Skip to main content
. 2015 Sep 17;2015:654098. doi: 10.1155/2015/654098

Table 1.

The core structure of indirubin (R5=O) with listed structures and actions of selected synthetic indirubin derivatives. X denotes halogen atoms (Br, I, Cl, and F).

Indirubin derivatives R1 R2 R3 R4 R5 R6 Main effects/properties Reference
Core structure of indirubins graphic file with name ECAM2015-654098.tab1.i001.jpg
Indirubin -H -H -H -H =O -H Antitumor effect [4–10]
N-Ethyl-indirubin
5-halogenoindirubins
 
 
 
 
 
 
 
N-Methylisoindigotin (meisoindigo) 		-CH2CH3 -H -H -H =O -H Higher antitumor potencies compared to indirubin [15–17]
-H -X -H -H =O -H
graphic file with name ECAM2015-654098.tab1.i002.jpg
Indirubin-3′-monoxime -H -H -H -H =NOH -H Inhibition of CDKs with high potency [9, 18]
5-Iodoindirubin-3′-monoxime -H -I -H -H =NOH -H Inhibition of GSK-3β [19]
Indirubin-5-sulfonic acid -H -SO3H -H -H =O -H
Indirubin-5-sulfonamide -H -SO2NH2 -H -H =O -H
5-Halogenoindirubins -H -X -H -H =O -H
C6 and C5, C6 halogen substit. of indirubin -H -H or -X -X -H =O -H More potent CDK and GSK-3β inhibitors [20]
3′-Substituted
7-halogenoindirubins 		-H or -CH3 -H -H -X =NOH, =NOCH3, =NOCOCH3 and others -H Lacking the inhibitory effects towards CDKs and GSK-3β but still inducing cell death [21]
E564 -H -H -H -H =NOCH2CH2OCH2CH2OH -H Inhibitory effect towards STAT3 signaling, contributing to apoptosis in human cancer cells [22]
E728 -H -OCH3 -H -H =NOH -H
E804 -H -H -H -H =NOCH2CH2CH(OH)CH2OH -H
5-Fluoro-indirubinoxime -H -F -H -H =NOH -H Antitumor activity in vitro and in several animal models [23–27]
5-Trimethylacetamino-indirubinoxime -H -NH
COtBu		 -H -H =NOH -H
5-Nitro-indirubinoxime -H -NO2 -H -H =NOH -H Additional anti-inflammatory properties in HUVECs [28]
7-Azaindirubin-3′-oxime graphic file with name ECAM2015-654098.tab1.i003.jpg Potent antiproliferative properties in cancer cell lines and inhibition of a series of kinases [29]
7-Bromo-5′-carboxyindirubin-3′-oxime -H -H -H -Br =NOH -COOH Novel inverse binding mode, with improved selectivity for DYRK kinases [30]
5-Diphenylacetamido-indirubin-3′-oxime -H -NHCOC
H(C6H5)2 		-H -H =NOH -H Novel mitochondria-targeting agent with antileukemic activity [31]
5′-OH-5-nitro-indirubin oxime (AGM130) -H -NO2 -H -H =NOH -OH Improved solubility compared to indirubin and effective induction of apoptosis of imatinib-resistant CML cells [32]