One-pot synthesis of tricyclic pyrano[3.2-c]chromene derivatives and their evaluation through in vitro immunomodulatory activity against T cells; Molecular docking investigations and ADME-Tox prediction studies

The aim of this work is the in vitro determination of the immunomodulation effect of pyrano[3,2-c]chromenes on the proliferation of T lymphocyts. These tricyclic heterocycles were prepared at room temperature via a one-pot, three-component condensation reaction involving 4‑hydroxy-2H-chromen-2-one, aromatic aldehydes, and malononitrile, using morpholine as a catalyst in a 1:1 ethanol/water mixture. This multicomponent reaction affords the product in high yields, in accordance with the criteria of green chemistry. The structure elucidation was accomplished by spectral data, IR, NMR (¹H, ¹³C, 2D). We determined the in vitro effects of 2-amino-4-(3‑hydroxy-5-methoxyphenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile (AC09) the 2-amino-5-oxo-4-(thiophen-2-yl)-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile (AC11) derivatives, on the proliferative responses of human T lymphocyts cells, cytokine secretion and intracellular redox status. The study revealed that compounds AC09 and AC11 are efficient immunostimulants in a dose-dependent manner.

Human lymphocytes were less sensitive to AC11 at high concentrations compared to the potency of AC09. Human lymphocyte IL-2, IFNγ and IL-4 secretions were significantly enhanced by those pyrano[3,2-c]chromenes derivatives in a dose-dependent manner. The levels of intracellular lymphocytes glutathione (GSH), were unaffected by AC09 and AC11 at any concentrations. AC09 and AC11 induce a significant increase in hydroperoxide and carbonyl protein contents at high concentrations. Conversely, a computational study using molecular modelling revealed that compounds AC09 and AC11 exhibit a strong affinity for the active site residues of Interferon-γ (IFN-γ; PDB ID: 6E3K) target. This is confirmed by the low score energy value and the formation of different types of interactions such as: hydrogen bonds, hydrophobic interactions, and van der Waals forces. Moreover, all Drug likeness's rules were validated, and no toxicity is presented by these compounds. Finally, in vitro studies, molecular docking techniques and ADME-T (Absorption, Distribution, Metabolism, Excretion and Toxicity) evaluations were successfully conducted, aiding in the identification of new IFN-γ target inhibitors. A comparative analysis /or studies was then carried out to highlight the complementary effects of the two approaches.