Synthesis and biological evaluation of flavonoid-based IP6K2 inhibitors

Figures & data

Figure 1. Examples of IP6K inhibitors.

Figure 2. In-house flavonoid compounds evaluated using ADP-Glo assay.

Scheme 1. Synthesis of fluoro-substituted flavonoid analogs with a variation of the B ring. Reagents and conditions: (i) (a) Acetyl chloride, pyridine, CH₂Cl₂, rt, 30 min, (b) AlCl₃, 150 °C, 10 min; (ii) appropriate aldehydes, Ba(OH)₂, MeOH (or EtOH), 50 °C, 1–17 h; (iii) I₂, DMSO, 110 °C, 6–24 h; (iv) BBr₃, CH₂Cl₂, 50 °C, 14–18 h.

Scheme 2. Synthesis of dihydroxy-substituted flavonoid analogs with a variation of the B ring. Reagents and conditions: (i) Appropriate aldehydes, Ba(OH)₂, MeOH (or EtOH), 50 °C, 11–20 h; (ii) I₂, DMSO, 110 °C, 11–17 h; (iii) BBr₃, CH₂Cl₂, 50 °C, 5–18 h.

Table 1. IC₅₀ values of the synthesised compounds 16a-16d against IP6K2.

Comp.	IP6K2 IC50 (μM)	Comp.	IP6K2 IC50 (μM)
16a	9.07	16c	41.9
16b	1.67	16d	2.89

Scheme 3. Synthesis of flavonoid analogs with a 3-OH group on the C ring. Reagents and conditions: (i) Appropriate aldehydes, NaOMe, THF, rt, 16–20 h; (ii) a. H₂O₂, NaOH (or NaOMe), EtOH (or MeOH), 40 °C, b. HCl, 16–20 h; (iii) BBr₃, CH₂Cl₂, 50 °C, 6-16 h.

Table 2. IC₅₀ values of the synthesised compounds against IP6K2.

For the IC₅₀ experiments, the compounds were tested in duplicates from 0.017 to 100 µM in eleven three-fold dilution steps. Values shown are the mean ± SD.

Figure 3. (a) Dose-response curve of compound 20s against IP6K2. (b) Dose-response curve of quercetin against IP6K2.

Table 3. Inhibition data of quercetin and compound 20s against IP6K1/2/3.

Comp.	IP6K1 IC50 (μM)^a	IP6K2 IC50 (μM)^b	IP6K3 IC50 (μM)^c	IP6K1 /IP6K2	IP6K3 /IP6K2
Quercetin	1.10	3.31	4.35	0.33	1.31
20s	2.87	0.55	3.56	5.22	6.47

^aFinal concentration of IP6K1 60 nM, substrate (IP6) 100 µM, ATP 1 mM; ^bFinal concentration of IP6K2 80 nM, substrate (IP6) 10 µM, ATP 10 µM; ^cFinal concentration of IP6K3 120 nM, substrate (IP6) 100 µM, ATP 1 mM.

Figure 4. (a) The best-docked pose of compound 20s with the 3D model of IP6K2. (b) The best-docked pose of quercetin with the 3D model of IP6K2. (c) Interaction between compound 20s and IP6K2. (d) Interaction between quercetin and IP6K2.