Figures & data
Figure 1. Timeline of treatment and Morris Water Maze (MWM) Test for treatment groups (VCO and αT).
Figure 2. VCO-enhanced memory in Wistar rats. VCO treated rats were subjected to behavioural study using the Morris Water Maze Test. The rodents were assessed as follows: (A) Escape latency, (B) escape distance, (C) time spent by the rat in the escape platform zone (probe test) and (D) average speed taken by the rat to reach escape platform. αT was also included for comparison purposes. Each bar represents mean ± SEM of n = 6. *p < 0.05, **p < 0.01, ***p < 0.001 when compared to control group.
Figure 3. Effects of VCO on cholinergic activity in rat brain. The cholinergic activity in rat brain was assessed: (A) AChE and (B) ACh. Each bar represents mean ± SEM of n = 6. *p < 0.05, **p < 0.01, ***p < 0.001 when compared to control; +p < 0.05, ++p < 0.01, +++p < 0.001 when compared to αT.
Figure 4. Effects of VCO on antioxidant activity in rat brain. The concentration of antioxidants in rat brain was measured: (A) SOD, (B) CAT, (C) GSH, (D) GPx and (E) GR. Each bar represents mean ± SEM of n = 6. *p < 0.05, **p < 0.01, ***p < 0.001 when compared to control; +p < 0.05, ++p < 0.01, +++p < 0.001 when compared to αT.
Figure 5. Effects of VCO on oxidative stress in rat brain. The oxidative stress in rat brain was determined: (A) MDA and (B) NO. Each bar represents mean ± SEM of n = 6. *p < 0.05, **p < 0.01, ***p < 0.001 when compared to control; + p < 0.05, ++p < 0.01, +++p < 0.001 when compared to αT.
Figure 6. Proposed mechanisms underlying VCO-induced memory improvement in normal adult Wistar rats. The enhanced memory under the influence of VCO is likely mediated through two biological components in the brain: cholinergic neurons and the microenvironment. For cholinergic neurons, VCO reduced AChE action which in turn increased ACh concentration in the brain. The increased ACh plays important role in effective synaptic transmission during acquiring new information and consolidation of memory. Within the microenvironment, on the other hand, VCO increased production of antioxidants in brain, namely SOD, CAT, GSH and GPx. The up-regulated antioxidants served as protection against lipid peroxidation (MDA) by oxidative stress (NO). The collective effects of these two components would eventually prevent or delay neurodegeneration.
