Kudzu is a flowering vine native to Japan, China and naturalized to the southeastern United States. It is widely used in traditional Chinese medicine to treat headaches, migraines, vertigo, tinnitus and other neurological disorders. It is also used to detoxify the liver, particularly after generous consumption of alcohol. Today, kudzu is being investigated as a potential treatment for curbing addictive behavior, including smoking.
Plant Profile
Kudzu is considered a highly invasive species and a persistent problem in the southeastern United States. In fact, according to the July 20, 2009 issue of "Science Daily," the "plant that ate the south" spreads faster than U.S. Agricultural Research Service scientists can mow or spray it with herbicide, easily covering an average of 150,000 acres each year.
Generally, the botanical name for kudzu is considered to be Pueraria lobata. However, there are a few other species in the same genus that are so closely related to kudzu in terms of physical structure and chemical compostiion that the common name applies to these plants as well.
Composition
According to a monograph provided by florahealth.com, kudzu contains several plant flavonoids that are responsible for its medicinal effects. Collectively, these compounds are called isoflavones. Of particular interest to researchers in regard to treating addiction are the chemicals daidzin and puerarin, which occur in the highest concentrations in kudzu's roots.
Mechanism of Action
Daidzin and puerarin have an effect on brain chemicals involved in neurotransmission, particularly on γ-aminobutyric acid, or GABA, glutamine and the "feel good" hormones serotonin and dopamine. The idea that kudzu might help people refrain from addictive behavior emerged from a 1998 Harvard study that demonstrated the effect of kudzu extracts on alcoholic hamsters. Until kudzu was administered, the hamsters imbibed the human equivalent of five cases of wine per day, but started choosing water over alcohol after treatment. More recently, a study led by Maria P. Arolfo and published in the November 2009 issue of "Alcoholism, Clinical and Experimental Research" showed that daidzin inhibits a liver enzyme called aldehyde dehydrogenase-2, or ALDH-2. This is significant because this enzyme normally eliminates acetaldehyde, a toxin that forms as by-product of metabolizing ethanol. In the absence of this event, the end result is a decreased interest in drinking, due to an unpleasant reaction commonly known as hangover.
Effect on Smoking
Unfortunately, kudzu has only been directly studied for its impact on alcoholism and not smoking. However, Jie Zhou and colleagues at Huazhong University of Science and Technology in China reported in the Oct. 28, 2010 issue of the "Journal of Ethnopharmacology" that puerarin, a major component of kudzu, protects the brain from toxicity by suppressing the activity of glutamate at receptor sites. Previously, Athina Markou and fellow researchers at Scripps Research Institute in California established a link between glutamate and GABA receptors in the brain and nicotine dependence, in the October 2004 issue of "Annals of the New York Academy of Sciences." Similarly, a study led by N.E. Paterson, published in the July 2008 issue of the "Journal of Pharmacology and Experimental Therapeutics," showed that regulating GABA reception in rats decreased the urge to self-medicate with alcohol, cocaine and nicotine.
References
- Science Daily: Controlling Kudzu with Naturally Occurring Fungus
- Flora: Kudzu Root, Herb Monograph
- "Alcoholism, Clinical and Experimental Research"; Suppression of Heavy Drinking and Alcohol Seeking by a Selective ALDH-2 Inhibitor; Arolfo MP et al.; 2009
- "Journal of Ethnopharmacology"; Puerarin Attenuates Glutamate-induced Neurofilament Axonal Transport Impairment; Zhou J et al.; 2010
- "Annals of the New York Academy of Sciences"; Role of Gamma-aminobutyric Acid (GABA) and Metabotropic Glutamate Receptors in Nicotine Reinforcement: Potential Pharmacotherapies for Smoking Cessation; Markou A et al.; 2004
- "Journal of Pharmacology and Experimental Therapeutics"; Positive Modulation of GABA(B) Receptors Decreased Nicotine Self-administration and Counteracted Nicotine-induced Enhancement of Brain Reward Function in Rats; Paterson NE et al.; 2008
