Chronic black tea extract consumption improves endothelial function in ovariectomized rats

Fung Ping LEUNG, Lai Ming Yung, Ching Yuen Ngai, Wai San Cheang, Xiao Yu Tian, Chi Wai Lau, Yang Zhang, Jian Liu, Zhen Yu Chen, Zhaoxiang BIAN, Xiaoqiang Yao, Yu Huang*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

14 Citations (Scopus)


Purpose: Menopause escalates the risk of cardiovascular diseases in women. There is an unmet need for better treatment strategy for estrogen-deficiency-related cardiovascular complications. Here we investigated the impact of chronic black tea extract (BT) consumption on cardiovascular function and lipid metabolism using a rat model of estrogen deficiency. Methods: Female Sprague–Dawley rats were ovariectomized (OVX) and treated with BT (15 mg/kg/day, 4 weeks; active ingredients: theaflavins) or estrogen (E2) treatment for 4 weeks. Serum was collected for measuring cholesterol, triacylglycerol and estradiol levels. Changes in vascular reactivity were examined. The protein levels of NADPH oxidases were assessed by Western blotting. Reactive oxygen species (ROS) level was measured using dihydroethidium fluorescence imaging. The concentrations of cGMP were measured using ELISA kit. Results: Aortic rings from control, BT-treated and E2-treated OVX rats exhibited a greater increase in Phe-induced contraction after inhibition of NO synthase compared with those from OVX rats. ACh-induced endothelium-dependent relaxations were augmented in aortae and renal arteries in BT/E2-treated OVX rats than in OVX rats. BT/E2 treatment improved flow-mediated dilatation in small mesenteric resistance arteries of OVX rats. BT/E2 treatment restored the eNOS phosphorylation level and reversed the up-regulation of NADPH oxidases and ROS overproduction in OVX rat aortae. ACh-stimulated cGMP production was significantly elevated in the aortae from BT- and E2-treated rats compared with those from OVX rats. BT/E2 treatment reduced circulating levels of total cholesterol. Conclusions: The present study reveals the novel benefits of chronic BT consumption to reverse endothelial dysfunction and favorably modifying cholesterol profile in a rat model of estrogen deficiency and provides insights into developing BT as beneficial dietary supplements for postmenopausal women.

Original languageEnglish
Pages (from-to)1963-1972
Number of pages10
JournalEuropean Journal of Nutrition
Issue number5
Publication statusPublished - 1 Aug 2016

Scopus Subject Areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

User-Defined Keywords

  • Aorta
  • Black tea
  • Endothelial dysfunction
  • Oxidative stress
  • Postmenopause
  • Theaflavins


Dive into the research topics of 'Chronic black tea extract consumption improves endothelial function in ovariectomized rats'. Together they form a unique fingerprint.

Cite this