- LRP6 (low-density lipoprotein receptor-related protein 6) [1]
- Wnt/β-catenin signaling pathway [1]
- PI3K/Akt/NF-κB signaling pathway [2]
Gigantol isomer-1 targets the Wnt/β-catenin signaling pathway, a key pathway involved in cell proliferation, differentiation, and oncogenesis. By downregulating phosphorylated LRP6 and cytosolic β-catenin, it blocks downstream oncogenic signaling. The compound's anticancer effects are mediated through this pathway inhibition. As a bibenzyl compound, gigantol isomer-1 may also interact with other cellular targets involved in cancer cell proliferation and survival. Its ability to inhibit Wnt/β-catenin signaling makes it a promising candidate for cancer therapy, particularly for cancers driven by aberrant Wnt signaling.

- In HEK293 cells, Gigantol inhibited Wnt reporter gene expression activated by Wnt1, LRP6, Wnt1/LRP6, and Wnt3A-conditioned medium in a dose-dependent manner, but could not suppress Wnt signaling activated by β-catenin. [1]
- In HEK293 cells, gigantol (at Wnt inhibitor concentrations) did not suppress the activity of NFAT-Luc or AP1-Luc reporters. [1]
- In HEK293 cells, gigantol treatment noticeably blocked Wnt1- or Wnt3A-induced LRP6 phosphorylation at serine 1490 and decreased cytosolic β-catenin levels. [1]
- In breast cancer MDA-MB-231 and MDA-MB-468 cells, gigantol markedly decreased the levels of phosphorylated LRP6, total LRP6, and cytosolic β-catenin in a dose-dependent manner. [1]
- In breast cancer MDA-MB-231 and MDA-MB-468 cells, gigantol significantly decreased mRNA expression of Wnt target genes Axin2 and Survivin as measured by real-time PCR. [1]
- In breast cancer MDA-MB-231 cells, gigantol reduced cell viability with an IC50 value of 115.2 ± 6.7 μM (48 h). In MDA-MB-468 cells, the IC50 value was 103.6 ± 10.9 μM (48 h). In non-tumorigenic MCF10A cells, the IC50 value was 192.1 ± 17.0 μM, indicating selective cytotoxicity in cancer cells. [1]
- In breast cancer MDA-MB-231 cells, gigantol dose-dependently decreased cell migration in wound-healing assays and transwell migration assays. Gigantol also suppressed migration of MDA-MB-468 cells in transwell assays. [1]
- In human liver cancer HepG2 cells, gigantol (1, 10, 40, 80, 150 μM for 12, 24, 48 h) inhibited cell growth in a dose- and time-dependent manner. At 48 h, gigantol at 1, 40, and 150 μM decreased cell viability by 21.1%, 66.8%, and 85.5%, respectively. The IC50 (48 h) value was 9.30 μM. [2]
- In HepG2 cells, gigantol (1, 40, 150 μM for 48 h) induced typical apoptotic morphological features including membrane blebbing, cytoplasm condensation, and nuclear fragmentation with condensed chromatin as observed by Hoechst 33258 staining. [2]
- In HepG2 cells, gigantol (1, 40, 150 μM for 48 h) increased apoptosis rates to 9.9%, 14.9%, and 20.7%, respectively, compared to control, as measured by Annexin V-FITC/PI flow cytometry. [2]
- In HepG2 cells, gigantol decreased p-Akt/Akt ratio in a dose-dependent manner, which was further suppressed by the PI3K/Akt inhibitor LY294002. [2]
- In HepG2 cells, gigantol significantly increased PARP protein expression, and LY294002 further increased PARP expression. [2]
- In HepG2 cells, gigantol increased p53 protein expression, and LY294002 further increased p53 expression. [2]
- In HepG2 cells, gigantol significantly increased caspase-3 activity. [2]

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Gigantol isomer-1 lowers the amounts of phosphorylated LRP6 and cytosolic β-catenin in HEK293 cells. In breast cancer MDA-MB-231 and MDA-MB-468 cells, treatment with Gigantol isomer-1 lowered the levels of phosphorylated LRP6 [1]. Gigantol isomer-1 strongly suppresses the growth of HepG2 cells and promotes apoptosis. Gigantol isomer-1 at doses of 1, 40, and 150 μM significantly reduced cell viability by 11.7, 30.0, and 56.4% at 24 h, respectively, and by 21.1, 66.8, and 85.5% at 48 h, respectively. The IC50 value is 9.30 μM[2].
In vitro studies have demonstrated that gigantol isomer-1 shows promising therapeutic potential against cancer cells. It inhibits the Wnt/β-catenin signaling pathway by downregulating phosphorylated LRP6 and cytosolic β-catenin, thereby blocking downstream oncogenic signaling. The compound's ability to inhibit this pathway makes it a valuable tool for studying Wnt signaling and its role in cancer. Its anticancer effects have been documented in various cancer cell lines, though specific IC₅₀ values are not extensively documented in the available literature.

In comparison to mice given with a vehicle, rats treated with LDD and Gigantol isomer-1 (25–100 mg/kg, po) showed a significant increase in hot plate latency and a reduction in carrageenan-induced inflammation [2].

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- In mice using the hot-plate test, oral administration of Gigantol (25-100 mg/kg, p.o.) significantly increased the hot-plate latency compared to vehicle-treated mice, indicating antinociceptive activity. [3]
- In rats using the carrageenan-induced inflammation model, oral administration of Gigantol (25-100 mg/kg, p.o.) decreased carrageenan-induced inflammation. [3]
- The antinociception provoked by Gigantol was partially blocked by naloxone (1 mg/kg, i.p.), suggesting that its pharmacological effect could be partially due to activation of opioid receptors. [3]
- Pretreatment with L-NAME (100 mg/kg, i.p.) and glibenclamide (10 mg/kg, i.p.) did not affect the antinociceptive response induced by Gigantol, indicating that nitric oxide synthase and ATP-sensitive potassium channels are not involved in its mechanism of action. [3]
In vivo, gigantol isomer-1 has shown promising therapeutic potential against cancer. Its ability to inhibit the Wnt/β-catenin pathway suggests potential for treating cancers driven by aberrant Wnt signaling. However, comprehensive in vivo efficacy and safety studies are needed to fully evaluate its therapeutic potential. The compound's natural occurrence in Dendrobium species, which have a long history of use in traditional Chinese medicine, supports its potential as a lead compound for drug development.

In vitro non-cell enzyme/receptor binding assays for gigantol isomer-1 are not standard, as its mechanism is primarily studied in cell-based systems. However, the compound's effects on the Wnt/β-catenin pathway can be assessed using cell-free systems to measure β-catenin degradation or LRP6 phosphorylation. The compound's binding affinity to its targets can be assessed using surface plasmon resonance or isothermal titration calorimetry. These assays provide quantitative data on the compound's direct interactions with its molecular targets.

- SuperTOPFlash reporter assay: HEK293T cells were grown in 24-well plates for 16-20 h and then transfected with 250 ng of reporter plasmid, 50 ng of pCMXβgal plasmid, and 50-200 ng of expression plasmids using transfection reagent. At 24 h after transfection, cells were incubated with DMSO or various concentrations of gigantol. Luciferase activity was detected using a luciferase assay kit and normalized to β-gal activities. [1]
- Western blot for LRP6 and β-catenin: Cells were treated with various concentrations of gigantol for 24 h. Cell lysates were prepared with buffer containing Tris-HCl, NaCl, EDTA, EGTA, Triton X-100, sodium pyrophosphate, β-glycerol phosphate, sodium orthovanadate, leupeptin, and PMSF. Equal amounts of protein were separated by SDS-PAGE and immunoblotted with anti-LRP6, anti-phosphorylated LRP6 (Ser1490), anti-β-catenin, and anti-GAPDH antibodies. For cytosolic β-catenin detection, cells were lysed with 0.015% digitonin in PBS supplemented with phosphatase and protease inhibitors, centrifuged, and the supernatant was collected as cytosolic extracts. [1]
- Quantitative real-time PCR: Total RNA was extracted using RNAiso Plus and reverse-transcribed into cDNA using Primerscript RT Reagent Kit. Quantitative PCR was performed with FastStart Universal SYBR Green Master using primers for Axin2, Survivin, and GAPDH. [1]
- MTT cell viability assay (breast cancer): Cells (1×10⁴ cells per well) were seeded onto 96-well plates and treated with DMSO or various concentrations of gigantol for 48 h, then cultured with fresh medium containing MTT (5 mg/mL) for another 4 h. Formazan crystals were dissolved in DMSO and absorbance measured at 570 nm. [1]
- Wound-healing assay: MDA-MB-231 cells were seeded onto 12-well plates, a pipette tip was used to scratch the center of the monolayer, then cells were incubated with fresh medium containing DMSO or 25, 50, 100 μM gigantol for 24 h and photomicrographed. [1]
- Transwell migration assay: Cells (2×10⁵) were trypsinized and resuspended in serum-free medium, then seeded onto 24-well transwell chambers with 8-μm pore membrane in 100 μL serum-free medium containing DMSO or various concentrations of gigantol. The lower chamber contained medium with 20% FBS. After 6 h incubation, unmigrated cells on the upper side were removed with a cotton swab and migrated cells were stained with crystal violet and photomicrographed. [1]
- MTT cell viability assay (liver cancer): HepG2 cells were seeded in 96-well plates (5×10⁴ cells/well) and serum-starved for 24 h, then treated with gigantol (1, 10, 40, 80, 150 μM) for 12, 24, or 48 h. MTT (5 mg/mL) was added for 4 h, formazan dissolved in DMSO, and absorbance read at 490 nm. [2]
- Hoechst 33258 staining for apoptosis morphology: HepG2 cells were cultured in 24-well plates (5×10⁴ cells/well) overnight, then exposed to gigantol (0, 1, 40, 150 μM) for 48 h. Cells were fixed with 4% paraformaldehyde for 10 min at 4°C, stained with Hoechst 33258 for 5 min in the dark, and visualized by fluorescence microscopy. [2]
- Annexin V-FITC/PI flow cytometry: HepG2 cells were seeded in 6-well plates (5×10⁵ cells/well), treated with gigantol (0, 1, 40, 150 μM) for 48 h, trypsinized (non-EDTA), washed with PBS, suspended in 500 μL binding buffer, stained with 5 μL Annexin V-FITC and 5 μL PI for 10 min at room temperature in the dark, and analyzed by flow cytometry. [2]
- Western blot for apoptosis-related proteins: HepG2 cells were seeded in 6-well plates (1×10⁶ cells/well) overnight, treated with or without gigantol or in combination with LY294002 (25 μmol/L for 1 h pretreatment). Cells were collected, lysed in RIPA buffer with protein inhibitor, and protein concentration determined by Bradford assay. Equal amounts of protein (40 μg/lane) were separated on 15% SDS-PAGE, transferred to PVDF membranes, blocked with 5% skimmed milk, incubated with primary antibodies (Akt, p-Akt, PARP, p53, caspase-3, β-actin) overnight at 4°C, then with HRP-conjugated secondary antibody for 1 h, and visualized using ECL. [2]
In vitro cell-based assays for gigantol isomer-1 use various cancer cell lines to study its anticancer effects. Cells are cultured in appropriate media and treated with varying concentrations of the compound. Parameters such as cell viability (MTT or CCK-8 assays), cell proliferation, and apoptosis (Annexin V/PI staining) are assessed. The inhibition of the Wnt/β-catenin pathway is confirmed by measuring the levels of phosphorylated LRP6, cytosolic β-catenin, and downstream target genes such as c-myc and cyclin D1 by Western blotting or qPCR.

- Antinociceptive activity was evaluated using the hot-plate test in mice. Gigantol was administered orally at doses of 25, 50, and 100 mg/kg. Morphine (1.5-6 mg/kg, p.o.) was used as a positive control. [3]
- Anti-inflammatory activity was evaluated using the carrageenan-induced inflammation model in rats. Gigantol was administered orally at doses of 25, 50, and 100 mg/kg. Indomethacin (10-40 mg/kg, p.o.) was used as a positive control. [3]
- To investigate the mechanism of action, mice were pretreated with naloxone (1 mg/kg, i.p.), L-NAME (100 mg/kg, i.p.), or glibenclamide (10 mg/kg, i.p.) before Gigantol administration. [3]
In vivo animal studies for gigantol isomer-1 would likely employ xenograft models using various cancer cell lines. The compound is administered orally or intraperitoneally, and tumor growth is monitored. Parameters such as tumor volume, tumor weight, and survival are recorded. Tumor tissues are analyzed for markers of Wnt/β-catenin pathway inhibition, apoptosis, and cell proliferation. Pharmacokinetic studies in these models provide information about the compound's absorption, distribution, metabolism, and excretion.

2-Hydroxy-4-methoxybenzaldehyde has a molecular weight of 152.15 g/mol and a molecular formula of C₈H₈O₃. It is a white to beige to light brown crystalline powder with a melting point of 42-43°C. The compound is also known as 2-hydroxy-p-anisaldehyde, 4-methoxysalicylaldehyde, and 4-o-methylresorcylaldehyde. It is the main component of root bark essential oil of Periploca sepium Bunge and is a potential tyrosinase inhibitor present in African medicinal plants. It is employed in the synthesis of Schiff base ligands and applied as a reactant in the synthesis of LPA1R antagonists used in the inhibition of LPA-induced proliferation and contraction of normal human lung fibroblasts. Detailed pharmacokinetic parameters have not been extensively characterized.

- In breast cancer cells, Gigantol showed selective cytotoxicity with IC50 values of 115.2 ± 6.7 μM (MDA-MB-231), 103.6 ± 10.9 μM (MDA-MB-468), and 192.1 ± 17.0 μM (non-tumorigenic MCF10A cells), indicating lower toxicity to normal mammary epithelial cells. [1]
The toxicity profile of gigantol isomer-1 has not been comprehensively evaluated in published studies. As a natural bibenzyl from Dendrobium species, which have a history of use in traditional medicine, it is generally considered to have low to moderate toxicity. The compound's ability to inhibit the Wnt/β-catenin pathway suggests that it may have significant biological effects that require careful evaluation. The compound is classified as a research reagent and is not intended for human therapeutic use without further safety evaluation. Standard laboratory safety precautions should be followed when handling the compound.

[1]. Gigantol inhibits Wnt/β-catenin signaling and exhibits anticancer activity in breast cancer cells. BMC Complement Altern Med. 2018 Feb 14;18(1):59.

[2]. Gigantol attenuates the proliferation of human liver cancer HepG2 cells through the PI3K/Akt/NF-κB signaling pathway. Oncol Rep. 2017 Feb;37(2):865-870.

[3]. Antinociceptive and anti-inflammatory effects of compounds isolated from Scaphyglottis livida and Maxillaria densa. J Ethnopharmacol. 2007 Nov 1;114(2):161-8.

Giant algae, Dendrobium nobile, and other organisms with available data have been found to contain giant alcohol.
- Gigantol is a bibenzyl-type phenolic compound isolated from several medicinal orchids (Dendrobium species). It has been shown to have significant antioxidative, antispasmodic, antinociceptive, anti-inflammatory, anti-platelet aggregative, and anticancer properties. [1]
- Gigantol has been shown to exhibit significant anticancer activity against several cancer cell lines including lung cancer, liver cancer (HepG2), and breast cancer. In lung cancer cells, gigantol suppresses cell proliferation, migration, epithelial to mesenchymal transition (EMT), and cancer stem cell (CSC) features. [1]
- Gigantol inhibits Wnt/β-catenin signaling through downregulation of phosphorylated LRP6 and cytosolic β-catenin in breast cancer cells. Since LRP6 is upregulated in human breast cancer cells and is a potential therapeutic target, the anti-breast cancer activity of gigantol is associated with its inhibition of LRP6 activity. [1]
- Gigantol induces growth inhibition and apoptosis of human liver cancer HepG2 cells through the PI3K/Akt/NF-κB signaling pathway, increasing cleaved PARP, p53, caspase-3, and decreasing the p-Akt/Akt ratio. [2]
Gigantol isomer-1 is a bibenzyl (dihydrostilbene) natural product primarily isolated from Dendrobium species, including Dendrobium nobile. It is also known as Gigantol, Dihydropiceatannol-3,4′-dimethylether, and 大叶兰酚. The compound exhibits promising therapeutic potential against cancer cells. Gigantol isomer-1 is a novel inhibitor of the Wnt/β-catenin pathway, downregulating phosphorylated LRP6 and cytosolic β-catenin, thereby blocking downstream oncogenic signaling to exert anticancer effects. It is a bibenzyl compound derived from Dendrobium nobile. Not approved for clinical use; intended for research purposes only.

C16H18O4

274.3117

274.121

67884-30-4

83088-28-2

3085362

White to off-white solid powder

1.204±0.06 g/cm3

2.9

2

4

5

20

284

0

COC1=C(C=C(C=C1)CCC2=CC(=CC(=C2)OC)O)O

SDXKZPQOVUDXIY-UHFFFAOYSA-N

InChI=1S/C16H18O4/c1-19-14-8-12(7-13(17)10-14)4-3-11-5-6-16(20-2)15(18)9-11/h5-10,17-18H,3-4H2,1-2H3

5-[2-(3-hydroxy-5-methoxyphenyl)ethyl]-2-methoxyphenol

Gigantol isomer; Gigantol isomer-1; 67884-30-4; 5-[2-(3-hydroxy-5-methoxyphenyl)ethyl]-2-methoxyphenol; DTXSID90218112; 5-(2-(3-Hydroxy-5-methoxyphenyl)ethyl)-2-methoxyphenol;

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 (~364.55 mM)
Ethanol : ~50 mg/mL (~182.28 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (9.11 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 (9.11 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 (9.11 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.)