Gastrodia elata is a perennial herb of the Orchidaceae (Orchid) family of plants. Gastrodia elata grows in parts of Asia including Nepal, Bhutan, Korea, Taiwan, Siberia, India and Japan. The plant grows in mountainous regions in forest clearings and it can reach approximately 2 meters in height, with a narrow stem and orange flowers. Gastrodia elata has a large rhizome (root) that has a historical use in traditional Chinese medicine, where it is used for its antioxidant, antiepileptic and anti-inflammatory properties. Gastrodia rhizome may also have certain effects on the central nervous system. For example, it has been shown that Gastrodia extracts may be useful in the treatment of convulsions. Convulsions are associated with a decrease in GABA levels and concomitant increase in glutamate levels in the brain. Gastrodia elata may attenuate these changes and prevent the development of convulsions. Gastrodia elata may also be useful in the treatment of anxiety, depression and stress.
The anxiolytic effects of Gastrodia elata have been studied in animals. For example, in one study, researchers investigated the mood elevating effects of Gastrodia elata in mice. Mice were administered an extract of Gastrodia elata or phenolic components extracted from the herb. When the mice were exposed to experimental stress, the gastrodia extracts significantly reduced the anxious behaviour of the mice. Of the phenolic constituents administered to the mice, both 4-hydroxybenzyl alcohol (HA) and 4-hyroxybenzaldehyde (HD) significantly reduced the anxious behaviour of the mice. The authors suggests that extracts of Gastrodia elata act on both the serotonergic and GABAergic systems in the mice. The effects on the serotonin system were likely elicited by 4-hydroxybenzyl alcohol, whereas the effects on the GABA system were likely elicited by the 4-hyroxybenzaldehyde. Therefore Gastrodia elata may have multiple mechanisms of action in the central nervous system and these may be due to the presence of phenolic acids.
Animal studies have also shown that extracts of Gastrodia elata may possess antidepressant effects. For example, in one study researchers administered Gastrodia elata extracts to rats that were exposed to experimental stress. The results of the study showed that the Gastrodia elata extracts conferred significant antidepressant effects on the rats. Analysis of the rats neurochemistry showed that the Gastrodia elata extracts had significantly increase dopamine turnover in the stratum of the brains of the rats. Also of note was the observation that the antidepressant effects of Gastrodia elata was superior to that of the selective serotonin reuptake inhibitor (SSRI) drug fluoxetine. In this case fluoxetine showed no benefits when compared to the placebo. Extracts of Gastrodia elata may therefore be a viable alternative to the use of prescription drugs for the treatment of depression. This antidepressant effect may be modulated in part through changes to the dopamine levels in certain parts of the brain.
In another animal experiment, researchers administered Gastrodia elata extract to rats and exposed them to experimental stress. A 21 day dosing of the Gastrodia elata extract to the rats had significant antidepressant effects on the rats, and these effects were similar to the selective reuptake inhibitor (SSRI) drug fluoxetine. There was also a significant increase in the concentrations of serotonin in the frontal cortex and dopamine in the stratum of the brains of the rats, suggesting that the Gastrodia elata extract had significantly modified monoamine levels. One of the phenolic components within Gastrodia elata, gastrodin, has also been investigated for its anxiolytic effects. Rats were administered gastrodin and then exposed to prolonged stress that was designed to model post-traumatic stress. The gastrodin was significantly able to attenuate the anxious behaviour of the rats following prolonged stress exposure. In addition, the gastrodin also decreased levels of a number of markers of inflammation.
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