Diosmetin exerts cardioprotective effect on myocardial ischaemia injury in neonatal rats by decreasing oxidative stress and myocardial apoptosis

Roles of flavonoids in ischemic heart disease: Cardioprotective effects and mechanisms against myocardial ischemia and reperfusion injury

BACKGROUND

Flavonoids are extensively present in fruits, vegetables, grains, and medicinal plants. Myocardial ischemia and reperfusion (MI/R) comprise a sequence of detrimental incidents following myocardial ischemia. Research indicates that flavonoids have the potential to act as cardioprotective agents against MI/R injuries. Several specific flavonoids, e.g., luteolin, hesperidin, quercetin, kaempferol, and puerarin, have demonstrated cardioprotective activities in animal models.

PURPOSE

The objective of this review is to identify the cardioprotective flavonoids, investigate their mechanisms of action, and explore their application in myocardial ischemia.

METHODS

A search of PubMed database and Google Scholar was conducted using keywords "myocardial ischemia" and "flavonoids". Studies published within the last 10 years reporting on the cardioprotective effects of natural flavonoids on animal models were analyzed.

RESULTS

A total of 55 natural flavonoids were identified and discussed within this review. It can be summarized that flavonoids regulate the following main strategies: antioxidation, anti-inflammation, calcium modulation, mitochondrial protection, ER stress inhibition, anti-apoptosis, ferroptosis inhibition, autophagy modulation, and inhibition of adverse cardiac remodeling. Additionally, the number and position of OH, 3'4'-catechol, C2=C3, and C4=O may play a significant role in the cardioprotective activity of flavonoids.

CONCLUSION

This review serves as a reference for designing a daily diet to prevent or reduce damages following ischemia and screening of flavonoids for clinical application.

Diosmetin Ameliorates HFD-induced Cognitive Impairments via Inhibiting Metabolic Disorders, Mitochondrial Dysfunction and Neuroinflammation in Male SD Rats

Currently, accumulating evidence has indicated that overnutrition-associated obesity may result in not only metabolic dysregulations, but also cognitive impairments. This study aimed to investigate the protective effects of Diosmetin, a bioflavonoid compound with multiple biological functions, on cognitive deficits induced by a high fat diet (HFD) and the potential mechanisms. In the present study, oral administration of Diosmetin (25, 50 and 100 mg/kg) for 12 weeks significantly reduced the body weight, restored glucose tolerance and normalized lipid profiles in the serum and liver in HFD-induced obese rats. Diosmetin also significantly ameliorated depression-like behaviors and impaired spatial memory in multiple behavioral tests, including the open field test, elevated plus-maze and Morris water maze, which was in accordance with the decreased pathological changes and neuronal damage in different regions of hippocampus as suggested by H&E and Nissl staining. Notably, our results also indicated that Diosmetin could significantly improve mitochondrial dysfunction induced by HFD through upregulating genes involved in mitochondrial biogenesis and dynamics, increasing mitochondrial ATP levels and inhibiting oxidative stress. Moreover, the levels of key enzymes involved in the TCA cycle were also significantly increased upon Diosmetin treatment. Meanwhile, Diosmetin inhibited HFD-induced microglial overactivation and down-regulated inflammatory cytokines both in the serum and hippocampus. In conclusion, these results indicated that Diosmetin might be a novel nutritional intervention to prevent the occurrence and development of obesity-associated cognitive dysfunction via metabolic regulation and anti-inflammation.

The Antioxidative Effects of Flavones in Hypertensive Disease

Hypertension is the leading remediable risk factor for cardiovascular morbidity and mortality in the United States. Excess dietary salt consumption, which is a catalyst of hypertension, initiates an inflammatory cascade via activation of antigen-presenting cells (APCs). This pro-inflammatory response is driven primarily by sodium ions (Na+) transporting into APCs by the epithelial sodium channel (ENaC) and subsequent NADPH oxidase activation, leading to high levels of oxidative stress. Oxidative stress, a well-known catalyst for hypertension-related illness development, disturbs redox homeostasis, which ultimately promotes lipid peroxidation, isolevuglandin production and an inflammatory response. Natural medicinal compounds derived from organic materials that are characterized by their anti-inflammatory, anti-oxidative, and anti-mutagenic properties have recently gained traction amongst the pharmacology community due to their therapeutic effects. Flavonoids, a natural phenolic compound, have these therapeutic benefits and can potentially serve as anti-hypertensives. Flavones are a type of flavonoid that have increased anti-inflammatory effects that may allow them to act as therapeutic agents for hypertension, including diosmetin, which is able to induce significant arterial vasodilation in several different animal models. This review will focus on the activity of flavones to illuminate potential preventative and potential therapeutic mechanisms against hypertension.

Diosmetin has therapeutic efficacy in colitis regulating gut microbiota, inflammation, and oxidative stress via the circ-Sirt1/Sirt1 axis

Diosmetin (3',5,7 -trihydroxy-4'-methoxy flavone) is a natural flavonoid compound in the citrus species, it exhibits a variety of pharmacological activities, but little is known of its effects on colitis. In this study we evaluated the therapeutic effects of diosmetin on mouse models of chronic and acute colitis. Chronic colitis was induced in mice by drinking water containing 3% dextran sulfate sodium (DSS) from D0 to D8, followed by administration of diosmetin (25, 50 mg · kg^-1 · d^-1) for another 8 days. Acute colitis was induced by drinking water containing 5% DSS from D0 to D7, the mice concomitantly received diosmetin (25, 50 mg · kg^-1 · d^-1) from D1 to D7. During the experiments, body weight and disease activity index (DAI) were assessed daily. After the mice were sacrificed, colon tissue and feces samples were collected, and colon length was measured. We showed that in both models, diosmetin administration significantly decreased DAI score and ameliorated microscopic colon tissue damage; increased the expression of tight junction proteins (occludin, claudin-1, and zonula occludens-1), and reduced the secretion of proinflammatory cytokines IL-1β, IL-6, TNF-α, and Cox-2 in colon tissue. We found that diosmetin administration remarkably inhibited colon oxidative damage by adjusting the levels of intracellular and mitochondrial reactive oxygen species, GSH-Px, SOD, MDA and GSH in colon tissue. The protection of diosmetin against intestinal epithelial barrier damage and oxidative stress were also observed in LPS-treated Caco-2 and IEC-6 cells in vitro. Furthermore, we demonstrated that diosmetin markedly increased the expression of Nrf2 and HO-1 and reduced the ratio of acetylated NF-κB and NF-κB by activating the circ-Sirt1/Sirt1 axis, which inhibited oxidative stress and inflammation in vivo and in vitro. Diosmetin reversed the effects of si-circSirt1 and si-Sirt1 in LPS-treated Caco-2 and IEC-6 cells. When the gut microbiota was analyzed in the mouse model of colitis, we found that diosmetin administration modulated the abundance of Bacteroidetes, Actinobacteria, Cyanobacteria and Firmicutes, which were crucial for inflammatory bowel disease. Our results have linked colitis to the circ-Sirt1/Sirt1 signaling pathway, which is activated by diosmetin. The results imply that diosmetin may be a novel candidate to alleviate DSS-induced colitis and can be a lead compound for future optimization and modification.

Anshen Buxin Liuwei Pill, a Mongolian Medicinal Formula, Could Protect H2O2-Induced H9c2 Myocardial Cell Injury by Suppressing Apoptosis, Calcium Channel Activation, and Oxidative Stress

Background

Anshen Buxin Liuwei pill (ABLP) is a Mongolian medicinal formula which has a therapeutic effect on the symptoms such as coronary heart disease, angina pectoris, arrhythmia, depression and irritability, palpitation, and short breath. However, its bioactivity against cardiac injury remains unclear.

Methods

The protective effect of ABLP was evaluated using H9c2 cells. Cell viability, intracellular Ca²⁺, reactive oxidative indices, and mitochondrial membrane potential (∆ψ) were assessed, respectively. The mRNA levels of Ca²⁺ channel-related genes (DHPR, RyR2, and SCN5A) and oxidative stress-related genes (Keap1, Nrf2, and HO-1) were measured by RT-PCR.

Results

0.5–50 μg/mL ABLP could significantly decrease H₂O₂-induced cell injury by suppressing cell necrosis/apoptosis and excess oxidative stress, ameliorating the collapse of ∆ψ, and reducing intracellular Ca²⁺ concentration. Furthermore, 0.5–50 μg/mL ABLP reversed H₂O₂-induced imbalance in the mRNA levels of DHPR, RyR2, SCN5A, Keap1, Nrf2, and HO-1 gene in H9c2 cells, which further illustrate the mechanism.

Conclusion

ABLP provided protective and therapeutic benefits against H₂O₂-induced H9c2 cell injury, indicating that this formula can effectively treat coronary disease. In addition, the present study also provides an in-depth understanding of the pharmacological functions of ABLP, which may lead to further successful applications of Mongolian medicine.

Diosmetin exerts cardioprotective effect on myocardial ischaemia injury in neonatal rats by decreasing oxidative stress and myocardial apoptosis

Myocardial injury caused by the myocardial ischaemia (MI) is still a troublesome condition in the clinic, including apoptosis, oxidative stress and inflammation. Diosmetin inhibits the cellular apoptosis and inflammatory response and enhances antioxidant activity. So, this study was designed to investigate the cardioprotective effects of diosmetin on MI model neonatal rats. Forty Sprague Dawley (SD) rats 7 days old were randomly divided into five groups. Four groups of rats received diosmetin (50, 100, and 200 mg/kg) or vehicle (MI group) after ischaemia. Another group received vehicle without ischaemia to serve as a control group. Rats were pretreated with diosmetin intraperitoneally for 7 days and intoxicated with isoproterenol (ISO, 85 mg/kg, sc) on the last 2 days. The expression of apoptotic molecules, myocardial systolic function index, antioxidant enzymes and myocardial enzyme was analyzed. Compared with the control group, the proliferation marker proteins of Ki67 were increased significantly (P < .05), the MI group significantly increased the cardiac apoptosis, oxidative stress and myocardial enzymes, and weakened myocardial contractility. The levels of p‐P65/P65 were increased significantly (P < .05) with decreased p‐AKT/AKT and p‐Nrf2/Nrf2 (P < .05). Nevertheless, pretreatment with diosmetin reversed these changes, especially high‐dose group. In summary, diosmetin has significant potential as a therapeutic intervention to ameliorate myocardial injury after MI and provides the rationale for further clinical studies.