Green tea catechins: defensive role in cardiovascular disorders / 中国天然药物

Green tea, Camellia sinensis (Theaceae), a major source of flavonoids such as catechins, has recently shown multiple cardiovascular health benefits through various experimental and clinical studies. These studies suggest that green tea catechins prevent the incidence of detrimental cardiovascular events, and also lower the cardiovascular mortality rate. Catechins present in green tea have the ability to prevent atherosclerosis, hypertension, endothelial dysfunction, ischemic heart diseases, cardiomyopathy, cardiac hypertrophy and congestive heart failure by decreasing oxidative stress, preventing inflammatory events, reducing platelet aggregation and halting the proliferation of vascular smooth muscle cells. Catechins afford an anti-oxidant effect by inducing anti-oxidant enzymes, inhibiting pro-oxidant enzymes and scavenging free radicals. Catechins present anti-inflammatory activity through the inhibition of transcriptional factor NF-κB-mediated production of cytokines and adhesion molecules. Green tea catechins interfere with vascular growth factors and thus inhibit vascular smooth muscle cell proliferation, and also inhibit thrombogenesis by suppressing platelet adhesion. Additionally, catechins could protect vascular endothelial cells and enhance vascular integrity and regulate blood pressure. In this review various experimental and clinical studies suggesting the role of green tea catechins against the markers of cardiovascular disorders and the underlying mechanisms for these actions are discussed.

Effect of Black Tea Aqueous Non-Dialysate on \it{Helicobacter pylori} Infection in Mongolian Gerbils

Objectives: Recently, the appearance of Helicobacter pylori (H. pylori) resistant to antibiotics has been reported. The development of an antibiotic therapy which would not induce resistant strains of H. pylori is anticipated. In the present study, the antibiotic effect of black tea aqueous non-dialysate (BTND), the fraction different from tea catechins, on H. pylori was investigated using Mongolian gerbils infected with H. pylori. Methods: BTND was extracted from black tea leaves. A 0.1 w/v% solution of BTND or green tea catechins (GTC) was provided as drinking water to male NGS/Sea Mongolian gerbils infected with H. pylori (ATCC43504) for two weeks. Their stomachs were then excised, the mucosal surfaces were macroscopically observed, and colony forming units (CFU) of H. pylori were counted. The data were compared between the BTND and GTC groups. Results: The CFU of H. pylori were significantly decreased by intake of BTND. The body weight of the animals tended to be larger in the group supplied with BTND than in that supplied with GTC. Gastric mucosal injury tended to be smaller in the animals supplied with BTND than in those with GTC. Conclusions: These results suggest that BTND may have an inhibitory effect on H. pylori infection.

Effect of black tea aqueous non-dialysate onHelicobacter pylori infection in Mongolian gerbils

<p><b>OBJECTIVES</b>Recently, the appearance ofHelicobacter pylori (H. pylori) resistant to antibiotics has been reported. The development of an antibiotic therapy which would not induce resistant strains ofH. pylori is anticipated. In the present study, the antibiotic effect of black tea aqueous non-dialysate (BTND), the fraction different from tea catechins, onH. pylori was investigated using Mongolian gerbils infected withH. pylori.</p><p><b>METHODS</b>BTND was extracted from black tea leaves. A 0.1 w/v% solution of BTND or green tea catechins (GTC) was provided as drinking water to male NGS/Sea Mongolian gerbils infected withH. pylori (ATCC43504) for two weeks. Their stomachs were then excised, the mucosal surfaces were macroscopically observed, and colony forming units (CFU) ofH. pylori were counted. The data were compared between the BTND and GTC groups.</p><p><b>RESULTS</b>The CFU ofH. pylori were significantly decreased by intake of BTND. The body weight of the animals tended to be larger in the group supplied with BTND than in that supplied with GTC. Gastric mucosal injury tended to be smaller in the animals supplied with BTND than in those with GTC.</p><p><b>CONCLUSIONS</b>These results suggest that BTND may have an inhibitory effect onH. pylori infection.</p>