Duguetia furfuracea (A.ST. Hil.) Saff.: Neuroprotective Effect on Chemically Induced Amnesia, Anxiolytic Effects and Preclinical Safety Evaluation in Mice

Abstract

Duguetia furfuracea, "araticum-seco", is known to contain several bioactive compounds that can mitigate oxidative stress and act on the central nervous system (CNS). This effect is partly attributed to its potent antioxidant and acetylcholinesterase (AChE) inhibitors. In this study, the effects were explored of the methanolic extract (MEDF) and alkaloid fraction (AFDF) of D. furfuracea (leaves) on cognitive behaviors in male mice with scopolamine (Scop)-induced cognitive impairment and biochemical parameters. Additionally, anxiolytic behavior, subacute toxicity, molecular docking and antioxidant activity were reported. MEDF (30, 100 or 300 mg/kg) or AFDF (30 mg/kg) were orally administered for 16 days and Scop (intraperitoneally, i.p.) between days 11 and 16. The anxiolytic behavior (open field test and marble burying) in healthy mice, and the Scop-induced memory impairment (object recognition test and Morris water maze (MWM)) were assessed, and the biochemical parameters (malondialdehyde (MDA) and AChE levels) were measured after euthanasia. The subacute toxicological impact of MEDF was assessed in female Swiss mice for 28 days. MEDF and AFDF were available for the DPPH, ABTS and β-carotene/linoleic acid models. The results revealed that MEDF and AFDF exhibit anxiolytic effects and significantly alleviated Sco-induced memory impairment, inhibited AChE in the cortex (40%) and MDA (51.51%) levels. Reticuline was reported in AFDF and molecular coupling with AChE involves link-type hydrogen bonds and van der Waals interactions. MEDF exhibited antioxidant capacity (DPPH, IC₅₀ = 18.10 ± 1.70 µg/mL; ABTS, IC₅₀ = 10.41 ± 1.69 µg/mL). MEDF did not reveal signs of toxicity. In conclusion, D. furfuracea shows promise in mitigating scopolamine-induced memory deficits, potentially because it inhibits AChE activity, reduces MDA levels, and enhances antioxidant activities.

Keywords: AChE; anxiety; dementia; scopolamine; “araticum seco”.

Figure 1

Experimental design of behavioral tests that assess anxiety, learning and memory in mice and biochemical parameters (MDA and AChE).

Figure 2

LC–MS (A) and (B) MS spectra/fragmentation at 1.84 min of AFDF.

Figure 3

Photomicrography of organs stained with H&E in 40× magnification. (A–D): brain sections from cerebral cortex; (E–H): muscle fibers in the cardiac muscle; (I–L): normal liver sections evidencing the central vein; (M–P): sections of spleen samples; (Q–T): kidney sections with normal architecture of glomeruli.

Figure 4

Marble burying test. Marbles were buried by mice treated with EMDF (30, 100, 300 mg/kg) and AFDF 30 mg/kg for 15 min on the tenth day of treatment. Values are presented as mean ± SEM. The symbol (*) denotes statistical difference from the vehicle, with p < 0.01 (**) and p < 0.001 (***) and (a, b) indicates the significant differences between treated groups (p < 0.05). The number of animals used in the experiments was n = 8 per group. Significance values were determined using ANOVA followed by Tukey multiple comparison test for the analysis.

Figure 5

Object recognition test. (A) Time spent by the animal in the familiar object zone. (B) Time spent by the animal in the new object zone. Values are expressed as mean ± standard error of the mean (SEM). (^# p < 0.05 and ^### p < 0.001) statistically different from the vehicle compared with Scop group, and (*) statistically different from the group treated compared with Scop (* p < 0.05 and ** p < 0.01). (a) indicates no significant differences between treated groups (p < 0.05). Significance values were obtained through analysis of variance (ANOVA) and Tukey’s Multiple Comparison Test post-test.

Figure 6

Effect of MEDF and AFDF on learning and memory in scopolamine-treated mice in the MWM test. (A) Escape latency of the acquisition trial over 4 days. (B) Distance covered since the first entry in the platform area. (C) The time the animal spent in the platform area. (D) The number of entries into the platform area. (E) Swimming trajectory performed by the group AFDF (30 mg/kg) during the test day (16th day, without the platform). Results were expressed as mean ± SEM (n = 8). (*) p < 0.05, (**) p < 0.01, (***) p < 0.001 versus the Scop-treated group; (##) p < 0.01, and (###) p < 0.001 versus the vehicle-Scop group. (a) indicates no significant differences between treated groups (p < 0.05). Significance values were obtained using analysis of variance (ANOVA) and Tukey’s multiple comparison test post-test.

Figure 7

Effect of MEDF (30, 100 and 300 mg/kg) and AFDF (30 mg/kg) in MDA levels in brain mice after daily administration of Scop (11th to 16th days). (**) p < 0.01 versus Scop-treated group. Each bar represents mean ± SEM. Significance values were obtained using ANOVA and Tukey’s multiple comparison test post-test.

Figure 8

Effect of MEDF (30, 100 and 300 mg/kg) and AFDF (30 mg/kg) on the AChE activity in the cerebral cortex (A) and hippocampus (B). (*) p < 0.05, (**) p < 0.01 versus the Scop-treated group, (##) p < 0.01 versus the Scop-vehicle group. Each bar represents mean ± SEM. Significance values were obtained using ANOVA and Tukey’s multiple comparison test post-test.

Figure 9

Docking interactions between the active residues site of the protein with the reticuline ligand.

Figure 10

Overall view of the AChE subunit complexed with reticuline.