Green tea’s popularity has grown quickly in recent years. Its fans can drink it, enjoy its flavor in their ice cream and slather it on their skin with lotions infused with it. Now, the tea could have a new, unexpected role - to improve the image quality of MRIs. Scientists report in the journal ACS Applied Materials & Interfaces that they successfully used compounds from green tea to help image cancer tumors in mice.
Sanjay Mathur and colleagues note that recent research has revealed the potential usefulness of nanoparticles - iron oxide in particular - to make biomedical imaging better. But the nanoparticles have their disadvantages. They tend to cluster together easily and need help getting to their destinations in the body. To address these issues, researchers have recently tried attaching natural nutrients to the nanoparticles. Mathur’s team wanted to see if compounds from green tea, which research suggests has anticancer and anti-inflammatory properties, could play this role.
Using a simple, one-step process, the researchers coated iron-oxide nanoparticles with green-tea compounds called catechins and administered them to mice with cancer. MRIs demonstrated that the novel imaging agents gathered in tumor cells and showed a strong contrast from surrounding non-tumor cells. The researchers conclude that the catechin-coated nanoparticles are promising candidates for use in MRIs and related applications.
The authors acknowledge funding from the University of Cologne and the EU Project Nanommune.
The American Chemical Society is a nonprofit organization chartered by the U.S. Congress. With more than 158,000 members, ACS is the world’s largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.
Green tea, native to China and India, has been consumed and hailed for its health benefits for centuries globally, but has only recently gained popularity in the US.
Tea is considered the most consumed beverage in the world behind water, however 78% of the tea consumed worldwide is black and only about 20% is green.
All types of tea except herbal tea are brewed from the dried leaves of the Camellia sinensis bush. The level of oxidation of the leaves determines the type of tea.
Green tea is made from un-oxidized leaves and is one of the less processed types of tea (with white tea the least) and therefore contains one of the most antioxidants and beneficial polyphenols.
Green tea was used in traditional Chinese and Indian medicine to control bleeding and heal wounds, aid digestion, improve heart and mental health and regulate body temperature.4 Recent studies have shown green tea can potentially have positive effects on everything from weight loss to liver disorders to type 2 diabetes.
According to the National Cancer Institute, the polyphenols in tea have been shown to decrease tumor growth in laboratory and animal studies and may protect against damage caused by ultraviolet UVB radiation.
In countries where green tea consumption is high cancer rates tend to be lower, but it is impossible to know for sure whether it is the green tea that prevents cancer in these specific populations or other lifestyle factors.
One large-scale clinical study compared green tea drinkers with non-drinkers and found that those who drank the most tea were less likely to develop pancreatic cancer, particularly women, who were 50% less likely to develop the disease.
Studies have also shown the positive impacts of green tea on breast, bladder, ovarian, colorectal, esophageal, lung, prostate, skin and stomach cancer.
Researchers believe that it is the high level of polyphenols in tea that help kill cancerous cells and stop them from growing, however the exact mechanisms by which tea interacts with cancerous cells is unknown.
Other studies have shown a lack of preventative effects of tea on cancer. The amount of tea required for cancer-preventive effects has also varied widely in studies - from 2- 10 cups per day.
In 2005, the FDA stated that “there is no credible evidence to support qualified health claims for green tea consumption and a reduced risk of gastric, lung, colon/rectal, esophageal, pancreatic, ovarian, and combined cancers.”