STRUCTURE AND ANTIBACTERIAL ACTIVITY OF ISOALANTOLACTONE DERIVATIVES
Aim. To study the antibacterial properties of isoalantolactone and its derivatives on opportunistic bacteria. Materials and Methods.We examined the activity of isoalantolactone, a major metabolite of Inula helenium L., and its 38 derivatives containing 11,13- exomethylenic bond (Ia-r), 11,13- sat- urated bond (IIa-t), heterocyclic derivatives with 7,11-double bond, С-8 epimers (IIIa-c), and alantolactone (IV) against Escherichia coli (25522 АТСС) and Pseudomonas aeruginosa (U-16) utilizing serial dilutions in a liquid medium. Results. From the group I, an antibacterial activity was detected only for substances Ic and Ig. While IIIa isomer had bactericidal properties on Escherichia coli, Ig agent showed only bacteriostatic activity. IIr agent, with a pyridine separated from lactone, demonstrated lower bacteriostatic activity on Escherichia coli even compared to Ig; however, it was more efficient against Pseudomonas aeruginosa. Among the uracil-substituted derivatives, only substance containing 5-bromuracil had antibacterial properties against both Escherichia coli and Pseudomonas aeruginosa. In addition, certain isoalantolactone derivatives inhibited Pseudomonas aeruginosa biolm formation. Conclusions. Among 38 derivatives of isoalantolactone, only five and three compounds showed antibacterial properties against Escherichia coli and Pseudomonas aeruginosa, respectively. This can be explained by the presence of pyridinil or bromuracil substituent in their structure.