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In the face of the emergence of bacteria resistant to common antibacterials and excessive accumulation of free radicals that can cause several diseases, it is important to look for new antibacterials and antioxidants. The goal of this work was to synthesize three chalcones derivatives by the Claisen-Schmidt condensation and then evaluate their antibacterial and antioxidant activities. The structure of these 3 compounds has been determined by NMR (1H and 13C) spectroscopy. The in vitro antibacterial activity assessed by Microdilution methods, was tested against Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa) at different concentrations ranging from 7.82 to 1000 µg/mL. All three synthesized chalcones showed good antibacterial activity against gram positive and negative bacteria used with a range of MIC ranging from 62.50 to 1000 µg/mL. However, the (E)-3-(3, 4-dimethoxyphenyl)-1-(2-hydroxyphenyl) prop-2-en-1-one showed excellent activity against Bacillus subtilis with Minimum Inhibitory Concentration (MIC) of 62.5 µg/mL which is similar to that of the standard (Ampicillin) against the same bacterial strain. Antioxidant activity evaluated using 2,2-diphenyl2-picryl- hydrazyle ( DPPH) revealed that all the synthesized chalcones showed an antioxidant activity with IC50 values of 8.22; 6.89 and 3.39 µg/mL for (E)-1-(2-hydroxyphenyl)-3-(4-hydroxyphenyl) prop-2-en-1-one, (E)-1-(2-hydroxyphenyl)-3-(4-methoxyphenyl) prop-2-en-1-one and (E)-3-(3, 4-dimethoxyphenyl)-1-(2-hydroxyphenyl) prop-2-en-1-one, respectively. These values are closer to that of ascorbic acid used as a standard. The results suggest that the synthesized chalcones, especially the (E)-3-(3, 4-dimethoxyphenyl)-1-(2-hydroxyphenyl) prop-2-en-1-one could be used, after in vivo and clinical tests, like antibacterial and antioxidant supplement or even replace current drug therapies.

Background: Malaria is one of the major global health problems in developing countries and faced to the increased resistance of Plasmodium falciparum against existing malarial agents, it is important to look for new antimalarial compounds that will be active in multiple stage of Plasmodium falciparum's life cycle. Objective: The goal of this work was to synthesize Amino Chalcone derivatives and Dihydroquinolone derivatives, then evaluate their antimalarial activity by standard computational and biological methods. Methods: These amino chalcones were synthesized by the Claisen-Schmidt condensation and by intramolecular cyclization of substituted amino chalcones for the Dihydroquinolones derivatives. Their structures have been determined by NMR ( 1 H and 13 C). The in-vitro antimalarial assays were carried out by using the maturation test of trophozoites into schizonts. The molecular docking of these compounds was performed by AutoDock vina program using Plasmodium falciparum dihydrofolate reductase-thymidylate synthase (PfDHFR-TS) (PDB ID 1J3I) as target protein. Results: All synthesized amino chalcones and dihydroquinolone derivatives were active against Fresh clinical isolates of Plasmodium falciparum with a range of EC50 ranging from 1.56 to 25µg/mL. However, the 2phenyl-2, 3-dihydroquinolin-4-(1H)-one (DHQ 2) and 2-(4-methoxyphenyl)-2, 3-dihydroquinolin-4-(1H)-one (DHQ 4) showed excellent antimalarial activity with IC50 of 3.125 and 1.56 µg/mL, respectively. Whereas the IC50 of Chloroquine use as reference was 1.56µg/mL. Based on absorption, distribution, metabolism and excretion (ADME) properties, all synthetized compounds satisfied the Lipinski rule. Conclusion: The results suggest that these synthesized compounds (DHQ 2 and DHQ 4), could be used, after in vivo and clinical tests, like antimalarial supplement or even replace current drug therapies.

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