Many quinazoline derivatives have been synthesized over the last few decades with great pharmacological potential, such as antimalarial, anti-inflammatory, antimicrobial, anticancer, and antiviral. But so far, no quinazoline–artemisinin hybrids have been reported in the literature. In the present study, five novel quinazoline–artemisinin hybrids were synthesized and evaluated for their in vitro biological activity against malarial parasites (Plasmodium falciparum 3D7), leukemia cells (CCRF-CEM and CEM/ADR5000), and human cytomegalovirus. Remarkably, hybrid 9 (EC₅₀ = 1.4 nM), the most active antimalarial compound of this study, was not only more potent than artesunic acid (EC₅₀ = 9.7 nM) but at the same time more active than the clinically used drugs dihydroartemisinin (EC₅₀ = 2.4 nM) and chloroquine (EC₅₀ = 9.8 nM). Furthermore, hybrids 9 and 10 were the most potent compounds with regard to anticytomegaloviral activity (EC₅₀ = 0.15–0.21 μM). They were able to outperform ganciclovir (EC₅₀ = 2.6 μM), which is the relevant standard drug of antiviral therapy, by a factor of 12–17. Moreover, we identified a new highly active quinazoline derivative, compound 14, that is most effective in suppressing cytomegalovirus replication with an EC₅₀ value in the nanomolar range (EC₅₀ = 50 nM). In addition, hybrid 9 exhibited an antileukemia effect similar to that of artesunic acid, with EC₅₀ values in the low micromolar range, and was 45 times more active toward the multidrug-resistant CEM/ADR5000 cells (EC₅₀ = 0.5 μM) than the standard drug doxorubicin.

Influence of pH on the extent of lipid peroxidation and the anti‐oxidant potential of an organoselenium compound is explored. Acidosis increased the rate of lipid peroxidation both in the absence and presence of Fe (II) in rat's brain, kidney and liver homogenate and phospholipids extract from egg yolk. The organoselenium compound significantly protected lipids from peroxidation, both in the absence and presence of Fe (II). Changing the pH of the reaction medium did not alter the anti‐oxidant activity of the tested compound. This study provides in vitro evidence for acidosis‐induced oxidative stress in brain, kidney, liver homogenate and phospholipids extract and the anti‐oxidant action of the tested organoselenium compound.