Synthetic Flavonoids as Novel Modulators of Platelet Function and Thrombosis

Naringin binds to protein disulfide isomerase to inhibit its activity and modulate the blood coagulation rates: Implications in controlling thrombosis

Currently used antithrombotic drugs are beset with several drawbacks which necessitates the need for new and cheaper alternatives. Protein disulfide isomerase (PDI) is secreted in the blood plasma in cellular stress conditions and initiates the thrombus formation. A screening of library of natural compounds revealed that naringin had a high binding affinity for the PDI (-8.2 kcal/mol). Recombinant PDI was purified using the affinity chromatography. Incubation of purified PDI (3 μM) with naringin (0-100 μM, pH 7.4, 25 °C) partially modulated its conformation. Consequently, the fluorescence emission spectra of the PDI binding to naringin were assessed using the Stern-Volmer equation, which indicated an association constant of 2.78 × 104 M-1 suggesting an appreciable affinity for the naringin, with a unique binding site. An insulin turbidity assay showed that PDI activity is decreased in the presence of naringin indicating inhibition. Molecular dynamic simulation studies showed the changes in the PDI structure on binding to the naringin. Incubation of naringin (80 μM) in fresh human plasma along with exogenous PDI (175 nM) showed a significant delay in the intrinsic and extrinsic coagulation pathways. We show that naringin is able to modulate the PDI conformation and activity resulting in altered blood coagulation rates.

Daidzein from Dietary Supplement to a Drug Candidate: An Evaluation of Potential

Daidzein (DDZ) is a well-known nutraceutical supplement belonging to the class of isoflavones. It is isolated from various sources such as alfalfa, soybean, and red clover. It demonstrates a broad array of pharmacological/beneficial properties such as cardiovascular exercise, cholesterol reduction, and anticancer, antifibrotic, and antidiabetic effects, which make it effective in treating a wide range of diseases. Its structure and operation are the same as those of human estrogens, which are important in preventing osteoporosis, cancer, and postmenopausal diseases. It is thus a promising candidate for development as a phytopharmaceutical. Addressing safety, efficacy, and physicochemical properties are the primary prerequisites. DDZ is already ingested every day in varying amounts, so there should not be a significant safety risk; however, each indication requires a different dose to be determined. Some clinical trials are already being conducted globally to confirm its safety, efficacy, and therapeutic potential. Furthermore, as a result of its therapeutic influence on health, in order to establish intellectual property, patents are utilized. In light of the vast potential of eugenol, this review presents a detailed data collection on DDZ to substantiate the claim to develop it in the therapeutic category.

Effects of Extraction Methods on Phenolic Content, Antioxidant and Antiplatelet Activities of Tomato Pomace Extracts

Aqueous and ethanolic extracts of tomato pomace were examined with the aim of optimizing the extraction process of compounds with cardioprotective activity. Once the results of the ORAC response variables, total polyphenols, °Brix, and antiplatelet activity of the extracts were obtained, a multivariate statistical analysis was performed using the Statgraphics Centurion XIX software. This analysis showed that the most relevant positive effects in the inhibition of platelet aggregation were 83 ± 2% when using the agonist TRAP-6, when the working conditions were the type of tomato pomace conditioning (drum-drying process at 115 °C), phase ratio (1/8), type of solvent (ethanol 20%), and type of extraction (ultrasound-assisted solid-liquid extraction). The extracts with the best results were microencapsulated and characterized by HPLC. The presence of chlorogenic acid (0.729 mg/mg of dry sample) was found, a compound that has a potential cardioprotective effect documented in various studies, in addition to rutin (2.747 mg/mg of dry sample) and quercetin (0.255 mg/mg of dry sample). These results show that the extraction efficiency of compounds with cardioprotective activity depends largely on the polarity of the solvent, thus playing an important role in the antioxidant capacity of the extracts of tomato pomace.

Development of a Novel Apigenin Dosage form as a Substitute for the Modern Triple Antithrombotic Regimen

The simultaneous administration of three antiplatelet agents has been proposed as an efficient strategy for the secondary prevention of atherothrombotic events and is included in the European guidelines. However, this strategy presented an increased risk of bleeding; therefore, the identification of new antiplatelet agents, with improved efficacy and diminished side effects, is of great importance. In silico studies, UPLC/MS Q-TOF plasma stability, in vitro platelet aggregation experiments, and pharmacokinetic studies were exploited. In the present study, it has been predicted that the flavonoid apigenin could target different platelet activation pathways, including P2Y12, protease-activated receptor-1 (PAR-1), and cyclooxygenase 1 (COX-1). To enhance apigenin's potency, hybridization with docosahexaenoic acid (DHA) was performed, as fatty acids have illustrated potent efficacy against cardiovascular diseases (CVDs). The new molecular hybrid, termed 4'-DHA-apigenin, demonstrated enhanced inhibitory activity against platelet aggregation induced by thrombin receptor activator peptide-6 (TRAP-6), adenosine diphosphate (ADP), and arachidonic acid (AA), with respect to the parent apigenin. The 4'-DHA-apigenin hybrid illustrated an almost 2-fold enhanced inhibitory activity, with respect to apigenin, and an almost 3-fold enhanced inhibitory activity, with respect to DHA, for the ADP-induced platelet aggregation. Additionally, the hybrid presented a more than 12-fold enhanced inhibitory activity with respect to DHA for the TRAP-6 induced platelet aggregation. Furthermore, a 2-fold enhanced inhibitory activity was recorded for the 4'-DHA-apigenin hybrid for the AA-induced platelet aggregation with respect to apigenin. To surmount the reduced LC-MS based plasma stability, a novel dosage form in olive oil has been developed. The 4'-DHA-apigenin olive oil-based formulation presented an enhanced antiplatelet inhibitory effect in three activation pathways. To further explore the pharmacokinetic profile of 4'-DHA-apigenin in olive oil formulations, a UPLC/MS Q-TOF protocol has been established to quantify the serum levels of apigenin after oral administration to C57BL/6J wild type mice. The olive oil-based formulation of 4'-DHA-apigenin demonstrated an increase in apigenin bioavailability of 262 %. This study may offer a new therapeutic strategy tailored to improve the treatment of CVDs.

A Comprehensive Literature Review on Cardioprotective Effects of Bioactive Compounds Present in Fruits of Aristotelia chilensis Stuntz (Maqui)

Some fruits and vegetables, rich in bioactive compounds such as polyphenols, flavonoids, and anthocyanins, may inhibit platelet activation pathways and therefore reduce the risk of suffering from CVD when consumed regularly. Aristotelia chilensis Stuntz (Maqui) is a shrub or tree native to Chile with outstanding antioxidant activity, associated with its high content in anthocyanins, polyphenols, and flavonoids. Previous studies reveal different pharmacological properties for this berry, but its cardioprotective potential has been little studied. Despite having an abundant composition, and being rich in bioactive products with an antiplatelet role, there are few studies linking this berry with antiplatelet activity. This review summarizes and discusses relevant information on the cardioprotective potential of Maqui, based on its composition of bioactive compounds, mainly as a nutraceutical antiplatelet agent. Articles published between 2000 and 2022 in the following bibliographic databases were selected: PubMed, ScienceDirect, and Google Scholar. Our search revealed that Maqui is a promising cardiovascular target since extracts from this berry have direct effects on the reduction in cardiovascular risk factors (glucose index, obesity, diabetes, among others). Although studies on antiplatelet activity in this fruit are recent, its rich chemical composition clearly shows that the presence of chemical compounds (anthocyanins, flavonoids, phenolic acids, among others) with high antiplatelet potential can provide this berry with antiplatelet properties. These bioactive compounds have antiplatelet effects with multiple targets in the platelet, particularly, they have been related to the inhibition of thromboxane, thrombin, ADP, and GPVI receptors, or through the pathways by which these receptors stimulate platelet aggregation. Detailed studies are needed to clarify this gap in the literature, as well as to specifically evaluate the mechanism of action of Maqui extracts, due to the presence of phenolic compounds.

Antithrombotic and antiplatelet effects of plant-derived compounds: a great utility potential for primary, secondary, and tertiary care in the framework of 3P medicine

Thromboembolism is the third leading vascular disease, with a high annual incidence of 1 to 2 cases per 1000 individuals within the general population. The broader term venous thromboembolism generally refers to deep vein thrombosis, pulmonary embolism, and/or a combination of both. Therefore, thromboembolism can affect both – the central and peripheral veins. Arterial thromboembolism causes systemic ischemia by disturbing blood flow and oxygen supply to organs, tissues, and cells causing, therefore, apoptosis and/or necrosis in the affected tissues. Currently applied antithrombotic drugs used, e.g. to protect affected individuals against ischemic stroke, demonstrate significant limitations. For example, platelet inhibitors possess only moderate efficacy. On the other hand, thrombolytics and anticoagulants significantly increase hemorrhage. Contextually, new approaches are extensively under consideration to develop next-generation antithrombotics with improved efficacy and more personalized and targeted application. To this end, phytochemicals show potent antithrombotic efficacy demonstrated in numerous in vitro, ex vivo, and in vivo models as well as in clinical evaluations conducted on healthy individuals and persons at high risk of thrombotic events, such as pregnant women (primary care), cancer, and COVID-19-affected patients (secondary and tertiary care). Here, we hypothesized that specific antithrombotic and antiplatelet effects of plant-derived compounds might be of great clinical utility in primary, secondary, and tertiary care. To increase the efficacy, precise patient stratification based on predictive diagnostics is essential for targeted protection and treatments tailored to the person in the framework of 3P medicine. Contextually, this paper aims at critical review toward the involvement of specific classes of phytochemicals in antiplatelet and anticoagulation adapted to clinical needs. The paper exemplifies selected plant-derived drugs, plant extracts, and whole plant foods/herbs demonstrating their specific antithrombotic, antiplatelet, and fibrinolytic activities relevant for primary, secondary, and tertiary care. One of the examples considered is antithrombotic and antiplatelet protection specifically relevant for COVID-19-affected patient groups.

Untargeted Plasma Metabolomics and Gut Microbiome Profiling Provide Novel Insights into the Regulation of Platelet Reactivity in Healthy Individuals

BACKGROUND

Considerable variation exists in platelet reactivity to stimulation among healthy individuals. Various metabolites and metabolic pathways influence platelet reactivity, but a comprehensive overview of these associations is missing. The gut microbiome has a strong influence on the plasma metabolome. Here, we investigated the association of platelet reactivity with results of untargeted plasma metabolomics and gut microbiome profiling.

METHODS

We used data from a cohort of 534 healthy adult Dutch volunteers (the 500 Functional Genomics study). Platelet activation and reactivity were measured by the expression of the alpha-granule protein P-selectin and the binding of fibrinogen to the activated integrin αIIbβ3, both in unstimulated blood and after ex vivo stimulation with platelet agonists. Plasma metabolome was measured using an untargeted metabolic profiling approach by quadrupole time-of-flight mass spectrometry. Gut microbiome data were measured by shotgun metagenomic sequencing from stool samples.

RESULTS

Untargeted metabolomics yielded 1,979 metabolites, of which 422 were identified to play a role in a human metabolic pathway. Overall, 92/422 (21.8%) metabolites were significantly associated with at least one readout of platelet reactivity. The majority of associations involved lipids, especially members of eicosanoids, including prostaglandins and leukotrienes. Dietary-derived polyphenols were also found to inhibit platelet reactivity. Validation of metabolic pathways with functional microbial profiles revealed two overlapping metabolic pathways ("alanine, aspartate, and glutamate metabolism" and "arginine biosynthesis") that were associated with platelet reactivity.

CONCLUSION

This comprehensive overview is an resource for understanding the regulation of platelet reactivity by the plasma metabolome and the possible contribution of the gut microbiota.

Protection against Neurological Symptoms by Consuming Corn Silk Water Extract in Artery-Occluded Gerbils with Reducing Oxidative Stress, Inflammation, and Post-Stroke Hyperglycemia through the Gut-Brain Axis

Corn silk (Stigma maydis), rich in flavonoids, is traditionally used to treat edema, depression, and hyperglycemia and may alleviate ischemic stroke symptoms in Chinese medicine. This study examined whether corn silk water extract (CSW) could alleviate ischemic stroke symptoms and post-stroke hyperglycemia in Mongolian gerbils with transient cerebral ischemia and reperfusion (I/R). After being given 0.05% (I/R-LCSW) and 0.2% (I/R-HCSW), 0.02% aspirin (I/R-aspirin), and cellulose (I/R-control) in their 40 energy% fat diets for three weeks, the gerbils underwent an artery occlusion for eight minutes and reperfusion. They took the assigned diet for an additional three weeks. Sham-operated gerbils without artery occlusion had the same diet as Sham-control. CSW intake reduced neuronal cell death in gerbils with I/R and dose-dependently improved the neurological symptoms, including drooped eyes, crouched posture, flexor reflex, and walking patterns. CSW intake also alleviated the short-term memory and spontaneous alteration and grip strength compared to the I/R-control group. The protection against ischemic stroke symptoms was associated with the reduced tumor necrosis factor-α, interleukin-1β, superoxide, and lipid peroxide levels, promoting superoxide dismutase activity in the hippocampus in the CSW groups, compared to the I/R-control. The blood flow measured by Doppler was improved with CSW compared to the I/R-control. Furthermore, CSW intake prevented the post-stroke hyperglycemia related to decreasing pancreatic β-cell mass as much as the Sham-control, and it was related to protection against β-cell apoptosis, restoring the β-cell mass similar to the Sham-control. CSW intake elevated the relative abundance of Lactobacillus, Bifidobacterium, Allobaculum, and Akkermansia compared to the I/R-control. Picrust2 analysis showed that CSW increased the propionate and butyrate metabolism and the starch and glucose metabolism but reduced lipopolysaccharide biosynthesis compared to the I/R-control. In conclusion, CSW intake protects against neuronal cell death and post-hyperglycemia by reducing oxidative stress and inflammation and increasing blood flow and the β-cell mass. The alleviation was associated with promoting the gut-brain axis by changing the gut microbiome community.

Understanding the Functional Activity of Polyphenols Using Omics-Based Approaches

Plant polyphenols are the main category of natural active substances, and are distributed widely in vegetables, fruits, and plant-based processed foods. Polyphenols have a beneficial performance in preventing diseases and maintaining body health. However, its action mechanism has not been well understood. Foodomics is a novel method to sequence and widely used in nutrition, combining genomics, proteomics, transcriptomics, microbiome, and metabolomics. Based on multi-omics technologies, foodomics provides abundant data to study functional activities of polyphenols. In this paper, physiological functions of various polyphenols based on foodomics and microbiome was discussed, especially the anti-inflammatory and anti-tumor activities and gut microbe regulation. In conclusion, omics (including microbiomics) is a useful approach to explore the bioactive activities of polyphenols in the nutrition and health of human and animals.

Immobilized Crosslinked Pectinase Preparation on Porous ZSM-5 Zeolites as Reusable Biocatalysts for Ultra-Efficient Hydrolysis of β-Glycosidic Bonds

In this study, we immobilized pectinase preparation on porous zeolite ZSM-5 as an enzyme carrier. We realized this immobilized enzyme catalyst, pectinase preparation@ZSM-5, via a simple combined strategy involving the van der Waals adsorption of pectinase preparation followed by crosslinking of the adsorbed pectinase preparation with glutaraldehyde over ZSM-5. Conformal pectinase preparation coverage of various ZSM-5 supports was achieved for the as-prepared pectinase preparation@ZSM-5. The porous pectinase preparation@ZSM-5 catalyst exhibited ultra-efficient biocatalytic activity for hydrolyzing the β-glycosidic bonds in the model substrate 4-nitrophenyl β-D-glucopyranoside, with a broad operating temperature range, high thermal stability, and excellent reusability. The relative activity of pectinase preparation@ZSM-5 at a high temperature (70 °C) was nine times higher than that of free pectinase preparation. Using thermal inactivation kinetic analysis based on the Arrhenius law, pectinase preparation@ZSM-5 showed higher activation energy for denaturation (315 kJ mol⁻¹) and a longer half-life (62 min⁻¹) than free pectinase preparation. Moreover, a Michaelis–Menten enzyme kinetic analysis indicated a higher maximal reaction velocity for pectinase preparation@ZSM-5 (0.22 µmol mg⁻¹ min⁻¹). This enhanced reactivity was attributed to the microstructure of the immobilized pectinase preparation@ZSM-5, which offered a heterogeneous reaction system that decreased the substrate–pectinase preparation binding affinity and modulated the kinetic characteristics of the enzyme. Additionally, pectinase preparation@ZSM-5 showed the best ethanol tolerance among all the reported pectinase preparation-immobilized catalysts, and an activity 247% higher than that of free pectinase preparation at a 10% (v/v) ethanol concentration was measured. Furthermore, pectinase preparation@ZSM-5 exhibited potential for practical engineering applications, promoting the hydrolysis of β-glycosidic bonds in baicalin to convert it into baicalein. This was achieved with a 98% conversion rate, i.e., 320% higher than that of the free enzyme.

Rutin present in Alibertia edulis extract acts on human platelet aggregation through inhibition of cyclooxygenase/thromboxane

Alibertia edulis leaf extract is commonly used in folk medicine, with rutin caffeic and vanillic acids being its major compounds. The Alibertia edulis leaf extract was investigated for its pharmacological effects via platelet aggregation, calcium mobilization, cyclic nucleotides levels, vasodilator-stimulated phosphoprotein Ser157 and Ser239 and protein kinase Cβ₂ phosphorylation, thromboxane B₂, cyclooxygenases 1 and 2, docking and molecular dynamics. Alibertia edulis leaf extract significantly inhibited (100-1000 μg mL^-1) platelet aggregation induced by different agonists. Arachidonic acid increased levels of calcium and thromboxane B₂, phosphorylation of vasodilator-stimulated phosphoprotein Ser157 and Ser239, and protein kinase Cβ, which were significantly reduced by Alibertia edulis leaf extract, rutin, and caffeic acid as well mixtures of rutin/caffeic acid. Cyclooxygenase 1 activity was inhibited for Alibertia edulis leaf extract, rutin and caffeic acid. These inhibitions were firsrtly explored by specific stabilization of rutin and caffeic acid compared to diclofenac at the catalytic site from docking score and free-energy dissociation profiles. Then, simulations detailed the rutin interactions close to the heme group and Tyr385, responsible for catalyzing the conversion of arachidonic acid to its products. Our results reveal the antiplatelet aggregation properties of Alibertia edulis leaf extract, rutin and caffeic acid providing pharmacological information about its origin from cyclooxygenase 1 inhibition and its downstream pathway.

Src-family Protein Tyrosine Kinases: A promising target for treating Cardiovascular Diseases

The Src-family protein tyrosine kinases (SFKs), a subfamily of non-receptor tyrosine kinases, are ubiquitously expressed in various cell types. Numerous studies have suggested that SFKs are related to signal transduction in major cardiac physiological and pathological processes, it is the activity of SFKs that is connected with the maintenance of cardiovascular homeostasis. Upon stimulation of various injury factors or stress, the phosphorylation state of SFKs is changed, which has been found to modulate different cardiac pathological conditions, such as hypertension, coronary heart disease, ischemic heart disease, myocardial ischemia-reperfusion injury, arrhythmia and cardiomyopathy via regulating cell growth, differentiation, movement and function, electrophysiologic signals. This review summarizes the basic information about SFKs, updates its role in the different processes underlying the development of multiple cardiovascular diseases (CVDs), and highlights their potential role as disease biomarkers and therapeutic targets, which would help understand the pathophysiology of CVDs and promote the further potential clinical adhibition.