The analysis of eligible studies showed that the administration of green tea beverages or extracts resulted in significant reductions in serum TC and LDL-cholesterol concentrations, but no effect on HDL cholesterol was observed.

No abstract

Lipid transfer proteins (LTPs), a class of small, ubiquitous proteins, play critical roles in various environmental stresses. However, their precise biological functions remain unknown. Here we isolated an extracellular matrix-localised LTP, NtLTP4, from Nicotiana tabacum. The overexpression of NtLTP4 in N. tabacum enhanced resistance to salt and drought stresses. Upon exposure to high salinity, NtLTP4-overexpressing lines (OE lines) accumulated low Na+ levels. Salt-responsive genes, including Na+/H+ exchangers (NHX1) and high-affinity K+ transporter1 (HKT1), were dramatically higher in OE lines than in wild-type lines. NtLTP4 might regulate transcription levels of NHX1 and HKT1 to alleviate the toxicity of Na+. Interestingly, OE lines enhanced the tolerance of N. tabacum to drought stress by reducing the transpiration rate. Moreover, NtLTP4 could increase reactive oxygen species (ROS)-scavenging enzyme activity and expression levels to scavenge excess ROS under drought and high salinity conditions. We used a two-hybrid yeast system and screened seven putative proteins that interact with NtLTP4 in tobacco. An MAPK member, wound-induced protein kinase, was confirmed to interact with NtLTP4 via co-immunoprecipitation and a firefly luciferase complementation imaging assay. Taken together, this is the first functional analysis of NtLTP4, and proves that NtLTP4 positively regulates salt and drought stresses in N. tabacum.

The effect of tea intake on blood pressure (BP) is controversial. We performed a meta-analysis of randomised controlled trials to determine the changes in systolic and diastolic BP due to the intake of black and green tea. A systematic search was conducted in MEDLINE, EMBASE and the Cochrane Controlled Trials Register up to May 2014. The weighted mean difference was calculated for net changes in systolic and diastolic BP using fixed-effects or random-effects models. Previously defined subgroup analyses were performed to explore the influence of study characteristics. A total of twenty-five eligible studies with 1476 subjects were selected. The acute intake of tea had no effects on systolic and diastolic BP. However, after long-term tea intake, the pooled mean systolic and diastolic BP were lower by 21·8 (95 % CI 2 2·4, 21·1) and 21·4 (95 % CI 22·2, 2 0·6) mmHg, respectively. When stratified by type of tea, green tea significantly reduced systolic BP by 2·1 (95 % CI 22·9, 2 1·2) mmHg and decreased diastolic BP by 1·7 (95 % CI 22·9, 2 0·5) mmHg, and black tea showed a reduction in systolic BP of 1·4 (95 % CI 22·4, 20·4) mmHg and a decrease in diastolic BP of 1·1 (95 % CI 21·9, 20·2) mmHg. The subgroup analyses showed that the BP-lowering effect was apparent in subjects who consumed tea more than 12 weeks (systolic BP 22·6 (95 % CI 23·5, 21·7) mmHg and diastolic BP 22·2 (95 % CI 2 3·0, 21·3) mmHg, both P,0·001). The present findings suggest that long-term ($12 weeks) ingestion of tea could result in a significant reduction in systolic and diastolic BP.