| Abstract | Proces otkrića lijekova obuhvaća sljedeće faze: odabir bolesti, odabir cilja na koji lijek djeluje, identificiranje biološkog testa, pronalazak spoja uzora. Jedan od in vivo testova koji se provodi u ovom kontekstu je i ispitivanje antibakterijske aktivnosti. U ovom je radu ispitivana antibakterijska aktivnost 12 novosintetiziranih spojeva na 4 vrste bakterija: S. aureus (G+), E. faecalis (G+), M. catarrhalis (G-), E. coli (G- , hiperosjetljiv soj bez efluks pumpi). Pritom je korištena metoda mikrodilucije koja se provodi u mikrotitarskim pločicama. U medij inokuliran određenom bakterijskom vrstom dodaju se testirani spojevi te se potom serijski razrjeđuju. Sintetizirani spojevi derivati su itakonske kiseline i antimalarika primakina, klorokina i meflokina, kao i derivati itakonske kiseline i fluoroanilina, piridina i indola. Iako za ove spojeve nije predviđena antibakterijska aktivnost, važno je provesti opsežna in vitro i in vivo ispitivanja potencijalnih novih lijekova jer se na taj način mogu otkriti nova, nepredviđena djelovanja. Ispitivani derivati itakonske kiseline nisu pokazali učinak inhibicije rasta gram-pozitivnih bakterija S. aureus i E. faecalis te gram-negativne bakterije E. coli. Značajniji učinak inhibicije rasta ispitivani su spojevi pokazali na gram-negativnoj bakteriji M. catarrhalis. Najpotentniji spoj je već postojeći antimalarik MQ (meflokin) čija minimalna inhibitorna koncentracija iznosi 1/0,5 μg/mL. Od novosintetiziranih spojeva najbolji učinak inhibicije bakterijskog rasta pokazao je spoj V9 (MIK = 4 μg/mL). Minimalne inhibitorne koncentracije spojeva povezane su s njihovom lipofilnosti. Kao jedan od parametara lipofilnosti uzet je logP te se pokazalo da je antibakterijski učinak spojeva na M. catarrhalis veći što je veća vrijednost logP. Razlog tome je hidrofobnost bakterijske membrane zbog prisutnih lipooligosaharida. Spojevi nisu pokazali učinak na E. coli, iako i ta bakterija ima prisutne lipopolisaharide na vanjskoj membrani, no oni su manje lipofilni te je manja penetracija spojeva u samu bakteriju. |
| Abstract (english) | Drugs discovery process includes the following stages: selection of disease, selection of drug target, identifying biological test, discovery of model compound. One of in vivo tests applied in this context is antibacterial activity testing. In this paper, the antibacterial activity of 12 newly synthesized compounds was tested against 4 species of bacteria: S. aureus (G+), E. faecalis (G+), M. catarrhalis (G-), E. coli (G-, hypersensitive strain without efflux pumps). On this occasion, microdilution method was applied, which is implemented using microtiter plates. The tested compounds were added to a medium inoculated by certain species of bacteria and then sequentially diluted. The synthesized compounds are derivatives of itaconic acid and anti-malarial drugs: primaquine, chloroquine and mefloquine, as well as the derivatives of itaconic acid and fluoroaniline, pyridine and indole. Although no antibacterial activity is envisaged for these compounds, it is important to conduct extensive in vitro and in vivo testing of potential new drugs, since in this way it is possible to detect new, unforeseen effects. The examined itaconic acid derivatives did not show growth inhibition effect on gram-positive bacteria S. aureus and E. faecalis, or on gram-negative bacteria E. coli. The examined compounds showed substantial growth inhibition effect on the gram-negative bacteria M. catarrhalis. The most potent compound is the already existing anti malaria drug MQ (mefloquine) with the minimum inhibitory concentration of 1/0.5 μg/mL. Out of the newly-synthesized compounds, V9 (MIC = 4 μg/mL) compound showed the best bacterial growth inhibition effect. Minimum inhibitory compound concentrations are related to their lipophilicity. Upon selecting logP as one of lipophilicity parameters, it was evident that antibacterial effect of the compounds on M. catarrhalis increased with the increase in the logP value. The reason for this is the hydrophobicity of bacterial membrane due to the presence of lipooligosaccharides. The compounds showed no effect on E. coli, although even that bacteria species has lipopolysaccharides present in the outer membrane, however as they are less lipophilic the penetration of compounds in the very bacteria is smaller. |
