Auxinole is a potent TIR1/AFB receptor phytohormone antagonist that can bind to TIR1 and prevent the formation of TIR1-IAA-Aux/IAA complex, thereby inhibiting the expression of auxin-responsive genes.

Physicochemical Properties

Molecular Formula	C20H19NO3
Molecular Weight	321.369765520096
Exact Mass	321.136
CAS #	86445-22-9
PubChem CID	13077496
Appearance	White to off-white solid powder
LogP	3.6
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	3
Rotatable Bond Count	5
Heavy Atom Count	24
Complexity	478
Defined Atom Stereocenter Count	0
SMILES	O=C(C(CC(C1C(C)=CC(C)=CC=1)=O)C1C2C(=CC=CC=2)NC=1)O
InChi Key	HGUYAIJBXSQXGV-UHFFFAOYSA-N
InChi Code	InChI=1S/C20H19NO3/c1-12-7-8-14(13(2)9-12)19(22)10-16(20(23)24)17-11-21-18-6-4-3-5-15(17)18/h3-9,11,16,21H,10H2,1-2H3,(H,23,24)
Chemical Name	4-(2,4-dimethylphenyl)-2-(1H-indol-3-yl)-4-oxobutanoic acid
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro

Strongly inhibiting the expression of auxin-responsive genes, auxinole binds to TIR1 to increase the TIR1-IAA-Aux/IAA complex. This is a powerful TIR1/AFB receptor auxin blocking antagonist. Furthermore, auxinole complementarily inhibits a variety of plant growth responses caused by hormones [1]. In root hair cells, auxinole significantly lowers the amount of IAA-triggered detoxification. The brief rise in [Ca2+]cyt is nevertheless entirely inhibited by auxinole (20 μM), which also fills the Ca2+ response[2].

References

[1]. Rational design of an auxin antagonist of the SCF(TIR1) auxin receptor complex. ACS Chem Biol. 2012 Mar 16;7(3):590-8. [2]. AUX1-mediated root hair auxin influx governs SCFTIR1/AFB-type Ca2+ signaling. Nat Commun. 2018 Mar 21;9(1):1174.

Solubility Data

Solubility (In Vitro)

DMSO : ≥ 125 mg/mL (~388.96 mM) Ethanol : ~2.5 mg/mL (~7.78 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (7.78 mM) (saturation unknown) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (7.78 mM) (saturation unknown) in 5% DMSO + 95% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. 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. Solubility in Formulation 3: ≥ 2.08 mg/mL (6.47 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 20.8 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. Solubility in Formulation 4: ≥ 2.08 mg/mL (6.47 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 20.8 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. Solubility in Formulation 5: ≥ 2.08 mg/mL (6.47 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 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	3.1117 mL	15.5584 mL	31.1168 mL
	5 mM	0.6223 mL	3.1117 mL	6.2234 mL
	10 mM	0.3112 mL	1.5558 mL	3.1117 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.