances the effect of exercise training on vascular aging by reducing oxidative stress in aged type 2 diabetic rats

Ursolic acid (UA) mediates the vasorelaxant activity via nitric oxide (NO) release, and upregulation of endothelial nitric oxide synthase (eNOS) in endothelial cells (ECs) in disease conditions with increased oxidative stress (OS). The present study aimed to reflect on the impact of 8 weeks of a combination of UA supplementation and resistance/endurance training in old male Wistar rats having a high-fat diet and/or low-dose streptozotocin-induced type 2 diabetes (HFD/STZ-induced T2D), with an emphasis on Sirtuin 1 (SIRT1)-endothelial nitric oxide synthase (eNOS) axis and OS indices in their aortic tissues. A total number of56 21-month-old male Wistar rats with HFD/STZ-induced T2D were randomized into seven groups (n = eight animals per group): (1) sedentary old nondiabetic (Control [C]); (2) sedentary HFD/STZ-induced T2D (Diabetic [D]); (3) sedentary HFD/STZ-induced T2D plus UA (Diabetic + Ursolic Acid [DU]); (4) endurance-trained HFD/STZ-induced T2D (Diabetic + Endurance Training [DE]); (5) resistance-trained HFD/STZ-induced T2D (Diabetic + Resistance Training [DR]); (6) endurance-trained HFD/STZ-induced T2D plus UA (Diabetic + Endurance Training + Ursolic Acid [DEU]); and (7) resistance-trained STZ-diabetic plus UA (Diabetic + Resistance Training + Ursolic Acid [DRU]) rats. The ladder-based resistance training group performed the ladder resistance training at 60% of the maximum voluntary carrying capacity (MVCC), 14-20 climbs in each session, with a one-min rest between each two trials, 5 days a week. The treadmill-based endurance exercise training protocol consisted of repeated bouts of high- and low-intensity training with 60-75% maximal running speed and 30%-40% maximal running speed in the course of 8 weeks, respectively. The animals in the supplement groups also took 500 mg of UA/kg of high-fat diet/day, resulting in a daily UA intake of approximately 250 mg UA per kg of body weight rat/day. The resistance/endurance training plus the UA consumption could partially reverse the levels of malondialdehyde (MDA), nitric oxide (NO), as well as total antioxidant capacity (TAC). It was concluded that oral 0.5% UA supplementation can prevent vascular aging biomarkers in a HFD/STZ-induced T2D model. Further studies are also required to clarify how chronic consumption of UA with/without training protocols reverses vascular aging process.

Mechanisms and Efficacy of Traditional Chinese Medicine in Heart Failure

Heart failure (HF) is one of the main public health problems at present. Although some breakthroughs have been made in the treatment of HF, the mortality rate remains very high. However, we should also pay attention to improving the quality of life of patients with HF. Traditional Chinese medicine (TCM) has a long history of being used to treat HF. To demonstrate the clinical effects and mechanisms of TCM, we searched published clinical trial studies and basic studies. The search results showed that adjuvant therapy with TCM might benefit patients with HF, and its mechanism may be related to microvascular circulation, myocardial energy metabolism, oxidative stress, and inflammation.

Evolving Roles of Natural Terpenoids From Traditional Chinese Medicine in the Treatment of Osteoporosis

Osteoporosis (OP) is a systemic metabolic skeletal disease which can lead to reduction in bone mass and increased risk of bone fracture due to the microstructural degradation. Traditional Chinese medicine (TCM) has been applied in the prevention and treatment of osteoporosis for a long time. Terpenoids, a class of natural products that are rich in TCM, have been widely studied for their therapeutic efficacy on bone resorption, osteogenesis, and concomitant inflammation. Terpenoids can be classified in four categories by structures, monoterpenoids, sesquiterpenoids, diterpenoids, and triterpenoids. In this review, we comprehensively summarize all the currently known TCM-derived terpenoids in the treatment of OP. In addition, we discuss the possible mechanistic-of-actions of all four category terpenoids in anti-OP and assess their therapeutic potential for OP treatment.

Salvia miltiorrhiza Protects Endothelial Dysfunction against Mitochondrial Oxidative Stress

Salvia miltiorrhiza (SM) is a common traditional Chinese medicine used in the treatment of cardiovascular and cerebrovascular diseases. Endothelial dysfunction plays an important role in the pathology of cardiovascular diseases. Endothelial dysfunction may induce inflammation and change vascular tone and permeability. The main pathological mechanism of endothelial dysfunction is the formation of reactive oxygen species (ROS). Mitochondria are the main source of energy and can also produce large amounts of ROS. Recent studies have shown that extracts of SM have antioxidative, anti-inflammatory, and antithrombus properties. In this review, we discuss the mechanism of oxidative stress in the mitochondria, endothelial dysfunction, and the role of SM in these oxidative events.

Beneficial Effects of Ursolic Acid and Its Derivatives-Focus on Potential Biochemical Mechanisms in Cardiovascular Conditions

Ursolic acid (UA) is a natural pentacyclic triterpenoid found in a number of plants such as apples, thyme, oregano, hawthorn and others. Several in vitro and in vivo studies have presented its anti-inflammatory and anti-apoptotic properties. The inhibition of NF-κB-mediated inflammatory pathways and the increased scavenging of reactive oxygen species (ROS) in numerous ways seem to be the most beneficial effects of UA. In mice and rats, administration of UA appears to slow down the development of cardiovascular diseases (CVDs), especially atherosclerosis and cardiac fibrosis. Upregulation of endothelial-type nitric oxide synthase (eNOS) and cystathionine-λ-lyase (CSE) by UA may suggest its vasorelaxant property. Inhibition of metalloproteinases activity by UA may contribute to better outcomes in aneurysms management. UA influence on lipid and glucose metabolism remains inconsistent, and additional studies are essential to verify its efficacy. Furthermore, UA derivatives appear to have a beneficial impact on the cardiovascular system. This review aims to summarize recent findings on beneficial effects of UA that may make it a promising candidate for clinical trials for the management of CVDs.

Targeting autophagy by natural product Ursolic acid for prevention and treatment of osteoporosis

With the growth of the aging population, osteoporosis is becoming a global health problem. Ursolic acid (UA) is an active ingredient existed in a variety of foods and nature plants and owns plenty of pharmacological effects especially in treating metabolic disease. Our predication from network pharmacology hinted that UA has potential for ameliorating osteoporosis. Firstly through in vivo experiment, we confirmed that UA administration obviously protected against ovariectomy (OVX)-induced osteoporosis in rats by improving microarchitectural deterioration of trabecular bone (P < 0.001), decreasing numbers of TRAP positive osteoclast in vertebra (P < 0.001), as well as decreasing serum osteoclast-specific cytokines release (P < 0.001). Besides, UA ameliorated kidney damage secondary to OVX-induced osteoporosis by ameliorating glomerular atrophy, decreasing BUN and creatinine levels in OVX rats. In vitro, UA noticeably decreased osteoclastic-special marker proteins c-Fos and NFATc1 expressions (P < 0.001) in response to RANKL stimulation in macrophagy. Importantly, autophagy pathway was activated in the process of osteoclast differentiation and blocked by UA pretreatment. Furthermore, autophagy inhibitors suppressed osteoclast differentiation (P < 0.001). Collectively, UA may ameliorate osteoporosis by suppressing osteoclast differentiation mediated by autophagy. Our research provides scientific support for UA treating osteoporosis and offers an optimal dose for daily intake of UA safely to prevent bone diseases.

Ethanolic Extract of Salvia hispanica L. Regulates Blood Pressure by Modulating the Expression of Genes Involved in BP-Regulatory Pathways

Hypertension (HT) is considered to be a potential risk factor for cardiovascular diseases and has been directly related to pathologies such as obesity and dyslipidemias. Angiotensin-converting enzyme inhibitors (ACEIs) blocked the renin-angiotensin-aldosterone cascade diminishing the production of angiotensin II and the level of bradykinin, produced by the kallikrein-kinin system. Although ACEIs are effective therapeutics in regulating HT, they present several side-effects that can be due to their mechanism of action (as hypotension, cough, dizziness, light-headedness or hyperkalemia) to specific drug molecular structure (skin rash, neutropenia and tasting disorders) or due to associated pathologies in the patients (it has been considered a possible nephrotoxic effect when ACEIs are administered in combination with angiotensin receptor blockers, in patients that present comorbidities as diabetes, acute kidney injury or chronic kidney disease). Therefore, it is necessary the searching for new products with ACEI activity that do not produce side effects. Interestingly, species of the plant genus Salvia have been found to possess hypotensive effects. In the present study, we analyzed the effects of the ethanolic extract of Salvia hispanica L. seeds (EESH) on the expression of genes involved in pathways regulating HT. Administration of EESH to hypertensive rats inhibited the angiotensin-converting enzyme (ACE) activity along with a decrease in Ace and elevation of Agtr1a and Nos3 gene expression, as compared to that in healthy rats. Moreover, these results were similar to those observed with captopril, an antihypertensive drug used as a control. No significant change in the expression of Bdkrb2 gene was observed in the different groups of rats. To conclude, our results demonstrate that EESH regulates blood pressure (BP) in hypertensive rats through transcriptionally regulating the expression of genes that participate in different pathways involving ACE.

Saponins from Tribulus terrestris L. Extract Down-regulate the Expression of ICAM-1, VCAM-1 and E-selectin in Human Endothelial Cell Lines

Atherosclerosis is an inflammatory disease in which intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin (SELE) are consistently expressed in the vascular endothelium. Several evidence support the crucial role of adhesion molecules in the development of atherosclerosis and plaque instability. Due to the anti-inflammatory activity of Tribulus terrestris (TT), the present study investigated the effect of aqueous extract and saponin fraction of TT on the expression of ICAM-1, VCAM-1, and SELE genes in endothelial cells during normal and lipopolysaccharide (LPS) induced conditions. Human umbilical vein endothelial cells (HUVEC) and human bone marrow endothelial cells (HBMEC) were cultured, stimulated by LPS, and treated with aqueous extract and saponin fraction of TT. Finally, the expression of ICAM-1, VCAM-1, and SELE genes were measured using quantitative real-time polymerase chain reaction. LPS-induced HUVECs and HBMECs significantly increased the expression of ICAM-1, VCAM-1, and SELE in comparison with control groups (P<0.001). Treatment of LPS-induced HUVECs and HBMECs by aqueous extract and saponin fraction of TT decreased the expression of all three mentioned genes significantly (P<0.001) in comparison with LPS-induced cells. Taken together, our data suggest that TT has an anti-inflammatory effect. In vivo study about anti-inflammatory effect of this herb may provide new insights into the development of a herbal drug for the prevention/therapy of atherosclerosis.

Physalis alkekengi L. Extract Reduces the Oxidative Stress, Inflammation and Apoptosis in Endothelial Vascular Cells Exposed to Hyperglycemia

To find new natural remedies in diabetes, this study investigated the biological activity of two extracts obtained from the fruits (PhyF) and herba (PhyH) of Physalis alkekengi var. franchetii L. on human umbilical vein endothelial cells (HUVECs) exposed to normo- and hyperglycemic conditions. The biological effect was quantified by malondialdehyde, IL-31 and IL-33 levels in correlation with physico-chemical characterization and antioxidant activity. Additionally, from PhyP extract, the caspase-3, IL-6, IL-10, tumor necrosis factor (TNF)-α and nuclear transcription factor NFkB expressions were evaluated. HPLC analysis revealed a significant number of phenolic compounds, especially in PhyF extract, with a good antioxidant activity as highlighted by TEAC, CUPRAC or DPPH methods. On HUVECS cells, the extracts were not toxic even at high concentrations. Particularly PhyF extract, diminished lipid peroxidation and inhibited the IL-31 and IL-33 secretions induced by hyperglycemia. The inhibitory effect on proinflammatory cytokines was noticed after both doses of PhyF extract in parallel with the upregulation of anti-inflammatory cytokine IL-10. Moreover, PhyF, especially in a low dose, reduced caspase-3 active form. These experimental findings suggest that Physalis fruits extract exerted beneficial effects in hyperglycemia by inhibition of oxidative stress, inflammation and apoptosis being a good adjuvant option in diabetes.

Pharmacological potential of the combination of Salvia miltiorrhiza (Danshen) and Carthamus tinctorius (Honghua) for diabetes mellitus and its cardiovascular complications

Metabolic syndrome, such as diabetes mellitus, obesity, atherosclerosis, and high blood pressure (HBP), are closely linked pathophysiologically. However, current monotherapies for metabolic syndrome fail to target the multifactorial pathology via multiple mechanisms, as well as resolving the dysfunctionality of the cells and organs of the body. We aimed to provide a comprehensive and up-to-date review of the pharmacological advances, therapeutic potential, and phytochemistry of Salvia miltiorrhiza, Carthamus tinctorius, and Danhong injection (DHI). We discussed the molecular mechanisms of the bioactive constituents relating to diabetes mellitus and metabolic disease for further research and drug development. Interestingly, Salvia miltiorrhiza, Carthamus tinctorius, and DHI have anti-inflammatory, anti-glycemic, anti-thrombotic, and anti-cancer properties; and they mainly act by targeting the dysfunctional vasculatures including the inflammatory components of the disease to provide vascular repair as well as resolving oxidative stress. The major bioactive chemical constituents of these plants include polyphenolic acids, diterpene compounds, carthamin, and hydroxysafflor yellow A. Treatment of diabetes mellitus and its associated cardiovascular complication requires a comprehensive approach involving the use of appropriate traditional Chinese medicine formula. Danshen, Honghua, and DHI target the multiple risk factors regulating the physiologic function of the body and restore normalcy, apart from the traditional advice on exercise and diet control as treatment options in a metabolic syndrome patient.

Black Sorghum Phenolic Extract Regulates Expression of Genes Associated with Oxidative Stress and Inflammation in Human Endothelial Cells

Oxidative stress is one of the primary factors leading to endothelial dysfunction, a major underlying cause of vascular disorders. This study aims to understand the key signalling pathways regulated by sorghum (Shawaya short black 1 variety; characterised to be very high in its antioxidant activity) under oxidative stress in endothelial cells. Human umbilical vein endothelial cells (HUVECs) were pre-treated with non-cytotoxic concentrations of phenolic-rich black sorghum extract (BSE) prior to induction of oxidative stress using hydrogen peroxide (H₂O₂). Treatment with BSE upregulated the expression of heme oxygenase 1 (HO1) and endothelial nitric oxide synthase (eNOS) and downregulated the levels of NADPH oxidase 4 (NOX4). BSE treatment significantly reduced the expression of pro-inflammatory mediators such as monocyte chemoattractant protein 1 (MCP1) and intracellular adhesion molecule 1 (ICAM1). Results from this study suggest that phenolic-rich BSE may reduce oxidative stress by regulating pro- and antioxidant signalling pathways and the expression of inflammatory mediators linked to endothelial dysfunction under oxidative stress.

Antioxidants and Atherosclerosis: Mechanistic Aspects

Atherosclerosis is a chronic inflammatory disease which is a major cause of coronary heart disease and stroke in humans. It is characterized by intimal plaques and cholesterol accumulation in arterial walls. The side effects of currently prescribed synthetic drugs and their high cost in the treatment of atherosclerosis has prompted the use of alternative herbal medicines, dietary supplements, and antioxidants associated with fewer adverse effects for the treatment of atherosclerosis. This article aims to present the activity mechanisms of antioxidants on atherosclerosis along with a review of the most prevalent medicinal plants employed against this multifactorial disease. The wide-ranging information in this review article was obtained from scientific databases including PubMed, Web of Science, Scopus, Science Direct and Google Scholar. Natural and synthetic antioxidants have a crucial role in the prevention and treatment of atherosclerosis through different mechanisms. These include: The inhibition of low density lipoprotein (LDL) oxidation, the reduction of reactive oxygen species (ROS) generation, the inhibition of cytokine secretion, the prevention of atherosclerotic plaque formation and platelet aggregation, the preclusion of mononuclear cell infiltration, the improvement of endothelial dysfunction and vasodilation, the augmentation of nitric oxide (NO) bioavailability, the modulation of the expression of adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) on endothelial cells, and the suppression of foam cell formation.

Ursolic acid prevents doxorubicin-induced cardiac toxicity in mice through eNOS activation and inhibition of eNOS uncoupling

In addition to the known antitumour effects of ursolic acid (UA), increasing evidence indicates that this molecule plays a role in cardiac protection. In this study, the effects of ursolic acid on the heart in mice treated with doxorubicin (DOX) were assessed. The results showed that ursolic acid improved left ventrical fractional shortening (LVFS) and left ventrical ejection fraction (LVEF) of the heart, increased nitrogen oxide (NO) levels, inhibited reactive oxygen species (ROS) production and decreased cardiac apoptosis in mice treated with doxorubicin. Mechanistically, ursolic acid increased AKT and endothelial nitric-oxide synthase (eNOS) phosphorylation levels, and enhanced eNOS expression, while inhibiting doxorubicin induced eNOS uncoupling through NADPH oxidase 4 (NOX4) down-regulation. These effects of ursolic acid resulted in heart protection from doxorubicin-induced injury. Therefore, ursolic acid may be considered a potential therapeutic agent for doxorubicin-associated cardiac toxicity in clinical practice.

Pentacyclic triterpenes: New tools to fight metabolic syndrome

BACKGROUND

Metabolic syndrome is a combination of dysregulated cardiometabolic risk factors characterized by dyslipidemia, impaired glucose tolerance, insulin resistance, inflammation, obesity as well as hypertension. These factors are tied to the increased risk for type-II diabetes and cardiovascular diseases including myocardial infarction in patients with metabolic syndrome.

PURPOSE

To review the proposed molecular mechanisms of pentacyclic triterpenes for their potential use in the metabolic syndrome.

METHODS

PubMed, Science Direct, and Google Scholar database were searched from commencement to April 2018. Following keywords were searched in the databases with varying combinations: "metabolic syndrome", "pentacyclic triterpenes", "transcription factors", "protein kinase", "lipogenesis", "adipogenesis", "lipolysis", "fatty acids", "gluconeogenesis", "cardiovascular", "mitochondria", "oxidative stress", "pancreas", "hepatic cells", "skeletal muscle", "3T3-L1", "C2C12", "obesity", "inflammation", "insulin resistance", "glucose uptake", "clinical studies" and "bioavailability".

RESULTS

Pentacyclic triterpenes, such as asiatic acid, ursolic acid, oleanolic acid, 18β-glycyrrhetinic acid, α,β-amyrin, celastrol, carbenoxolone, corosolic acid, maslinic acid, bardoxolone methyl and lupeol downregulate several metabolic syndrome components by regulating transcription factors, protein kinases and enzyme involved in the adipogenesis, lipolysis, fatty acid oxidation, insulin resistance, mitochondria biogenesis, gluconeogenesis, oxidative stress and inflammation.

CONCLUSION

In vitro and in vivo studies suggests that pentacyclic triterpenes effectively downregulate various factors related to metabolic syndrome. These phytochemicals may serve as promising candidates for clinical trials for the management of metabolic syndrome.

Evaluation of Apricot, Bilberry, and Elderberry Pomace Constituents and Their Potential To Enhance the Endothelial Nitric Oxide Synthase (eNOS) Activity

Pomace, the press residue from different fruits accumulating as waste product in food industry, contains high amounts of secondary metabolites that could be utilized for health-related applications. This study aims at evaluating the potential of pomaces of apricot, bilberry, and elderberry to serve as a source for endothelial nitric oxide synthase (eNOS)-activating compounds. Five extracts obtained from the lyophilized pomace of apricot and elderberry with solvents of different polarity were found to enhance A23187-stimulated eNOS activity when tested at 50 μg/mL in an [¹⁴C]-l-arginine to [¹⁴C]-l-citrulline conversion assay in the human endothelium-derived cell line EA.hy926 (p < 0.05). The bioassay-guided fractionation of the extracts obtained with methanol/water (70:30) led to several active fractions from apricot pomace (p < 0.05) and elderberry pomace (p < 0.01). Liquid chromatography-mass spectrometry-based chemical analysis of the extracts and active fractions pointed mainly to triterpenoic acids as active compounds. One particular dihydroxytriterpenoic acid, characteristic for elderberry, was enriched as the main compound in the two most active fractions and might serve as a promising lead structure for further studies.

Atheroprotective effects and molecular targets of bioactive compounds from traditional Chinese medicine

Traditional Chinese medicine (TCM) has served the Chinese people since antiquity, and is playing an important role in today's healthcare. However, there has been controversy in the use of these traditional herbs due to unclear components and absence of scientific proof. As China plans to modernize traditional medicine, successful attempts to better understand the molecular mechanisms of TCM have been made by focusing on isolating active ingredients from these remedies. In this review, we critically examined the current evidence on atheroprotective effects of bioactive compounds from TCM using in vitro or in vivo models in the past two decades. A total of 47 active compounds were included in our review, which were introduced in the order of chemical structures, source, model, efficacy and mechanism. Notablely, this review highlighted the cellular and molecular mechanisms of these active compounds in prevention and treatment of atherosclerosis. Two compounds were also involved in double-blind, randomized, placebo-controlled clinical trials (RCTs). Besides, we introduced the legislations of the People's Republic of China ensuring quality and safety of products used in TCM. In summary, studies on bioactive compounds from TCM will provide a new approach for better management of atherosclerosis.

Oleanolic, Ursolic, and Betulinic Acids as Food Supplements or Pharmaceutical Agents for Type 2 Diabetes: Promise or Illusion?

Oleanolic (OA), ursolic (UA), and betulinic (BA) acids are three triterpenic acids (TAs) with potential effects for treatment of type 2 diabetes (T2DM). Mechanistic studies showed that these TAs act as hypoglycemic and antiobesity agents mainly through (i) reducing the absorption of glucose; (ii) decreasing endogenous glucose production; (iii) increasing insulin sensitivity; (iv) improving lipid homeostasis; and (v) promoting body weight regulation. Besides these promising beneficial effects, it is believed that OA, UA, and BA protect against diabetes-related comorbidities due to their antiatherogenic, anti-inflammatory, and antioxidant properties. We also highlight the protective effect of OA, UA, and BA against oxidative damage, which may be very relevant for the treatment and/or prevention of T2DM. In the present review, we provide an integrative description of the antidiabetic properties of OA, UA, and BA, evaluating the potential use of these TAs as food supplements or pharmaceutical agents to prevent and/or treat T2DM.

Triterpenoic Acids from Apple Pomace Enhance the Activity of the Endothelial Nitric Oxide Synthase (eNOS)

Pomace is an easy-accessible raw material for the isolation of fruit-derived compounds. Fruit consumption is associated with health-promoting effects, such as the prevention of cardiovascular disease. Increased vascular nitric oxide (NO) bioavailability, for example, due to an enhanced endothelial nitric oxide synthase (eNOS) activity, could be one molecular mechanism mediating this effect. To identify compounds from apple (Malus domestica Borkh.) pomace that have the potential to amplify NO bioavailability via eNOS activation, a bioassay-guided fractionation of the methanol/water (70:30) extract has been performed using the (14)C-L-arginine to (14)C-L-citrulline conversion assay (ACCA) in the human endothelium-derived cell line EA.hy926. Phytochemical characterization of the active fractions was performed using the spectrophotometric assessment of the total phenolic content, as well as TLC, HPLC-DAD-ELSD, and HPLC-MS analyses. Eleven triterpenoic acids, of which one is a newly discovered compound, were identified as the main constituents in the most active fraction, accompanied by only minor contents of phenolic compounds. When tested individually, none of the tested compounds exhibited significant eNOS activation. Nevertheless, cell stimulation with the reconstituted compound mixture restored eNOS activation, validating the potential of apple pomace as a source of bioactive components.

ENOS deficiency causes podocyte injury with mitochondrial abnormality

The contribution of endothelial nitric oxide synthase (eNOS) to podocyte integrity remains unclear. This study therefore examined podocytes and mitochondrial abnormalities in eNOS deficient mice. Absence of eNOS caused glomerular hypertrophy, along with occasional glomerular sclerosis and mesangiolysis. While many glomeruli did not have such advanced lesions, ultrastructural analysis showed cellular hypertrophy, vacuolization, lysosomal enlargement, and microvillus formation in podocytes of eNOS knockout (KO) mice. Increased oxidative stress was associated with mitochondrial abnormalities, including an increase in number, coupled with a reduction in size, of mitochondria in podocytes of eNOS-KO mice. While the levels of expression of several mitochondrial proteins were not altered, the d-17 mutation in mitochondrial DNA was significantly associated with the eNOS deficiency. Renal ATP level in the renal cortex and mitochondrial respiration in the primary podocytes were significantly lower in eNOS-KO mice, suggesting that renal mitochondria may be functionally impaired. Podocytes cultured with endothelial conditioned medium lacking NO consistently showed a greater degree of mitochondrial fragmentation and an increase in mitochondrial oxidative stress, with these mitochondrial alterations rescued by an NO donor. In conclusion, eNOS may be necessary to maintain podocyte integrity, especially mitochondrial function.

A bioinformatic and mechanistic study elicits the antifibrotic effect of ursolic acid through the attenuation of oxidative stress with the involvement of ERK, PI3K/Akt, and p38 MAPK signaling pathways in human hepatic stellate cells and rat liver

NADPH oxidases (NOXs) are a predominant mediator of redox homeostasis in hepatic stellate cells (HSCs), and oxidative stress plays an important role in the pathogenesis of liver fibrosis. Ursolic acid (UA) is a pentacyclic triterpenoid with various pharmacological activities, but the molecular targets and underlying mechanisms for its antifibrotic effect in the liver remain elusive. This study aimed to computationally predict the molecular interactome and mechanistically investigate the antifibrotic effect of UA on oxidative stress, with a focus on NOX4 activity and cross-linked signaling pathways in human HSCs and rat liver. Drug-drug interaction via chemical-protein interactome tool, a server that can predict drug-drug interaction via chemical-protein interactome, was used to predict the molecular targets of UA, and Database for Annotation, Visualization, and Integrated Discovery was employed to analyze the signaling pathways of the predicted targets of UA. The bioinformatic data showed that there were 611 molecular proteins possibly interacting with UA and that there were over 49 functional clusters responding to UA. The subsequential benchmarking data showed that UA significantly reduced the accumulation of type I collagen in HSCs in rat liver, increased the expression level of MMP-1, but decreased the expression level of TIMP-1 in HSC-T6 cells. UA also remarkably reduced the gene expression level of type I collagen in HSC-T6 cells. Furthermore, UA remarkably attenuated oxidative stress via negative regulation of NOX4 activity and expression in HSC-T6 cells. The employment of specific chemical inhibitors, SB203580, LY294002, PD98059, and AG490, demonstrated the involvement of ERK, PI3K/Akt, and p38 MAPK signaling pathways in the regulatory effect of UA on NOX4 activity and expression. Collectively, the antifibrotic effect of UA is partially due to the oxidative stress attenuating effect through manipulating NOX4 activity and expression. The results suggest that UA may act as a promising antifibrotic agent. More studies are warranted to evaluate the safety and efficacy of UA in the treatment of liver fibrosis.

Antifibrotic effect of ursolic acid in the liver and related mechanisms

Numerous studies have found that NADPH oxidase (NOX) plays a key role in the development of hepatic fibrosis. The activation of NOX in hepatic stellate cells (HSCs) is followed by production of reactive oxygen species and activation of PI3K/Akt and P38MAPK signaling pathways, which in turn causes the excessive expression of type I collagen and its deposition in the liver. Ursolic acid (UA) is a Chinese herbal monomer that widely exists in multiple medicinal plants. Studies have found that UA markedly ameliorates liver fibrosis in experimental animals, and reduces hepatocyte necrosis. In this paper, we review the recent advances in understanding the antifibrotic effect of UA in the liver and the related mechanisms.

Chinese Herbal Compounds for the Prevention and Treatment of Atherosclerosis: Experimental Evidence and Mechanisms

Atherosclerosis is a leading cause of disability and death worldwide. Research into the disease has led to many compelling hypotheses regarding the pathophysiology of atherosclerotic lesion formation and the resulting complications such as myocardial infarction and stroke. Herbal medicine has been widely used in China as well as other Asian countries for the treatment of cardiovascular diseases for hundreds of years; however, the mechanisms of action of Chinese herbal medicine in the prevention and treatment of atherosclerosis have not been well studied. In this review, we briefly describe the mechanisms of atherogenesis and then summarize the research that has been performed in recent years regarding the effectiveness and mechanisms of antiatherogenic Chinese herbal compounds in an attempt to build a bridge between traditional Chinese medicine and cellular and molecular cardiovascular medicine.

Antimicrobial activity of oleanolic and ursolic acids: an update

Triterpenoids are the most representative group of phytochemicals, as they comprise more than 20,000 recognized molecules. These compounds are biosynthesized in plants via squalene cyclization, a C30 hydrocarbon that is considered to be the precursor of all steroids. Due to their low hydrophilicity, triterpenes were considered to be inactive for a long period of time; however, evidence regarding their wide range of pharmacological activities is emerging, and elegant studies have highlighted these activities. Several triterpenic skeletons have been described, including some that have presented with pentacyclic features, such as oleanolic and ursolic acids. These compounds have displayed incontestable biological activity, such as antibacterial, antiviral, and antiprotozoal effects, which were not included in a single review until now. Thus, the present review investigates the potential use of these triterpenes against human pathogens, including their mechanisms of action, via in vivo studies, and the future perspectives about the use of compounds for human or even animal health are also discussed.

Salvia miltiorrhiza: an ancient Chinese herbal medicine as a source for anti-osteoporotic drugs

ETHNOPHARMACOLOGICAL RELEVANCE

Red sage (Salvia miltiorrhiza Bunge), also known as Danshen in Chinese, has been used historically and is currently exploited in combination with other herbs to treat skeletal diseases in traditional Chinese medicine (TCM). With the advance of modern analytical technology, a multitude of bone-targeting, pharmaceutically active, compounds has been isolated and characterized from various sources of TCM including those produced in Salvia miltiorrhiza root. The aim of the review is to provide a comprehensive overview about the historical TCM interpretation of the action of Salvia miltiorrhiza in osteoporosis, its use clinical trials, its main phytochemical constituents, and its action on bone-resorptive and bone formation-stimulating mechanisms in in vitro and in vivo studies.

MATERIALS AND METHODS

Literature sources used were Pubmed, CNKI.net, Cqvip.com, PubChem, and the Web of Science. For the inquiry, keywords such as Salvia, danshen, osteoporosis, bone, osteoclast and osteoblast were used in various combinations. About 130 research papers and reviews were consulted.

RESULTS

In TCM, the anti-osteopororotic effect of Salvia miltiorrhiza is ascribed to its action on liver and blood stasis as main therapeutic targets defining osteoporosis. 36 clinical trials were identified which used Salvia miltiorrhiza in combination with other herbs and components to treat post-menopausal, senile, and secondary osteoporosis. On average the trials were characterized by high efficacy (>80%) and low toxicity problems. However, various limitations such as small patient samples, short treatment duration, frequent lack of detailed numerical data, and no clear endpoints must be taken into consideration. To date, more than 100 individual compounds have been isolated from this plant and tested in various animal models and biochemical assays. Compounds display anti-resorptive and bone formation-stimulating features targeting different pathways in the bone remodeling cycle. Pathways affected include the activation of osteoblasts, the modulation of osteoclastogenesis, and the inhibition of collagen degradation by cathepsin K.

CONCLUSIONS

The inclusion of Salvia miltiorrhiza in more than 30% of all herbal clinical trials successfully targeting osteoporosis has stimulated significant interest in the identification and characterization of individual constituents of this herb. The review highlights the anti-osteoporotic potential of Salvia miltiorrhiza in clinical applications and the potential of the herb to provide potent compounds targeting specific pathways in bone resorption and bone formation.

Role of rutin on nitric oxide synthesis in human umbilical vein endothelial cells

Nitric oxide (NO), produced by endothelial nitric oxide synthase (eNOS), is a major antiatherogenic factor in the blood vessel. Oxidative stress plays an important role in the pathogenesis of various cardiovascular diseases, including atherosclerosis. Decreased availability of endothelial NO promotes the progression of endothelial dysfunction and atherosclerosis. Rutin is a flavonoid with multiple cardiovascular protective effects. This study aimed to investigate the effects of rutin on eNOS and NO production in cultured human umbilical vein endothelial cells (HUVEC). HUVEC were divided into four groups: control; oxidative stress induction with 180 μM H₂O₂; treatment with 300 μM rutin; and concomitant induction with rutin and H₂O₂ for 24 hours. HUVEC treated with rutin produced higher amount of NO compared to control (P < 0.01). In the oxidative stress-induced HUVEC, rutin successfully induced cells' NO production (P < 0.01). Rutin promoted NO production in HUVEC by inducing eNOS gene expression (P < 0.05), eNOS protein synthesis (P < 0.01), and eNOS activity (P < 0.05). Treatment with rutin also led to increased gene and protein expression of basic fibroblast growth factor (bFGF) in HUVEC. Therefore, upregulation of eNOS expression by rutin may be mediated by bFGF. The results showed that rutin may improve endothelial function by augmenting NO production in human endothelial cells.

Ursolic acid protects monocytes against metabolic stress-induced priming and dysfunction by preventing the induction of Nox4

AIMS

Dietary supplementation with ursolic acid (UA) prevents monocyte dysfunction in diabetic mice and protects mice against atherosclerosis and loss of renal function. The goal of this study was to determine the molecular mechanism by which UA prevents monocyte dysfunction induced by metabolic stress.

METHODS AND RESULTS

Metabolic stress sensitizes or "primes" human THP-1 monocytes and murine peritoneal macrophages to the chemoattractant MCP-1, converting these cells into a hyper-chemotactic phenotype. UA protected THP-1 monocytes and peritoneal macrophages against metabolic priming and prevented their hyper-reactivity to MCP-1. UA blocked the metabolic stress-induced increase in global protein-S-glutathionylation, a measure of cellular thiol oxidative stress, and normalized actin-S-glutathionylation. UA also restored MAPK phosphatase-1 (MKP1) protein expression and phosphatase activity, decreased by metabolic priming, and normalized p38 MAPK activation. Neither metabolic stress nor UA supplementation altered mRNA or protein levels of glutaredoxin-1, the principal enzyme responsible for the reduction of mixed disulfides between glutathione and protein thiols in these cells. However, the induction of Nox4 by metabolic stress, required for metabolic priming, was inhibited by UA in both THP-1 monocytes and peritoneal macrophages.

CONCLUSION

UA protects THP-1 monocytes against dysfunction by suppressing metabolic stress-induced Nox4 expression, thereby preventing the Nox4-dependent dysregulation of redox-sensitive processes, including actin turnover and MAPK-signaling, two key processes that control monocyte migration and adhesion. This study provides a novel mechanism for the anti-inflammatory and athero- and renoprotective properties of UA and suggests that dysfunctional blood monocytes may be primary targets of UA and related compounds.

Endothelial dysfunction - a major mediator of diabetic vascular disease

The vascular endothelium is a multifunctional organ and is critically involved in modulating vascular tone and structure. Endothelial cells produce a wide range of factors that also regulate cellular adhesion, thromboresistance, smooth muscle cell proliferation, and vessel wall inflammation. Thus, endothelial function is important for the homeostasis of the body and its dysfunction is associated with several pathophysiological conditions, including atherosclerosis, hypertension and diabetes. Patients with diabetes invariably show an impairment of endothelium-dependent vasodilation. Therefore, understanding and treating endothelial dysfunction is a major focus in the prevention of vascular complications associated with all forms of diabetes mellitus. The mechanisms of endothelial dysfunction in diabetes may point to new management strategies for the prevention of cardiovascular disease in diabetes. This review will focus on the mechanisms and therapeutics that specifically target endothelial dysfunction in the context of a diabetic setting. Mechanisms including altered glucose metabolism, impaired insulin signaling, low-grade inflammatory state, and increased reactive oxygen species generation will be discussed. The importance of developing new pharmacological approaches that upregulate endothelium-derived nitric oxide synthesis and target key vascular ROS-producing enzymes will be highlighted and new strategies that might prove clinically relevant in preventing the development and/or retarding the progression of diabetes associated vascular complications.

Dietary supplementation with two Lamiaceae herbs-(oregano and sage) modulates innate immunity parameters in Lumbricus terrestris

INTRODUCTION

Lamiaceae herbs have are well known for their immunomodulatory effects, however, the mechanism by which they effect innate immune system is not clearly understood.

OBJECTIVE

The effect of dietary supplementation with two Lamiaceae herbs (oregano and sage) modulation of on innate immunological parameters was investigated in Lumbricus terrestris.

MATERIALS AND METHODS

Animals were fed (ad libitum) on herbs supplemented diet [(0.1% (w/v) and 0.5% (w/v)] for 6 days. Changes in immune competent cell counts, viability, and relative neutrophil-like cell counts were determined in response to herb treatment. Changes in nitric oxide, phagocytic activity, and respiratory burst index were also determined in response to herb treatment relative to control. Additionally, effect of herb co-treatment cyclophosphamide (50 mg/kg-BW) induced immunosuppression was also evaluated.

RESULTS

Our results suggested abrogation of CP-induced immunosuppression in response to co-treatment with herbs. Significant increase in nitric oxide-mediated immune-competent cell counts, viability, and differentiation into neutrophil-like cells were observed in response to dietary supplementation with Lamiaceae herbs. Significantly higher phagocytic activity relative to control was also noted in response to dietary intake of oregano and sage. However, the respiratory burst index did not increase exponentially in response to herb treatments, suggesting a potential enhancement in pathogen recognition and antioxidant defenses.

CONCLUSION

Lamiaceae herbs may have potential immune-modulatory properties important for human health and merits further investigation.

Aqueous extract of danshen (Salvia miltiorrhiza Bunge) protects ovariectomized rats fed with high-fat diet from endothelial dysfunction

OBJECTIVE

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality in postmenopausal women. Danshen, the dried root of Salvia miltiorrhiza Bunge, has been used clinically in China to treat CVD and dyslipidemia in postmenopausal women, and its major active ingredients have been found to have an estrogenic effect. The aim of this study was to elucidate the underlying mechanism of danshen's protective effects on vascular function in an ovariectomized (OVX) hyperlipidemic rat model.

METHODS

Thirty-five 6-month-old female Sprague-Dawley rats were randomly divided into five groups: sham-operated rats with low-fat control diet + vehicle, sham-operated rats with high-fat diet (HFD) + vehicle, OVX rats with HFD + vehicle, OVX rats with HFD + 17β-estradiol (1 mg kg d, PO), and OVX rats with HFD + danshen aqueous extract (600 mg kg d, PO). After 12 weeks of treatment, gains in body weight and serum lipid profile levels in rats were measured and histological examination of livers was carried out. Vascular function was evaluated by measuring relaxation responses. Molecular mechanisms were also analyzed in isolated aorta.

RESULTS

Treatment with danshen aqueous extract reduced body weight gain, improved serum lipid profiles, and prevented formation of fatty liver induced by HFD and OVX. In addition, danshen could increase endothelial-dependent vasorelaxation and displayed vasoprotection in OVX rats fed with HFD, primarily by stimulating nitric oxide (NO) production, up-regulating the mRNA expression of endothelial NO synthase, and down-regulating the mRNA expression of tumor necrosis factor α, intercellular cell adhesion molecule-1, and vascular cell adhesion molecule-1 in the isolated aortas.

CONCLUSIONS

We conclude for the first time that danshen aqueous extract could protect OVX rats fed with HFD from endothelial dysfunction. Its effect may be related to its abilities to normalize serum lipid profiles and enhance NO availability in the vascular system. Our findings indicate that danshen aqueous extract could be a promising natural supplement for postmenopausal women for preventing CVD.

Pharmacological approaches to the treatment of oxidative stress-induced cardiovascular dysfunctions

Cardiovascular diseases are a growing major global health problem. Our understanding of the mechanisms of pathophysiology of cardiovascular diseases has been gaining significant advances and a wealth of knowledge implicates oxidative stress as a key causative agent. However, to date, most efforts to treat heart failure using conventional antioxidant therapies have been less than encouraging. With increasing incidences of cardiovascular disease in young as well as in aging populations, and the problem of long-term diminishing efficacy of conventional therapeutics, the need for new treatments has never been greater. In this review, a variety of therapeutic targets and compounds applied to treat cardiovascular diseases via inhibition of oxidative stress are presented.

Modulation of esterified drug metabolism by tanshinones from Salvia miltiorrhiza ("Danshen")

The roots of Salvia miltiorrhiza ("Danshen") are used in traditional Chinese medicine for the treatment of numerous ailments including cardiovascular disease, hypertension, and ischemic stroke. Extracts of S. miltiorrhiza roots in the formulation "Compound Danshen Dripping Pill" are undergoing clinical trials in the United States. To date, the active components of this material have not been conclusively identified. We have determined that S. miltiorrhiza roots contain potent human carboxylesterase (CE) inhibitors, due to the presence of tanshinones. K(i) values in the nM range were determined for inhibition of both the liver and intestinal CEs. As CEs hydrolyze clinically used drugs, the ability of tanshinones and S. miltiorrhiza root extracts to modulate the metabolism of the anticancer prodrug irinotecan (CPT-11) was assessed. Our results indicate that marked inhibition of human CEs occurs following incubation with both pure compounds and crude material and that drug hydrolysis is significantly reduced. Consequently, a reduction in the cytotoxicity of irinotecan is observed following dosing with either purified tanshinones or S. miltiorrhiza root extracts. It is concluded that remedies containing tanshinones should be avoided when individuals are taking esterified agents and that patients should be warned of the potential drug-drug interaction that may occur with this material.

Therapeutic effects of water soluble danshen extracts on atherosclerosis

Danshen is a traditional Chinese medicine with many beneficial effects on cardiovascular diseases. The aim of this study was to evaluate the mechanisms responsible for the antiatherogenic effect of water soluble Danshen extracts (DEs). Rat vascular smooth muscle cells (VSMCs) and human umbilical vein endothelial cells (HUVECs) were treated with DE. To evaluate the effects of DE in vivo, carotid balloon injury and tail vein thrombosis were induced in Sprague-Dawley (SD) rats and iliac artery stent was induced in New Zealand white rabbits. The inhibitory action of DE on platelet aggregation was confirmed with an impedance aggregometer. DE inhibited the production of reactive oxygen species, and the migration and proliferation of platelet-derived growth factor-BB stimulated VSMCs. Furthermore, DE prevented inflammation and apoptosis in HUVECs. Both effects of DE were reconfirmed in both rat models. DE treatment attenuated platelet aggregation in both in vivo and ex vivo conditions. Pretreatment with DE prevented tail vein thrombosis, which is normally induced by κ-carrageenan injection. Lastly, DE-treated rabbits showed decreased in-stent restenosis of stented iliac arteries. These results suggest that water soluble DE modulates key atherogenic events in VSMCs, endothelial cells, and platelets in both in vitro and in vivo conditions.

Inhibition of cell surface expression of endothelial adhesion molecules by ursolic acid prevents intimal hyperplasia of venous bypass grafts in rats

OBJECTIVES

Despite rapid progress in surgical techniques, there is still a significant lack of surgery-supportive pharmacological treatments. The aim of this study was to test the hypothesis that ursolic acid (UA) may prevent intimal hyperplasia of venous bypass grafts.

METHODS

The hypothesis was tested by means of primary cell isolation and culture followed by real-time polymerase chain reaction, western blotting, fluorescence microscopy and fluorescence-activated cell sorting analyses, as well as an in vivo rat model for intimal hyperplasia of venous bypass grafts and immunohistochemistry and histochemistry.

RESULTS

The local application of UA significantly inhibited intimal hyperplasia in vivo (intimal thickness control: 25 µm, UA group: 18 µM-8 weeks after surgery). The UA treatment of grafts significantly resulted in reduced endothelial vascular cell adhesion molecule-1 (VCAM-1) expression, reduced infiltration of the grafts vessel wall by CD45-positive cells and increased smooth muscle cell (SMC) death. In in vitro condition, it could be shown that UA inhibits VCAM-1 expression downstream of NFκB and is likely to interfere with VCAM-1 protein synthesis in endothelial cells. Quantification of cell death in vascular smooth muscle cells treated with UA indicated that UA is a potent inducer of SMC apoptosis.

CONCLUSIONS

Our results suggest that UA-mediated inhibition of endothelial VCAM-1 expression reduces the infiltration of venous bypass grafts by CD45-positive cells and inhibits intimal hyperplasia. Apoptosis induction in SMCs may be another method in which UA reduces intimal thickening. UA may constitute a surgery-supportive pharmacon that reduces intimal hyperplasia of vein grafts.

Attenuation of aortic injury by ursolic acid through RAGE-Nox-NFκB pathway in streptozocin-induced diabetic rats

Vascular complications are the leading causes of morbidity and mortality in diabetes mellitus (DM). The RAGE (receptor for advanced glycation end products)-NADPH oxidase-NF-κB signal transduction pathway plays an important role in the development of oxidative stress-related vascular complications in DM. Ursolic acid (UA), a pentacyclic triterpenoid derived from plants, has been reported to have multiple pharmacological effects, including a potent antioxidant activity. This study aimed to investigate both the effect of UA on aortic injury in streptozotocin (STZ)-induced diabetic rats and the drug's mechanism of action. STZ-induced diabetic animals were randomized in one of the following 4 groups: no treatment (diabetic model group), aminoguanidine (AG, 100 mg/kg), high-dose UA (50 mg/kg), and low-dose UA (25 mg/kg). A non-diabetic control group was followed concurrently. After 8 weeks, the diabetic model rats exhibited: severe aortic arch injury, histologically elevated serum glucose, fructosamine, and glycosylated hemoglobin; and accumulation of advanced glycation end products (AGEs) in the arota. In addition, the levels of RAGE protein, transcription factor NF-κB p65, and the p22phox subunit of NADPH oxidase were increased, as were the serum levels of malondialdehyde and tumor necrosis factor-alpha (TNF-α; p < 0.01 vs control), suggesting that the mechanisms of oxidative stress contributed to vascular injury in the diabetic model group. In contrast, rats treated with UA (50 mg/kg) had a markedly less vascular injury and significantly improved biochemical parameters. Oxidative balance was also normalized in the UA-treated rats, and a marked reduction in the levels of RAGE and p22phox paralleled the reduced activation of NF-κB p65 and TNF-α (p < 0.01 and p < 0.05, respectively, vs diabetic model). These findings suggest that UA may suppress oxidative stress, thus blunting activation of the RAGE-NADPH oxidase-NF-κB signal transduction pathway, to ameliorate vascular injury in the STZ-induced DM rats.

Therapeutic effect of enhancing endothelial nitric oxide synthase (eNOS) expression and preventing eNOS uncoupling

Nitric oxide (NO) produced by the endothelium is an important protective molecule in the vasculature. It is generated by the enzyme endothelial NO synthase (eNOS). Similar to all NOS isoforms, functional eNOS transfers electrons from nicotinamide adenine dinucleotide phosphate (NADPH), via the flavins flavin adenine dinucleotide and flavin mononucleotide in the carboxy-terminal reductase domain, to the heme in the amino-terminal oxygenase domain. Here, the substrate L-arginine is oxidized to L-citrulline and NO. Cardiovascular risk factors such as diabetes mellitus, hypertension, hypercholesterolaemia or cigarette smoking reduce bioactive NO. These risk factors lead to an enhanced production of reactive oxygen species (ROS) in the vessel wall. NADPH oxidases represent major sources of this ROS and have been found upregulated in the presence of cardiovascular risk factors. NADPH-oxidase-derived superoxide avidly reacts with eNOS-derived NO to form peroxynitrite (ONOO(-)). The essential NOS cofactor (6R-)5,6,7,8-tetrahydrobiopterin (BH(4) ) is highly sensitive to oxidation by this ONOO(-). In BH(4) deficiency, oxygen reduction uncouples from NO synthesis, thereby converting NOS to a superoxide-producing enzyme. Among conventional drugs, compounds interfering with the renin-angiotensin-aldosterone system and statins can reduce vascular oxidative stress and increase bioactive NO. In recent years, we have identified a number of small molecules that have the potential to prevent eNOS uncoupling and, at the same time, enhance eNOS expression. These include the protein kinase C inhibitor midostaurin, the pentacyclic triterpenoids ursolic acid and betulinic acid, the eNOS enhancing compounds AVE9488 and AVE3085, and the polyphenolic phytoalexin trans-resveratrol. Such compounds enhance NO production from eNOS also under pathophysiological conditions and may thus have therapeutic potential.

Extract of Salvia miltiorrhiza (Danshen) induces Nrf2-mediated heme oxygenase-1 expression as a cytoprotective action in RAW 264.7 macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Danshen (Salvia miltiorrhiza) is widely used in traditional herbal medicines for relief of a variety of symptoms related to complications arising from vascular diseases such as hypertension, diabetes, and atherosclerosis. Induction of heme oxygenase-1 (HO-1) expression protects against oxidative stress-induced cell damage, which plays an important role in cytoprotection in a variety of pathological models.

MATERIALS AND METHODS

In the present study, we investigated the effect of Danshen on the up-regulation of HO-1, an inducible and cytoprotective enzyme in RAW 264.7 macrophages. Molecular mechanisms underlying the effects, especially protective effects, was elucidated by analyzing the activation of transcription factors and their upstream signalling, and by evaluating the inhibitory effect of HO-1 on ROS production.

RESULTS

Danshen induced HO-1 mRNA expression and protein production, and nuclear translocation of NF-E2-related factor 2 in RAW 264.7 macrophages. Pharmacological inhibitors of PI3K/Akt and MEK1 attenuated HO-1 induction in Danshen-stimulated RAW 264.7 macrophages. Furthermore, Danshen pretreatment reduced intracellular production of reactive oxygen species after stimulation with hydrogen peroxide; this effect was reversed by the HO-1 inhibitor ZnPP.

CONCLUSION

Danshen induced HO-1 expression through PI3K/Akt-MEK1-Nrf2 pathway and reduced intracellular production of reactive oxygen species via induction of HO-1 expression. The results support a role of HO-1 in the cytoprotective effect of Danshen.

Prunella vulgaris suppresses HG-induced vascular inflammation via Nrf2/HO-1/eNOS activation

Vascular inflammation is an important factor which can promote diabetic complications. In this study, the inhibitory effects of aqueous extract from Prunella vulgaris (APV) on high glucose (HG)-induced expression of cell adhesion molecules in human umbilical vein endothelial cells (HUVEC) are reported. APV decreased HG-induced expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin. APV also dose-dependently inhibited HG-induced adhesion of HL-60 monocytic cells. APV suppressed p65 NF-κB activation in HG-treated cells. APV significantly inhibited the formation of intracellular reactive oxygen species (ROS). HG-stimulated HUVEC secreted gelatinases, however, APV inhibited it. APV induced Akt phosphorylation as well as activation of heme oxygenase-1 (HO-1), eNOS, and nuclear factor E2-related factor 2 (Nrf2), which may protect vascular inflammation caused by HG. In conclusion, APV exerts anti-inflammatory effect via inhibition of ROS/NF-κB pathway by inducing HO-1 and eNOS expression mediated by Nrf2, thereby suggesting that Prunella vulgaris may be a possible therapeutic approach to the inhibition of diabetic vascular diseases.

Ursolic acid protects diabetic mice against monocyte dysfunction and accelerated atherosclerosis

AIMS

Accelerated atherosclerosis is a major diabetic complication initiated by the enhanced recruitment of monocytes into the vasculature. In this study, we examined the therapeutic potential of the phytonutrients ursolic acid (UA) and resveratrol (RES) in preventing monocyte recruitment and accelerated atherosclerosis.

METHODS AND RESULTS

Dietary supplementation with either RES or UA (0.2%) protected against accelerated atherosclerosis induced by streptozotocin in high-fat diet-fed LDL receptor-deficient mice. However, mice that received dietary UA for 11 weeks were significantly better protected and showed a 53% reduction in lesion formation while mice fed a RES-supplemented diet showed only a 31% reduction in lesion size. Importantly, UA was also significantly more effective in preventing the appearance of proinflammatory GR-1(high) monocytes induced by these diabetic conditions and reducing monocyte recruitment into MCP-1-loaded Matrigel plugs implanted into these diabetic mice. Oxidatively stressed THP-1 monocytes mimicked the behavior of blood monocytes in diabetic mice and showed enhanced responsiveness to monocyte chemoattractant protein-1 (MCP-1) without changing MCP-1 receptor (CCR2) surface expression. Pretreatment of THP-1 monocytes with RES or UA (0.3-10μM) for 15h resulted in the dose-dependent inhibition of H(2)O(2)-accelerated chemotaxis in response to MCP-1, but with an IC(50) of 0.4μM, UA was 2.7-fold more potent than RES.

CONCLUSION

Dietary UA is a potent inhibitor of monocyte dysfunction and accelerated atherosclerosis induced by diabetes. These studies identify ursolic acid as a potential therapeutic agent for the treatment of diabetic complications, including accelerated atherosclerosis, and provide a novel mechanism for the anti-atherogenic properties of ursolic acid.

Ursolic acid causes DNA-damage, p53-mediated, mitochondria- and caspase-dependent human endothelial cell apoptosis, and accelerates atherosclerotic plaque formation in vivo

OBJECTIVE

The plant derived triterpene ursolic acid (UA) has been intensively studied in the past; mainly as an anti-cancer compound and for its cardiovascular protective properties. Based on the controversy of reports suggesting anti-angiogenic and cytotoxic effects of UA on one side and cardiovascular and endothelial protective effects on the other side, we decided to assess UA effects on primary human endothelial cells in vitro and atherosclerotic plaque formation in vivo.

METHODS AND RESULTS

Our in vitro analyses clearly show that UA inhibits endothelial proliferation and is a potent inducer of endothelial cell death. UA causes DNA-damage, followed by the activation of a p53-, BAK-, and caspase-dependent cell-death pathway. Oral application of UA in APO E knockout mice potently stimulated atherosclerotic plaque formation in vivo, which was correlated with decreased serum levels of the athero-protective cytokine IL-5.

CONCLUSIONS

Due the potent endothelial cell death inducing activity of UA, a systemic application of UA in the treatment of cardiovascular diseases seems unfavourable. UA as an anti-angiogenesis, anti-cancer and - locally applied - cardiovascular drug may be helpful. The DNA damaging activity of UA may however constitute a serious problem.

Clinically useful anticancer, antitumor, and antiwrinkle agent, ursolic acid and related derivatives as medicinally important natural product

Medicinal plants are becoming an important research area for novel and bioactive molecules for drug discovery. Novel therapeutic strategies and agents are urgently needed to treat different incurable diseases. Many plant derived active compounds are in human clinical trials. Currently ursolic acid is in human clinical trial for treating cancer, tumor, and skin wrinkles. This review includes the clinical use of ursolic acid in various diseases including anticancer, antitumor, and antiwrinkle chemotherapies, and the isolation and purification of this tritepernoid from various plants to update current knowledge on the rapid analysis of ursolic acid by using analytical methods. In addition, the chemical modifications of ursolic acid to make more effective and water soluble derivatives, previous and current information regarding, its natural and semisynthetic analogs, focusing on its anticancer, cytotoxic, antitumor, antioxidant, anti-inflammatory, anti-HIV, acetyl cholinesterase, α-glucosidase, antimicrobial, and hepatoprotective activities, briefly discussion is attempted here for its research perspectives. This review article contains fourteen medicinally important ursolic acid derivatives and 351 references.

Physiological roles of NOX/NADPH oxidase, the superoxide-generating enzyme

NADPH oxidase is a superoxide (O₂^•−)-generating enzyme first identified in phagocytes, essential for their bactericidal activities. Later, in non-phagocytes, production of O₂^•− was also demonstrated in an NADPH-dependent manner. In the last decade, several non-phagocyte-type NADPH oxidases have been identified. The catalytic subunit of these oxidases, NOX, constitutes the NOX family. There are five homologs in the family, NOX1 to NOX5, and two related enzymes, DUOX1 and DUOX2. Transgenic or gene-disrupted mice of the NOX family have also been established. NOX/DUOX proteins possess distinct features in the dependency on other components for their enzymatic activities, tissue distributions, and physiological functions. This review summarized the characteristics of the NOX family proteins, especially focused on their functions clarified through studies using gene-modified mice.

Betulinic acid protects against cerebral ischemia-reperfusion injury in mice by reducing oxidative and nitrosative stress

Increased production of reactive oxygen and nitrogen species following cerebral ischemia-reperfusion is a major cause for neuronal injury. In hypercholesterolemic apolipoprotein E knockout (ApoE-KO) mice, 2h of middle cerebral artery (MCA) occlusion followed by 22h of reperfusion led to an enhanced expression of NADPH oxidase subunits (NOX2, NOX4 and p22phox) and isoforms of nitric oxide synthase (neuronal nNOS and inducible iNOS) in the ischemic hemisphere compared with the non-ischemic contralateral hemisphere. This was associated with elevated levels of 3-nitrotyrosine, an indicator of peroxynitrite-mediated oxidative protein modification. Pre-treatment with betulinic acid (50mg/kg/day for 7days via gavage) prior MCA occlusion prevented the ischemia reperfusion-induced upregulation of NOX2, nNOS and iNOS. In parallel, betulinic acid reduced the levels of 3-nitrotyrosine. In addition, treatment with betulinic acid enhanced the expression of endothelial eNOS in the non-ischemic hemispheres. Finally, betulinic acid reduced infarct volume and ameliorated the neurological deficit in this mouse stroke model. In conclusion, betulinic acid protects against cerebral ischemia-reperfusion injury in mice. This is likely to result from a reduction of oxidative stress (by downregulation of NOX2) and nitrosative stress (by reduction of nNOS and iNOS), and an enhancement of blood flow (by upregulation of eNOS).