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C8499 Sigma-Aldrich

Cucurbitacin B hydrate

≥97% (HPLC)

Synonym: (2β,9β,10α,16α,23E)-25-(acetyloxy)-2,16,20-trihydroxy-9-methyl-19-Norlanosta-5,23-diene-3,11,22-trione



Related Categories Bioactive Small Molecule Alphabetical Index, Bioactive Small Molecules, CI-CZ, Cell Biology, Cell Signaling and Neuroscience,
Quality Level   100
assay   ≥97% (HPLC)
form   powder
color   white to beige
solubility   DMSO: 10 mg/mL, clear
storage temp.   2-8°C
SMILES string   CC1(C)C([C@@H](O)C[C@]2([H])C1=CC[C@]([C@@](C[C@@H](O)[C@]3([H])[C@@](C)(O)C(/C=C/C(C)(C)OC(C)=O)=O)(C)[C@]3(C)C4)([H])[C@@]2(C)C4=O)=O
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



Cucurbitacin B hydrate has been used:
• as a signal transducer and activator of transcription 3 (stat3) inhibitor to determine its effect on the expression of human lysosomal acid lipase (hLAL) in myeloid-derived suppressor cells (MDSCs).
• as an ecdysone receptor (EcR) antagonist injection to lower the levels of 20-hydoxyecdysone (20E) signaling in butterflies.
• to determine its effect on the cell viability of pancreatic cancer cell lines.


5, 25 mg in glass bottle

Biochem/physiol Actions

Cucurbitacin B also exhibits anti-cancer activity by inhibiting telomerase and c-Myc in breast cancer. It also exhibits anti- artherosclerotic activity. Cucurbitacin B also possesses anti-inflammatory and anti-microbial activity.

Cucurbitacin B is a triterpenoid constituent of Cucurbitaceae plant species. Cucurbitacin B inhibits proliferation in a wide variety of tumor cell lines (IC50 15-30 nM) by inducing apoptosis and inducing cell cycle arrest at G2/M phase. Although the mechanism of action is unclear, Cucurbitacin B inhibits STAT 3 phosphorylation and expression levels and has been shown to block JAK2 activity. Curcubitacin B also inhibits the transcriptional activity of HIF1a and Nf-KB. Curcubitacin B is structurally similar to the JAK inhibitor Curcubitacin I.

Features and Benefits

This compound is a featured product for Kinase Phosphatase Biology research. Click here to discover more featured Kinase Phosphatase Biology products. Learn more about bioactive small molecules for other areas of research at sigma.com/discover-bsm.

This compound is featured on the JAKs page of the Handbook of Receptor Classification and Signal Transduction. To browse other handbook pages, click here.

Safety & Documentation

Safety Information

GHS06  GHS06
Signal word 
Hazard statements 
Precautionary statements 
UN 2811 6.1 / PGI
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable


Certificate of Analysis (COA)

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Certificate of Origin (COO)

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Protocols & Articles


Discover Bioactive Small Molecules for Kinase Phosphatase Biology

Phosphorylation is a ubiquitous cellular regulatory mechanism that mediates signal transduction pathways, which carry signals from the cell surface to the nucleus or cytoplasm, by altering the activi...
Keywords: Apoptosis, Bioactive small molecules, Cancer, Diseases, Inflammation, Metabolism, Neurodegenerative Diseases, Phosphorylations, Transduction


The Janus kinases were initially identified as a novel subfamily of 120-140 kDa cytoplasmic tyrosine kinases that uniquely contained two, tandem domains with homology to tyrosine kinase catalytic dom...
Keywords: Atomic absorption spectroscopy, Catalysis, Diseases, Genetic, Growth factors, Hormones, Phosphorylations, Transcription, Transduction, transformation

The Role of Inflammation in Neurodegeneration

It is well established that the brain can sense and react to peripheral insults through the rapid induction of fever and other neuroendocrine changes in response to events such as infection and tissu...
Scott Hauser, Technology Transfer Specialist, Sigma® Life Science
Biofiles, Vol. 8, No. 19
Keywords: Adhesion, Central Nervous System, Diseases, Gene expression, Inflammation, Neurodegenerative Diseases, Reductions

Peer-Reviewed Papers


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