Synthesis, structure activity relationship and biological evaluation of indole sulfonohydrazide derivatives as antagonists of P2Y1 and P2Y6 receptors

The P2Y receptors play a significant role in regulating various physiological functions, such as neurotransmission and inflammatory response. They are also considered promising therapeutic targets for the treatment and prevention of conditions like neurological disorders, pain, cardiovascular diseases, thrombosis, and Cancer. Active research is ongoing to identify antagonists of P2Y Receptor. Although extensive research has been conducted on P2Y receptors inhibitors, only a limited number of P2Y receptors antagonists have been identified and approved by regulatory authority. In the current research, new indole sulfonohydrazide derivatives (3a-3 k) were synthesized in good yield. Based on toxicity assays performed on h-1321 N1 astrocytoma cell line, these low molecular weight compound showed a safe toxicity profile. The synthesized derivatives were also screened against tP2Y1 and rP2Y6 receptors using a calcium mobilization assay. The results showed that compounds 3a, 3b, 3 h and 3 k were potent against tP2Y1 with IC₅₀ values of 9.91 ± 1.01 μM, 3.49 ± 0.31 μM, 9.72 ± 0.82 μM, and 6.14 ± 0.17 μM, respectively. Additionally, three compounds, i.e., 3d, 3f, and 3 h, exhibited potency against rP2Y6 with IC₅₀ value of 9.22 ± 1.10 μM, 16.25 ± 0.27 μM, and 1.89 ± 0.11 μM, respectively. Molecular docking study was conducted to support the in vitro analysis, which revealed that the tested compounds showed favorable interaction with the Amino acids of the target P2Y1 Receptor, including Phe62, Phe66, Leu102, Thr103, Pro105, Ala106, Phe119 and Met123. An in silico pharmacokinetic study was also performed, which revealed that the synthesized compounds met all the criteria for favorable gastrointestinal absorption, indicating potential for oral bioavailability. The stability and reactivity of compounds were determined by using the Guassian09 programme in which the density functional theory (DFT) calculations were performed by using the B3LYP/SVP level.

Calcium assay; In silico studies; Indole sulfonohydrazide derivatives; Purinergic signaling; Receptors.