Encapsulating Drugs In Green Tea ‘Missiles’

Scientists have used an antioxidant in green tea to make cancer drug delivery more precise and potent.

AsianScientist (Oct. 7, 2014) – A group of researchers from the Institute of Bioengineering and Nanotechnology (IBN) of Singapore’s Agency for Science, Technology and Research(A*STAR) has taken the health benefits of green tea to the next level, using one of its ingredients to develop a drug delivery system which kills cancer cells more efficiently. This research has been published in Nature Nanotechnology.

“The numerous health benefits of green tea have inspired us to utilize it in drug delivery systems. This is the first time that green tea has been used as a material to encapsulate and deliver drugs to cancer cells,” said IBN executive director, Professor Jackie Y. Ying.

A key challenge in chemotherapy is ensuring that the drugs are delivered only to the tumor in order to avoid harming the surrounding healthy tissues and organs. To address this, research has focused on developing more effective drug carriers. When injected into the body, these carriers act like homing missiles, traveling through the body to zoom in on the target cells where they will release the cancer-destroying drugs.

The IBN research team (from right to left): Dr. Susi Tan, Dr. Motoichi Kurisawa, Prof. Jackie Y. Ying, Dr. Gao Shujun, Dr. Chung Joo Eun and Ms. Nunnarpas Yongvongsoontorn. Credit: A*STAR.
The IBN research team (from right to left): Dr. Susi Tan, Dr. Motoichi Kurisawa, Prof. Jackie Y. Ying, Dr. Gao Shujun, Dr. Chung Joo Eun and Ms. Nunnarpas Yongvongsoontorn. Credit: A*STAR.

In the present study, the IBN research team have designed a therapeutic nanocarrier for drug delivery using epigallocatechin gallate (EGCG), an antioxidant found in green tea. The core of this carrier was made of an oligomer of EGCG (OEGCG), which encapsulates the drugs and proteins; while the shell of the carrier was made of polyethylene glycol (PEG)-EGCG, a known ‘stealth’ molecule that acts to camouflage the carrier, preventing it from being detected and filtered out of the body by the immune system before it reaches the tumor.

Herceptin, a protein drug currently used to treat breast cancer, was loaded into the drug delivery system, forming micellar nanocomplexes of less than 100 nanometers in dimension which not only protected the drug from rapid proteolysis and renal clearance, but also provided tumor targeting.

Animal studies revealed that IBN’s green tea nanocomplex loaded with Herceptin reduced tumor growth much more effectively when compared to administering Herceptin on its own. Using the new nanocarrier, twice as much drug accumulated in the cancer cells, indicating an improved tumor targeting ability. At the same time, the drug accumulation in the other organs was lowered substantially, by 70 percent in the liver and kidney, and by 40 percent in the lung.

“We have developed a green tea-based carrier, in which the carrier itself displayed anti-cancer effect, and can boost cancer treatment when used together with the protein drug. Unlike conventional therapy, our green tea carrier can eradicate more cancer cells and accumulate significantly less drugs in vital organs where they could cause adverse side effects,” said Dr. Motoichi Kurisawa, IBN principal research scientist and team leader.

IBN has filed a patent on their green tea nanocarrier and is developing this technology for clinical applications. The green tea-based micellar complexes are also being examined for the delivery of active ingredients in personal care and nutritional products.

The article can be found at: Chung et al. (2014) Self-assembled Micellar Nanocomplexes Comprising Green Tea Catechin Derivatives and Protein Drugs for Cancer Therapy.


Source: A*STAR.
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