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SUNY Upstate researchers find milk thistle extract may hold the key to developing effective herb-based treatments for neurological disorders

An extract from milk thistle, an herb long used in European folk medicine as a liver tonic, shows the ability to boost both the immune and nervous systems at the same time. If these findings found in a laboratory setting prove correct in human trials, then researchers at SUNY Upstate Medical University may have found the newest plant-based product to be used to treat numerous neurological disorders, including Alzheimer's and Parkinson's disease, brain trauma, stroke and spinal cord injury.

The result comes from the collaborative works by scientists in the Neuroscience laboratory and the Transplantation and Immunology laboratory in the Department of Surgery at SUNY Upstate Medical University in Syracuse, N.Y.

Findings from the study, "Neuroimmunological Effects of Five Commonly Used Herbal Products," were released at the 2001 Annual Meeting of the Society for Neuroscience, held last month in San Diego. Study investigators are Smita Kittur, M.D.; Skuntala Wilasrusmee, M.D.; Karen Straube-West, Ph.D.; Chumpon Wilasrusmee, M.D.; Burk Jubelt, M.D.; and Dilip S. Kittur, M.D., Smita Kittur is also affiliated with the Veterans Administration Medical Center in Syracuse.

"Our findings contribute to the much needed scientific data about herbal products and how they can be used to develop new therapeutic agents to fight disease," said Smita Kittur, the study's principal investigator. "It was interesting and surprising to us that milk thistle extract consistently demonstrated both neuro- and immunostimulatory effects. This means that this product can boost the immune system to help fight infection and possibly serve as a catalyst to aid in the regeneration of new nerve cells."

The Upstate research team was the first to use a uniform test to learn the effects, if any, that herbs have on both these systems within the human body. "With this method of study, we can now properly compare and relate the effects many herbal products have on both of these vital systems that control so much of what makes us healthy," said co-investigator Wilasrusmee. "This is something that to our knowledge has never before been accomplished."

To conduct the study, researchers used both nerve and white blood cells from mice to study how each of five commonly-used herbal products would affect the cells. The herbal products included ginger, St. John's Wort, echinacea, tea and milk thistle. The dried preparations of these products were homogenized in a culture medium to enhance their solubility, sieved through a 0.45 mm Millipore filter paper to remove particulate material and bacterial contaminants, and used fresh the same day. All experiments were done in triplicate and repeated twice to confirm the results.

"Surprisingly, we found that milk thistle extract not only helped the nerve cells to grow more neurites (branches of nerve cells necessary for their normal function and that aid in the regeneration of new cells), but it also kept the nerve cells alive longer," said Smita Kittur. "We did not find this result in any of the other herbs we had tested."

"We also found that St. John's Wort, widely used as a treatment for depression, had only an immunostimulatory effect. Tea had a suppressive effect on both the nervous and immune systems, while ginger had only an immunosuppressive effect," she said.

Herbal products are being used more and more as dietary supplements and therapeutic agents. However, these products may have both risks and benefits. The SUNY research team echos the thoughts of other researchers in that more studies must be performed to determine the actual correlations between the use of herbal products and their clinical effects.

For example, Smita Kittur says that according to their findings, ginger and tea can potentially be developed as immunosuppressive agents that can be used in organ transplantation, helping the body to accept the new organ. However, she cautions that they might also cause adverse side effects in reducing immune response to infection. "More studies on herbal products and their impact on the human body are needed before we can effectively use them as a therapy or as a supplement," she added.

The next step in their research, the scientists say, is to study the mechanisms of action of these herbal products in animals and eventually conduct this experiment in human clinical trials.

"These herbal products need to be standardized so that everybody can have the same results when using these products," Smita Kittur said. "We also need to better understand the serious and minor side effects these herbal products have on our nervous and immune systems. Lastly we hope to learn through future studies how these herbs interact with traditional medicines."