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.
Gastrodia elata extracts may be neuroprotective. For example, in cell culture models, Gastrodia elata extracts have been shown to possess neuroprotective effects. In particular, Gastrodia elata extracts have been shown to cause neurodegeneration by inhibiting stress related proteins and switching on neuroprotective genes. Administration of Gastrodia elata extract as a water solution is able to attenuate behavioural changes in rats when they are exposed to experimental stress. For example, one study showed increases in serotonin and dopamine turnover in cerebral tissue of rats after 4 weeks of exposure. Water extracts of Gastrodia elata are also able to significantly decrease corticosterone levels in rats. Both water extracts of Gastrodia elata and isolated gastrodin are also able to inhibit monoamine oxidase and have been shown to have antidepressant effects in rats. A number of chemicals have been isolated from Gastrodia elata extracts. These include a number of phenolic acids such as 4-hydroxybenzyl alcohol, 4-hydroxybenzaldehyde, vanillin, vanillyl alcohol gastrol and gastrodin. Of these gastrodin, 4-hydroxybenzyl alcohol and 4-hydroxybenzaldehyde have been shown to contribute significantly to the central nervous system effects of Gastrodia elata extracts. One study showed that whole extracts of Gastrodia elata as well as isolated gastrodin and 4-hydroxybenzyl alcohol all have antidepressant effects in rats. The antidepressant effects seen in these extracts are related to changes in monoamine levels in certain parts of the brain. Image from: By Qwert1234 – Qwert1234’s file, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9061124.
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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