EA4, a quinone derivative, is a novel and potent a rPLA2 inhibitor that inhibits rPLA2 with a Ki of 130 µM. rPLA2 is a calcium-dependent cytosolic phospholipase A2(cPLA2) initially isolated and characterized from bovine and human red blood cells (RBCs). It has a molecular mass of 42 kDa and biochemical properties similar to cPLA2 Type IV. EA4 inhibits the ionophore-induced arachidonic acid release from human and bovine red blood cells (RBCs), indicating that rPLA2 is responsible for the Ca2+-dependent release of arachidonic acid from mammalian RBCs. EA4 causes significant time- and concentration-dependent induction of cytochrome P450 1A1 (CYP1A1) mRNA and protein in murine hepatoma Hepa-1c1c7 cells. EA4 also modulates CYP1A1 and CYP1B1 expression in other cell lines such as MCF-7, Hep-G2, and HL-60.

Physicochemical Properties

Molecular Formula	C19H17N2O2CL
Molecular Weight	340.80348
Exact Mass	340.097
CAS #	389614-94-2
PubChem CID	10042917
Appearance	Light blue to blue solid powder
Density	1.3±0.1 g/cm3
Boiling Point	508.3±50.0 °C at 760 mmHg
Flash Point	261.2±30.1 °C
Vapour Pressure	0.0±1.3 mmHg at 25°C
Index of Refraction	1.634
LogP	4.42
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	4
Heavy Atom Count	24
Complexity	534
Defined Atom Stereocenter Count	0
InChi Key	XAZVKSMDPVMMPP-UHFFFAOYSA-N
InChi Code	InChI=1S/C19H17ClN2O2/c1-3-22(4-2)13-9-7-12(8-10-13)15-16(20)19(24)17-14(18(15)23)6-5-11-21-17/h5-11H,3-4H2,1-2H3
Chemical Name	7-chloro-6-[4-(diethylamino)phenyl]-5,8-quinolinedione
Synonyms	EA4; EA 4; EA-4
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 Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.
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	rPLA2 and cPLA2 are inhibited by EA4 (9 μM, 24 μM)[1]. EA4 has a 130 μM Ki value that inhibits rPLA2 [1]. In a time-regulated manner, EA4 (50 μM) strongly suppresses the release of AA from light erythrocytes caused by A23187 [1].
References	[1]. Purification and characterization of a cytosolic, 42-kDa and Ca2+-dependent phospholipase A2 from bovine red blood cells: its involvement in Ca2+-dependent release of arachidonic acid from mammalian red blood cells. The Journal of biological chemistry vol. 277,23 (2002): 21086-94.

Solubility Data

Solubility (In Vitro)

DMSO : ~50 mg/mL (~146.71 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 1 mg/mL (2.93 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 10.0 mg/mL clear DMSO stock solution to 400 μL of PEG300 and mix evenly; then add 50 μL of Tween-80 to the above solution and mix evenly; then add 450 μL of 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 2: ≥ 1 mg/mL (2.93 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 10.0 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.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.9343 mL	14.6714 mL	29.3427 mL
	5 mM	0.5869 mL	2.9343 mL	5.8685 mL
	10 mM	0.2934 mL	1.4671 mL	2.9343 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.