Grewia asiatica Berry Juice Diminishes Anxiety, Depression, and Scopolamine-Induced Learning and Memory Impairment in Behavioral Experimental Animal Models

Abstract

Grewia asiatica L. fruit natively called phalsa is a popular berry of Pakistan and widely consumed in the form of fresh juices and carbonated drinks in the summer season. The berry is enriched with antioxidants such as phenols, flavonoids, anthocyanins, and vitamin C. Scientifically, it is the least explored berry in terms of neuromodulatory activities, and therefore, in the designed study, chronically fed rats with the different dilutions (5%-30%) of fruit juice were subjected to behavioral assessment for anxiety, depression, and cognition (spatial memory) followed by biochemical analysis of isolated brains. Results revealed a prominent impact of 20 and 30% dilutions of fruit exudate as treated animals showed anxiolytic behavior to central zone (P < 0.05) of open field test (OFT) and open arms of elevated plus maze (EPM) (P < 0.05) in anxiety models. Overall, immobility of rats treated with a higher concentration of exudate in forced swim test (FST) was reduced (P < 0.05) presenting antidepressant-like activity. Moreover, in learning and memory experimental models, the treated animals reversed scopolamine-induced amnesic effects as evident from improved step-through latencies (P < 0.05 vs. scopolamine; passive avoidance test), spontaneous alternation behavior (P < 0.05 vs. scopolamine; Y-maze test), discrimination index (P < 0.05 vs. scopolamine; novel object recognition test), and escape latencies (P < 0.05 vs. scopolamine; Morris water maze). Biochemical studies of isolated brains from treated rats demonstrated significantly elevated levels of superoxide dismutase and glutathione peroxidase (P < 0.05), whereas levels of acetylcholinesterase and malondialdehyde level (P < 0.05) were reduced, indicating its potential to reduce oxidative damage in the brain and modulation with the cholinergic system. The outcomes of studies support the benefits of phytoconstituents possessed by G. asiatica fruit in the amelioration of neurological disorders that could be due to their antioxidative capacity or due to interaction with GABAergic, serotonergic, and cholinergic systems in the brain.

Keywords: Grewia asiatica; Morris water maze; amnesia; anxiety; depression; escape latency.

Figure 1

Schematic presentation of behavioral studies.

Figure 2

Assessment of total phenol (A), flavonoid (B), and anthocyanin (C) content in methanolic extracts of different concentrations of fruit pulp of Grewia asiatica. Data expressed as mean ± SEM (n = 3) and evaluated by one-way ANOVA followed by Tukey's test. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, comparison between 5 and 10%, 10 and 20%, and 20 and 30% dilutions of G. asiatica exudate (Gr.Ex).

Figure 3

In vitro evaluation of 1,1-diphenyl-2-picrylhydrazyl (DPPH) (A), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (B), and acetylcholinesterase (AChE) (C) % inhibition capacity of methanolic extracts prepared for different concentrations of fruit juice of Grewia asiatica. Data expressed as mean ± SEM (n = 3) and evaluated by one-way ANOVA followed by Tukey's test. *P < 0.05, **P < 0.01, ***P < 0.001, comparison between 5 and 10%, 10 and 20%, and 20 and 30% dilutions of G. asiatica exudate (Gr.Ex).

Figure 4

Anxiolytic effect of various dilutions of Grewia asiatica exudate (Gr.Ex) and diazepam on the (A) number of center zone entries and (B) duration in the center zone in the open field test. Data expressed as mean ± SEM (n = 6) and evaluated by one-way ANOVA followed by Tukey's test. ****P < 0.0001, comparison between control animals and diazepam group. ^ccP < 0.01, ^cccP < 0.01, comparison between control animals and 20% Gr.Ex-treated group. ^ddddP < 0.0001, comparison between control animals and 30% Gr.Ex-treated group.

Figure 5

Anxiolytic effect of various dilutions on (A) open arm entries and (B) time spent in the open arm in the elevated plus maze test. Data expressed as mean ± SEM (n = 6) and evaluated by one-way ANOVA followed by Tukey's test. ***P < 0.001, ****P < 0.0001, comparison between control animals and diazepam group. ^cP < 0.05, comparison between control animals and 20% Grewia asiatica exudate (Gr.Ex)-treated group. ^dP < 0.05, ^dddP < 0.0001, comparison between control animals and 30% Gr.Ex-treated group.

Figure 6

Antidepressant-like effect by various dilutions of Grewia asiatica exudate (Gr.Ex) on immobility of rats in the forced swimming test. Data expressed as mean ± SEM (n = 6) and evaluated by one-way ANOVA followed by Tukey's test. ***P < 0.001, comparison between control animals and fluoxetine group. ^cP < 0.05, comparison between control animals and 20% Gr.Ex-treated group. ^ddP < 0.01, comparison between control animals and 30% Gr.Ex-treated group.

Figure 7

Effect of Grewia asiatica exudate (Gr.Ex) on (A) step-through latencies and (B) time spent in the dark in the passive avoidance test. Data expressed as mean ± SEM (n = 6) and evaluated by two-way ANOVA followed by Tukey's test. ****P < 0.0001, comparison of control animals with scopolamine-treated group. ^####P < 0.0001, comparison between scopolamine- and piracetam-treated groups. ^bP < 0.05, ^bbbP < 0.001, comparison between scopolamine- and 10% Gr.Ex-treated groups. ^cccP < 0.001, ^ccccP < 0.0001, comparison between scopolamine- and 20% Gr.Ex-treated groups. ^ddddP < 0.0001, comparison between scopolamine- and 30% Gr.Ex-treated groups.

Figure 8

Effect of Grewia asiatica exudate (Gr.Ex) on spontaneous alternation behavior in the Y-maze task. Data expressed as mean ± SEM (n = 6) and evaluated by one-way ANOVA followed by Tukey's test. **P < 0.01, comparison of control animals with scopolamine-treated group. ^##P < 0.01, comparison between scopolamine- and piracetam-treated groups. ^dP < 0.05, comparison between scopolamine and 30% Gr.Ex-treated groups.

Figure 9

Impact of Grewia asiatica exudate (Gr.Ex) on (A) novel object exploration time and (B) discrimination index in the novel object recognition test. Data expressed as mean ± SEM (n = 6) and evaluated by one-way ANOVA followed by Tukey's test. *P < 0.05, ***P < 0.001, comparison between control animals and scopolamine-treated group. ^####P < 0.0001, comparison between scopolamine- and piracetam-treated groups. ^cP < 0.05, comparison between scopolamine- and 20% Gr.Ex-treated groups. ^ddP < 0.01, ^dddP < 0.001, comparison between scopolamine- and 30% Gr.Ex-treated groups.

Figure 10

Effect of Grewia asiatica exudate (Gr.Ex) on (A) escape latencies, (B) entries in the platform zone, (C) swimming time in the platform zone, and (D) distance traveled in the Morris water maze test. Data expressed as mean ± SEM (n = 6). Escape latencies were evaluated by two-way ANOVA, while one-way ANOVA followed by Tukey's test was used to evaluate other parameters. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, comparison between control animals and scopolamine-treated group. ^####P < 0.0001, comparison between scopolamine- and piracetam-treated groups. ^ccP < 0.01, ^ccccP < 0.0001, comparison between scopolamine- and 20% Gr.Ex-treated groups. ^dddP < 0.001, ^ddddP < 0.0001, comparison between scopolamine- and 30% Gr.Ex-treated groups.

Figure 11

Evaluation of biochemical activity in the brain. Levels of acetylcholinesterase (A), malondialdehyde (B), superoxide dismutase (C), and glutathione peroxidase (D). Data expressed as mean ± SEM (n = 3) and evaluated by one-way ANOVA followed by Tukey's test. *P < 0.05, **P < 0.01, ***P < 0.001, comparison between control animals and scopolamine-treated group. ^###P < 0.001, ^####P < 0.0001, comparison between scopolamine- and piracetam-treated groups. ^cP < 0.05, comparison between scopolamine and 20% Grewia asiatica exudate (Gr.Ex)-treated groups. ^dP < 0.05, ^ddP < 0.01 comparison between scopolamine- and 30% Gr.Ex-treated groups.