Pu-Erh Tea Relaxes the Thoracic Aorta of Rats by Reducing Intracellular Calcium

Abstract

Previous studies suggested that pu-erh tea aqueous extract could lower blood pressure and ameliorate hypertension symptoms. However, the antihypertension mechanisms of pu-erh tea remain unclear. In this work, the direct effects of pu-erh tea on vessels and cells were investigated by detecting isometric tension and intracellular calcium ([Ca2+]i), respectively. Additionally, to identify the main active components, the aqueous extract of pu-erh was separated by organic solvents to obtain various fractions, and the effects of these fractions on arteries were assessed. The results showed that pu-erh aqueous extract vasodilated rat thoracic aortas preconstricted by phenylephrine or KCl. These vasodilation effects were not significantly affected by the removal of the endothelium or by preincubation with potassium channel blockers (tetraethylammonium, glibenclamide, aminopyridine, or barium chloride). Moreover, pu-erh aqueous extract could reduce the vessel contractibility induced by CaCl2 and phenylephrine under KCl-depolarizing or Ca2+-free buffer conditions, respectively. Furthermore, pu-erh aqueous extract attenuated the KCl-induced increase in [Ca2+]i in cultured rat aortic smooth muscle A7r5 cells. In addition, the chloroform precipitate of pu-erh aqueous extract produced the most potent vasodilation. Theabrownins (the characteristic components of pu-erh tea) accounted for 41.91 ± 1.09 % of the chloroform precipitate and vasodilated arteries in an endothelium-independent manner. In addition, the vasodilation effect of caffeine was verified. In conclusion, theabrownins and caffeine should be the two main active components in pu-erh tea. Pu-erh aqueous extract vasodilated arteries in an endothelium-independent manner, which might partly be attributed to the decrease in extracellular Ca2+ influx. Moreover, our study provided data on the potential mechanism of the hypotensive actions of pu-erh tea, which might improve our understanding of the effect of pu-erh tea on the prevention and treatment of hypertension.

Aged Ripe Pu-erh Tea Reduced Oxidative Stress-Mediated Inflammation in Dextran Sulfate Sodium-Induced Colitis Mice by Regulating Intestinal Microbes

“…Compared with P2020, P2006 had better protective effects on the DSS-induced colitis mice. In this study, compared with P2020, the contents of caffeine and gallic acid in P2006 were significantly decreased, while catechin and tea polysaccharide were significantly increased (Figure S1K), which was consistent with the results of a recent study by Zhang et al and Luo et al 43,44 Polysaccharides have been shown to alleviate LPS-induced kidney damage and intestinal inflammation. 45,46 By increasing the level of antioxidant enzymes, reducing the production of proinflammatory cells, and promoting the phagocytic function of the macrophage system, polysaccharide plays an important role in antioxidation and anti-inflammation.…”

“…Compared with P2020, P2006 had better protective effects on the DSS-induced colitis mice. In this study, compared with P2020, the contents of caffeine and gallic acid in P2006 were significantly decreased, while catechin and tea polysaccharide were significantly increased (Figure S1K), which was consistent with the results of a recent study by Zhang et al and Luo et al , Polysaccharides have been shown to alleviate LPS-induced kidney damage and intestinal inflammation. , By increasing the level of antioxidant enzymes, reducing the production of proinflammatory cells, and promoting the phagocytic function of the macrophage system, polysaccharide plays an important role in antioxidation and anti-inflammation. Additionally, catechin has radical scavenging activities (hydroxyl, peroxyl, and superoxide), showing strong antioxidant ability. , Catechin-enriched green tea and oolong tea significantly increased the antioxidant activity of mice, reducing lipid peroxidation and liver inflammation, and has the effect of improving mildly hypercholesterolemic subjects .…”

Aged Pu-Erh Tea Reduced Oxidative Stress-Mediated Inflammation in DSS-Induced Colitis Mice by Regulating Intestinal Microbes

“…Compared with P2020, P2006 had better protective effects on the DSS-induced colitis mice. In this study, compared with P2020, the contents of caffeine and gallic acid in P2006 were signi cantly decreased, while catechin and tea polysaccharide were signi cantly increased (Figure S1K), which was consistent with the results of a recent study by Zhang and Luo et al [34,35]. Polysaccharides have been shown to alleviate LPS-induced kidney damage and intestinal in ammation [36,37].…”

Characteristics of bacterial community during the pile fermentation of Pu-erh tea in a five-ton batch of Pu-erh tea commercial production process

“…Ripened Pu-erh tea extract (RPT) was a potential anti-in ammatory nutraceutical for the prevention and treatment of colonic colitis (Huang et al 2020). Luo et al (2019) reported the potential mechanism of Pu-erh tea aqueous extract on the prevention and treatment of hypertension.…”