Crocetin suppresses angiotensin II-induced vascular smooth-muscle cell proliferation through inhibition of ERK1/2 activation and cell-cycle progression

The Pharmacological Activities of Crocus sativus L.: A Review Based on the Mechanisms and Therapeutic Opportunities of its Phytoconstituents

Crocus species are mainly distributed in North Africa, Southern and Central Europe, and Western Asia, used in gardens and parks as ornamental plants, while Crocus sativus L. (saffron) is the only species that is cultivated for edible purpose. The use of saffron is very ancient; besides the use as a spice, saffron has long been known also for its medical and coloring qualities. Due to its distinctive flavor and color, it is used as a spice, which imparts food preservative activity owing to its antimicrobial and antioxidant activity. This updated review discusses the biological properties of Crocus sativus L. and its phytoconstituents, their pharmacological activities, signaling pathways, and molecular targets, therefore highlighting it as a potential herbal medicine. Clinical studies regarding its pharmacologic potential in clinical therapeutics and toxicity studies were also reviewed. For this updated review, a search was performed in the PubMed, Science, and Google Scholar databases using keywords related to Crocus sativus L. and the biological properties of its phytoconstituents. From this search, only the relevant works were selected. The phytochemistry of the most important bioactive compounds in Crocus sativus L. such as crocin, crocetin, picrocrocin, and safranal and also dozens of other compounds was studied and identified by various physicochemical methods. Isolated compounds and various extracts have proven their pharmacological efficacy at the molecular level and signaling pathways both in vitro and in vivo. In addition, toxicity studies and clinical trials were analyzed. The research results highlighted the various pharmacological potentials such as antimicrobial, antioxidant, cytotoxic, cardioprotective, neuroprotective, antidepressant, hypolipidemic, and antihyperglycemic properties and protector of retinal lesions. Due to its antioxidant and antimicrobial properties, saffron has proven effective as a natural food preservative. Starting from the traditional uses for the treatment of several diseases, the bioactive compounds of Crocus sativus L. have proven their effectiveness in modern pharmacological research. However, pharmacological studies are needed in the future to identify new mechanisms of action, pharmacokinetic studies, new pharmaceutical formulations for target transport, and possible interaction with allopathic drugs.

The dopamine receptor D4 regulates the proliferation of pulmonary arteries smooth muscle in broilers by downregulating AT1R

The major cause of pulmonary vascular remodeling in broilers is abnormal proliferation of vascular smooth muscle cells (VSMCs), and one of the main causes of pulmonary hypertension syndrome (PHS) in broilers is pulmonary artery vascular remodeling. Forty Arbor Acres (AA) broilers were randomly divided into four groups (n = 10): a control group (deionized water, 0 g/L NaCl), a freshwater group (FW, deionized water + 1 g/L NaCl), highly salinized freshwater group 1 (H-SFW-1, deionized water + 2.5 g/L NaCl) and highly salinized freshwater group 2 (H-SFW-2, deionized water + 5 g/L NaCl). The results of in vivo experiments showed that vascular smooth muscle of the broilers could be significantly proliferated by intake of high-salinity fresh water (H-SFW-1 & H-SFW-2), which significantly increased the content of angiotensin II (Ang II) and the expression of angiotensin II type 1 (AT1) receptor protein. Meanwhile, it significantly decreased the expression of dopamine receptor D4 (DRD4) protein. The results of in vitro experiments showed that exogenous Ang II induced the proliferation of primary VSMCs in broilers, which could be significantly inhibited by DRD4 agonists (D4A, HY-101384A) and enhanced by DRD4 inhibitors (D4I, HY-B0965). In addition, the results of immunoblotting and fluorescence quantitative PCR showed that AT1 receptors could be negatively regulated by DRD4 in VSMCs of broilers, either at the transcriptional or translational level. At the same time, the expression of AT1 receptor could be increased by DRD4 inhibition by D4I and decreased by DRD4 activation by D4A. The negative regulatory effect of DRD4 on AT1 receptor occurred in a dose-dependent manner. These results indicate that long-term intake of highly salinized fresh water can cause PHS in broilers, accompanied by varying degrees of proliferation of pulmonary artery smooth muscle. This mechanism may involve response of its receptor being induced by increased Ang II, while DRD4 can negatively regulate it.

Crocetin Prevents RPE Cells from Oxidative Stress through Protection of Cellular Metabolic Function and Activation of ERK1/2

Age-related macular degeneration (AMD) is a leading cause for visual impairment in aging populations with limited established therapeutic interventions available. Oxidative stress plays an essential role in the pathogenesis of AMD, damaging the retinal pigment epithelium (RPE), which is essential for the function and maintenance of the light-sensing photoreceptors. This study aimed to evaluate the effects of crocetin, one of the main components of Saffron, on an in vitro RPE model of tert-butyl hydroperoxide (TBHP) induced oxidative stress using ARPE19 cells. The effects of crocetin were assessed using lactate de-hydrogenase (LDH) and ATP assays, as well as immunocytochemistry for cell morphology, junctional integrity, and nuclear morphology. The mechanism of crocetin action was determined via assessment of energy production pathways, including mitochondrial respiration and glycolysis in real-time as well as investigation of extracellular signal-regulated kinase 1/2 (ERK1/2) activation and distribution. Our results show that crocetin pre-treatment protects ARPE19 cells from TBHP-induced LDH release, intracellular ATP depletion, nuclear condensation, and disturbance of junctional integrity and cytoskeleton. The protective effect of crocetin is mediated via the preservation of energy production pathways and activation of ERK1/2 in the first minutes of TBHP exposure to potentiate survival pathways. The combined data suggest that a natural antioxidant, such as crocetin, represents a promising candidate to prevent oxidative stress in RPE cells and might halt or delay disease progression in AMD.

Beneficial Cardiovascular Effects of Hydroalcoholic Extract from Crocus Sativus in Hypertension Induced by Angiotensin II

Objectives

Angiotensin II (AngII), a major product of renin-angiotensin system (RAS) has important role in induction of hypertension and antihypertensive effect of several medicinal plant was mediated by effect on this agent. Therefore, this study examined the possible effect of hydroalcoholic extract of Crocus sativus (C. sativus) on hypertension induced by AngII.

Methods

Six groups (n = 6) of rats were used as follow: 1) Control, 2) AngII (300 ng/kg), 3) Losartan (Los, 10 mg/kg) + AngII and 4-6) C. sativus extract (10, 20 & 40 mg/kg,) + AngII. The femoral artery and vein were cannulated for recording cardiovascular parameters and drugs administration, respectively. All drugs were injected intravenously (i.v). Los and all doses of C. sativus injected 10 min before AngII. Systolic blood pressure (SBP), mean arterial blood pressure (MAP) and heart rate (HR) were recorded throughout the experiment and those peak changes (Δ) were calculated and compared to control and AngII.

Results

AngII significantly increased ΔMAP, ΔSBP and ΔHR than control (P < 0. 01 to P < 0.001) and these increments were significantly attenuated by Los. All doses of C. sativus significantly reduced peak ΔMAP, ΔSBP, and ΔHR than AngII group (P < 0. 05 to P < 0.001). In addition, peak ΔMAP, ΔSBP in doses 10 and 20 were significant than Los + AngII group (P < 0.05 to P< 0.01) but in dose 40 only MAP was significant (P < 0.05). Peak ΔHR in all doses of C sativus was not significant than Los+ AngII.

Conclusion

Regarding the improving effect of the C. sativus extract on AngII induced hypertension, it seems that this ameliorating effect partly mediated through inhibition of RAS.

The Protective Role of Crocus Sativus L. (Saffron) Against Ischemia- Reperfusion Injury, Hyperlipidemia and Atherosclerosis: Nature Opposing Cardiovascular Diseases

Background:

Reactive oxygen species and reactive nitrogen species, which are collective-ly called reactive oxygen-nitrogen species, are inevitable by-products of cellular metabolic redox reac-tions, such as oxidative phosphorylation in the mitochondrial respiratory chain, phagocytosis, reac-tions of biotransformation of exogenous and endogenous substrate in endoplasmic reticulum, eico-sanoid synthesis, and redox reactions in the presence of metal with variable valence. Among medici-nal plants, there is growing interest in Crocus Sativus L. It is a perennial, stemless herb, belonging to Iridaceae family, cultivated in various countries such as Greece, Italy, Spain, Israel, Morocco, Tur-key, Iran, India, China, Egypt and Mexico.

Objective:

The present study aims to address the anti-toxicant role of Crocus Sativus L. in the case of cardiovascular disease and its role towards the cardioprotective role of Crocus Sativus L.

Materials and

Methods:

An electronic literature search was conducted by the two authors from 1993 to August 2017. Original articles and systematic reviews (with or without meta-analysis), as well as case reports were selected. Titles and abstracts of papers were screened by a third reviewer to deter-mine whether they met the eligibility criteria, and full texts of the selected articles were retrieved.

Results:

Our review has indicated that scientific literature confirms the role of Crocus Sativus L. as a cardiovascular-protective agent. The literature review showed that Saffron is a potent cardiovascular-protective agent with a plethora of applications ranging from ischemia-reperfusion injury, diabetes and hypertension to hyperlipidemia.

Conclusion:

Literature findings represented in current review herald promising results for using Crocus Sativus L. and/or its active constituents as a cardiovascular-protective agent and in particular, Crocus Sativus L. manifests beneficial results against ischemia-reperfusion injury, hypertension, hy-perlipidemia and diabetes

Saffron; An updated review on biological properties with special focus on cardiovascular effects

OBJECTIVE

Saffron as a natural product has long been used to impede and treat different disorders including cardiovascular disease (CVDs). Stigma is the most principal part of saffron. Various compounds such as carotenoids and flavonoids are the essential components of saffron stigma. The health benefits of saffron have been shown in previous studies; however, there is a lack of comprehensive data on the mechanistic aspects of its cardiovascular-health properties. This current comprehensive review focuses on the medicinal applications of saffron, and then the new findings regarding its cardiovascular-health effects and various cellular and molecular mechanisms of action will be debated.

METHODS

The literature search of MEDLINE, Embase, PubMed, Google Scholar and Cochrane Library was performed for all comparative studies since 2000-2018 with the limitations of the English language.

RESULTS

The results provided new evidence about antioxidant, anti-inflammatory, anti- atherogenic, anti- apoptotic, anti- hypertensive, and hypolipidemic effects of saffron. Pharmacological effects of saffron are due to a number of ingredients contained within this spice, including safranal, crocetin and crocins.

CONCLUSIONS

Our study concludes that saffron with wide range of usefulness in medicine may be the potent candidate in the process of new drug production for the treatment of CVDs.

A comprehensive review of the pharmacological potential of Crocus sativus and its bioactive apocarotenoids

Crocus sativus is an herbaceous plant that belongs to family Iridaceae. It is commonly known as saffron and has been used for medicinal purposes since many centuries in India and other parts of the world. Saffron of commercial importance comprises of dried stigmas of the plant and is rich in flavonoids, vitamins, and carotenoids. Carotenoids represent the main components of saffron and their cleavage results in the formation of apocarotenoids such as crocin, picrocrocin, and safranal. Studies conducted during the past two decades have revealed the immense therapeutic potential of saffron. Most of the therapeutic properties are due to the presence of unique apocarotenoids having strong free radical scavenging activity. The mode of action of these apocarotenoids could be: modulatory effects on detoxifying enzymes involved in combating oxidative stress, decreasing telomerase activity, increased the proapoptotic effect, inhibition of DNA, RNA and protein synthesis, and by a strong binding capacity of crocetin with tRNA. The present review focuses on the therapeutic role of saffron and its bio oxidative cleavage products and also highlights the possible molecular mechanism of action. The findings reported in this review describes the wide range of applications of saffron and attributes its free radical scavenging nature the main property which makes this spice a potent chemotherapeutic agent for the treatment of various diseases.

Effect of crocetin on vascular smooth muscle cells migration induced by advanced glycosylation end products

Crocetin is a major active constituent of Gardenia jasminoides J. Ellis, and can aid in the prevention of cardiovascular disease. The effect and possible mechanism of crocetin on the migration of vascular smooth muscle cells (VSMCs) induced by advanced glycosylation end products (AGEs) were investigated. VSMCs were pre-incubated with or without crocetin and exposed to AGEs subsequently. The invasion of the cells was investigated using a 24-well Cell Invasion Chamber. The anti-proliferative activity of crocetin was evaluated by MTT assay and VSMCs cell-cycle distribution was examined by flow cytometry. Cytokine TNF-α and IL-6 secreted by VSMCs and the amount of matrix metalloproteinase MMP-2 and MMP-9 in the culture supernatant were detected by ELISA. The expression level of RAGE (AGEs receptor), in cells was analyzed by western blot. The results demonstrated that AGEs increased about two-fold migration of VSMCs compared with control (OD=0.778±0.191 vs OD=0.413±0.214, P<0.01), and the proliferation increased by about 20% (OD=0.335±0.043 vs OD=0.281±0.037, P<0.01). Pre-treatment with crocetin (1.0μM) or RAGE antibody (10μg/ml) could inhibit the AGEs triggered migration of VSMCs obviously. Furthermore, both crocetin and RAGE antibody inhibited the increase of RAGE protein in VSMCs stimulated by AGEs. The levels of TNF-α and IL-6 decreased in the crocetin (1.0μM) pre-treated group compared to the AGEs (without pre-treated) group (37.60±3.08pg/ml vs 46.59±1.92pg/ml, 32.11±4.69pg/ml vs 49.99±8.84pg/ml, respectively). Crocetin (1.0μM) also reduced the value of MMP-2 and MMP-9 compared with the AGEs group (2.81±0.35ng/ml vs 6.40±0.85ng/ml, 2.69±0.25ng/ml vs 4.32±0.57ng/ml, respectively). In summary, crocetin inhibits the migration of VSMCs induced by AGEs through RAGE-dependent signaling pathway. And it is meaningful to diabetic vascular complications.

Inhibitory effects of 2,3,4',5-tetrahydroxystilbene-2-O-β-D-glucoside on angiotensin II-induced proliferation of vascular smooth muscle cells

OBJECTIVE

To investigate the effect of 2,3,4',5-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), an active component extracted from the root of Polygonum multiflorum, on angiotensin II (Ang II)-induced proliferation of cultured rat vascular smooth muscle cells (VSMCs) and to identify the potential mechanism.

METHODS

Cell proliferation and cell cycle were determined by cell counting, 5-bromo-2'-deoxyuridine incorporation assay, proliferating cell nuclear antigen protein expression and flow cytometry. Levels of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2), mitogenic extracellular kinase 1/2 (MEK1/2) and Src in VSMCs were measured by Western blot. The expression of c-fos, c-jun and c-myc mRNA were measured by reverse transcription polymerase chain reaction (RT-PCR). Intracellular reactive oxygen species (ROS) was measured by fluorescence assay.

RESULTS

TSG significantly inhibited Ang II-induced VSMCs proliferation and arrested cells in the G /S checkpoint (P<0.05 or P<0.01). TSG decreased the levels of phosphorylated ERK1/2, MEK1/2 and Src in VSMCs (P<0.05 or P<0.01). TSG also suppressed c-fos, c-jun and c-myc mRNA expression <0.05 or P<0.01). In addition, the intracellular ROS was reduced by TSG (P<0.01).

CONCLUSIONS

TSG inhibited Ang II-induced VSMCs proliferation. Its antiproliferative effect might be associated with down-regulation of intracellular ROS, followed by the suppression of the Src-MEK1/2-ERK1/2 signal pathway, and hence, blocking cell cycle progression.

Anticancer Effect and Molecular Targets of Saffron Carotenoids

Saffron carotenoids, crocin and crocetin, have shown anticancer activity in various animal models of cancer and against different cancerous cell lines. The radical scavenging property and activation of antioxidant defense system are two well-known characteristics of these compounds. However, the results of the studies indicated other mechanisms could also be involved in this function. Insights into various molecular mechanisms of action for crocin and crocetin have been obtained in recent years. The results indicated that despite the structural similarity of crocin and crocetin, their anticancer effects may exert through different mechanisms. Particular interest concerns the ROS-dependent signaling pathways of crocetin. Saffron compounds are safe and may provide inexpensive therapy for treating cancer. They also have protective potential in targeting other disorders including diabetes, Alzheimer's and cardiovascular disease, cognitive deficits, ischemia-induced retinal damage, and many other diseases.

The effect of endothelial progenitor cells on angiotensin II-induced proliferation of cultured rat vascular smooth muscle cells

Previous studies have demonstrated that endothelial progenitor cells (EPCs) could delay the progress of vascular remodeling in blood vessel-proliferating diseases. The proliferation of vascular smooth muscle cells (VSMCs) is a pivotal factor in cardiovascular diseases. In this study, we investigated whether EPCs could inhibit the Angiotensin II (Ang II)-induced proliferation of VSMCs. The effect of early EPC-conditioned medium (E-EPC-CM), late EPCs-CM (L-EPC-CM), and HUVEC-CM on Ang II-induced proliferation of VSMCs was assessed by BrdU incorporation, total protein content, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, and flow cytometry. Reverse transcriptase-polymerase chain reaction and Western blot were performed to analyze the effect of different CMs on Ang II-induced phosphorylations of ERK, JNK, p38, and NF-κB subunit p65 and the expressions of c-myc and c-fos. E-EPC-CM, L-EPC-CM, and HUVEC-CM significantly inhibited the Ang II-induced DNA synthesis, total protein expression, cell survival, and cell cycle progress of VSMCs. Furthermore, E-EPC-CM significantly inhibited the Ang II-induced phosphorylation of ERK, JNK, p38, and p65 (nuclear translocation of p65) and the expressions of c-myc and c-fos. Taken together, these data suggested that EPCs may delay the progress of vascular remodeling in blood vessel-proliferating diseases by inhibiting Ang II-induced proliferation of VSMCs through inactivating MAPKs and NF-κB signaling pathways and by reducing the expressions of c-myc and c-fos.

The role of crocetin in protection following cerebral contusion and in the enhancement of angiogenesis in rats

The protective role of crocetin following cerebral contusion and its effects on the enhancement of angiogenesis in rats was investigated. A total of 60 Sprague-Dawley rats were divided into three groups (n = 20 each): crocetin therapy group (cerebral contusion treated with crocetin), cerebral trauma control group (without treatment), sham operation control group. The effect of crocetin was examined by modified Neurological Severity Scores (mNSS), electron microscopy, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) procedure, western blotting analysis of Bcl-2 protein expression, microvessel count (MVC), endothelial cell culture and immunocyto-chemistry. The mNSS results indicated that neurological function of therapy group was significantly recovered seven days and fifteen days after the trauma. The TUNEL staining and electron microscopy revealed that crocetin treatment led to an inhibition of neuronal apoptosis 72 h following treatment; this finding was confirmed by western blot analysis of B cell lymphoma/leukemia-2 (Bcl-2) protein expression. Expression levels of vascular endothelial growth factor receptor-2 (VEGFR-2) and serum response factor (SRF) were higher in the crocetin therapy group in comparison to the two other experimental groups. Our results demonstrate that the protective effects of crocetin upon brain injury may be related to its ability to inhibit apoptosis at early stages of the injury and its ability to promote angiogenesis at the sub-acute stage.

A role for the cell cycle phosphatase Cdc25a in vitamin D-dependent inhibition of adult rat vascular smooth muscle cell proliferation

We have explored the mechanism(s) underlying 1,25 dihydroxyvitamin D's (1,25(OH)(2)D) suppression of agonist-induced vascular smooth muscle cell (VSMC) proliferation. Quiescent cultured adult rat VSMC were treated with 1,25(OH)(2)D for 48h and endothelin (ET) or angiotensin II (AII) for the final 24h. We show that VSMC responded to 1,25(OH)(2)D or its less hypercalcemic analogue RO 25-6760 with ∼70% inhibition of ET-dependent (3)H-thymidine incorporation. The inhibition was linked to a comparable reduction in ET-stimulated cyclin-dependent kinase 2 (Cdk2) activity and suppression of an ET-induced Cdk2 activator, cell division cycle 25 homolog A (Cdc25A). Both 1,25(OH)(2)D and RO 25-6760 completely inhibited the ET-dependent increase in Cdc25A mRNA and protein levels, phosphatase and promoter activities. 1,25(OH)(2)D also suppressed AII-induced DNA synthesis, Cdk2 activity and Cdc25A gene transcription. Inhibition of Cdc25A gene expression using a siRNA approach resulted in significant inhibition of ET or AII-dependent Cdk2 activity and (3)H-thymidine incorporation. The Cdc25A siRNA-mediated inhibition of ET or AII-induced Cdk2 activity and DNA synthesis was not additive with that produced by 1,25(OH)(2)D treatment. These data demonstrate that 1,25(OH)(2)D inhibits VSMC proliferation through a Cdc25A-dependent mechanism and suggest that this hormone may prove useful in the management of disorders characterized by aberrant proliferation of VSMC in the vascular wall.