Jabuticaba-Induced Endothelium-Independent Vasodilating Effect on Isolated Arteries

Jaboticaba (Myrciaria jaboticaba) Attenuates Ventricular Remodeling after Myocardial Infarction in Rats

The cardiac remodeling after myocardial infarction is characterized by inflammation and oxidative stress. Thus, this study aimed to test the hypothesis that jaboticaba, due to its anti-inflammatory and antioxidants properties, attenuates cardiac remodeling after myocardial infarction. Wistar rats were submitted to myocardial infarction due to coronary artery occlusion, and divided into four experimental groups: C, sham control animals; I, animals submitted to myocardial infarction, received a standard diet; IJ2, animals submitted to myocardial infarction, received a standard diet plus 2% jaboticaba; and IJ4, animals submitted to myocardial infarction, received a standard diet plus 4% jaboticaba. After a three-month follow-up, echocardiography, histology, oxidative stress, and cardiac energy metabolism were analyzed. There was no difference in infarct size or mortality among the infarcted groups. The IJ4 group displayed improved diastolic function, as assessed by isovolumetric relaxation time normalized to the heart rate. As expected, the percentage of collagen was higher in all infarcted groups than in the C group. However, the IJ2 group had less collagen than groups I and IJ4. The IJ4 group presented lower PFK activity than I and IJ2, and lower pyruvate dehydrogenase activity than controls, whereas the IJ2 group showed no differences compared to the control group in both LDH and ATP synthase activity. The 2% and 4% doses attenuated lipid peroxidation and increased the activity of glutathione peroxidase compared with the I group. In conclusion, jaboticaba attenuated the remodeling process after myocardial infarction, which was associated with decreased oxidative stress and improved energy metabolism.

Review of Natural Resources With Vasodilation: Traditional Medicinal Plants, Natural Products, and Their Mechanism and Clinical Efficacy

For decades, chronic diseases including cardiovascular and cerebrovascular diseases (CCVDs) have plagued the world. Meanwhile, we have noticed a close association between CCVDs and vascular lesions, such as hypertension. More focus has been placed on TMPs and natural products with vasodilation and hypotension. TMPs with vasodilatory and hypotensive activities are mainly from Compositae, Lamiaceae, and Orchidaceae (such as V. amygdalina Del., T. procuinbens L., M. glomerata Spreng., K. galanga L., etc.) whereas natural products eliciting vasorelaxant potentials were primarily from flavonoids, phenolic acids and alkaloids (such as apigenin, puerarin, curcumin, sinomenine, etc.). Furthermore, the data analysis showed that the vasodilatory function of TMPs was mainly concerned with the activation of eNOS, while the natural products were primarily correlated with the blockage of calcium channel. Thus, TMPs will be used as alternative drugs and nutritional supplements, while natural products will be considered as potential therapies for CCVDs in the future. This study provides comprehensive and valuable references for the prevention and treatment of hypertension and CCVDs and sheds light on the further studies in this regard. However, since most studies are in vitro and preclinical, there is a need for more in-depth researches and clinical trials to understand the potential of these substances.

Endothelium-Independent Vasodilatory Effect of Sailuotong (SLT) on Rat Isolated Tail Artery

Background

Sailuotong (SLT) is a standardized three-herb formulation consisting of extracts of Panax ginseng, Ginkgo biloba, and Crocus sativus for the treatment of vascular dementia (VaD). Although SLT has been shown to increase cerebral blood flow, the direct effects of SLT on vascular reactivity have not been explored. This study aims to examine the vasodilatory effects of SLT and the underlying mechanisms in rat isolated tail artery.

Methods

Male (250-300 g) Wistar Kyoto (WKY) rat tail artery was isolated for isometric tension measurement. The effects of SLT on the influx of calcium through the cell membrane calcium channels were determined in Ca²⁺-free solution experiments.

Results

SLT (0.1-5,000 μg/ml) caused a concentration-dependent relaxation in rat isolated tail artery precontracted by phenylephrine. In the contraction experiments, SLT (500, 1,000, and 5,000 μg/mL) significantly inhibited phenylephrine (0.001 to 10 μM)- and KCl (10-80 mM)-induced contraction, in a concentration-dependent manner. In Ca²⁺-free solution, SLT (500, 1,000, and 5,000 μg/mL) markedly suppressed Ca²⁺-induced (0.001-3 mM) vasoconstriction in a concentration-dependent manner in both phenylephrine (10 μM) or KCl (80 mM) stimulated tail arteries. L-type calcium channel blocker nifedipine (10 μM) inhibited PE-induced contraction. Furthermore, SLT significantly reduced phenylephrine-induced transient vasoconstriction in the rat isolated tail artery.

Conclusion

SLT induces relaxation of rat isolated tail artery through endothelium-independent mechanisms. The SLT-induced vasodilatation appeared to be jointly meditated by blockages of extracellular Ca²⁺ influx via receptor-gated and voltage-gated Ca²⁺ channels and inhibition of the release of Ca²⁺ from the sarcoplasmic reticulum.

Radical Scavenger Capacity of Jabuticaba Fruit (Myrciaria cauliflora) and Its Biological Effects in Hypertensive Rats

Jabuticaba is an exotic fruit native to Brazil that has been arousing medicinal interest. Using chemical (HPLC-PDA, resonance mass spectra, and NMR), electroanalytical (differential pulse voltammetry, radical scavenging assay), and pharmacological (in vivo and in vitro) approaches, we have identified its bioactive compounds and hypotensive effects on hypertensive rats. The hydroalcoholic extract of jabuticaba (HEJ) presents a great quantity of phenolic compounds, and several molecules with hydroxyl groups present high efficiency as an antioxidant. The treatment with HEJ (100 and 300 mg/kg/day, for four weeks) presented hypotensive effects on L-NAME-induced hypertensive rats, possibly improving the nitric oxide bioavailability because of its high antioxidant potential. Furthermore, renal and cardiac hypertrophies were also attenuated after the HEJ treatment. Moreover, the vascular responses to contractile and dilating agonists were improved with the HEJ treatment, which is also able to induce nitric oxide production in endothelial cells.