Cucurbitacin B exerts its pharmacological effects by modulating multiple signaling pathways, including JAK/STAT3, Nrf2/ARE, NF-κB, AMPK, MAPK, PI3K/Akt, CIP2A/PP2A, Wnt/β-catenin, FAK, Notch, and Hippo-YAP.
Anti-HIV-1 activity with an EC₅₀ of 0.09 μg/mL.
Anti-HSV-1 activity with an IC₅₀ of 1.74 μmol/L. [1]

Cucurbitacin B slows cell growth in CCA cell lines and prevents the cell purifying cycle process in the G2/M phase at concentrations up to 40 μM, lasting 12–48 hours [2]. In BY4741 yeast cells, cucurbitacin B (0.1, 0.3, and 1 μM) decreased the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) while increasing the levels of SOD-1 and total superoxide dismutase (T-SOD) [3].

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Cucurbitacin B (0.5 μM) inhibited LPS-induced release of pro-inflammatory mediators (TNF-α, IL-6, IL-12, IL-1β, NO, PGE2), reduced expression of co-stimulatory molecules (CD40, CD80, CD86), and suppressed ROS generation in macrophages, partly via induction of HO-1 through Nrf2 activation. [1]
Cucurbitacin B (0.1, 0.3, 1 μmol/L) antagonized oxidative stress in yeast, improved SOD activity and survival rate, and reduced ROS and MDA levels, suggesting anti-aging effects via regulating autophagy and aging-related genes. [1]
Cucurbitacin B (0.5 μmol/L) alleviated microglia-induced neuroinflammatory damage and protected cortical neurons by activating the Nrf2/ARE pathway and inhibiting the STAT/NF-κB pathway. [1]
Cucurbitacin B (0.3 μmol/L) promoted cofilin phosphorylation in neurons, contributing to neuroprotection. [1]
Cucurbitacin B inhibited cell growth and proliferation in various cancer cell lines (e.g., colorectal, laryngeal, hepatic, pancreatic, breast, nasopharyngeal) by inducing cell cycle arrest (G1/S, G2/M, or S phase) and apoptosis, often through inhibition of STAT3 phosphorylation and modulation of cyclins (cyclin D1, B1), CDKs, p21, p53, and Bcl-2 family proteins. [1]
Cucurbitacin B induced cytoskeleton disruption (F-actin and microtubule) in glioblastoma and breast cancer cells within minutes, leading to morphological changes, growth inhibition, and cell cycle arrest, mediated partly by JNK/c-Jun activation or ROS-dependent pathways. [1]
Cucurbitacin B inhibited migration and invasion of breast, lung, liver, and cholangiocarcinoma cells by downregulating FAK, MMP-9, VEGF, and Wnt/β-catenin signaling. [1]
Cucurbitacin B (20-200 nM) induced protective autophagy in hepatocellular carcinoma and breast cancer cells, characterized by upregulation of LC3-II, beclin-1, p-ULK1 and downregulation of p-mTOR and p-Akt. [1]
Cucurbitacin B (6-860 nM) inhibited DNA methyltransferases (DNMTs) and histone deacetylases, and modulated expression of tumor-related genes (e.g., CDKN1A, c-Myc) in lung cancer cells. [1]
Cucurbitacin B reversed gefitinib resistance in NSCLC cells by upregulating miR-17-5p/STAT3 axis and inducing lysosomal degradation of EGFR. [1]
Cucurbitacin B (100-1000 nM) inhibited proliferation, migration, and tubulogenesis of human umbilical vascular endothelial cells (HUVECs), indicating anti-angiogenic activity. [1]
Cucurbitacin B (0.1, 0.2, 0.3 mg/mL) inhibited host cell invasion, intracellular growth, and growth recovery of Cryptosporidium parvum in a cell monolayer model. [1]
Cucurbitacin B (100-300 nM) inhibited adipocyte differentiation in 3T3-L1 and C3H10T1/2 cells by inhibiting STAT3 signaling. [1]
Cucurbitacin B (0.01, 0.1, 1 mM) prevented cardiomyocyte hypertrophy by affecting autophagy via inhibition of the AKT/mTOR/FOXO3a axis. [1]

Cucurbitacin B (5 mg/kg, abdominal, 10 days) prevents gunitis caused by gold carrageenan [4]. Cucurbitacin B (20–50 mg/kg, intraperitoneal injection, 28 days) can improve memory function, prevent STZ-ICV toxicity to neuronal scaffolds, and lessen AD-like symptoms [5].

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Cucurbitacin B (1 mg/kg) significantly inhibited carrageenan-induced paw swelling in rats and carrageenan-induced pleurisy in mice, attributed to inhibition of cyclooxygenase products and PGE2. [1]
Cucurbitacin B alleviated imiquimod-induced psoriasis-like dermatitis in mice by inhibiting NF-κB and STAT3 activation. [1]
In a rat model of ligation-induced periodontitis, Cucurbitacin B (12.5, 25, 50 mg/kg) reduced inflammatory response by down-regulating pro-inflammatory cytokines and COX-2. [1]
Cucurbitacin B (5 mg/kg) displayed anti-inflammatory activity in a rat model of carrageenan-induced prostatitis. [1]
Cucurbitacin B (2.5 mg/kg) inhibited gouty arthritis in mice by inhibiting NLRP3 inflammasome formation and key glycolytic enzymes in macrophages. [1]
Cucurbitacin B (1, 2, 5 mg/kg) protected against sepsis-induced acute lung injury in rats in a dose-dependent manner, improving gas exchange and reducing edema and inflammation. [1]
Cucurbitacin B (0.1 mg/kg) promoted neurogenesis and alleviated memory deficits in APP/PS1 mice, related to activation of GR/PLC/PKC and TrkA/Ras/Raf/ERK pathways. [1]
Cucurbitacin B exhibited antitumor activity in xenograft models of various cancers (e.g., laryngeal, hepatic, pancreatic, breast, colon, lung). It inhibited tumor growth, induced apoptosis and cell cycle arrest, and inhibited metastasis and angiogenesis, often through modulation of STAT3, FAK, MMPs, and Wnt/β-catenin pathways. [1]
Cucurbitacin B (1, 5 mg/kg) inhibited CCl4-induced liver fibrosis in mice by inhibiting oxidative stress and inflammatory responses via the STAT3 pathway. [1]
Cucurbitacin B (1, 2, 4 mg/kg) alleviated concanavalin A-induced liver fibrosis in mice by inhibiting the SIRT1/IGFBPpP1/TGFβ1 axis. [1]
Cucurbitacin B (0.1 mg/kg) reduced blood glucose levels in diabetic mice by regulating intestinal AMPK and inducing release of GLP-1 and insulin. [1]
Cucurbitacin B inhibited hyperglycemia and reduced hemolymph glucose in Drosophila melanogaster fed a high-sugar diet. [1]
Cucurbitacin B (0.2 mg/kg) prevented pressure overload-induced cardiac hypertrophy in mice. [1]
A low dose of Cucumis melo L. extract (mainly Cucurbitacin B) reduced blood pressure in normal and hypertensive mouse models by increasing vasodilation and inhibiting vasoconstriction. [1]

The antioxidant effect of Cucurbitacin B was evaluated in vitro by assessing its ability to directly scavenge free radicals such as DPPH and ABTS, increase ferric-reducing antioxidant power and metal-chelating activity, and reduce phosphomolybdate. [1]

Cell Viability Assay [2]
Cell Types: CCA Cell Line
Tested Concentrations: 0.1, 1 0.5, 1,5, 10, 20, 40 μM
Incubation Duration: 24 and 48 hrs (hours)
Experimental Results: Cell viability diminished in a dose-dependent and time-dependent manner , IC50 value is 13: 44 μM at 24 hrs (hours) and 1.55 at 48 hrs (hours).

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Cell cycle analysis[2]
Cell Types: CCA Cell Line
Tested Concentrations: 0.1, 1, 10 μM
Incubation Duration: 24 hrs (hours)
Experimental Results: Cell cycle progression is arrested in G2/M phase.

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Western Blot Analysis[2]
Cell Types: CCA Cell line
Tested Concentrations: 0.1, 1 0.5, 1,5, 10, 20, 40 μM
Incubation Duration: 12 and 24 h
Experimental Results: The expression of Cyclin A, Cyclin D1, Cdc25A diminished but increased reached the level of p21.

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For anti-proliferative assays, cells (e.g., various cancer cell lines) were treated with different concentrations of Cucurbitacin B for specified durations (e.g., 24, 48, 72 h). Cell viability/proliferation was then assessed using methods like MTT or similar assays to calculate IC₅₀ values. [1]
To assess apoptosis, cells treated with Cucurbitacin B were analyzed using Annexin V/PI staining by flow cytometry to quantify apoptotic cell populations. Morphological changes like chromatin condensation and apoptotic bodies were also observed under microscopy. [1]
For cell cycle analysis, after treatment with Cucurbitacin B, cells were fixed, stained with propidium iodide, and analyzed by flow cytometry to determine the distribution of cells in different phases (G0/G1, S, G2/M). [1]
To evaluate effects on the cytoskeleton, cells were treated with Cucurbitacin B and then fixed and stained for F-actin (using phalloidin) and microtubules (using anti-tubulin antibodies). Changes in morphology and cytoskeletal structure were observed using fluorescence microscopy. [1]
For migration and invasion assays, transwell chambers with or without Matrigel coating were used. Cells treated with or without Cucurbitacin B were seeded in the upper chamber, and after incubation, cells that migrated/invaded to the lower chamber were stained and counted. [1]
Autophagy induction was assessed by detecting the conversion of LC3-I to LC3-II via western blot or immunofluorescence. The expression of other autophagy-related proteins like beclin-1, p62, and p-ULK1 was also analyzed. [1]
Western blot analysis was performed to investigate signaling pathways. After treatment with Cucurbitacin B, cells were lysed, proteins were separated by SDS-PAGE, transferred to membranes, and probed with specific antibodies against target proteins (e.g., p-STAT3, cyclins, caspases, MAPKs). [1]

Animal/Disease Models: Carrageenan-induced prostatic inflammation in rats [4]
Doses: 5mg/kg/day, 10 days
Route of Administration: Oral
Experimental Results:Reduce TNF-α, IL-1b, COX-2 and iNOS levels.

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Animal/Disease Models: STZ-ICV AD-like dementia rat prototype [5]
Doses: 20, 50mg/kg/day for 28 days
Route of Administration: intraperitoneal (ip) injection
Experimental Results: TNF-α, IL-1β, MPO, iNOS , acetylcholinesterase and glutamate levels, but not gamma-aminobutyric acid. Increased density of viable neurons in rat cortex and hippocampus.

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In the carrageenan-induced rat paw edema model, Cucurbitacin B (1 mg/kg) or vehicle was administered intraperitoneally (i.p.) or orally (p.o.) before or after carrageenan injection into the hind paw. Paw volume was measured at intervals to assess swelling. [1]
In xenograft tumor models, immunodeficient mice (e.g., nude mice, BALB/c mice) were subcutaneously inoculated with human cancer cells. After tumors reached a palpable size, mice were randomized into groups and treated with Cucurbitacin B (at various doses, e.g., 0.1-1 mg/kg, via i.p. injection) or vehicle control for a specified period. Tumor volume and body weight were measured regularly. At the endpoint, tumors were harvested, weighed, and subjected to histological and molecular analysis. [1]
In the CCl4-induced liver fibrosis model, mice were injected intraperitoneally with CCl4 (diluted in olive oil) multiple times per week for several weeks to induce fibrosis. Cucurbitacin B (1, 5 mg/kg, i.p.) or vehicle was administered during or after the induction period. Liver tissues and serum were collected for analysis of fibrosis markers, hydroxyproline content, and histology. [1]
In the concanavalin A (Con A)-induced acute liver injury model, mice were injected intravenously with Con A. Cucurbitacin B (1, 2, 4 mg/kg, i.p.) was administered prior to or after Con A injection. Liver damage was assessed by serum transaminase levels, cytokine levels, and liver histology. [1]
In the streptozotocin (STZ)-induced or genetic (db/db) diabetic mouse model, Cucurbitacin B (0.1 mg/kg, p.o. or i.p.) was administered for a period. Blood glucose levels were monitored regularly. At the endpoint, plasma insulin, GLP-1, and other metabolic parameters were measured. [1]
For pharmacokinetic studies, rats (Wistar or SD) were administered Cucurbitacin B intravenously (e.g., 0.1-1.3 mg/kg) or orally (e.g., 1-20 mg/kg). Blood samples were collected at multiple time points post-dose. Plasma was separated and analyzed for Cucurbitacin B concentration using HPLC-MS/MS or UPLC-MS/MS methods. [1]

Cucurbitacin B can be absorbed and eliminated in rats. In Wistar rats, cucurbitacin B had a wide volume of distribution (Vd = 51.65 ± 39.16 L/kg) after intravenous injection (0.1 mg/kg) and a high tissue/plasma concentration ratio (K_app) in multiple organs, with the highest concentrations in the lungs, spleen and kidneys. [1] The half-lives (t₁/₂) of cucurbitacin B in Wistar rats after intravenous injection (0.1 mg/kg and 1 mg/kg) were 5.08 ± 2.87 h and 5.09 ± 2.20 h, respectively. Cucurbitacin B was eliminated more quickly after oral administration of 20 mg/kg (t₁/₂ = 2.50 ± 0.58 h). [1]
It has been reported that the absolute oral bioavailability of cucurbitacin B in rats is low (e.g., 10% at 2 and 4 mg/kg doses, and 1.37% at 8 mg/kg dose). [1]
Time to peak concentration (T_max) varies with route of administration and dose: approximately 7 minutes after intravenous injection (1.3 mg/kg) and up to 3 hours after oral administration (8 mg/kg). [1]
Less than 1% of the administered dose was detected in urine and feces, indicating minimal renal and fecal excretion. Metabolism may involve complex phase I and II enzymatic reactions rather than direct glucuronidation. [1]
The mean plasma concentration-time curve of cucurbitacin B sometimes exhibits a bimodal pattern, which may be due to distribution, reabsorption, or enterohepatic circulation. [1]
When cucurbitacin B is formulated into collagen peptide-loaded mixed micelles, its bioavailability is improved (relative bioavailability increased by 3.43 times), thereby enhancing its solubility and oral absorption. [1]

Cucurbitacin B exhibits moderate cytotoxicity to both cancer cells and normal cells. However, low doses are generally not toxic to normal cells and experimental animals. [1] In a homozygous mouse model of bladder cancer induced by MB49 cells, treatment with cucurbitacin B (1 mg/kg) did not cause significant changes in body weight, nor were any adverse effects observed in the lungs, liver, kidneys, heart, or bladder. [1] At concentrations below 100 nM, cucurbitacin B caused approximately 50% cell death in non-small cell lung cancer (NSCLC) cells, but was not cytotoxic to normal human pulmonary fibrosis cells. [1]
HCT-8 cells showed no cytotoxicity after 4 hours of treatment with cucurbitacin B at concentrations below 0.5 μL/mL, but showed toxicity after 4 hours of treatment at a concentration of 0.75 μL/mL, with more pronounced toxicity at 24 and 48 hours. [1]
The oral LD₁₀ of cucurbitacin B in mice has been reported to be 5 mg/kg. [1]
No toxicities or side effects commonly associated with conventional chemotherapy drugs have been reported in the clinical use of cucurbitacin tablets (containing cucurbitacin B and E). [1]

[1]. Cucurbitacin B: A review of its pharmacology, toxicity, and pharmacokinetics. Pharmacol Res. 2023;187:106587.

[2]. Targeted Modulation of FAK/PI3K/PDK1/AKT and FAK/p53 Pathways by Cucurbitacin B for the Antiproliferation Effect Against Human Cholangiocarcinoma Cells. Am J Chin Med. 2020;48(6):1475-1489.

[3]. Cucurbitacin B Exerts Antiaging Effects in Yeast by Regulating Autophagy and Oxidative Stress. Oxid Med Cell Longev. 2019;2019:4517091.

[4]. Aljohani OS. Phytochemical evaluation of Cucumis prophetarum: protective effects against carrageenan-induced prostatitis in rats. Drug Chem Toxicol. 2022;45(4):1461-1469.

[5]. Liu Z, Kumar M, Kabra A. Cucurbitacin B exerts neuroprotection in a murine Alzheimer's disease model by modulating oxidative stress, inflammation, and neurotransmitter levels. Front Biosci (Landmark Ed). 2022;27(2):71.

[6]. Cucurbitacin-B inhibits neuroblastoma cell proliferation through up-regulation of PTEN. Eur Rev Med Pharmacol Sci. 2014;18(21):3297-303.

[7]. Cucurbitacin B inhibits proliferation and induces apoptosis via STAT3 pathway inhibition in A549 lung cancer cells. Mol Med Rep. 2014 Dec;10(6):2905-11.

[8]. Cucurbitacin B induced ATM-mediated DNA damage causes G2/M cell cycle arrest in a ROS-dependent manner. PLoS One. 2014 Feb 4;9(2):e88140.

[9]. Inhibition of Integrin-HER2 signaling by Cucurbitacin B leads to in vitro and in vivo breast tumor growth suppression. Oncotarget. 2014 Apr 15;5(7):1812-28.

Cucurbitacin B is a cucurbitacin whose lanostane skeleton is multiplely substituted with hydroxyl, methyl, and oxo substituents, with unsaturated bonds at positions 5 and 23; the hydroxyl group at C-25 is acetylated. It is a cucurbitacin, a secondary α-hydroxy ketone, and a tertiary α-hydroxy ketone. It is derived from the hydride of lanostane. Cucurbitacin B has been reported to exist in Trichosanthes kirilowii, Trichosanthes trifoliata, and other organisms with relevant data. Mechanism of Action: The binding of cucurbitacin to glucocorticoid receptors in cell-free HeLa systems and intact cells was investigated by competing with (3)H-cortisol. Cucurbitacin reduced (3)H-cortisol binding. The difference in binding affinity at the two temperatures suggests that cucurbitacin is metabolized under physiological conditions. A linear correlation exists between the logarithm of the relative binding affinity of cucurbitacin and its cytotoxic activity. Therefore, the binding of cucurbitacin to glucocorticoid receptors appears to be a necessary step for these compounds to exert their cytotoxic effects.
Eight bioactive cucurbitacins isolated from the root of Gentiana macrophylla, including cucurbitacin B, are cytotoxic to tissue cultures of KB and HELA cells. Cucurbitacin B is effective against transplanted sarcoma 180 and Ehrlich ascites carcinoma in mice.
In rats with IM Walker carcinosarcoma 256 and mice with Lewis lung cancer, administration of 0.8–1.6 mg/kg of cucurbitacin B inhibited tumor development, but the safety range between effective and toxic doses is small, thus its prospects as a therapeutic agent are not good.

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Cucurbitacin B (CuB) is the most abundant and active member of the cucurbitacins, which are highly oxidized tetracyclic triterpenoids that are mainly isolated from Cucurbitaceae plants (e.g., melons). [1]
It has a wide range of pharmacological activities, including anti-inflammatory, antioxidant, antiviral, hypoglycemic, hepatoprotective, neuroprotective and anticancer effects. [1]
Its antitumor mechanisms include inhibiting cell growth/proliferation, inducing cell cycle arrest, apoptosis, cytoskeleton disruption, autophagy, and inhibiting migration/invasion and angiogenesis. [1]
Derivatives of cucurbitacin B (e.g., 2-position modified ACB and DBCB) have been synthesized to improve selectivity, reduce nonspecific toxicity, enhance solubility, and maintain or improve anticancer activity. [1] Cucurbitacin tablets (mainly composed of cucurbitacin B and E) have been used clinically in China as adjuvant therapy for chronic hepatitis and primary liver cancer, showing efficacy in relieving symptoms, improving liver function, and prolonging survival, with low toxicity. [1]

C32H46O8

558.7029

558.319

6199-67-3

Cucurbitacin E;18444-66-1;Cucurbitacin I;2222-07-3

5281316

White to off-white solid powder

1.2±0.1 g/cm3

699.3±55.0 °C at 760 mmHg

184-186ºC

218.8±25.0 °C

0.0±5.0 mmHg at 25°C

1.568

2.31

3

8

6

40

1210

9

CC(=O)OC(C)(C)/C=C/C(=O)[C@@](C)([C@H]1[C@@H](C[C@@]2([C@@]1(CC(=O)[C@@]3([C@H]2CC=C4[C@H]3C[C@@H](C(=O)C4(C)C)O)C)C)C)O)O

IXQKXEUSCPEQRD-DKRGWESNSA-N

InChI=1S/C32H46O8/c1-17(33)40-27(2,3)13-12-23(36)32(9,39)25-21(35)15-29(6)22-11-10-18-19(14-20(34)26(38)28(18,4)5)31(22,8)24(37)16-30(25,29)7/h10,12-13,19-22,25,34-35,39H,11,14-16H2,1-9H3/b13-12+/t19-,20+,21-,22+,25+,29+,30-,31+,32+/m1/s1

(R,E)-6-((2S,8S,9R,10R,13R,14S,16R,17R)-2,16-dihydroxy-4,4,9,13,14-pentamethyl-3,11-dioxo-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)-6-hydroxy-2-methyl-5-oxohept-3-en-2-yl acetate

Cucurbitacin B; Cuc B; NSC 49451; NSC 144154.

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)

DMSO : ≥ 100 mg/mL (~178.99 mM)
H2O : ~1 mg/mL (~1.79 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (4.47 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 (4.47 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.)