| Abstrakt: |
THE AIM of the current study was to assess in vitro reactivating potency of newly synthesized oximes cholinesterase reactivators against tabun and comparison to the effi cacy of currently available oximes. MATERIAL AND METHODS. Newly synthesized oximes named as follow - BT-07, BT-07 (4M), BT-08 and BT-10 and classical oximes 2-PAM, obidoxime, TMB-4 and HI-6 were evaluated as reactivators of enzyme activity in case of in vitro inhibited by tabun rat brain acetylcholinesterase (AChE). Rat brain homogenate diluted in distilled water (2%,w/v) was used as a source of AChE. The homogenate was inhibited with tabun (5.10-8 mol/L) for 30 minutes and then tested oximes were added for 20 minutes at 25°C in concentrations 1.10-4, 1.10-5, 1.10-6 and 1.10-7 mol/L. The activity AChE was determined by Ellman's method. Spectrophotometer “Hospitex Diagnostics“-Screen master, was used. The percentage of reactivation (%R) was calculated from the measured activities of the intact enzyme (Ao), tabun -inhibited enzyme (AI), and reactivated enzyme (AR), using the following equation %R = [1 - (Ao - AR) / (Ao - AI)] x 100. DATE ANALYSIS: Statistical signifi cance was determined by using Student's t-test and differences were considered signifi cant when p<0.05. RESULTS. The results obtained from current study showed that in the experimental conditions used the best reactivation potency demonstrated compound BT0-7 (4M) that was able to reactivate 72% of enzyme activity at concentration 1.10-4 mol/L and 17.3% at concentration 1.10-6 mol/L. Very good reactivation effi cacy, but not so high as BT-07 (4M), was recorded for TMB-4 that restored 52% and 31.5% of enzyme activity at concentrations 1.10-4 mol/L and 1.10-5 mol/L, respectively. Obidoxime ensured good reactivation (31%) as well but only at the highest concentration used. The rest of the oxime compounds tested were completely ineffective in restoration of the activity in case of tabun inhibited brain AChE. CONCLUSION: On the base of results obtained from this study could be concluded that only oximes possess a typical chemical structure are able to reactivate in vitro tabun inhibited AChE. Such chemical structure commonly could be described as follow: 1. Position of the oxime group at position 4 in pyridinium ring 2. A distinct type and length of the bridge between pyridinium rings and 3. The type of the substitute groups in pyridinium rings. [ABSTRACT FROM AUTHOR] |
