Protective Effects of Baicalin on Experimental Myocardial Infarction in Rats

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.

Evidence construction of baicalin for treating myocardial ischemia diseases: A preclinical meta-analysis

BACKGROUND

Baicalin, a flavonoid glycoside isolated from Scutellaria baicalensis Georgi, has shown potential pharmacological effects on myocardial ischemia diseases. Nevertheless, systematic preclinical studies on baicalin in the treatment of ischemic diseases are scarce.

PURPOSE

To assess the efficacy and potential mechanisms of baicalin in myocardial ischemia (RI), myocardial ischemia-reperfusion (IR) injury and myocardial infarction (MI) animal models for future clinical research.

METHODS

Preclinical studies published prior to August 27^th, 2022 were retrieved from PubMed, Embase, Web of Science and Cochrane Library. CAMARADES list was used to evaluate the quality of included researches. Meta-analyses of cardiac pathology and function parameters, myocardial injury markers and other indicators were performed by STATA 15.0 software. Potential mechanisms are categorized and summarized. Dose-response interval analyses were used to analyze the dose-response relationship between baicalin and myocardial ischemia disease.

RESULTS

Fourteen studies and 222 animals were included in the analysis. The results showed that compared with the control group, baicalin could reduce myocardial infarction size associated with cardiac pathological condition and the corresponding cardiac pathological index containing CK-MB, CK and cTnT. Additionally, heart function indicators including LVSP, LVFS, LVEF, -dp/dt max, dp/dt max were increased by baicalin. As for subgroup analyses, baicalin also demonstrated certain effect on CK-MB and LVSP by administration method or stage. Furthermore, it displayed obvious effect on myocardial ischemia diseases when the dose is maintained at 100-150 mg/kg based on dosage analyses.

CONCLUSION

Based on the relevant literature retrieved, this is the first meta-analysis on baicalin in treating myocardial ischemia diseases. Notably, we linked the dynamic development of the disease and discussed it pertinently, from RI, IR injury to MI. Baicalin exhibits positive effects on myocardial ischemia diseases (especially when the dose is 100-150 mg/kg), which is achieved by regulating key pathological indicators and various signaling pathways.

Regulatory Mechanisms of Baicalin in Cardiovascular Diseases: A Review

Cardiovascular diseases (CVDs) is the leading cause of high morbidity and mortality worldwide, which emphasizes the urgent necessity to develop new pharmacotherapies. In eastern countries, traditional Chinese medicine Scutellaria baicalensis Georgi has been used clinically for thousands of years. Baicalin is one of the main active ingredients extracted from Chinese herbal medicine S. baicalensis. Emerging evidence has established that baicalin improves chronic inflammation, immune imbalance, disturbances in lipid metabolism, apoptosis and oxidative stress. Thereby it offers beneficial roles against the initiation and progression of CVDs such as atherosclerosis, hypertension, myocardial infarction and reperfusion, and heart failure. In this review, we summarize the pharmacological features and relevant mechanisms by which baicalin regulates CVDs in the hope to reveal its application for CVDs prevention and/or therapy.

Metabolomics profiling of haloperidol and validation of thromboxane-related signaling in the early development of zebrafish

Haloperidol is a common butyrophenone-derivative antipsychotic drug that is used clinically to treat schizophrenia and to control Tourette disorder. Haloperidol has been shown to be an embryonic toxicant and to cause a variety of adverse effects that affect human embryonic development. However, the pathway impaired by haloperidol during the developmental stages remains unclear. To elucidate the innate toxicological pathway of haloperidol, we investigated the lethality of haloperidol during the embryonic development of zebrafish. We observed that haloperidol caused serious morphological changes, with an LD₅₀ of 9.7 x 10^-6 ± 2.4 x 10^-6 μg/L. Next, we established a systematic approach to perform metabolite profiling in embryonic zebrafish with various concentrations of haloperidol and analyzed the metabolites using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS). A total of 304 metabolites were identified and 86 metabolites were chosen to predict potential pathways. Among the metabolites, we found through prediction that numerous metabolomics-biological pathways are associated with haloperidol, including peroxisome-proliferator-activated receptor (ppar), thromboxane, and mTOR signaling. Quantitative real time-qPCR was then used to validate the gene expression potentially associated with the thromboxane, which is a metabolic product of arachidonic acid and considered to be important for cell proliferation and the inflammatory response. To sum up, analysis of metabolites in the zebrafish model provides a system for mining biomarkers that reflect biological significance and highlight the therapeutic potency in humans. In addition, it may show potential for application to other pharmaceuticals to identify their various activities and clarify functional mechanisms in the future.

Baicalin relaxes vascular smooth muscle and lowers blood pressure in spontaneously hypertensive rats

Scutellaria baicalensis Georgi is an extensively used medicinal herb for the treatment of hypertension in traditional Chinese medicine. Baicalin is the most abundant flavone compound present in Scutellaria baicalensis Georgi and endothelium-dependent vascular activities of baicalin have been suggested. However, the pharmacological implications and mechanisms of baicalin under hypertensive conditions remain to be investigated. The current study examined the blood pressure-lowering effect of baicalin in a spontaneously hypertensive rat (SHR) model. Moreover, vascular activities and mechanisms of baicalin were investigated under hypertensive conditions. The results demonstrate that baicalin treatment lowers the blood pressure in SHRs in vivo. Ex vivo vascular reactivity assay reveals that baicalin relaxes phenylephrine (PE)-constricted SHR aortas in an endothelium-independent manner. Baicalin attenuates Angiotensin II (Ang II) or potassium chloride (KCl)-induced vasoconstriction in SHR aortas as well. Baicalin also relaxes SHR aortas in the presence of different Ca²⁺ channel blockers such as nifedipine and SKF96365 in response to PE-induced constriction. Most importantly, ATP-sensitive potassium channel (K_ATP) blockade partially abrogated the vasorelaxant effect of baicalin. In summary, the current study demonstrates for the first time that intracellular Ca²⁺ regulation in vascular smooth muscle is mechanistically implicated in the vasorelaxant effect of baicalin under hypertensive conditions. Furthermore, activated K_ATP channels are in part required for the vasorelaxant effect of baicalin under hypertensive conditions. Thus, the work here sheds novel pharmacological and mechanistic insights into the blood pressure-lowering effect of baicalin, which may help better understand the therapeutic application of Scutellaria baicalensis Georgi in the treatment of hypertension.