Quercetin improves postischemic recovery of heart function in doxorubicin-treated rats and prevents doxorubicin-induced matrix metalloproteinase-2 activation and apoptosis induction

(-)-Epigallocatechin-3-gallate (EGCG) attenuates arsenic-induced cardiotoxicity in rats

Chronic arsenic exposure in drinking water is associated with the abnormalities of cardiac tissue. Excessive generation of ROS induced by arsenic has a central role in arsenic-induced cardiotoxicity. (-)-Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea, possesses a potent antioxidant capacity and exhibits extensive pharmacological activities. This study was aim to evaluate the effect of EGCG on arsenic-induced cardiotoxicity in vivo and in vitro. Treatment with NaAsO2 seriously affected the morphology and ultrastructure of myocardium, and induced cardiac injuries, oxidative stress, intracellular calcium accumulation and apoptosis in rats. In consistent with in vivo study, the injuries, oxidative stress and apoptosis were also observed in NaAsO2-treated H9c2 cells. All of these effects induced by NaAsO2 were attenuated by EGCG. These results suggest EGCG could attenuate NaAsO2-induced cardiotoxicity, and the mechanism may involve its potent antioxidant capacity.

Polyphenol protection and treatment of hypertension

INTRODUCTION

High blood pressure is the major risk factor for cardiovascular diseases and the rising prevalence of human hypertension precedes the trend toward a global epidemic of unhealthy ageing. A focus on lifestyle and dietary interventions minimizes dependency on pharmacological antihypertensive therapies.

REVIEW

Observational studies indicate that the intake of dietary flavonoids is associated with a decreased risk of cardiovascular disease (CVD). The evidence suggests that the dietary intakes of polyphenol-rich foods, herbs and beverages including flavonols, anthocyanidins, proanthocyanidins, flavones, flavanones, isoflavones and flavan-3-ols, improves vascular health, thereby significantly reducing the risk of hypertension and CVD. Consumption is associated with an improvement in endothelial function via vascular eNOS and Akt activation. Increased NO bioavailability improves vasodilation and blood circulation, effects protein kinases, ion channels and phosphodiesterases, counteracting vascular inflammation and LDL oxidative stress. Importantly, some polyphenols also inhibit the activity of matrix metalloproteinases, inhibit angiotensin converting enzyme activity and thereby improving SBP and DSB. We review the improvement of polyphenol intake on blood pressure and endothelial function for the treatment of hypertension, including not only observational but also RCTs and pre-clinical studies.

CONCLUSION

The antihypertensive phytotherapy of polyphenol-rich foods for protection and improving endothelial function with vascular relaxation occurs via the NO-cGMP pathway and ACE inhibition. OPCs stimulate endothelium-dependent vasodilation, suppress vasoconstrictor ET-1 synthesis, activate a laminar shear stress response in endothelial cells and also inhibit the activity of metalloproteinases including ACE lowering blood pressure.

Quercetin attenuates cardiomyocyte apoptosis via inhibition of JNK and p38 mitogen-activated protein kinase signaling pathways

Quercetin (Que), a plant-derived flavonoid, possesses various biological functions. Moreover, Que exerts multiple beneficial actions in treatment of cardiovascular diseases and there are an inverse association between Que intakes and occurrence and development of various cardiovascular diseases. Some researchers have inferred that the mechanisms of Que to protect cardiomyocytes from ischemia/reperfusion (I/R) injury may be involved in modulation of intracellular signal pathways and regulation of proteins expression in vivo. The current study investigated whether Que has any protective effects on cardiomyocytes from hypoxia/reoxygenation (H/R) in vitro and its potential cardioprotective mechanisms. The cell viability of Que on H9c2 cardiomyoblast cells was assessed by MTT. Apoptosis was evaluated by both Hoechst33342 staining and Flow cytometric analysis (FACS). Furthermore, the effect of Que, SP600125 (JNK inhibitor) and SB203580 (p38 inhibitor) on mitogen-activated protein kinases (MAPKs) and the expression of apoptosis related proteins (Bcl-2, Bax and caspase-3) was determined by Western blotting. MTT assays showed that pretreatment with Que could increase the viability of H9c2 cardiomyocytes that suffered H/R. Both Hoechst33342 staining and FACS confirmed that Que could remarkably suppress the H/R-induced apoptotic cardiomyocytes. In addition, Que significantly alleviated H/R-induced the phosphorylation of JNK and p38, which further increased Bcl-2 expression and inhibited the activation of Bax and caspase-3 directly or indirectly. In summary, our results imply that Que can induce cardioprotection by inhibition of JNK and p38 mitogen-activated protein kinase signaling pathways and modulate the expression of Bcl-2 and Bax proteins that provides a new experimental foundation for myocardial ischemia disease therapy.