In our tactic to construct bio-active molecules, a series of novel pyrimido[2,1-c][1,2,4]triazine-3,4-diones based heterocycles, were synthesized and evaluated for their in vitro antimicrobial impacts. The exploratory bioassay results declared that, the majority of the evaluated compounds exhibited considerable anti-microbial activity comparable to the reference drugs. Conjugates 15j, 15f, 15i, 15h, 15g and 15a were found to be the most potent antibacterial, indicating that conjugates bearing electron-attracting substituents exhibited higher potency than these with electron-releasing substituents.

Previous studies showed that some lamellarin-resembling annelated azaheterocyclic carbaldehydes and related imino adducts, sharing the 1-phenyl-5,6-dihydropyrrolo[2,1-a]isoquinoline (1-Ph-DHPIQ) scaffold, are cytotoxic in tumor cells and may reverse multidrug resistance (MDR) mediated by P-glycoprotein (P-gp). Herein, we synthesized and evaluated for their antiproliferative activity in four tumor cell lines (RD, HCT116, HeLa, A549) and ability of inhibiting P-gp-mediated MDR some ten diversely substituted 1-Ph-DHPIQ derivatives bearing at position 2 carboxylate groups (COOH, COOEt), nitriles (CN) and Mannich bases (e.g., morpholinomethyl derivatives). Lipophilicity parametrization and molecular docking calculations improved the understanding of the structure-activity relationships in cytotoxicity and P-gp inhibition of the investigated 1-Ph-DHPIQs, which led us to disclose a novel Mannich base HCl salt (8b’), which proved to be cytotoxic to all the tested tumor cell lines in the low micromolar range (IC50 < 20 M) and to inhibit in-vitro the efflux pumps P-gp and MRP1 responsible for MDR, with IC50s of 0.45 and 12.1 M, respectively.

A series of diethylamine Mannich base of asymmetrical mono-carbonyl analogs of curcumin (AMACs) were synthesized and evaluated for cytotoxic activity against Hela Cell lines. The structures of the synthesized compounds were confirmed on the basis of FTIR, ¹H-NMR, ¹³C-NMR and mass spectral data. Preliminary cytotoxic test using BSLT showed that all the synthesized compounds exhibited more potent cytotoxic activity than that of curcumin. While results of MTT assay showed that all the synthesized compounds exhibited more potent antiproliferative activity against HeLa cell lines than that of cisplatin. Compound 2b exhibited as the most potent compound of the series. Compound 2a, 2b, 2c, and 2f had IC₅₀ (µM) less than that of compound 1a, 1b, 1c and 1f indicating that the addition of diethylamine Mannich base improves the antiproliferative activity of the parent compound.