Essential Oil of Lippia origanoides Kunth: Nanoformulation, Anticholinesterase Activity, and Molecular Docking

Abstract

This study investigates the therapeutic potential of Lippia origanoides essential oil (LOEO) in neurological and pharmaceutical applications. The chemical composition of LOEO was analyzed using gas chromatography-mass spectrometry (GC-MS), revealing major constituents, such as carvacrol, thymol, and γ-gurjunene, known for their antioxidant and antimicrobial properties. LOEO demonstrated significant acetylcholinesterase (AChE)-inhibitory activity, particularly in a nanoformulation that enhances bioavailability and stability. Additionally, the major constituent carvacrol, when tested in isolation, also exhibited AChE-inhibitory activity comparable to that of the nanoformulation. Molecular docking analysis indicated strong binding affinities between LOEO compounds and AChE, supporting its therapeutic potential for neurodegenerative diseases like Alzheimer's. Additionally, in silico pharmacokinetic predictions revealed favorable absorption and blood-brain barrier penetration profiles for key constituents. Despite promising results, this study acknowledges the need for in vivo validation and long-term stability assessments of the nanoformulation. Future research should focus on pharmacodynamic studies and evaluating the oil's effectiveness in animal models. These findings highlight LOEO as a valuable candidate for developing natural therapies for neurodegenerative diseases.

Keywords: acetylcholinesterase nanoemulsion; carvacrol.

Figure 1

Macroscopic characteristics (translucency) of the Lippia origanoides formulation with 1% essential oil and 9% polysorbate 20.

Figure 2

Temperature influence (25–75 °C) in the droplet size distribution by the intensity of the Lippia origanoides formulation.

Figure 3

Zeta potential distribution of the Lippia origanoides formulation before (A) and after (B) thermal stress. The graph lines represent zeta potential measurements under different temperatures or conditions (e.g., 25 °C, 35 °C, 45 °C). Stability is indicated by the proximity or overlap of the lines.

Figure 4

Anticholinesterase activity (IC₅₀) of samples: LOEO = essential oil of L. origanoides; CVC = carvacrol; and NF = nanoformulation. Control = physostigmine. The data are presented as mean ± standard deviation. Statistical analysis was performed using ANOVA followed by a Tukey post hoc test, with significance defined at p < 0.05. The letters “a, b, c” indicate statistically different groups based on inhibitory activity against acetylcholinesterase: “a” for the control, “b” for the LOEO and carvacrol samples (similar to each other), and “c” for the nanoformulation, which showed the highest inhibitory efficacy.

Figure 5

Statistical analyses of the binding energy values of donepezil compared to the major compounds of Lippia origanoides essential oil. Statistical analysis was performed using ANOVA followed by a Tukey post hoc test, with significance defined at p < 0.05. The letters “a, b, c” indicate statistically different groups based on inhibitory activity against acetylcholinesterase: “a” for the control, “b” for the LOEO and carvacrol samples (similar to each other), and “c” for the nanoformulation, which showed the highest inhibitory efficacy.

Figure 6

Two-dimensional diagram illustrating the interactions between donepezil and the acetylcholinesterase (AChE) enzyme (4EY7).

Figure 7

Two-dimensional diagram of the interactions between carvacrol (A), p-cymene (B), thymol (C), γ-terpinene (D), linalool (E), and γ-gurjunene (F), with the acetylcholinesterase (AChE) enzyme (4EY7).