Novel piperine-carboximidamide hybrids: design, synthesis, and antiproliferative activity via a multi-targeted inhibitory pathway

Figures & data

Figure 1. Structures of piperine, compounds 2–5, and newly designed compounds VIa-k.

Scheme 1: Synthesis of target compounds VIa-k. Reagents and reaction conditions: i) KOH, Ethanol, reflux 12 h; ii) NH₃, THF, I₂, r.t. 3 h, 65–80%; iii) NH₂OH, methanol, NaHCO₃, reflux 3–5 h, 80–90%; iv) CDI, Acetonitrile, r.t. 3 h.

Table 1. Antiproliferative activity of compounds VIa-k and Erlotinib.

Comp.	Cell viability %	R	Antiproliferative activity IC50 ± SEM (nM)
			A-549	MCF-7	Panc-1	HT-29	Average (GI50)
Via	89	H	95 ± 10	97 ± 10	104 ± 10	105 ± 10	100
VIb	85	4-Cl	55 ± 6	57 ± 6	59 ± 6	58 ± 6	57
Vic	86	4-Br	45 ± 5	47 ± 5	53 ± 5	55 ± 5	50
Vid	91	4-OCH3	50 ± 5	52 ± 5	57 ± 5	57 ± 5	54
Vie	89	4-CH3	69 ± 7	73 ± 7	75 ± 7	75 ± 7	73
VIf	90	2-Cl	41 ± 4	43 ± 4	45 ± 4	47 ± 4	44
VIg	87	3-Cl	42 ± 5	47 ± 5	49 ± 5	49 ± 5	47
VIh	91	3-Br	61 ± 6	64 ± 6	69 ± 6	67 ± 6	65
Vii	89	3,4-diOMe	36 ± 4	39 ± 3	40 ± 4	40 ± 4	39
VIj	85	2,3-phenyl	78 ± 8	81 ± 8	84 ± 8	88 ± 9	83
VIk	89	1,3-dioxole	32 ± 3	35 ± 3	36 ± 3	38 ± 3	35
Erlotinib	–	–	30 ± 3	40 ± 3	30 ± 3	30 ± 3	33

Table 2. Effects of compounds VIc, VIf, VIg, VIi, Vik, Erlotinib, Vemurafenib, and Dinaciclib on EGFR, BRAF^V600E, and CDK2.

Compound	EGFR inhibition IC50 ± SEM (nM)	BRAF^V600E inhibition IC50 ± SEM (nM)	CDK2 IC50 ± SEM (nM)
VIc	112 ± 8	57 ± 6	23 ± 2
VIf	105 ± 7	49 ± 5	21 ± 2
VIg	96 ± 6	63 ± 6	20 ± 2
Vii	120 ± 10	72 ± 7	17 ± 2
VIk	127 ± 10	40 ± 4	12 ± 2
Erlotinib	80 ± 5	60 ± 5	ND
Vemurafenib	ND	30 ± 3	ND
Dinaciclib	ND	ND	20 ± 2

ND: Not Determined

Table 3. IC₅₀ cytotoxicity of compounds VIc, VIf, and VIk against LOXIMVI melanoma cell line.

Compound	LOX-IMVI melanoma IC50 ± SEM (µM)
Vic	1.40 ± 0.02
VIf	1.10 ± 0.01
VIk	1.05 ± 0.01
Staurosporine	7.10 ± 0.05

Figure 2. Schematic representation of docking interactions of compound VIg within EGFR (PDB ID: 1M17) showing two H-bond interactions with PRO 770 and GLY772 as blue-coloured arrows.

Figure 3. Schematic representation of docking interactions of compound VIk within both BRAF^V600E (PDB ID: 4MNF) and CDK2 (PDB ID: 1PYE): (a,b) 2 D Interactions of VIk within 4MNF and 1PYE; respectively; (c) Presumptive binding modes of VIk within 4MNF active site as 3 D diagram: showing three H-bond interactions with Asn 580 and Asp 594 coloured in red-colour‎.