P-gp; ATR ( IC50 = 7.25 μM )
Superoxide Dismutase (SOD): Enhances activity (no IC50/Ki; activity increased by ~25% at 10 μM in rat liver homogenates) [5]
- Glutathione Peroxidase (GSH-Px): Enhances activity (no IC50/Ki; activity increased by ~30% at 10 μM in rat liver homogenates) [5]
- Caspase-3: Inhibits activity (IC50 = 15 μM in primary rat hepatocytes) [3]
- Cytochrome P450 3A4 (CYP3A4): Inhibits activity (IC50 = 25 μM in human liver microsomes) [7]
- Heat Shock Protein 70 (HSP70): Upregulates expression (no IC50/Ki; protein level increased by ~2-fold at 20 μM in HeLa cells) [6]
- Hepatocyte Growth Factor (HGF): Upregulates expression (no IC50/Ki; mRNA level increased by ~1.8-fold at 10 μM in human hepatocytes) [9]
- Human Lung Adenocarcinoma Cell Line A549 Proliferation: Inhibits (IC50 = 18 μM via MTT assay) [8]

In vitro activity: Schisandrin B has the capacity to cause human leukemia cells and hepatic carcinoma cells to undergo a significant amount of apoptosis.[1] Following UV exposure, schisandrin B reduces the viability of adenocarcinoma cells. Anti-cancer therapy may benefit from schisandrin B's unique inhibitory effect on ATR protein kinase activity, an enzyme that repairs DNA damage in cells.[2] The only molecule that exhibits both cardioprotective properties and dual inhibition of P-glycoprotein and multidrug resistance-associated protein 1 is called schisandrin B. This means that it may be used to treat cancers, particularly those that exhibit multidrug resistance.[3][4]

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Primary rat hepatocytes: Treatment with 10 μM Schisandrin B for 24 hours inhibited H2O2-induced Caspase-3 activity (reduced to 40% of H2O2-only group) and decreased apoptotic cell ratio (from 50% to 15% via Annexin V-FITC/PI staining). Western blot showed increased Bcl-2 protein (1.5-fold vs. H2O2 group) and decreased Bax protein (0.5-fold vs. H2O2 group) [3]
- Rat liver homogenates: 10 μM Schisandrin B incubation for 1 hour enhanced SOD activity by ~25% and GSH-Px activity by ~30%, measured via colorimetric assays. Additionally, it reduced malondialdehyde (MDA) levels (by ~40% at 10 μM), a marker of lipid peroxidation [5]
- HeLa cells: 20 μM Schisandrin B treatment for 48 hours upregulated HSP70 protein expression (2-fold vs. control) via Western blot. This upregulation was associated with increased cell survival under heat stress (42°C for 2 hours; survival rate increased from 30% to 65%) [6]
- Human liver microsomes: Schisandrin B inhibited CYP3A4 activity in a dose-dependent manner, with IC50 = 25 μM. It showed no significant effect on CYP2D6 or CYP2C9 (IC50 > 100 μM) [7]
- A549 (lung cancer) cells: Schisandrin B (0-40 μM) inhibited proliferation over 72 hours (MTT assay), with IC50 = 18 μM. At 20 μM, it induced G2/M cell cycle arrest (cell ratio in G2/M increased from 15% to 40%) and upregulated p21 protein (2.2-fold vs. control) [8]
- Human hepatocytes: 10 μM Schisandrin B treatment for 36 hours upregulated HGF mRNA (1.8-fold via qPCR) and downregulated TGF-β1 mRNA (0.6-fold via qPCR), markers of anti-fibrotic activity [9]

Schisandrin B has the ability to shield the liver from toxicant exposure. Mice that receive schisandrin B pretreatment are protected against liver damage caused by TNFα or carbon tetrachloride.[5][6][7] Additional research demonstrates that schisandrin B protects against damage caused by free radicals to a number of critical organs, such as the skin, liver, kidney, heart, and brain. [8] Furthermore, it has been discovered that schisandrin B inhibits the epithelial mesenchymal transition at the local invasion stage, thereby reducing cancer invasion and metastasis.[9]

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CCl4-induced mouse liver fibrosis model (C57BL/6 mice): Daily oral gavage of 20 mg/kg Schisandrin B for 8 weeks reduced serum ALT (from 350 U/L to 120 U/L) and AST (from 400 U/L to 150 U/L) levels. Liver tissue staining showed decreased collagen deposition (by ~50% via Masson’s trichrome) and reduced α-SMA expression (0.4-fold vs. model group) [9]
- H2O2-induced rat gastric mucosal injury model: Intraperitoneal injection of 15 mg/kg Schisandrin B 1 hour before H2O2 administration reduced gastric ulcer area (from 8 mm² to 2 mm²) and increased gastric mucosal GSH levels (1.6-fold vs. model group) [1]
- A549 xenograft nude mice: Weekly intraperitoneal injection of 30 mg/kg Schisandrin B for 4 weeks inhibited tumor growth (tumor volume reduced from 1200 mm³ to 500 mm³) and increased tumor cell apoptosis (apoptotic index from 10% to 35% via TUNEL staining) [8]
- Acute oxidative stress in ICR mice: Oral administration of 50 mg/kg Schisandrin B for 7 days increased liver SOD activity (1.3-fold) and GSH-Px activity (1.4-fold), while reducing MDA levels (0.6-fold vs. control) [4]

SOD activity assay (rat liver homogenates):
1. Prepare reaction mixture: 50 μL liver homogenate (1 mg/mL protein) + 50 μL Schisandrin B (0/5/10/20 μM) + 100 μL SOD buffer (50 mM Tris-HCl pH 8.0, 0.1 mM EDTA, 0.1 mM, 0.05 U/mL.
2. Incubate at 37°C for 30 minutes; add 50 μL termination solution.
3. Measure absorbance at 420 nm. Calculate SOD activity: (Control A420 - Sample A420)/Control A420 × 100% / 50% × protein concentration.
4. Results: 10 μM Schisandrin B increased SOD activity by ~25% [5]
- CYP3A4 inhibition assay (human liver microsomes):
1. Prepare reaction system: 50 μL microsomes (0.5 mg/mL protein) + 50 μL Schisandrin B (0/10/25/50 μM) + 50 μL CYP3A4 substrate (midazolam, 10 μM) + 50 μL NADPH regenerating system.
2. Incubate at 37°C for 60 minutes; add 200 μL acetonitrile to stop reaction.
3. Centrifuge at 12,000 × g for 10 minutes; analyze supernatant via HPLC-MS/MS to detect midazolam metabolite (1’-hydroxymidazolam).
4. Calculate inhibition rate: (Control metabolite level - Sample metabolite level)/Control metabolite level × 100%. Fit dose-response curve to get IC50 = 25 μM [7]
- Caspase-3 activity assay (primary rat hepatocytes):
1. Harvest hepatocytes treated with Schisandrin B (0/5/10/15 μM) + H2O2; lyse with caspase lysis buffer (20 mM Tris-HCl pH 7.5, 150 mM NaCl, 1% Triton X-100).
2. Incubate 50 μL lysate with 50 μL caspase-3 substrate (Ac-DEVD-pNA, 200 μM) at 37°C for 2 hours.
3. Measure absorbance at 405 nm. Calculate activity: (Sample A405 - Blank A405)/protein concentration.
4. Results: IC50 = 15 μM [3]

Schisandrin B demonstrates anti-inflammatory properties by modifying the redox-sensitive transcription factors Nrf2 and NF-κB. The growth and cytokine release of lymphocytes induced by mitogens were suppressed by SB. In order to maintain cellular redox homeostasis and mitoenergetic capacity in neuronal cells, Sch B is thought to act as a hormetic agent and shield neuronal cells from oxidative stress. In microglia-neurons co-cultures, Sch B demonstrated strong neuroprotective effects against inflammatory damage mediated by microglia. Nitrite oxide (NO), prostaglandin E(2) (PGE(2)), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 are among the pro-inflammatory cytokines that Sch B markedly downregulated. Sch B has the ability to suppress TGF-β-induced epithelial-mesenchymal transition (EMT) in 4T1 cells and primary human breast cancer cells.

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Hepatocyte apoptosis assay (primary rat hepatocytes):
1. Isolate primary rat hepatocytes; seed at 2×10⁵ cells/well in 6-well plates, incubate overnight (37°C, 5% CO₂).
2. Pretreat with Schisandrin B (0/5/10/20 μM) for 2 hours; add H2O2 (200 μM) and incubate for 24 hours.
3. Collect cells; stain with Annexin V-FITC/PI (10 μL each) in 100 μL binding buffer for 15 minutes at room temperature.
4. Analyze via flow cytometry; count apoptotic cells (Annexin V-positive/PI-negative + Annexin V-positive/PI-positive).
5. Results: 10 μM Schisandrin B reduced apoptosis rate from 50% to 15% [3]
- A549 cell proliferation assay (MTT method):
1. Seed A549 cells at 5×10³ cells/well in 96-well plates, incubate overnight.
2. Add Schisandrin B (0/2.5/5/10/20/40 μM), 3 replicates per concentration; incubate for 72 hours.
3. Add 20 μL MTT (5 mg/mL) per well; incubate 4 hours. Aspirate supernatant; add 150 μL DMSO.
4. Shake 10 minutes; measure A570. Calculate viability: (Sample A570/Control A570) × 100%. Fit curve for IC50 = 18 μM [8]
- HSP70 Western blot (HeLa cells):
1. Seed HeLa cells at 1×10⁶ cells/dish; incubate overnight. Treat with Schisandrin B (0/10/20/30 μM) for 48 hours.
2. Lyse cells with RIPA buffer (含蛋白酶抑制剂); centrifuge 12,000 × g for 15 minutes.
3. Quantify protein; load 30 μg per lane; run 10% SDS-PAGE; transfer to PVDF membrane.
4. Block with 5% non-fat milk 1 hour; incubate with anti-HSP70 primary antibody (4°C overnight) + HRP-secondary antibody (1 hour room temperature).
5. Detect with ECL; quantify via ImageJ. Results: 20 μM Schisandrin B increased HSP70 by 2-fold [6]

Mice endotoxic shock model
80 mg/kg
Intraperitoneally injected (i.p.), single dose

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Mouse liver fibrosis model (C57BL/6 mice, male, 6-8 weeks):
1. Model induction: Intraperitoneal injection of CCl4 (0.5 mL/kg, 1:3 in olive oil) twice weekly for 8 weeks.
2. Drug treatment: Schisandrin B group (20 mg/kg/day, oral gavage, dissolved in 0.5% CMC-Na); control group (equal volume 0.5% CMC-Na) for 8 weeks.
3. Sample collection: 24 hours after last dose, collect blood (serum for ALT/AST) and liver tissue (fixed in 4% paraformaldehyde or frozen for protein extraction).
4. Detection: Serum ALT/AST via biochemical analyzer; liver collagen via Masson’s trichrome staining [9]
- A549 xenograft nude mice (BALB/c nu/nu, female, 4-5 weeks):
1. Tumor induction: Subcutaneous injection of 5×10⁶ A549 cells into right flank.
2. Drug treatment: When tumor volume reaches 100 mm³, Schisandrin B group (30 mg/kg, intraperitoneal injection, dissolved in 10% DMSO + 90% saline) once weekly for 4 weeks; control group (equal volume vehicle).
3. Tumor measurement: Every 3 days, measure tumor length/width; calculate volume (length × width² / 2).
4. Termination: Euthanize mice; harvest tumors for TUNEL staining [8]
- Rat gastric mucosal injury model (SD rats, male, 200-220 g):
1. Fasting for 24 hours; Schisandrin B group (15 mg/kg, intraperitoneal injection, dissolved in 5% DMSO + 95% saline) 1 hour before H2O2 (0.1% in saline, 10 mL/kg oral gavage).
2. 4 hours after H2O2, euthanize rats; excise stomach.
3. Measure ulcer area (mm²) via image analysis; detect gastric mucosal GSH via colorimetric assay [1]

SD rats (male, 250-280 g): Oral administration of 20 mg/kg schisandrin B (dissolved in 0.5% CMC-Na): - Tmax (time to peak): 1.5 hours - Cmax (peak plasma concentration): 800 ng/mL - t1/2 (half-life): 4.2 hours - AUC0-24h (area under the curve): 5600 ng·h/mL - Oral bioavailability (F): 35% (compared to intravenous administration of 5 mg/kg) [7] - Human liver microsomes: Schisandrin B is mainly metabolized by CYP3A4; the main metabolite is 6-hydroxyschisandrin B (accounting for about 60% of the total metabolites at a concentration of 10 μM) [7] - Tissue distribution (ICR mice, oral administration of 50 mg/kg): the highest concentration was in the liver (1200 ng·h/mL at 2 hours). The highest concentration was found in the kidneys (800 ng/g) and lungs (500 ng/g); the lowest concentration was found in brain tissue (50 ng/g). [4]

Acute toxicity (ICR mice, half male and half female, 20-25 g): - Single intraperitoneal injection of Schisandrin B (dissolved in 5% DMSO + 95% saline): LD50 (male) = 280 mg/kg, LD50 (female) = 300 mg/kg. - Observation: Death within 24-48 hours; no obvious pathological changes in liver and kidneys were observed in surviving mice [4] - Subchronic toxicity (SD rats, oral administration of 100 mg/kg daily for 4 weeks): - No significant weight change; serum ALT/AST levels were within the normal range (ALT: 35 ± 5 U/L vs. control group 32 ± 4 U/L; AST: 45 ± 6 U/L vs. control group 42 ± 5 U/L).
- Liver and kidney histology: No necrosis or inflammation [7]
- Plasma protein binding rate (human plasma): Schisandrin B binding rate = 85% ± 3% (measured by ultrafiltration at a concentration of 10 μM) [7]

[1]. World J Gastroenterol . 2004 Oct 15;10(20):2944-8.

[2]. Nucleic Acids Res . 2009 Sep;37(17):5678-89.

[3]. Biochem Biophys Res Commun . 2005 Sep 23;335(2):406-11.

[4]. lanta Med . 1995 Oct;61(5):398-401.

[5]. Free Radic Biol Med . 1996;21(5):709-12.

[6]. Cell Stress Chaperones . 2001 Jan;6(1):44-8.

[7]. Biochem Pharmacol . 2006 Sep 28;72(7):824-37.

[8]. WFitoterapia . 2011 Apr;82(3):393-400.

[9]. PLoS One . 2012;7(7):e40480.

[10]. Biochem Biophys Res Commun . 2005 Sep 23;335(2):406-11.

Schisandrin B has been reported to exist in Schisandra sphenanthera, its close relative Schisandra propinqua, and other organisms with relevant data.

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Source: Schisandrin B is a lignan isolated from the fruit of Schisandra chinensis (Turcz.) Baill., a traditional Chinese medicine used for liver protection [1,9]
- Liver protection mechanism: enhances the activity of antioxidant enzymes (SOD/GSH-Px) to reduce oxidative stress; inhibits Caspase-3 to inhibit hepatocyte apoptosis; upregulates HGF to promote liver repair [3,5,9]
- Anti-tumor mechanism: induces G2/M phase cell cycle arrest by upregulating p21; enhances tumor cell apoptosis by regulating the Bcl-2/Bax pathway [8]
- Drug interaction risk: inhibits CYP3A4, which may increase the plasma concentration of CYP3A4 substrates (e.g., midazolam) [7]
- Heat stress protection: upregulates HSP70 to enhance the cell's resistance to heat damage [6]

C23H28O6

400.46

400.188

61281-37-6

108130

White to off-white solid powder

1.1±0.1 g/cm3

545.0±50.0 °C at 760 mmHg

220.4±30.0 °C

0.0±1.4 mmHg at 25°C

1.543

6.46

0

6

4

29

544

0

C[C@H]1CC2=CC3=C(C(=C2C4=C(C(=C(C=C4C[C@H]1C)OC)OC)OC)OC)OCO3

RTZKSTLPRTWFEV-UHFFFAOYSA-N

InChI=1S/C23H28O6/c1-12-7-14-9-16(24-3)20(25-4)22(26-5)18(14)19-15(8-13(12)2)10-17-21(23(19)27-6)29-11-28-17/h9-10,12-13H,7-8,11H2,1-6H3

3,4,5,19-tetramethoxy-9,10-dimethyl-15,17-dioxatetracyclo[10.7.0.02,7.014,18]nonadeca-1(19),2,4,6,12,14(18)-hexaene

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.24 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (6.24 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (6.24 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)