Tian ma

 GENERAL

Tian ma (Gastrodia elata) is an orchid. The tuber of this orchid has been used in Traditional Chinese Medicine (TCM) for a long time. "ma" is the name for hemp, among other things, and likewise for other fibrous long-stemmed plants such as ephedra (mahuang). The German name of Tian ma is "Himmelshanfwurzel".

Tian ma is found in the southwest, northeast and central regions of China, among others. It grows in clearings or on the edge of forests in humid mountainous areas at an altitude of 400-3200m. This medicinally important orchid does not produce leafy greens, and lives saprophytically, decomposing dead material. The entire growth cycle of Gastrodia elata takes place underground, except for the flowering phase when seeds are formed. In addition, Tian ma lives in a symbiotic association with Armillaria species, which are fungal species that provide nutrients and energy to the plant. Tian ma is very popular in Chinese medicine and is also a well-known "medicinal" food in China. Due to the increasing demand for Gastrodia elata as an herbal remedy in China, it is listed as rare and endangered (see Liu et al. 2015: 127). Gastrodia elata is equally used as a medicine in Taiwan, Japan, Korea, and India (see Chen et al. 2011: 31).

At least 5 forms of Gastrodia elata are cultivated in China: G. elata f. glauca, G. elata f.elata, G. elata f. viridis, G. elata f. flavida, G. elata f. alba. Whereas in China, G. elata f. glauca is mainly grown (see Wang et al. 2018: 167).

Tian ma is considered a first-class herbal medicine in China and has been used in Chinese medicine for a long time. In Shennong's classic materia medica (shen nong ben cao jing), it is considered to be related to the liver meridian (cf. Zhan et al. 2016: 4).

GASTRODIA ELATA IN TCM

The origins of acupuncture known from TCM can allegedly be dated back to 10,000 BC. Stone needles were used in an attempt to relieve pain and drain abscesses. Later, the techniques were systematized based on the principles of Taoist philosophy (Qi, Yin and Yang). Through observation it was found that the needle sensation radiates along a line, which ultimately led to the development of the theory of meridians (see Focks 2010: 6).

Tian ma is considered to be related to the liver meridian, which is associated with the regulation of mood according to TCM theory (see Lin et al. 2018: 222). Traditional TCM classics also state that this orchid can tonify qi and liver, strengthen the body, nourish yin, improve health, rejuvenate the body, and prolong life. In this regard, tian ma is described as being neutral in nature and sweet in taste (see Zhan et al. 2016: 8).

EFFECT AND DOSAGE IN TCM

The effects of tian ma are described as anticonvulsant, analgesic, and sedative, and it is also used against general paralysis, epilepsy, and tetanus (see Tang 1992: 545). Furthermore, it is also used against anxiety and depressive mood (see Lin et al. 2018: 133). Further indications include convulsions, headache, dizziness, twitching, and spasms for example. Liu et al. (2015) also describe its use in hypertension and neurodegenerative diseases.

The dosage given is 3-10 grams of the root, or 1-1.5g of the dried root powder (see Liu et al. 2005: 684). Although tian ma is considered a relatively safe herbal remedy, it is recommended not to exceed the dose, as side effects may occur.

PREPARATIONS IN TCM

Tian ma has great value in nutrition and health according to Liu (2015).

For example, tian ma is also prepared as wine, where the tuber of Gastrodia elata and other herbs, fruits, and barks are steeped in a Chinese spirit for at least one week. Furthermore, its use as a tea is also common. The orchid is also used as a "kitchen material", although the fresh tuber is often preferred. It is used, among other things, to flavor soup or porridge, and also meat, fish, chicken and rice (see Liu et al. 2015: 131).

SAFETY & TOXICITY

"Toxicity of Tian ma in humans is very low." (Liu et al. 2015: 132). Although Tian ma is considered a safe herbal medicine, it is suggested not to exceed the recommended dose. Improper use and overdose may result in side effects such as skin rash, dizziness, chest tightness, shortness of breath, nausea, and vomiting (see Liu et al. 2015: 132).

PHARMACOLOGY

A total of about 80 compounds have been isolated from Gastrodia elata, with about 80% of them still poorly defined until now. Gastrodia elata contains phenolic glycosides, organic acids, volatile oils, sterols, polysaccharides, etc., among others. Most significant in terms of action are the phenolic glycosides gastrodine and gastrodigenine which have anticonvulsant, sedative and analgesic effects.

The antiepileptic mechanism or components such as gastrodine, gastrodigenine, 4-hydroxybenzylaldehyde, vanillyl alcohol, and vanillin appear to act via the GABA signaling pathway, either by inhibiting the enzymes that degrade the neurotransmitter GABA or by a direct effect on the GABA/benzodiazepine receptor (see Liu et al. 2015: 130).

The phenolic compounds such as the aforementioned gastrodine, 4-hydroxybenzyl alcohol (4-HBA), or even vanillin play a significant role in neuropharmacology due to their antioxidant, anti-inflammatory, and neuroprotective effects (cf. Lin et al. 2018: 222).

GASTRODINE

The content of gastrodine in tubers of Gastrodia elata from different areas can vary, encompassing 0.16% - 1.18%. The content strongly depends on when the tubers are collected. For example, the content of gastrodin was 0.31% in September, 0.23% in December, and 0.93% in July (see Tang 1992: 545).

Studies have confirmed the sedative-hypnotic properties of gastrodine. It is suggested that even an ethanol extract of Gastrodia elata could improve pentobarbital-induced sleep behavior and REM sleep. In addition, studies have also confirmed the anticonvulsant effects of Gastrodia elata. There also seems to be an analgesic effect for example in headaches, neuralgia and rheumatic pain. In addition, anti-inflammatory properties have also been noted. In addition, it seems to have a direct inhibitory effect on the Vesicular Stomatitis Virus (VSV). It has also been observed in trials that gastrodine appears to slightly decrease the heart rate. This effect appeared to last up to 2 hours before the heart rate returned to normal (see Liu et al. 2016: 212).

ANTI-DEPRESSIVE EFFECTS?

Lin et al. point to studies that showed improvement in neurological disorders such as Alzheimer's, Parkinson's, and depression (see Lin et al. 2018: 133). They also refer to a study that attributes an effect to gastrodine similar to that of fluoxetine. However, this study did not involve testing in humans. Lin et al. state that MAO-A activity is reduced by gastrodine and thus there may be an effect on monoamines (=a group of neurotransmitters such as serotonin). Another neurotransmitter which interacts with monoamines is GABA. GABA seems to play an important role in anxiety and epileptic seizures. Lin et al. cite a study showing that derivatives of 4-HBA and vanillin inhibit GABA transaminase activity (=a process in the brain in which the neurotransmitter GABA is broken down and converted by an enzyme) (see Lin et al. 2018: 228).

SIDE EFFECTS & TOXICITY

Tang et al. describe Gastrodin had no toxic effects on mice when administered below 5g/kg orally or intravenously. According to Tang et al, gastrodine appears to be less effective than diazepam but has fewer side effects (see Tang et al 1992: 546).

Tian ma is generally described as nontoxic and without side effects when used in a prescribed manner. However, reports describe that allergic reactions, anaphylactic shock, and acute renal failure have occurred with intravenous administration of a tian ma extract. Administration of a very high dose (80g in 3 hours) resulted in flushing, dizziness, headache, visual disturbances, general weakness, loss of muscle coordination, and unconsciousness. Tian ma should not be taken during pregnancy or while breastfeeding (see Teoh 2016: 383).

NOTE

If diseases exist, it is not advisable to try to "cure" them with Tian ma on your own. A possible intake should be discussed beforehand with a doctor or a TCM specialist. Furthermore, no claim to the accuracy of the data collected!

Sources:

Chen, Pei-Ju et al. (2011): Gastrodiae Rhizoma (tian ma): a review of biological activity and anti-depressant mechanisms. In: Journal of Traditional and Complementary Medicine 1 (1): 31-40.

Focks, Claudia (2010): Leitfaden Chinesische Medizin. München: Urban & Fischer Verlag.

Lin, Yu-En et al. (2018): Recent Research Progress on the Anti-depressant like Effect and Neuropharmacological Potential of Gastrodia elata Blume. In: Current Pharmacological Reports (4): 220-237.

Liu, Chongyun et al. (2005): Chinese Herbal Medicine. Modern Applications of Traditional Formulas. New York: CRC Press LLC

Liu, Yanze et al. (2015): Dietary Chinese Herbs. Chemistry, Pharmacology and Clinical Evidence. Wien: Springer Verlag.

Liu, Yang et al. (2016): The Chemical Composition, Pharmacological Effects, Clinical Applications and Market Analysis of Gastrodia elata. In: Pharmaceutical Chemistry Journal 51 (3): 211-2015.

Theo, Eng Soon (2016): Medicinal Orchids of Asia. Switzerland: Springer International Publishing.

Wang, Zhi Wei et al. (2018): Chemical constituents from the rhizomes of Gastrodia elata f. glauca and their potential neuroprotective effects. In: Phytochemistry Letters 24: 167-171.

Zhan, Hong-Dan et al. (2016): The rhizome of Gastrodia elata Blume – an ethnopharmacological review. In: Journal of Ethnopharmacology (189): 361-385.