Flavonoids: Antiplatelet Effect as Inhibitors of COX-1

Evaluation of the efficacy of diosmin and chrysin against tau-fluvalinate exposure in rats

Tau-fluvalinate is a type 2 pyrethroid insecticide. Diosmin and chrysin are flavonoids with antioxidant and anti-apoptotic effects. Role of diosmin and chrysin against infavorable toxic effects caused by tau-fluvalinate and the underlying mechanisms of these effects were investigated. Six groups were formed and diosmin, chrysin, tau-fluvalinate, tau-fluvalinate + diosmin and tau-fluvalinate + chrysin were administered orally to rats at a dose of 20 mg/kg.bw except for the control group, once a day for 21 days, respectively. Tau-fluvalinate elevated MDA and NO levels while diminishing the activities of antioxidant enzymes (SOD, CAT, GSH-Px, GR, GST, G6PD) and GSH levels in the majority of the analyzed blood and tissues, statistically significant. Serum triglyceride, cholesterol, total protein and albumin levels as well as LDH and PChE activities decreased. Conversely, serum creatinine, AST, ALT and ALP levels/activities increased. Elevated protein levels of caspase 3, caspase 9, p53 and Bax and decreased protein levels of Bcl-2 were observed in the liver. There were negative changes in body/some organ weights. Diosmin and chrysin administration resulted in a marked recovery in tau-fluvalinate-induced toxic effects, but this improvement was not complete. These flavonoids may be considered as promising potential therapeutic options to alleviate the adverse effects associated with tau-fluvalinate intoxication.

Post-operative epidural haematoma as complication of overconsumption of dried fruit in lumbar spinal surgery: a case report and review of the literature

PURPOSE

Mebos, a traditional South Africa confection consisting of dried, pulped, and sugared apricots, is rich in fibre and vitamins, but also contains salicylic acid, flavonoids, and citric acid. We report a case of postoperative surgical site bleeding in a healthy patient who consumed approximately 2 kg of mebos per day prior to his elective spinal surgery.

METHODS

The clinical course of a previously healthy 54-year-old male patient with cauda equina syndrome secondary to lumbar spinal stenosis who underwent surgical intervention with subsequent bleeding into the surgical site is discussed. The cause was investigated through biochemical analysis, thromboelastometry (ROTEM®) and mass and absorption spectrometry were applied to assess flavonoid, citric acid, and salicylic acid content.

RESULTS

ROTEM® revealed an abnormal clotting profile with an increased clot forming time, suggesting intrinsic coagulopathy. Mass and absorption spectrometry revealed a high total flavonoid content as well as citric acid concentration in the mebos. Salicylic acid was at detection limits of the instrument.

CONCLUSION

Results highlighted the effect of flavonoids and citric acid and therefore explain the abnormal clotting profile in this patient. Inhibition of coagulation prior to elective surgery is a known contraindication and may pose great risks in spinal surgery. In the present report, we demonstrated an association between inhibition of coagulation and an excess of the flavonoids content and citric acid concentration in mebos consumed in the days prior to elective spinal surgery.

Potential antiplatelet agents with grape seed - backbone polyphenols: computational studies

The study focused on grape seed-derived polyphenols for their antiplatelet, anti-inflammatory, and fibrinolytic properties through molecular docking and dynamics simulations. Compounds were evaluated for their effects on P2Y12, PTP1B, thromboxane A2, and other targets. Compounds 1 and 6 showed strong inhibitory potential on P2Y12. Compounds 2 and 7, plus epigallocatechin gallate, demonstrated effective inhibition on NF-KB and COX1. The compounds exhibited drug-like properties and potential for new thrombotic disease therapies. The research sheds light on the interactions between polyphenols and target proteins, paving the way for novel antiplatelet strategies.

Antiplatelet Effects of Flavonoid Aglycones Are Mediated by Activation of Cyclic Nucleotide-Dependent Protein Kinases

Flavonoid aglycones are secondary plant metabolites that exhibit a broad spectrum of pharmacological activities, including anti-inflammatory, antioxidant, anticancer, and antiplatelet effects. However, the precise molecular mechanisms underlying their inhibitory effect on platelet activation remain poorly understood. In this study, we applied flow cytometry to analyze the effects of six flavonoid aglycones (luteolin, myricetin, quercetin, eriodictyol, kaempferol, and apigenin) on platelet activation, phosphatidylserine externalization, formation of reactive oxygen species, and intracellular esterase activity. We found that these compounds significantly inhibit thrombin-induced platelet activation and decrease formation of reactive oxygen species in activated platelets. The tested aglycones did not affect platelet viability, apoptosis induction, or procoagulant platelet formation. Notably, luteolin, myricetin, quercetin, and apigenin increased thrombin-induced thromboxane synthase activity, which was analyzed by a spectrofluorimetric method. Our results obtained from Western blot analysis and liquid chromatography-tandem mass spectrometry demonstrated that the antiplatelet properties of the studied phytochemicals are mediated by activation of cyclic nucleotide-dependent signaling pathways. Specifically, we established by using Förster resonance energy transfer that the molecular mechanisms are, at least partly, associated with the inhibition of phosphodiesterases 2 and/or 5. These findings underscore the therapeutic potential of flavonoid aglycones for clinical application as antiplatelet agents.

Quercetin prophylaxis protects the kidneys by modulating the renin-angiotensin-aldosterone axis under acute hypobaric hypoxic stress

The study presented here aims at assessing the effects of hypobaric hypoxia on RAAS pathway and its components along with mitigation of anomalies with quercetin prophylaxis. One hour prior to hypobaric hypoxia exposure, male SD rats were orally supplemented with quercetin (50 mg/kg BW) and acetazolamide (50 mg/kg BW) and exposed them to 25,000 ft. (7,620 m) in a simulated environmental chamber for 12 h at 25 ± 2 °C. Different biochemical parameters like renin activity, aldosterone, angiotensin I, ACE 2 were determined in plasma. As a conventional response to low oxygen conditions, oxidative stress parameters (ROS and MDA) were elevated along with suppressed antioxidant system (GPx and catalase) in plasma of rats. Quercetin prophylaxis significantly down regulated the hypoxia induced oxidative stress by reducing plasma ROS & MDA levels with efficient enhancement of antioxidants (GPx and Catalase). Further, hypoxia mediated regulation of renin and ACE 2 proves the outstanding efficacy of quercetin in repudiating altercations in RAAS cascade due to hypobaric hypoxia. Furthermore, differential protein expression of HIF-1α, NFκB, IL-18 and endothelin-1 analyzed by western blotting approves the biochemical outcomes and showed that quercetin significantly aids in the reduction of inflammation under hypoxia. Studies conducted with Surface Plasmon Resonance demonstrated a binding among quercetin and ACE 2 that indicates that this flavonoid might regulate RAAS pathway via ACE 2. Henceforth, the study promotes the prophylaxis of quercetin for the better adaptability under hypobaric hypoxic conditions via modulating the RAAS pathway.

Effectiveness and pharmacological mechanisms of Chinese herbal medicine for coronary heart disease complicated with heart failure

ETHNOPHARMACOLOGICAL RELEVANCE

Chinese herbal medicine (CHM) is widely used for treating coronary heart disease complicated with heart failure (CHD-HF). However, the exact mechanisms involved are still not fully understood.

AIM OF THE STUDY

To assess the clinical effectiveness and potential pharmacological mechanisms of CHM for treating CHD-HF.

METHODS

Eight databases were retrieved for Randomized Controlled Trials of CHM for CHD-HF published from their inception to March 2023. Quality assessment of include studies was performed by the Cochrane risk-of-bias. Meta-analysis was used to assess the effectiveness of CHM for CHD-HF, and then core drugs and active ingredients were selected by data mining and network pharmacology. Finally, cluster and enrichment analysis were adopted to explore the potential targets and signaling pathways.

RESULTS

A total of 52 studies enrolling 5216 patients were included. Meta-analysis revealed that CHM treatment groups significantly improved left ventricular ejection fraction (LVEF), 6-min walk test (6-MWT), left ventricular end-diastolic dimension (LVEDD) and left ventricular end systolic diameter (LVESD) than control groups: [LVEF: SMD = 0.7, 95%CI (0.54, 0.87), p < 0.00001, I2 = 80%; 6-MWT: SMD = 0.72, 95%CI (0.58, 0.86), p < 0.0001, I2 = 67%; LVEDD: SMD = -0.79, 95%CI (-0.89, -0.69), p < 0.0001, I2 = 49%; LVESD: SMD = -0.6 (-0.74, -0.46), p < 0.0001, I2 = 0%]. The results of various biological information analysis showed the internal relationship between prescriptions, core drugs, active ingredients and therapeutic targets. Twelve core herbs with the most commonly use and high correlation were selected from 110 CHMs of 52 prescriptions for CHD-HF treatment, and further 65 effective components were screened out according to the most strength value, which were divided into 12 compounds such as terpenoids, flavonoids, steroids and alkaloids and etc. At the same time, 67 therapeutic targets of active ingredients in CHD-HF were filtrated. On these bases, cluster and enrichment analysis of the components and targets were used to explore relevant pharmacological mechanisms, mainly including anti-myocardial cell damage, anti-inflammation, anti-apoptosis, anti-fibrosis, regulation of oxidative stress, anticoagulation and angiogenesis, and improvement of glucose and fatty acid metabolism.

CONCLUSION

CHM are effective in treating CHD-HF compared with conventional treatment. Some of the included studies have high risks in the implementation of blinding, so more high-quality studies are needed. The active ingredients of CHM could protect the myocardium and improve pathological environment of CHD-HF in various ways. And CHM has the advantage of multi-component and multi-target treatment for complex diseases.

Factors Influencing Venous Remodeling in the Development of Varicose Veins of the Lower Limbs

One of the early symptoms of chronic venous disease (CVD) is varicose veins (VV) of the lower limbs. There are many etiological environmental factors influencing the development of chronic venous insufficiency (CVI), although genetic factors and family history of the disease play a key role. All these factors induce changes in the hemodynamic in the venous system of the lower limbs leading to blood stasis, hypoxia, inflammation, oxidative stress, proteolytic activity of matrix metalloproteinases (MMPs), changes in microcirculation and, consequently, the remodeling of the venous wall. The aim of this review is to present current knowledge on CVD, including the pathophysiology and mechanisms related to vein wall remodeling. Particular emphasis has been placed on describing the role of inflammation and oxidative stress and the involvement of extracellular hemoglobin as pathogenetic factors of VV. Additionally, active substances used in the treatment of VV were discussed.

Unveiling the Molecular Mechanism of Diosmetin and its Impact on Multifaceted Cellular Signaling Pathways

BACKGROUND

Diosmetin is an O-methylated flavone and the aglycone part of the flavonoid glycosides diosmin that occurs naturally in citrus fruits. Pharmacologically, diosmetin is reported to exhibit anticancer, antimicrobial, antioxidant, oestrogenic, and anti-inflammatory activities.

OBJECTIVE

This comprehensive review was aimed to critically explore diverse pharmacological activities exhibited by diosmetin. Along with that, this review can also identify potential research areas with an elucidation of the multifactorial underlying signaling mechanism of action of diosmetin in different diseases.

METHODS

A comprehensive collection of evidence and insights was obtained from scientific journals and books from physical libraries and electronic platforms like Google Scholar and PubMed. The time frame selected was from year 1992 to July 2023.

RESULTS

The review delves into diosmetin's impact on cellular signaling pathways and its potential in various diseases. Due to its ability to modulate signaling pathways and reduce oxidative stress, it can be suggested as a potential versatile therapeutic agent for mitigating oxidative stressassociated pathogenesis.

CONCLUSION

The amalgamation of the review underscores diosmetin's promising role as a multifaceted therapeutic agent, highlighting its potential for drug development and clinical applications.

Research progress of quercetin in cardiovascular disease

Quercetin is one of the most common flavonoids. More and more studies have found that quercetin has great potential utilization value in cardiovascular diseases (CVD), such as antioxidant, antiplatelet aggregation, antibacterial, cholesterol lowering, endothelial cell protection, etc. However, the medicinal value of quercetin is mostly limited to animal models and preclinical studies. Due to the complexity of the human body and functional structure compared to animals, more research is needed to explore whether quercetin has the same mechanism of action and pharmacological value as animal experiments. In order to systematically understand the clinical application value of quercetin, this article reviews the research progress of quercetin in CVD, including preclinical and clinical studies. We will focus on the relationship between quercetin and common CVD, such as atherosclerosis, myocardial infarction, ischemia reperfusion injury, heart failure, hypertension and arrhythmia, etc. By elaborating on the pathophysiological mechanism and clinical application research progress of quercetin's protective effect on CVD, data support is provided for the transformation of quercetin from laboratory to clinical application.

Flavonoids as a therapeutical option for the treatment of thrombotic complications associated with COVID-19

The SARS-CoV-2 outbreak has been one of the largest public health crises globally, while thrombotic complications have emerged as an important factor contributing to mortality. Therefore, compounds that regulate the processes involved in thrombosis could represent a dietary strategy to prevent thrombotic complications involved in COVID-19. In August 2022, various databases were consulted using the keywords "flavonoids", "antiplatelet", "anticoagulant", "fibrinolytic", and "nitric oxide". Studies conducted between 2019 and 2022 were chosen. Flavonoids, at concentrations mainly between 2 and 300 μM, are capable of regulating platelet aggregation, blood coagulation, fibrinolysis, and nitric oxide production due to their action on multiple receptors and enzymes. Most of the studies have been carried out through in vitro and in silico models, and limited studies have reported the in vivo and clinical effect of flavonoids. Currently, quercetin has been the only flavonoid evaluated clinically in patients with COVID-19 for its effect on D-dimer levels. Therefore, clinical studies in COVID-19 patients analyzing the effect on platelet, coagulant, fibrinolytic, and nitric oxide parameters are required. In addition, further high-quality studies that consider cytotoxic safety and bioavailability are required to firmly propose flavonoids as a treatment for the thrombotic complications implicated in COVID-19.

Antioxidant Potential of Diosmin and Diosmetin against Oxidative Stress in Endothelial Cells

Phlebotropic flavonoids, including diosmin and its aglycone diosmetin, are natural polyphenols widely used in the prevention and treatment of chronic venous insufficiency (CVI). As oxidative stress plays an important role in the development of pathophysiology of the cardiovascular system, the study aimed to investigate the protective effects of diosmin and diosmetin on hydrogen peroxide (H₂O₂)-induced oxidative stress in endothelial cells. The cells were pretreated with different concentrations of the flavonoid prior to the H₂O₂ exposure. The cell viability, the level of intracellular reactive oxygen species (ROS), the activity of cellular antioxidant enzymes-including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase GPx-and the malondialdehyde (MDA) level were assessed. It was found that the H₂O₂-induced oxidative stress was ameliorated by diosmin/diosmetin in a concentration-dependent manner. The flavonoids restored the activity of cellular antioxidant enzymes and lowered the MDA level upregulated by the H₂O₂ exposure. These results indicate that diosmin and diosmetin may prevent oxidative stress in endothelial cells; therefore, they may protect against the development and progression of oxidative-stress-related disorders.

Roles of Embryonic Lethal Abnormal Vision-Like RNA Binding Proteins in Cancer and Beyond

Embryonic lethal abnormal vision-like (ELAVL) proteins are RNA binding proteins that were originally discovered as indispensable regulators of the development and functioning of the nervous system. Subsequent studies have shown that ELAVL proteins not only exist in the nervous system, but also have regulatory effects in other tissues. ELAVL proteins have attracted attention as potential therapeutic targets because they stabilize multiple mRNAs by binding within the 3′-untranslated region and thus promote the development of tumors, including hepatocellular carcinoma, pancreatic cancer, ovarian cancer, breast cancer, colorectal carcinoma and lung cancer. Previous studies have focused on these important relationships with downstream mRNAs, but emerging studies suggest that ELAVL proteins also interact with non-coding RNAs. In this review, we will summarize the relationship of the ELAVL protein family with mRNA and non-coding RNA and the roles of ELAVL protein family members in a variety of physiological and pathological processes.