Review of Effects of Active Components of Gastrodiae Rhizoma on Central Nervous

Hua ZHU, Piaoling HUANG, Wenqi YANG, Anda WEI, Ruiting HE, Zhonghua DAI

Guangxi University of Chinese Medicine, Nanning 530200, China; Key Laboratory of Zhuang and Yao Medicine of Guangxi, Nanning 530200, China

Abstract In order to explore the pharmacological effects of active components of Gastrodiae Rhizoma on the central nervous system, through consulting related literatures, this paper summarized the pharmacological effects of the active components of Gastrodiae Rhizoma. The pharmacological effects of the active components of Gastrodiae Rhizoma on the central nervous system include improving the ability of learning and memory, analgesia, sedation and hypnosis, anticonvulsant, anti-aging, anti-anxiety and neuroprotective effects. The active components of Gastrodiae Rhizoma have certain curative effect in the treatment of some diseases of the central nervous system. At present, it has been widely used clinically. There are no toxic and side effects at conventional doses, and it is worth popularizing and applying.

Key words Gastrodiae Rhizoma, Active components, Central nervous system, Pharmacological effects

1 Introduction

Gastrodiae Rhizoma is dry tuber ofGastrodiaelataBlume (Orchidaceae). Originally named as Chijian, initially recorded in theDivineFarmers’ClassicofMateriaMedica, and it was listed as premium medicinal product. There is also record of Gastrodiae Rhizoma inMateriaMedicaoftheKaibaoEra. It is a perennial parasitic plant. The host isArmillariamellea, and it takes mycelia or secretions of mycelia as nutrient sources.G.elatais mainly produced in Sichuan, Yunnan, and Guizhou. According to the records ofChinesePharmacopoeia2015 (Volume I)[1], Gastrodiae Rhizoma is sweet in taste, and slightly warm in nature, and has functions of extinguishing wind to arrest convulsions, pacifying the liver and suppressing yang, and dispeling wind to free the collateral vessels. The main active components of Gastrodiae Rhizoma are gastrodin,G.elatapolysaccharides and gastrodigenin, they have significant curative effects on treatment of headache, dizziness, epilepsy, hemiplegia and other neural pain. In this paper, we mainly summarized the pharmacological effects of Gastrodiae Rhizoma on the central nervous system[2-5].

2 Main pharmacological effects

2.1 Improving the ability of learning and memoryIn a rat model of vascular dementia induced by the left middle cerebral artery infarction, Zhang Leduoetal.[6]found that Gastrodiae Rhizoma can enhance the learning and memory ability of vascular dementia rats and reduce the acetylcholinesterase activity, increase acetylcholinease activity in the brain, reduced glutamate content, and they also observed that gastrodin has a significant protective effect on PC12 cell damage caused by hydrogen peroxide, they inferred that the mechanism of gastrodin against vascular dementia may be related to upregulating the cholinergic system, improving cellular energy metabolism, and scavenging the free radicals in the brain. Starting from the aspect related to vascular dementia (VD) and hippocampal tissue damage, Duan Xiaohuaetal.[7]performed the experiment of Gastrodiae Rhizoma extract on VD model rats in a Morris water maze and found that Gastrodiae Rhizoma extract can reduce the MDA content in hippocampus of vascular dementia rats, while increased the activity of SOD and GSH-PX and the ratio of SOD/MDA. They speculated that Gastrodiae Rhizoma extract can improve the learning and memory ability of VD model rats through reducing lipid peroxidation and oxidative damage. After administering mice in different groups different doses ofG.elatapolysaccharides for 8 weeks, Xie Xueyuanetal.[8]tested the learning and memory abilities of mice with Morris water maze. Experimental data show that the gastrodin high dose group can significantly improve the escape latency of aging mice in the Morris water maze. Gastrodia water-soluble polysaccharide (PGEB-3-H) can improve the learning and memory ability of mice with memory impairment caused by scopolamine[9].

2.2 Analgesic effectsUsing the randomized control method, Guo Xueting and Nie Yongxia[10]selected 90 migraine patients and randomly divided them into gastrodin treatment group and control group, then they carried out univariate experiments to observe the intensity of pain, the frequency of headache attacks, the duration, the effective rate of treatment and the total effective rate of the migraine in gastrodin treatment group and control group after treatment. The experimental results show that gastrodin can shorten the course of the disease and improve the symptoms of headache, and the recent effects are satisfactory without obvious adverse reactions. In experimental research, Xu Minetal.[11]used an animal model of chronic sciatic nerve compression injury caused by surgery on some rats, and randomly divided SD rats into a sciatic nerve chronic compression injury group and a sham operation group, and a sciatic nerve chronic compression injury group, and the sciatic nerve chronic compression injury group was divided into control group and experimental group. They used electronic Von-Frey Anesthesiometers to measure the reflex threshold of rat mechanical withdrawal. According to their experimental results, gastrodin can reduce neuropathic pain in rats, and they believed that its mechanism may be related to the inhibition of spinal dorsal horn and dorsal root ganglion pERK1/2 pathway activation. The mechanism of gastrodin in preventing migraine attacks may be associated with regulating the release of monoamine neurotransmitters and the recovery of metabolic mechanisms in the body, accordingly improving brain and blood vessel dysfunction[12]. At present, experimental and clinical studies have proven that gastrodin has obvious analgesic effects and gastrodin can significantly improve the symptoms of migraine, shorten the course of treatment, but it has no obvious adverse reactions[13]. The mechanism of analgesic action of Gastrodiae Rhizoma extract[14]may be achieved through inhibiting the release of 5-HT in serum, inhibiting the release of peripheral pain substances, reducing SP, inhibiting 5-HT peripheral receptors, metabolites, and reducing the depolarization of pain-receptor receptors, increasing the depolarization of anti-pain receptors, reducing the impulse to send pain information, affecting certain neurons associated with pain-related nuclei, and activating analgesics.

2.3 Sedative and hypnotic effectsShi Lingetal.[15]carried out acupoint injection of gastrodin and acupuncture gastrodin on 80 patients with insomnia. After conducting a feasibility experiment, from the experimental data, they concluded that the acupoint injection of gastrodin injection has a good effect on the treatment of insomnia. Tang Daxuanetal.[16]determined the sedative effect of Gastrodiae Rhizoma extract (hereinafter referred to as TM) through experiments on synergistic effect of pentobarbital sodium on the sleep time of mice and the sub-hypnotic dose in mice. Experiments have shown that TM 10 g/kg can significantly prolong the sleeping time of mice, and TM 20 g/kg can significantly increase the sleeping rate of mice under the pencobarbital dose, which is significantly different from the control group. Subsequent studies have shown that gastrodin has a certain effect on improving hypnosis in mice. Through administering 0.3 mg/mL gastrodin to mice (2 mL/piece), Zou Ningetal.[17]found that gastrodin had a significant inhibitory effect on the autonomic activity of mice, significantly shortened the time required for mice to fall asleep and increased the sleepiness index compared with sodium barbiturate, it had a more significant inhibitory effect on the autonomic activity of mice, and it could effectively shorten the time required for the mice to fall asleep, increase the sleepiness index, and gastrodin and barbiturate have a synergistic effect on sedation and hypnosis.

2.4 Anticonvulsant effectsUsing the method of mouse electric convulsions and the method of mouse pentylenetetrazole (PTZ) convulsions, Tang Daxuanetal.[16]explored the anticonvulsant effects of TM. According to their experimental results, TM 20 g/kg can significantly reduce the convulsive rate of electroconvulsant mice and pentylenetetrazole mice, and has significant differences with the control group. According to the research by Lian Yajunetal.[18], none of the rats in the topiramate (TPM) group and the Gastrodiae Rhizoma group reached the ignition standard, epilepsy-like discharges on the EEG were significantly suppressed, and the density of growth-associated protein (GAP-43) immune response products in the hippocampus increased, indicating that gastrodin has an antiepileptic effect and can inhibit the overexpression of GAP-43 in the hippocampus, and both TPM and gastrodin have the same anticonvulsant effect.

2.5 Anti-aging effectsAfter giving mice of different groups different doses ofG.elatapolysaccharide for 8 weeks, Xie Xueyuanetal.[8]measured the activities of superoxide dismutase, glutathione peroxidase and monoamine oxidase and the content of malondialdehyde in mice. From the results of the high dose treatment group, it can be seen that the recovery of neurons in the brain tissue was obviously promoted, and the enzyme activities of superoxide dismutase and glutathione peroxide in the blood of aging mice were significantly increased. In studying the effects of gastrodin on the expression of aging-related genes in the hippocampus and the frontal cortex of fast-aging mice, Wang Zhaojunetal.[19]found that gastrodin can regulate the expression level of some aging genes to exert its own anti-aging, but the effect of gene regulation on aging is not obvious for the late stage of aging. According to the study by Kong Xiaoweietal.[20], continuous subcutaneous injection of 5% D-galactose into the neck and back of mice for 42 consecutive days can cause a subacute aging model; through measuring the activity of antioxidant enzymes and lipid peroxides in the serum and cells of model mice, they found that in model group mice, the superoxide dismutase SOD, catalase CAT, glutathione GSH-Px activity decreased significantly, while MDA content increased significantly. By contrast, after 32 d of administering Gastrodiae Rhizoma polysaccharide, the above parameters of aging model mice were significantly improved or got close to normal levels. These indicate that Gastrodiae Rhizoma polysaccharide may play a role in delaying cell senescence by scavenging excess free radicals and reducing the content of MDA.

2.6 Anti-anxiety effectsClinical observation has shown that gastrodin has an adjuvant effect on anxiety neurosis with a total effective rate of 100%[21]. After a field survey, through sampling the cases of neurotic anxiety in the hospital, Zhang Jin[22]performed a targeted treatment with gastrodin and found that gastrodin had a significant effect in the treatment of neurotic anxiety. This provides a reference for gastrodin in the treatment of anxiety.

2.7 Neuroprotective effectsAt present, the neuroprotective effect of gastrodin in Gastrodiae Rhizoma is a hot topic both at home and abroad. In the limited craniocerebral injury model produced by the hydraulic craniocerebral injury instrument, Liu Jianxinetal.[23]found that gastrodin has protective effect on limited craniocerebral injury, and its mechanism is related to excitatory amino acids and calcium content in brain tissue. After studying the effects of gastrodin on apoptosis and S100 β and inducible nitric oxide synthase protein expression in rats with transient middle cerebral artery occlusion, Yang Jieetal.[24]believed that gastrodin could inhibit apoptosis of cells and thus has a protective effect on nerves.

3 Conclusions and prospects

Gastrodiae Rhizoma is a valuable Chinese medicine. The active components of Gastrodiae Rhizoma are widely applied in the clinical treatment of central nervous system diseases. After consulting related literature of active components of Gastrodiae Rhizoma, we summarized pharmacological effects of the active components of Gastrodiae Rhizoma on the central nervous system, including improving the ability of learning and memory, analgesia, sedation and hypnosis, anticonvulsant, anti-aging, anti-anxiety and neuroprotective effects. We intended to provide some references for the follow-up in-depth study of Gastrodiae Rhizoma in central nervous system diseases, and provide a practical guiding significance for developing the medicinal value of Gastrodiae Rhizoma. Besides, it is expected to provide some value for Gastrodiae Rhizoma in beauty and health care. For example, Gastrodiae Rhizoma has anti-aging effects. It is necessary to study whether it is possible to extract its active components in future studies and add them to beauty products to become a new generation of beauty drugs.