Chinese medicine herb extract keeps anxiety under control

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April 25, 2007  
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gou teng, uncaria rhynchophylla, chinese medicine, anxiety, depressionCM NEWS – A study on rats shows that the extract of a plant commonly used in traditional Chinese medicine is an effective anti-anxiety agent.

Gou teng, ??, or Uncaria rhynchophylla, has been used to treat infantile convulsions, headaches, dizziness, hypertension and apoplexy. It has also been shown to be effective in lowering the excitement of the central nervous system.

In a recently published journal written by a group of scientists of the Department of Oriental Pharmaceutical Science at South Korea’s Kyung Hee University, the anxiolytic effects of the aqueous extract of gou teng might act on serotonin in the brain.

Serotonin is believed to play an important role in the regulation of anger, aggression, body temperature, mood, sleep, vomiting, sexuality, and appetite. Low levels of serotonin have been associated with several disorders, namely increase in aggressive and angry behaviors, clinical depression, Obsessive-compulsive disorder (OCD), migraine, irritable bowel syndrome, tinnitus, fibromyalgia, bipolar disorder, anxiety disorders[citation needed] and intense religious experiences.

What is serotonin? Serotonin (5-hydroxytryptamine, or 5-HT) is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system (CNS) and enterochromaffin cells in the gastrointestinal tract of animals including humans. Serotonin is also found in many mushrooms and plants, including fruits and vegetables.

The purpose of this study was to characterize the putative anxiolytic-like effects of the aqueous extract of hooks with stem of gou teng, the scientists write.

What is anxiolytic? An anxiolytic is a drug prescribed for the treatment of symptoms of anxiety. Some anxiolytics have been shown to be useful in the treatment of anxiety disorders as have antidepressants such as the class of selective serotonin reuptake inhibitors (SSRIs).

Anxiolytics are generally divided into two groups of medication, benzodiazepines and non-benzodiazepines.

Benzodiazepines are prescribed for short-term relief of severe and disabling anxiety. Common medications are lorazepam (Ativan®), clonazepam (Klonopin®), alprazolam (Xanax®), and diazepam (Valium®). Benzodiazepines may also be indicated to cover the latent periods associated with the medications prescribed to treat an underlying anxiety disorder.

Non-benzodiazepines Buspirone (Buspar®) is a serotonin 1A agonist. It lacks the sedation and the dependence associated with benzodiazepines and causes much less cognitive impairment. It may be less effective than benzodiazepines in patients who have been previously treated with benzodiazepines as the medication does not provide the euphoria and sedation that these patients may expect or equate with anxiety relief.

Certain herbs, such as St. John’s wort, kava (kava kava), bacopa monniera and Valerian are reputed to have anxiolytic properties.

The effects were measured using the elevated plus maze and the hole-board apparatus in rats and mice. The hole board test is a generally used method for screening the potential anxiolytic character of drugs. The test is based on the assumption, that head-dipping activity of the animals is inversely proportional to their anxiety state.

elevated plus mazeWhat is elevated plus maze? Consisting of two open arms and two arms that are enclosed by high walls, this maze is commonly used to assess anxiety-like behavior in laboratory rats. The open arms are perpendicular to the closed arms, with the four arms intersecting to form the shape of a plus sign. The elevated plus-maze is usually elevated approximately 50 centimeters above the floor.

Security is provided by the closed arms while the open arms offer exploratory value. Therefore, one might expect anxious rats to spend less time in the open arms than those that are less fearful.

When placed in an elevated plus-maze for the first time, a rat’s behaviour is largely based on its anxiety level. Normal rats that have not received any anti-anxiety drugs will become moderately anxious in this new environment. Thus, they tend to prefer the closed arms over the less secure open arms. Meanwhile, rats treated with anti-anxiety drugs (e.g., diazepam, commonly known as valium) tend to be less anxious, so they spend more time in the open arms compared to normal rats, and they are generally less active.

In this study, single or repeated treatments of the aqueous extract of gou teng (200 mg/kg/day, p.o.) for 7 days. Control rats were treated with an equal volume of saline, and positive control rats with buspirone (1 mg/kg).

The results showed that gou teng significantly increased the time-spent and entries into open arms of the elevated plus maze, and reduced the time-spent and entries into the closed arms versus saline controls.

However, there was no changes in spontaneous locomotor activity or myorelaxant effects were observed versus saline controls.

In the hole-board test, repeated treatment with the aqueous extract of gou teng (100 or 200 mg/kg/day, p.o.) significantly increased the number of head-dips.

In conclusion, the scientists said that gou teng, or Uncaria rhynchophylla, is an effective anxiolytic agent, and acts via the serotonergic nervous system.

[J Ethnopharmacol. 2006 Nov 24;108(2):193-7]