Schisandrins: A Comprehensive Reference
1. Identity, Botanical Source, and Common Names
Schisandrins (also spelled schizandrins) are a group of bioactive chemical compounds found in Schisandra rubriflora, Schisandra sphenanthera, and Schisandra chinensis. Schisandrin itself is classified as a lignan. The parent plant, Schisandra chinensis (Turcz.) Baill., belongs to the family Schisandraceae, and its fruits are the primary commercial and medicinal source of these compounds.
Native to northeastern China and eastern Russia, this climbing plant is widely distributed in the northeastern part of China, Korea, and Japan. Schisandra is a deciduous woody vine that can grow over 20 feet long, high into the tree canopy of wild forests of eastern Asia, with clusters of white flowers followed by medicinal red berries that are often wild-harvested from these biodiverse habitats.
The fruit is internationally known under a variety of names. Schisandra is best known for its medicinal red berries that are a distinctive combination of five different flavors: sweet, sour, salty, bitter, and pungent — because of this, schisandra berry is called wu wei zi, or "five flavors fruit," in China. Other recorded common names include Gomishi and Kita-gomishi (Japanese), Omiza (Korean), and Limonnik (Russian).
The plant's scientific names recognized across species include Schisandra arisanensis Hayata, Schisandra chinensis (Turcz.) Baillon, Schisandra fructus, Schisandra rubriflora Franch., and Schisandra sphenanthera Rehd.
Common Preparations and Dosage Forms
According to the Chinese Pharmacopoeia, the standard preparation consists of 3–9 g of dried berries, typically decocted in water for oral administration or processed into pills or powders. Existing Schisandra chinensis preparations are also available as alcoholic tinctures and are used in the form of drops. Modern supplement formulations include standardized extracts (standardized to schisandrin and/or gamma-schisandrin content), encapsulated powders, and concentrated liquid extracts. Traditionally, the berries are harvested in the fall, dried, and then ground to make the powdered medicinal herb. Schisandra chinensis fruit has been included in the list of available healthy foods by the Ministry of Health of China since 2002.
2. Traditional and Historical Use
Its medicinal use dates back to the Eastern Han Dynasty (25–220 AD), as recorded in the Shennong Bencao Jing (Divine Farmer's Materia Medica), where it was documented to have astringent, qi-tonifying, fluid-generating, kidney-nourishing, and heart-calming properties according to Traditional Chinese Medicine (TCM) theories. It was first written about in the first century BC in China's first herbal encyclopedia, Shen Nong's Materia Medica, where it was listed as a "superior herb."
The renowned Ming Dynasty pharmacologist Li Shizhen explicitly noted in the Bencao Gangmu (Compendium of Materia Medica) that Schisandra chinensis was used to treat liver deficiency syndromes.
Schisandra has a long history of use in traditional Chinese medicine to treat liver conditions, stomach disorders, and as a tonic to improve vitality; it is also used in various formulas for fatigue and sleep. The fruit was used as an astringent tonic to astringe the lungs and the kidneys, replenish energy, promote the production of body fluids, tonify the kidney, and induce sedation.
Though schisandra is believed to benefit all systems of the body with its dynamic full range of the five tastes, it is said to benefit all the five yin organs: the Liver, Kidneys, Heart, Lungs, and Spleen.
Beyond China, the plant also has documented use in Russia. Centuries ago in Russia, it was used by the Nanai people to promote stamina for hunters going on long voyages without much rest or nourishment. In TCM formulation practice, Shengmai San (SMS), first recorded in Yi Xue Yuan Li and one of the most famous Chinese herbal formulae, consists of Panax ginseng, Ophiopogon japonicus, and Schisandra chinensis in a dosage proportion of 5:3:1.5.
3. Key Constituents and Active Compounds
The major bioactive compounds of Schisandra chinensis include phenolic acids, triterpenoids, and lignans, along with other constituents such as polysaccharides, essential oils, and vitamins, found in various parts of the plant, including its flowers, leaves, seeds, stems, and fruits. Among these compounds, lignans — a unique class of polyphenolic compounds — have garnered particular interest because of their diverse biological activities, including the modulation of immune responses and the regulation of cellular signaling pathways.
The most active lignans are dibenzocyclooctadiene derivative lignans such as schisandrin, schisandrin A, schisandrin B, schisandrin C, gomisin A, gomisin B, gomisin C, gomisin G, gomisin J, and gomisin K3.
Lignans are common components of S. chinensis, formed as secondary plant metabolites by oxidative dimerisation of two phenylpropanoid units, connected by a β,β′-ether bond, which constitutes the basic chemical structure. Lignans occur in various parts of the plant, primarily in the fruit, but also in the seeds, shoots, and leaves.
So far, 358 dibenzocyclooctadiene lignans have been reported, with 37 of them exhibiting hepatoprotective effects.
The principal individual schisandrins are described below:
- Schisandrin (Schisandrin A / Deoxyschisandrin): Schisandrin A (Sch A) and schisandrin B (Sch B) are the most abundant active dibenzocyclooctadiene lignans in the fruits of Schisandra sphenanthera and Schisandra chinensis, respectively. Schisandrin A is recognized for attenuating ferroptosis and necroptosis triggered by hyperglycemia, conferring anti-inflammatory advantages and presenting a potential diabetes therapy.
- Schisandrin B (Sch B / Gomisin N): Schisandrin B is isolated from Schisandra chinensis and documented to possess diversified pharmacological properties, among them antioxidant, anti-inflammation, cardioprotection, and neuroprotection.
- Schisandrin C: Bifendate (DDB) and bicyclol are synthetic analogues of schisandrin C, the most effective compound found in Schisandra fruit against liver injury.
- Schisandrol A and B (Gomisin A): Schisandrol B exhibits notable protective effects against acetaminophen-induced hepatotoxicity through the activation of the Nrf2/ARE pathway.
- Schisantherin A: Schisantherin A markedly curtails oxidative stress and inflammation induced by isoproterenol, offering prophylactic protection against myocardial infarction-induced cardiac injury.
- Gomisin A: Gomisin A is one of the most abundant bioactive lignans in S. chinensis with a significant CYP3A inhibitory effect.
Lignans such as schisandrin and gomisin A are highly lipophilic, which limits their solubility in water, making their absorption in the GI tract inefficient. After oral administration, these compounds often undergo extensive first-pass metabolism in the liver, where they are rapidly metabolized before reaching systemic circulation.
4. Mechanisms of Action
4.1 Antioxidant and Cytoprotective Pathways
The most extensively characterized mechanism of schisandrins involves modulation of the cellular antioxidant defense system, particularly through the Nrf2 pathway. Schisandrin B causes a time-dependent activation of MAPK in AML12 hepatocytes, particularly ERK1/2; this MAPK activation is followed by an enhancement in Nrf2 nuclear translocation and the eliciting of a glutathione antioxidant response. Schisandrin B triggers a redox-sensitive ERK/Nrf2 signalling pathway, which then elicits a cellular glutathione antioxidant response and protects against oxidant-induced apoptosis.
The hepatoprotective effects of Sch B are associated with attenuating oxidative stress by activating nuclear factor-erythroid 2-related factor 2 (Nrf2)-mediated antioxidant signaling and suppressing hepatic stellate cell activation by inhibiting the transforming growth factor-β (TGF-β)/Smad signaling pathway.
4.2 Anti-Inflammatory Mechanisms
Pre-incubation with Sch A or Sch B produces an anti-inflammatory action in LPS-stimulated RAW264.7 cells, as evidenced by the inhibition of the pro-inflammatory c-Jun N-terminal kinases/p38 kinase/nuclear factor-κB (NF-κB) signaling pathway as well as the suppression of various pro-inflammatory cytokines and effectors. Upon incubation, Sch B results in the activation of the nuclear factor (erythroid-derived 2)-like factor 2 (Nrf2) and the induction of a significant increase in the expression of thioredoxin (TRX).
Schisandrin A and Schisandrin B alleviate hepatic inflammation and oxidative damage in vivo by increasing hepatic β-oxidation and fatty acid oxidation, inhibiting lipid peroxidation, and regulating the NF-κB/p38/ERK MAPK and Nrf2/HO-1 signaling pathways.
4.3 Hepatoprotective Mechanisms
Liver protection is one of the most prominent pharmacological effects of Schisandra chinensis, as its fruits and extracts are widely used in China to manage chemical and viral liver injuries; this protective effect is mediated through multiple mechanisms, including enhanced liver detoxification and tissue regeneration.
Enhanced cytochrome P450 activity, glutathione production, and glycogen synthesis have been observed in preclinical models, improving detoxification and regeneration capacity.
4.4 Adaptogenic and Neuroprotective Mechanisms
The stress-protective activity of adaptogens including schisandrin-containing preparations has been linked with the hypothalamic-pituitary-adrenal (HPA) axis and the regulation of key mediators of stress response, such as molecular chaperons (e.g., HSP70), stress-activated c-Jun N-terminal protein kinase 1 (JNK1), Forkhead box O (FOXO) transcription factor DAF-16, cortisol, and nitric oxide.
It has been demonstrated that schisandrin B stimulates the expression of Hsp70 in normal cells, which is associated with the enhancement of mitochondrial glutathione status, antioxidant activity, ATP generation, mitigation of age-related impairments in mitochondrial antioxidant status and functional ability in various tissues, and enhancement in cognitive functions and an increase in the survival of aging in rodents.
Animal studies showed that 26 days of co-administration of Sch B significantly improved the behavioral performance of amyloid-β (Aβ 1–40)-infused rats in step-through tests; Sch B attenuated Aβ-induced increases in oxidative and nitrosative stresses, inflammatory markers such as inducible nitric oxide synthase, cyclooxygenase-2, interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α, and DNA damage.
4.5 Cytochrome P450 Interactions
A key challenge in the pharmacology of schisandrins lies in their interaction with drug-metabolizing enzymes, particularly cytochrome P450 enzymes and especially CYP3A4, which is involved in the metabolism of many drugs; this interaction can lead to potential drug–drug interactions where the concurrent use of Schisandra chinensis with other medications might either inhibit or induce the metabolism of those drugs, causing either toxicity or reduced efficacy.
5. Scientific Evidence by Area of Use
5.1 Liver Protection (Hepatoprotection)
Preclinical Evidence (Strong): Many studies have demonstrated that Schisandra chinensis exhibits hepatoprotective effects in various murine models of liver injury. A 2025 systematic review and preclinical meta-analysis published in Frontiers in Pharmacology assessed Schisandra chinensis across multiple animal models of liver injury. Compared with the model group, all intervention groups demonstrated significant reductions in AST levels. In animal models, Schisandra extracts decreased inflammatory cytokines and oxidative stress markers and increased endogenous antioxidant activity, suggesting utility in mitigating liver inflammation and damage; additional preclinical studies demonstrated attenuated liver enzyme levels, necrosis, and fibrosis progression in chemical-induced hepatotoxicity with Schisandra treatment.
Clinical Evidence (Limited but Positive): A limited number of human clinical trials have examined the effects of Schisandra chinensis on liver function and disease progression, with modest evidence for hepatoprotective effects. Small human trials in hepatitis and nonalcoholic fatty liver disease showed improved liver enzymes and symptoms with Schisandra supplementation but were limited in quality and sample size.
Clinically Translated Drugs: The most direct clinical evidence for schisandrin-derived hepatoprotection comes from pharmaceutical agents derived from schisandrin C. Bicyclol is a synthetic derivative of Schisandrin C, one of the dibenzocyclooctadiene lignans found in the fruit of Schisandra chinensis. Bicyclol functions primarily as a hepatoprotective agent, exerting its effects through potent antioxidant activity, significant anti-inflammatory effects, induction of cellular autophagy, stimulation of heat shock protein expression, and antiviral properties — particularly against Hepatitis B Virus; it has achieved regulatory approval and established clinical use in China for drug-induced liver injury (DILI) and the management of elevated transaminases in chronic hepatitis. Bifendate (DDB), a synthetic intermediate of Schisandrin C extracted from Schisandrae chinensis, is clinically used to treat hepatitis in China. Seven Schisandra fruit-derived drugs, including preparations of Schisandra extracts, DDB, and bicyclol, are marketed in China.
The lignan extract of Schisandra chinensis as a hepatoprotectant has been widely used along with routinely prescribed agents to treat viral and drug-induced hepatitis in China in acute or chronic liver disease.
Evidence Strength: Preclinical evidence is robust; clinical human evidence from well-powered randomized controlled trials remains limited, though the derivation of approved hepatoprotective drugs (bifendate, bicyclol) from these same lignans provides indirect clinical validation of the biological activity.
5.2 Adaptogenic and Anti-Stress Effects
Preclinical/Animal Evidence: In animal studies, in the placebo group, p-SAPK/p-JNK, NO, and cortisol were increased significantly (by 200–300% compared to basal levels) following restraint stress, whilst in animals that had received multiple doses of adaptogens/stress-protectors, the levels of NO and cortisol remained practically unchanged.
Clinical Evidence: Studies on animals and isolated neuronal cells have revealed that adaptogens exhibit neuroprotective, anti-fatigue, antidepressive, anxiolytic, nootropic, and CNS stimulating activity; additionally, a number of clinical trials demonstrate that adaptogens exert an anti-fatigue effect that increases mental work capacity against a background of stress and fatigue, particularly in tolerance to mental exhaustion and enhanced attention. Clinical trials using Schisandra chinensis on mental performance in humans (13 studies) have been the subject of systematic review. In a systematic review of medicinal plants and their impact on the microbiome-gut-brain axis, results from 3 clinical studies provided support for the beneficial effects of S. chinensis in anxiety and depression via the MGBA; the fruit extract, particularly the lignans, were found to be the most effective in the relief of anxiety and depressive disorders, whereas a polysaccharide-rich extract was able to regulate intestinal homeostasis and reduce potentially harmful bacteria.
Evidence Strength: Animal and in vitro evidence for anti-stress effects is consistent. Human clinical evidence is suggestive but derives from small, methodologically variable trials. Robust, large-scale RCTs specifically isolating schisandrins in humans are lacking.
5.3 Physical Performance and Muscle Function
Clinical Evidence: In a randomized, double-blind, placebo-controlled trial of adult women supplemented with Schisandra chinensis extract for 12 weeks, quadriceps muscle strength (QMS) showed a significant interaction in ANOVA results (p = 0.001), and with paired t-tests, QMS was significantly increased (p < 0.001) and lactate level at rest was significantly decreased (p < 0.05) after 12 weeks in the SC group. Supplementation of SC extract may help to improve QMS as well as decrease lactate level at rest in adult women.
A randomized, double-blind, placebo-controlled trial involving 54 elderly participants reported significant increases in muscle performance without any noted side effects.
In a clinical study, schisandra tablets containing 91.1 mg of extract per tablet (extract standardized for schisandrin and gamma-schisandrin at a level of 3.1 mg/tablet) were used to improve athletic performance.
Evidence Strength: Preliminary positive signal in small, controlled human trials. Insufficient large-scale replication to establish clinical efficacy definitively.
5.4 Neuroprotection and Cognitive Function
Preclinical Evidence: Schisandrin, a principal component, has been demonstrated in animal models to modulate intestinal flora, consequently diminishing hippocampal neuron loss and ameliorating the cognitive deficits linked to Alzheimer's disease. Schisandrin B, an antioxidant lignan from Schisandra chinensis, has been shown in preclinical studies to protect mouse brain against scopolamine- and cisplatin-induced neuronal dysfunction.
Animal research showed that 26 days of co-administration of Sch B significantly improved the behavioral performance of Aβ (1–40)-infused rats; at the same time, Sch B attenuated Aβ-induced increases in oxidative and nitrosative stresses, inflammatory markers, and DNA damage.
Evidence Strength: Animal and cell-based evidence for neuroprotection is substantial. Human clinical evidence for cognitive enhancement or neuroprotection with isolated schisandrins is currently limited and preliminary. Animal studies suggest it may improve mental and physical functioning, but only a small number of studies have been conducted in humans and are too limited to draw any conclusions.
5.5 Cardiovascular Protection
Preclinical Evidence: Schisandrin B has been proved to possess anti-inflammatory, antioxidant, and anti-endoplasmic reticulum (ER) stress effects in many rodent tissues. In a rat myocardial ischemia-reperfusion (I/R) injury model, male healthy rats were randomly divided into five groups receiving Sch B at 20, 40, or 80 mg/kg, and Sch B treatment significantly protected against myocardial I/R injury, as demonstrated by the decrease in the percentage of infarct formation.
Schisandrin B has been shown to protect against doxorubicin (Dox)-induced acute cardiotoxicity via enhancing cardiomyocytic glutathione redox cycling that could attenuate oxidative stress generated from Dox. Many studies have shown that the lignans schisandrin, schisandrol B, schisantherin A, deoxyschisandrin, and schisandrin B are major components responsible for treating coronary heart disease, according to preclinical and TCM clinical formulation research.
In a murine model, schisandrin B conferred dose-dependent protection against brain infarction caused by cerebral ischemia/reperfusion, with protection ranging from 10% to 33%.
Evidence Strength: Cardioprotective data is largely preclinical (animal models). Further clinical studies are mandatory to determine whether Sch B is really cardioprotective in clinical settings. No large-scale human RCTs for primary cardiovascular endpoints have been published as of available evidence.
5.6 Anti-inflammatory and Immune Modulation
Schisandrin B is a dibenzocyclooctadiene derivative used commonly in traditional Chinese medicine for the treatment of hepatitis and myocardial disorders and has been shown to modulate cellular redox balance. Sch B alters the redox status of lymphocytes by enhancing basal reactive oxygen species levels and altering the GSH/GSSG ratio; it induces nuclear translocation of the redox-sensitive transcription factor Nrf2 and increases the transcription of its dependent genes; and it inhibits mitogen-induced proliferation and cytokine secretion by lymphocytes.
Modern pharmacological studies have revealed that Schisandra chinensis exhibits anti-inflammatory, immunomodulatory, antitussive, and antiasthmatic properties, making it clinically valuable for treating disorders of the central nervous system, cardiovascular system, digestive system, and endocrine system.
Evidence Strength: Evidence is primarily in vitro and animal-based. Human data on immune modulation by isolated schisandrins is not robustly established.
6. Body Systems and Health Areas of Association
- Hepatic system: The fruit, rich in active constituents like lignans, organic acids, polysaccharides, and triterpenoids, is traditionally employed for liver protection, immune enhancement, and cardiovascular defense.
- Central nervous system: Neuroprotection, cognitive function support, sedation, adaptogenic stress response (preclinical and limited clinical evidence).
- Cardiovascular system: Cardioprotection from ischemia-reperfusion injury and chemotherapy-associated cardiotoxicity (mainly preclinical).
- Respiratory system: The fruits have been used in traditional herbal medicine to treat chronic coughs, enuresis, fatigue, night sweats, and insomnia.
- Musculoskeletal system: Improvement in muscle performance and reduction of exercise-related lactate (preliminary human clinical evidence).
- Endocrine/adrenal system: HPA axis modulation, cortisol regulation (animal and limited human evidence).
- Gastrointestinal system: Gut microbiota modulation (in vitro and animal evidence; limited clinical signal for mood-related outcomes via gut-brain axis).
7. Dosage Forms and Reported Study Dosages
The following dosages are reported directly from identified scientific sources and are not extrapolated:
- Adaptogenic use (powdered fruit): 1.5 to 6 g/day of powdered product.
- Chinese Pharmacopoeia standard: 3–9 g of dried berries, decocted in water for oral administration or processed into pills or powders.
- Athletic performance (clinical tablet study): Schisandra tablets containing 91.1 mg of extract per tablet, standardized for schisandrin and gamma-schisandrin at 3.1 mg/tablet.
- Cardioprotective (rat ischemia-reperfusion model): Sch B at doses of 20 mg/kg, 40 mg/kg, and 80 mg/kg body weight.
- Chronic cardiotoxicity prevention (rat model): Sch B given intragastrically at 50 mg/kg two hours prior to doxorubicin (2.5 mg/kg) weekly over a 5-week period.
- Ischemia-reperfusion prevention (rat model): Sch B administered via oral gavage at 20 mg/kg, 40 mg/kg, and 80 mg/kg once daily for 5 days before surgery.
8. Safety Considerations and Drug Interactions
8.1 General Tolerability
Clinical studies have consistently demonstrated the safety profile of Schisandra chinensis, highlighting its promise as a well-tolerated therapeutic agent; a study examining its effects on hypertension found no recorded side effects, further confirming its short-term safety and tolerability.
Some adverse effects have been reported, including heartburn, gastric upset, and urticaria. Long-term human safety is not well established: while some sources suggest Schisandra can be taken long-term based on traditional use, modern clinical data on chronic use beyond 12 weeks is limited.
8.2 Pregnancy and Special Populations
Schisandra is not recommended for use during pregnancy, lactation, or for young children. Various compounds from the stem of Schisandra propinqua were cytotoxic against rat luteal cells and human decidual cells in vitro. The safety of schisandra for pregnant or nursing women, children, or people with severe liver or kidney disease has not been established.
8.3 Drug Interactions via CYP Enzyme Modulation
Schisandrins are among the most clinically significant herbal constituents with respect to pharmacokinetic drug interactions due to their potent modulation of cytochrome P450 enzymes and drug transporters.
Clinically important herb–drug interactions with Schisandra lignans as the perpetrators have been reported for midazolam, sirolimus, and tacrolimus; administration of S. sphenanthera extract in Chinese transplant recipients expressing CYP3A5 enzyme reduced by 40% the tacrolimus dose required to achieve the predefined target of trough blood concentrations.
Schisantherin A and Schisandrol B, but not Schisandrin A, potently inhibited CYP3A4-mediated metabolism; all three compounds showed a strong reversible inhibition on CYP2C8 enzyme with Ki of less than 0.5 μmol/L.
In vitro studies indicated that schisantherin A (STA) was a time-dependent and reversible inhibitor of CYP3A4 while only a reversible inhibitor of CYP3A5; schisandrin A (SIA) inhibited CYP3A4 and CYP3A5 in a time-dependent manner but also reversibly inhibited CYP3A5.
In clinical settings, Schisandra extracts markedly increased the blood concentration of tacrolimus by inhibiting the CYP3A enzyme in liver transplant patients.
Because of its documented effects on hepatic and gastric enzyme activity, particularly CYP-450 3A, schisandra may interfere with the metabolism of co-administered drugs (e.g., midazolam); findings from a study of healthy volunteers suggest that dosage adjustment may be needed in individuals concomitantly taking P-glycoprotein (P-gp) substrates (e.g., tacrolimus).
Schisantherin A has been shown to increase the bioavailability of at least one co-administered drug, probably due to inhibition of P-gp in the intestine, thereby increasing systemic absorption; as a result, careful monitoring must be conducted when these are used in combination.
8.4 Evidence Limitations
Despite the significant therapeutic potential of Schisandra chinensis and its lignans, several challenges and limitations are associated with their use, particularly in clinical settings; these issues primarily stem from poor bioavailability, variability in extraction and quantification methods, uncertainties regarding long-term safety, and a lack of robust clinical evidence from human trials.
Schisandra chinensis has biologically relevant mechanisms that warrant further human research on its role as a hepatoprotective phytotherapy; well-designed, large-scale clinical trials are needed to establish efficacy and safety for liver disease applications.
References
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