Biomolecular Evaluation of Lavandula stoechas L. for Nootropic Activity

Abstract

Lavandula Stoechas L. is widely known for its pharmacological properties. This study was performed to identify its biomolecules, which are responsible for enhancement of memory. L. stoechas aqueous extract was first purified by liquid column chromatography. The purified fractions were analyzed for in vitro anti-cholinesterase activity. The fraction that produced the best anti-cholinesterase activity was named an active fraction of L. stoechas (AfL.s). This was then subjected to GC-MS for identifications of biomolecules present in it. GC-MS indicated the presence of phenethylamine and α-tocopherol in AfL.s. Different doses of AfL.s were orally administered (for seven days) to scopolamine-induced hyper-amnesic albino mice and then behavioral studies were performed on mice for two days. After that, animals were sacrificed and their brains were isolated to perform the biochemical assay. Results of behavioral studies indicated that AfL.s improved the inflexion ratio in mice, which indicated improvement in retention behavior. Similarly, AfL.s significantly (p < 0.001) reduced acetylcholinesterase and malondialdehyde contents of mice brain, but on the other hand, it improved the level of choline acetyltransferase, catalase, superoxide dismutase, and glutathione. It was found that that high doses of AfL.s (≥400 mg/Kg/p.o.) produced hyper-activity, hyperstimulation, ataxia, seizures, and ultimate death in mice. Its LD₅₀ was calculated as 325 mg/Kg/p.o. The study concludes that α-tocopherol and phenethylamine (a primary amine) present in L. stoechas enhance memory in animal models.

Keywords: AChE; L. stoechas; acetylcholine; aromatic amine; choline acetyltransferase; enhancement of memory; phenethylamine.

Figure 1

General scheme of fractionation by column chromatography.

Figure 2

Effect of AfL.s on (A) initial transfer latency; (B) retention transfer latency; (C) inflexion ratio in the elevated plus maze paradigm; (D) time spent (sec) in the light compartment on day 1; (E) time spent (sec) in the dark compartment on day 1; (F) time spent (sec) in the light compartment on day 2; (G) time spent (sec) in the dark compartment on day 2; (H) number of hole pokings by mice on day 1, and (I) number of hole pokings by mice on day 2. Data are presented as mean ± SEM (n = 6) and one-way ANOVA (Dunnett’s test) was applied by comparing G-II to G-I (presented by “a” on the bar). All other groups were compared to G-II (presented by “b” on the bar). The signs ns, *, ** and *** presented the p values as ≥0.05, ≤0.05, ≤0.01, and ≤0.001, respectively).

Figure 2

Effect of AfL.s on (A) initial transfer latency; (B) retention transfer latency; (C) inflexion ratio in the elevated plus maze paradigm; (D) time spent (sec) in the light compartment on day 1; (E) time spent (sec) in the dark compartment on day 1; (F) time spent (sec) in the light compartment on day 2; (G) time spent (sec) in the dark compartment on day 2; (H) number of hole pokings by mice on day 1, and (I) number of hole pokings by mice on day 2. Data are presented as mean ± SEM (n = 6) and one-way ANOVA (Dunnett’s test) was applied by comparing G-II to G-I (presented by “a” on the bar). All other groups were compared to G-II (presented by “b” on the bar). The signs ns, *, ** and *** presented the p values as ≥0.05, ≤0.05, ≤0.01, and ≤0.001, respectively).

Figure 3

Effect of AfL.s on concentration of (A) acetylcholinesterase (AChE); (B) MDA; (C) SOD; (D) CAT; and (E) GSH in brain homogenate. Data are presented as mean ± SEM (n = 6) and one-way ANOVA (Dunnett’s test) was applied by comparing G-II to G-I (presented by “a” on bar). All other groups were compared to G-II (presented by “b” on bar). The signs ns, *, ** and *** presented the p values as ≥0.05, ≤0.05, ≤0.01, and ≤0.001, respectively).

Figure 3

Effect of AfL.s on concentration of (A) acetylcholinesterase (AChE); (B) MDA; (C) SOD; (D) CAT; and (E) GSH in brain homogenate. Data are presented as mean ± SEM (n = 6) and one-way ANOVA (Dunnett’s test) was applied by comparing G-II to G-I (presented by “a” on bar). All other groups were compared to G-II (presented by “b” on bar). The signs ns, *, ** and *** presented the p values as ≥0.05, ≤0.05, ≤0.01, and ≤0.001, respectively).

Figure 4

Effect of AfL.s on concentration of ChAT in mice brains. Data are presented as mean ± SEM (n = 6) and one-way ANOVA (Dunnett’s test) was applied by comparing all groups with G-I. The signs ns, *, ** and *** presented the p values as ≥ 0.05, ≤ 0.05, ≤ 0.01, and ≤ 0.001 respectively.