New 2,3-Benzodiazepine Derivative: Synthesis, Activity on Central Nervous System, and Toxicity Study in Mice

Abstract

We report the design and synthesis of a new diazepine derivative, 4-(4-methoxyphenyl)-2,3,4,5-tetrahydro-2,3-benzodiazepin-1-one (VBZ102), and the evaluation of its anxiolytic-like profile, memory impairment effect, and toxicity in Swiss mice. VBZ102 was evaluated for central nervous system effects in an open field, light-dark box, and novel object recognition tests under oral administration for acute and sub-acute treatment. We tested the VBZ102 toxicity in mice through a determination of LD₅₀ values and examination of the biochemical and histopathological parameters. The VBZ102 induced an anxiolytic effect at different doses both in the light-dark box and open field tests. Unlike other benzodiazepines (e.g., bromazepam), a sedative effect was noted only after administration of the VBZ102 at 10.0 mg/kg.

Keywords: benzodiazepines; central nervous system; mouse behavioral model; toxicity.

Figure 1

2,3-Benzodiazepines with anxiolytic activity.

Figure 2

Hydrogenation of 2,3-benzodiazepin-1-ones. Reagents and conditions: H₂, 10 % Pd/C, MeOH-HCl, r.t., atmospheric pressure.

Figure 3

Effects of VBZ102, vehicle, and bromazepam on (A) the number of total squares crossed in the open field test, (B) the time spent in the center in the open field test, (C) the time spent in the light area in the LDB test, and (D) the number of transitions in the LDB test. The data are expressed as mean $\pm$ standard deviation. The analysis was done using two-way repeated-measures analysis of variance followed by the Tukey post-hoc test. *** p $\le$ 0.001, ** p $\le$ 0.01, * p $\le$ 0.05, compared to the respective session of the vehicle group. ^### p ≤ 0.001, ^# p ≤ 0.05, compared to the bromazepam group.

Figure 4

Effects of the VBZ102, vehicle, and bromazepam on (A) the time spent in the center in the open field test, (B) the number of total squares crossed in the open field test, (C) the time spent in the light area in the LDB test, and (D) the number of transitions between the light and dark compartments in the LDB test. The data are expressed as mean $\pm$ standard deviation. The analysis was done using two-way repeated-measures analysis of variance followed by the Tukey post-hoc test. *** p $\le$ 0.001, ** p $\le$ 0.01, * p $\le$ 0.05, compared to the respective session of the vehicle group. ^### p ≤ 0.001, ^## p ≤ 0.01, ^# p ≤ 0.05, compared to the bromazepam group.

Figure 5

Novel object recognition test. (A) Time spent by different groups of mice to explore the novel object. (B) Discrimination index performance of different groups of mice. The data are expressed as mean $\pm$ standard deviation. The analysis was done using two-way repeated-measures analysis of variance followed by the Tukey post-hoc test. *** p $\le$ 0.001, ** p $\le$ 0.01, compared to the vehicle group, ^### p ≤ 0.001, ^# p ≤ 0.05, compared to the bromazepam group.

Figure 6

Histopathological examination of liver, kidneys, and brain of mice in the chronic oral toxicity study. (A,D,G) The control group; (B,E,H) the group treated with 10.0 mg/kg of the VBZ102; (C,F,I) the group treated with 1.0 mg/kg of the VBZ102. (A,D,G) Normal cells. (B) Nuclear degenerescence, vacuolation, and steatosis within cells; the nuclei are not centered, although, there is no inflammatory infiltrate around the centrilobular vein. (E) Normal cells. (H) Presence of a clear halo around perivascular halo vessels. (C) Degeneration of the plasma membrane, vacuolation, steatosis, and infiltrate around the centrilobular vein. (F) Normal cells. (I) Normal cells (hematoxylin and eosin (H&E) ×400).