IngredientsLigustrazine has the chemical name tetramethylpyrazine, because it is a pyrazine ring with four symmetrically placed methyl groups; it is sometimes simply called TMP. It is classified as an alkylpyrazine. Its systematic IUPAC name is 2,3,5,6-tetramethylpyrazine, and it carries the CAS registry number 1124-11-4. It is also referred to by the synonyms Chuanxingzine, Chuanxiongzine, Ligustizine, and Tetrapyrazine in the chemical and pharmaceutical literature.
Ligustrazine appears as colorless needle crystals, is soluble in hot water, petroleum ether, chloroform, and dilute hydrochloric acid, is slightly soluble in ether, and insoluble in cold water. It has a melting point of 77–80°C and a boiling point of 190°C. Ligustrazine has a particular odor, moisture absorption, and sublimation.
Tetramethylpyrazine (ligustrazine, TMP) is a natural compound isolated from Chinese herbal medicine Ligusticum wallichii (Chuan Xiong), which has been extensively used for medicinal purposes for more than 2000 years. Ligustrazine, also known as tetramethylpyrazine, is an alkylpyrazine extracted from Chuan Xiong, a dry rhizome of the Chinese herb Ligusticum wallichii, that is widely used in China for the treatment of vascular diseases.
The herb has been obtained from Ligusticum chuanxiong (= Ligusticum wallichii) in China and from Cnidium officinale in Japan. Recent evaluation of the genetic material of these two source materials has led to the suggestion that they are, in fact, the same plant, and that Cnidium officinale should be renamed as Ligusticum chuanxiong.
Tetramethylpyrazine, also known as ligustrazine, is a chemical compound found in nattō and in fermented cocoa beans. It is also present in french fries, bread, cooked meats, tea, cocoa, coffee, beer, spirits, peanuts, filberts, dairy products, and soy products as a fragrance and flavouring ingredient. Its biosynthesis involves amination of acetoin, the latter derived from pyruvate.
The content of ligustrazine in Chuanxiong is only 0.01%–0.02%. The compounds contained in Ligusticum chuanxiong can be divided into five kinds: essential oil (EO), alkaloids, phenolic acids, phthalide lactones, and other constituents. Key bioactive compounds also include senkyunolide A, ligustilide, and Ligusticum chuanxiong polysaccharides (LCP).
TMP was firstly isolated in 1957 and has been increasingly studied for its action on myocardial and cerebral infarction since the 1970s. Isolated alkaloids from chuanxiong, and purified synthetic ligustrazine, have been used in China as medicinal agents for 30 years.
Ligustrazine is available in both naturally isolated and synthetically produced forms. The most widely used salt form of TMP in clinical therapy is TMP phosphate (TMPP). Clinical preparations documented in the published literature include intravenous infusion solutions, oral tablets, transdermal patches, and inhalation formulations. In a clinical trial for the treatment of pressure sores, ligustrazine was applied with a transdermal patch. For treatment of bronchial asthma, ligustrazine was administered by inhalation. For treatment of vertebrobasilar insufficiency, ligustrazine was administered intravenously (80 mg of ligustrazine in 250 mL of 5% glucose or 0.9% normal saline for 15 days). Ligustrazine is also frequently formulated in combination injectable preparations alongside other traditional Chinese medicine actives, most notably Salvia miltiorrhiza (danshen) extracts.
Ligusticum chuanxiong is mainly distributed in Sichuan Province, China, and was first recorded in the Divine Husbandman's Classic of the Materia Medica (Shen Nong Ben Cao Jing). The dried rhizomes of Ligusticum chuanxiong have the function of activating blood and promoting Qi, and were first recorded in the earliest complete pharmacopeia of China, Shennong Bencao Jing, from the Warring States Period to the Han Dynasty.
Since the rhizome of this plant was first described in Shennong's Classic of Materia Medica, it has been considered as 'qi medicine in the blood' in traditional Asian medicine because of its excellent efficacy in stimulating blood circulation and warding off winds; thus, it is used widely for various pain and gynecological diseases.
It has been used in Japanese, Korean, and other traditional medicine for over 2000 years. The rhizome of Ligusticum chuanxiong is warm in property and pungent in flavor, with functions of promoting the circulation of the blood and qi, expelling wind, and alleviating pain, and it has long been used as a traditional Chinese medicine in folk remedies and is widely applied in food preparation as a health protection.
Ligusticum wallichii has a long medicinal history in China and is used in the treatment of headache, promoting blood and Qi circulation, curing chills, and alleviating pain. Clinically, it is mainly used for the treatment of cardiovascular and cerebrovascular diseases.
Chuan Xiong's use dates back to the Shennong Bencao Jing, where it was listed as a top-grade herb for treating headaches, strokes, and menstrual issues. The Mingyi Bielu noted its ability to clear wind-related symptoms and stagnant blood.
In traditional Asian medicine, Ligusticum chuanxiong Hort is mainly used for improving blood circulation or for analgesic and anti-inflammatory purposes, and has a long history of use for pain disorders in the head and face, such as headache.
Ligusticum is considered one of the 50 fundamental herbs in Traditional Chinese Medicine. It is widely used to treat gynecological disorders and disorders due to blood clotting, including injuries and coronary and cerebral clotting. It is also commonly used to treat colds and flu, headaches, and neck and shoulder pain.
Classical TCM formulas incorporating ligustrazine-containing herb include Chuanxiong Chatiao San, a formula used historically for wind-related headache, which combined the herb with other botanicals. The concept of xue yu ("blood stasis"), an impairment of blood flow associated with pain, clotting, and circulatory dysfunction, has underpinned much of the traditional rationale for using this herb across East Asian medical traditions.
Ligustrazine (2,3,5,6-tetramethylpyrazine) is the main active ingredient of Ligusticum wallichii. Modern pharmacological research shows that its main ingredients are ligustrazine and ferulic acid. While the whole rhizome contains multiple bioactive constituents, the bulk of pharmacological research has focused on the isolated alkaloid TMP.
The structural formula of TMP shows that the pyrazine ring largely determines its pharmacodynamics, while the side chain is mainly responsible for its pharmacokinetics. The pyrazine ring on the TMP molecule is the key group for its pharmacological effect, but the methyl group in its side chain is easily excreted by oxidative metabolism, which leads to the short half-life of TMP and weakens its pharmacological effect.
TMP is a bioactive alkaloid with significant attention for its therapeutic potential in cerebrovascular diseases and cognitive impairment, mainly due to its antioxidant, anti-inflammatory, and anti-apoptotic properties. However, its clinical application is often limited by suboptimal pharmacokinetic characteristics and modest potency.
Aberrant activation of platelets has a critical role in thrombotic vascular events, including atherosclerosis, arterial thrombosis, and myocardial infarction. The process of platelet activation is associated with multiple intracellular signaling pathways, including the phosphoinositide 3-kinase/AKT serine/threonine kinase (Akt) pathway. As the most pharmacologically active component of Rhizoma Ligusticum Wallichii, ligustrazine has been demonstrated to possess a potent antiplatelet activity.
Tetramethylpyrazine was tested for its antiplatelet activities in human platelet suspensions. In human platelets, tetramethylpyrazine (0.5–1.5 mM) dose-dependently inhibited platelet aggregation, as measured by a turbidimetric method.
A key mechanistic pathway involves nitric oxide. In one study, TMP (50–200 µM) significantly increased production of nitrate and cyclic GMP in human platelets within a 15-minute incubation period. TMP concentration-dependently inhibited intracellular Ca²⁺ mobilization in human platelets stimulated by collagen (5 µg/mL). Furthermore, TMP concentration- and time-dependently triggered endothelial-type constitutive nitric oxide synthase (ecNOS) protein expression in human platelets. These results indicated that TMP at micromolar concentrations stimulated nitric oxide production in human platelets via a novel mechanism that activated ecNOS protein expression.
Ligustrazine is an inhibitor of phosphodiesterase, which has been widely used for the treatment of cardiovascular diseases in China. Modern pharmacological experimental studies showed that ligustrazine plays a vital role in antithrombosis in vivo; the mechanism seems to be related to the inhibition of platelet aggregation and protection of endothelium.
2,3,5,6-Tetramethylpyrazine (0.1 mM) induces vasodilation in precontracted isolated and endothelium-denuded rat tail artery strips and reduces blood pressure in anesthetized rats. TMP has the effects of inhibiting platelet aggregation, reducing blood viscosity, increasing coronary flow, scavenging free radicals, protecting cerebral vessels, and expanding renal vessels.
Experimental results showed that tetramethylpyrazine inhibited platelet adhesion to brain microvascular endothelial cells, alleviated expression of inflammatory cytokines and adhesion molecules on those cells. TMP protected brain microvascular endothelial cells and inhibited platelet adhesion after oxygen-glucose deprivation/reoxygenation injury, an effect partially mediated by inhibiting P38 MAPK and NF-κB signaling pathways.
Ligustrazine's anti-neuroinflammatory effects also involve microglial modulation. TMP is an active alkaloid in Ligusticum chuanxiong Hort and has various biological activities, including anti-inflammatory and neuroprotection properties.
Ligustrazine reduces kainate-induced increases in production of reactive oxygen species (ROS) and cytotoxicity in primary rat hippocampal neurons when used at a concentration of 5 µM. Rodent studies have demonstrated neuroprotective effects of tetramethylpyrazine against post-stroke brain injury and highlighted its role in antioxidant, anti-inflammation, and anti-apoptosis activity.
TMP decreases infarct volume, caspase-3 activation, and hypoxia-inducible factor-1α (HIF-1α) levels in a rat model of focal cerebral ischemia induced by middle cerebral artery occlusion (MCAO) when administered at a dose of 20 mg/kg.
Using permanent cerebral ischemia in rats and oxygen/glucose deprivation and reoxygenation in rat primary neuron/glia cultures, research has found that preservation or restoration of mitochondrial dynamics and functional integrity and alleviation of mitochondria-oriented pro-oxidant, pro-inflammatory, and pro-apoptotic cascades are alternative neuroprotective mechanisms of TMP.
In animal models, TMP exerts anti-atherosclerosis functions mediated by anti-inflammatory action, antioxidant action, amelioration of lipid metabolism disorder, protection of endothelial function, antiplatelet activity, reducing the proliferation and migration of smooth muscle cells, and inhibition of angiogenesis and antiplatelet aggregation.
Over the past two decades, there has been a growing body of evidence demonstrating the positive effects of ligustrazine on cerebral ischemic stroke in both in vivo and in vitro studies. A 2024 systematic review and meta-analysis published in Frontiers in Pharmacology (Wang et al.) comprehensively evaluated preclinical evidence. While numerous studies have delved into the neuroprotective effects and potential mechanisms of ligustrazine in cerebral ischemic stroke models, most have primarily focused on specific pathways or a limited set of efficacy indicators, and a comprehensive and quantitative analysis of the various mechanisms of action of ligustrazine in cerebral ischemic stroke has yet to be reported.
A meta-analysis of clinical trials in cerebral infarction is among the most cited human evidence. 19 RCTs totally involving 1,969 patients were included. The primary outcome measures were Neurological Deficit Score (NDS) and clinical effective rate. The secondary outcome measure was adverse events. Meta-analysis showed that ligustrazine could improve clinical efficacy and NDS of cerebral infarction with [OR = 3.60, 95% CI (2.72, 4.78), P < 0.00001] and [WMD = −3.87, 95% CI (−4.78, −2.95), P < 0.00001]. Moreover, ligustrazine in the treatment group exerted better clinical effects in improving the Blood Rheology Index (BRI) in patients compared with the control group.
Important limitations: All of the included studies claimed randomization, but only 1 study reported the method of random sequence generation. No study mentioned allocation concealment and blinding procedures. The dropout data were not reported in all of the included studies, and selective reporting was found in the majority of the trials. Due to the existing low-quality research, more large-scale and multicentric RCTs are required to provide clear evidence for its clinical efficacy.
In clinical applications, ligustrazine in high dosage (480 mg/day) was found to lower fibrinogen and improve blood circulation in patients who suffered a stroke.
A meta-analysis was designed to compare the efficacy and safety of ligustrazine preparations and conventional medicine by including 16 RCTs and 1,356 participants. Ligustrazine combined with conventional medicine was associated with an increased rate of marked improvement in symptoms and an increased rate of marked improvement of ECG compared with conventional Western medicine alone. Additionally, the use of ligustrazine was associated with significant trends in the reduction of the consumption of nitroglycerin and the level of fibrinogen when compared with conventional Western medicine alone. The meta-analysis found that ligustrazine was associated with some benefits for people with unstable angina.
A preclinical systematic review was conducted to investigate the efficacy of ligustrazine for animal models of myocardial ischemia/reperfusion injury and its possible mechanisms. Twenty-five studies involving 556 animals were identified by searching 6 databases from inception to August 2017. The methodological quality was assessed by using the CAMARADES 10-item checklist. Meta-analyses showed ligustrazine can significantly decrease the myocardial infarct size, cardiac enzymes, and troponin compared with control (P < 0.01). The possible mechanisms of ligustrazine for myocardial infarction are antioxidant, anti-inflammatory, and anti-apoptosis activities, and improving coronary blood flow and myocardial metabolism. The findings indicated that ligustrazine exerts cardioprotection through multiple signaling pathways in myocardial ischemia/reperfusion injury. This evidence is preclinical only; well-designed human RCTs in this specific indication remain scarce.
A meta-analysis of 25 randomized controlled trials conducted by Wang et al. suggests that ligustrazine improves renal function in patients with diabetic nephropathy. Studies in rodents and cultured cells indicate that this clinical benefit may be related to its anti-inflammatory properties.
In studies of rat diabetic nephropathy induced by streptozotocin, tetramethylpyrazine was shown to significantly improve renal function and down-regulate blood glucose and urine protein excretion in rats with diabetic nephropathy. Diabetic nephropathy resulted in an increase in the expression of vascular endothelial growth factor, while tetramethylpyrazine administration greatly decreased the expression. Clinical studies have shown that tetramethylpyrazine has a certain therapeutic effect on diabetic nephropathy and has high safety.
When combined with standard therapy, ligustrazine was shown to reduce the incidence of contrast agent-induced nephropathy in unstable angina patients undergoing coronary angiography and/or percutaneous coronary intervention. In rats with contrast agent-induced nephropathy, pretreatment with ligustrazine improved kidney function, normalized renal mitochondrial dynamics, and reduced renal expression of CCL2, CCR2, IL-6, and TNFα.
Ligustrazine has been shown to reduce renal macrophage infiltration and fibrosis in a rat model of obstructive nephropathy. The antifibrotic effects of ligustrazine have been further shown in TGF-β1-treated HK-2 cells, in which it reduces epithelial-to-mesenchymal transition and myofibroblast activation. The clinical translation of these renal fibrosis findings remains at the preclinical stage; robust human trials are lacking.
Ligustrazine has been shown to provide benefit in patients with bronchial asthma. For treatment of bronchial asthma, ligustrazine was administered by inhalation in clinical investigations. The strength of this evidence is limited; most published research is from smaller trials within China, and independent large-scale replication is lacking.
Ligustrazine has been shown to promote healing in patients with pressure sores. In a clinical trial for the treatment of pressure sores, ligustrazine was applied with a transdermal patch. Evidence in this area remains preliminary and is based on small clinical investigations.
As a major alkaloid in Ligusticum chuanxiong Hort, tetramethylpyrazine plays an increasingly significant role in the context of neurodegenerative diseases, including roles as an anti-inflammatory, antioxidative, and antiplatelet agent. Reviews focus on the latest advances in the roles and mechanisms of action of TMP in neurodegenerative diseases to stimulate new concepts and methods for prevention and treatment. Evidence in human neurodegenerative disease settings (such as Alzheimer's disease or Parkinson's disease) remains largely preclinical and in vitro; clinical data in human neurodegenerative conditions are not yet established.
In the past decades, researchers explored other pharmacological capabilities of TMP in various diseases, such as coronary heart disease, diabetes, cancers, and liver injury. Recent studies have indicated that tetramethylpyrazine possesses antitumor effects on hepatocellular carcinoma (HCC), but the detailed mechanism remains unclear. All evidence in the oncology domain is preclinical (cell lines and animal models). No clinical trials have established efficacy of ligustrazine as an antitumor agent in humans.
TMP has various pharmacological properties, including analgesia, anti-inflammatory, anti-tumor, anti-oxidative, anti-apoptotic, anti-angiogenic, endothelial protectant, blood activator, and stasis remover. Ligustrazine has been studied for conditions such as endometriosis, pregnancy-induced hypertension, and premature ovarian failure in Chinese-language literature, but these constitute limited, often small-scale clinical investigations without replication in high-quality international trials.
The absorption of TMPP (TMP phosphate) after oral administration is variable and incomplete, with low bioavailability of 10%–30%. Pharmacokinetic studies have shown that after oral or intravenous injection, TMP is mainly distributed in tissues such as liver, brain, kidney, and small intestine, and is eventually excreted from urine through the kidney.
A pharmacokinetic study in healthy human subjects provides the most detailed human data. The main pharmacokinetic parameters in this study were as follows: T½ was 1.79 ± 0.82 hours; Tmax was 0.76 ± 0.37 hours; Cmax was 961.14 ± 309.64 ng/mL; AUC0–12h was 1,744.69 ± 643.49 ng·h/mL. In this bioequivalence study, 20 healthy male subjects were randomly divided into two groups according to a two-period crossover design; a single oral dose of 200 mg test or reference tablets was given with a 7-day washout period under fasting conditions. The relative bioavailability of TMPP tablets was 102.4 ± 26.0%, and no serious adverse events were reported.
Ligustrazine and its numerous metabolites have outstanding pharmacokinetic characteristics, such as rapid metabolism, broad distribution, and no accumulated toxic effect.
Owing to the inherent low bioavailability of the oral form, researchers have investigated alternative delivery systems. The structure modification to improve the bioavailability has been broadly investigated, which opened new perspectives for drug discovery. During the past decades, over 300 novel TMP derivatives had been designed and synthesized.
Ligustrazine has a wide range of pharmacological activities, with high safety and fewer side effects. In the meta-analysis of cerebral infarction trials, ten trials contained safety assessments and stated that no obvious side effects were found. It is safe to use and has minimal adverse effects according to the reviewed gynecological literature; however, this general statement should be interpreted in the context of the mostly small and poorly blinded trials it is drawn from.
One of the common side effects of Ligustrazine Hydrochloride is gastrointestinal discomfort. Patients may experience symptoms such as nausea, vomiting, and abdominal pain. These side effects are generally mild and tend to resolve on their own without the need for medical intervention.
Another notable side effect is the potential for allergic reactions. Some individuals may develop hypersensitivity to Ligustrazine Hydrochloride, manifesting as skin rashes, itching, or more severe reactions such as angioedema or anaphylaxis.
Ligustrazine Hydrochloride may also affect the cardiovascular system. While it is often used to treat conditions related to blood flow and circulation, some patients may experience adverse cardiovascular effects, including palpitations, dizziness, and hypotension (low blood pressure).
Hematological side effects are also a concern. Some patients may experience changes in blood cell counts, including leukopenia (reduction in white blood cells) or thrombocytopenia (reduction in platelets).
One of the primary concerns regarding drug interactions is with other vasodilators and antihypertensive drugs. When taken together, these medications can cause an excessive drop in blood pressure, leading to symptoms such as dizziness, fainting, and hypotension. Careful monitoring and dose adjustments are necessary when these drugs are used concomitantly.
The anticoagulant effects of Ligustrazine Hydrochloride necessitate caution when used with other anticoagulants or antiplatelet agents, such as warfarin, heparin, or aspirin. Co-administration of these drugs can increase the risk of bleeding complications. In such cases, regular monitoring of coagulation parameters is advised.
Several overarching limitations bear emphasis across all areas of ligustrazine research. The majority of clinical trials originate from China and are published in Chinese-language journals, limiting independent international scrutiny. Methodological weaknesses are pervasive: all of the included studies in the cerebral infarction meta-analysis claimed randomization, but only 1 study reported the method of random sequence generation, and no study mentioned allocation concealment and blinding procedures. This pattern is representative of the broader clinical literature. Ligustrazine is rarely studied in isolation from combination formulas or standard care, making it difficult to attribute effects to the compound alone. Its clinical application is often limited by suboptimal pharmacokinetic characteristics and modest potency. Larger, multicentric, double-blind RCTs with standardized outcome measures are required in all major therapeutic areas before definitive conclusions about efficacy can be drawn.
Health conditions that Ligustrazin may help support.
Body systems that Ligustrazin may help support.
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