{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T13:59:07Z","timestamp":1785419947704,"version":"3.56.0"},"reference-count":28,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T00:00:00Z","timestamp":1783296000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003336","name":"Bulgarian National Science Fund","doi-asserted-by":"crossref","award":["Project KP-06-COST\/20 from 25 August 2025"],"award-info":[{"award-number":["Project KP-06-COST\/20 from 25 August 2025"]}],"id":[{"id":"10.13039\/501100003336","id-type":"DOI","asserted-by":"crossref"}]},{"award":["Project KP-06-COST\/20 from 25 August 2025"],"award-info":[{"award-number":["Project KP-06-COST\/20 from 25 August 2025"]}],"id":[{"id":"https:\/\/ror.org\/05eg49r29","id-type":"ROR","asserted-by":"publisher"}]},{"name":"EU and Bulgarian Government","award":["PRIDST 2021-2027"],"award-info":[{"award-number":["PRIDST 2021-2027"]}]},{"name":"European Union Next Generation EU","award":["BG-RRP-2.004-0008-C01"],"award-info":[{"award-number":["BG-RRP-2.004-0008-C01"]}]},{"award":["BG-RRP-2.004-0008-C01"],"award-info":[{"award-number":["BG-RRP-2.004-0008-C01"]}],"id":[{"id":"https:\/\/ror.org\/019w4f821","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Foodborne diseases remain a major global public health concern. According to the World Health Organization (WHO), contaminated food causes nearly 500,000 deaths annually. Consequently, the development of novel strategies to control foodborne pathogens and prevent microorganism-induced plant diseases remains an important research priority, attracting considerable scientific attention worldwide. This study describes the design and synthesis of novel dihydropyrazolines containing an ethylpiperazine moiety as potential antimicrobial agents. The antibacterial activity of the newly synthesized heterocyclic compounds, along with their corresponding chalcone precursors, was evaluated against Gram-positive and Gram-negative foodborne pathogens and phytopathogenic bacteria. The assessment was performed using a two-step protocol comprising an initial qualitative screening of selected bacterial species, followed by a quantitative evaluation of the inhibitory effects of individual compounds and their combinations. Among the tested compounds, pyrazolines 4a and 4b and chalcone 3b exhibited notable strain-dependent antibacterial activity, particularly against phytopathogenic strains of Pseudomonas syringae, while compound 4a demonstrated the highest efficacy against the Gram-negative foodborne pathogens Escherichia coli, Salmonella enterica and Listeria monocytogenes. Thus, the potential of the N-ethylpiperazine moiety as a key structural feature contributing to the antimicrobial activity of the studied compounds is revealed.<\/jats:p>","DOI":"10.3390\/molecules31132380","type":"journal-article","created":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T13:43:14Z","timestamp":1783345394000},"page":"2380","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Synthesis and Antibacterial Activity of Novel N-Ethylpiperazine-Containing Dihydropyrazolines and Their Chalcone Precursors Against Foodborne and Phytopathogenic Bacteria"],"prefix":"10.3390","volume":"31","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0426-2820","authenticated-orcid":false,"given":"Meglena I.","family":"Kandinska","sequence":"first","affiliation":[{"name":"Faculty of Chemistry and Pharmacy, Sofia University \u201cSt. Kliment Ohridski\u201d, 1 James Bourchier Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter G.","family":"Boyadzhiev","sequence":"additional","affiliation":[{"name":"Faculty of Chemistry and Pharmacy, Sofia University \u201cSt. Kliment Ohridski\u201d, 1 James Bourchier Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Trayana S.","family":"Nedeva","sequence":"additional","affiliation":[{"name":"Faculty of Biology, Sofia University \u201cSt. Kliment Ohridski\u201d, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stanimira T.","family":"Ivanova","sequence":"additional","affiliation":[{"name":"Faculty of Biology, Sofia University \u201cSt. Kliment Ohridski\u201d, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Viliana D.","family":"Miteva","sequence":"additional","affiliation":[{"name":"Faculty of Biology, Sofia University \u201cSt. Kliment Ohridski\u201d, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-0673-342X","authenticated-orcid":false,"given":"Asya A.","family":"Asenova","sequence":"additional","affiliation":[{"name":"Faculty of Biology, Sofia University \u201cSt. Kliment Ohridski\u201d, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7748-4133","authenticated-orcid":false,"given":"Vesela V.","family":"Lozanova","sequence":"additional","affiliation":[{"name":"Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University-Sofia, 2 Zdrave Str., 1431 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Valentin S.","family":"Lozanov","sequence":"additional","affiliation":[{"name":"Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University-Sofia, 2 Zdrave Str., 1431 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8490-9243","authenticated-orcid":false,"given":"Iliyana K.","family":"Rasheva","sequence":"additional","affiliation":[{"name":"Faculty of Biology, Sofia University \u201cSt. Kliment Ohridski\u201d, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria"},{"name":"Centre of Competence \u201cSustainable Utilization of Bio-resources and Waste of Medicinal and Aromatic Plants for Innovative Bioactive Products\u201d (BIORESOURCES BG), 1000 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,6]]},"reference":[{"key":"ref_1","unstructured":"World Health Organization (WHO) (2026, May 15). 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