EXPLORING MENTHOL'S MULTIFACETED PHARMACOLOGICAL ACTIVITIES: A MOLECULAR DOCKING APPROACH

ABSTRACT

Menthol, a naturally available compound from various plants like mint, experience regarded as having extensive biological activities. In this study, we applied In Silico molecular docking techniques to gain insights into the binding and interaction of menthol to important biological targets such as Fungal Immunomodulatory Protein (FIP), Gamma-Aminobutyric Acid (GABA) receptor, Micro bacterium saccharophilum, and the Muscarinic Acetylcholine Receptor. Using computational methods, we investigated the binding and interaction mechanisms of menthol with these targets, unstead, examining its therapeutic potential for the treatment of disease. Menthol relates to the expressed targets in an interesting fashion, and thus can be a promising tool in the regulation of immune responses, neurotransmission, flora invaders, and cholinergic signaling pathways. This study will make significant contribution to the comprehensive biological research field about menthol and will give suggestion for the further experimental verification and drug production that targets these signaling pathways.

АННОТАЦИЯ

Ментол, природное соединение, получаемое из различных растений, таких как мята, известен своими разнообразными биологическими активностями. В данном исследовании мы применили методы In Silico молекулярного докинга для изучения взаимодействия ментола с важными биологическими мишенями, такими как иммуномодулирующий белок грибов (FIP), рецептор гамма-аминомасляной кислоты (GABA), Microbacterium saccharophilum и мускариновый ацетилхолиновый рецептор. С использованием вычислительных методов были исследованы механизмы связывания и взаимодействия ментола с этими мишенями, что позволило оценить его терапевтический потенциал для лечения различных заболеваний. Ментол проявляет интересное взаимодействие с указанными мишенями, что делает его перспективным инструментом для регулирования иммунных ответов, нейротрансмиссии, борьбы с патогенной флорой и управления холинергическими сигнальными путями. Это исследование вносит значительный вклад в изучение биологических свойств ментола и предоставляет рекомендации для дальнейшей экспериментальной проверки и разработки лекарственных средств, нацеленных на данные сигнальные пути.

Keywords: menthol, molecular docking, Fungal Immunomodulatory Protein (FIP), GABA receptor, Microbacterium saccharophilum, Muscarinic Acetylcholine Receptor, immune response, neurotransmission, computational biology, drug development.

Ключевые слова: ментол, молекулярный докинг, иммуномодулирующий белок грибов (FIP), рецептор GABA, *Microbacterium saccharophilum*, мускариновый ацетилхолиновый рецептор, иммунный ответ, нейротрансмиссия, вычислительная биология, разработка лекарств.

Introduction

Menthol, a naturally occurring compound found in various plant species, has garnered significant attention for its diverse pharmacological properties [1]. While commonly known for its aromatic and cooling effects [2; 3], menthol exhibits a broad spectrum of biological activities that underscore its therapeutic potential [4]. Recent studies have highlighted menthol's role as an antimicrobial agent with potent antibacterial properties [5], an antioxidant that mitigates oxidative stress [6, 7], and an anti-inflammatory compound that aids in managing inflammatory disorders [8]. Additionally, menthol's ability to modulate the immune system and its potential anticancer properties have positioned it as a promising candidate for therapeutic development [9, 10].

The pharmacological effects of menthol are attributed to its interactions with specific molecular targets in the human body. These include the Fungal Immunomodulatory Protein (FIP), Gamma-Aminobutyric Acid (GABA) receptor, Microbacterium saccharophilum, and the Muscarinic Acetylcholine Receptor, which play critical roles in immune regulation, neurotransmission, microbial growth control, and cholinergic signaling, respectively. Molecular docking, a computational technique widely employed in drug discovery, offers a valuable approach to studying the interactions between small molecules like menthol and their target proteins. By simulating these interactions, researchers can elucidate the mechanisms underlying menthol's biological activities and predict its therapeutic applications.

The primary objective of this study is to investigate menthol's binding interactions with FIP, GABA receptor, Microbacterium saccharophilum, and Muscarinic Acetylcholine Receptor through molecular docking simulations. By analyzing these interactions, the study aims to uncover the molecular basis of menthol's pharmacological effects, providing insights into its potential applications in immune modulation, neurobiology, antimicrobial therapy, and cholinergic disorders.

This research contributes to the growing body of knowledge on menthol's multifaceted biological activities and lays the groundwork for its integration into therapeutic strategies targeting diverse biomedical challenges.

2. Materials and Methods

1. Fungal Immunomodulatory Protein (FIP) - PDB ID: 7WDM

Virtual docking simulations of FIP were made with the Autodock Vina 4.2 version. The electrostatic energies for all the non-bonds between the moving atoms were considered. The generator of random numbers was seeded with values 8416 and 1709399371. The grid point spacing was set to 0.525 Angstroms, with an even number of user-specified grid points: 78 x-points, 54 y-points, and 60 z-points. In our maps, the grid center point coordinates were (-13.471, 9.373, -68.291), whereas the minimum in the grid and the maximum coordinates were (-33.946, -4.802, -84.041) and (7.004, 23.548, -52.541).

2. GABA Receptor - PDB ID: 7CA3

The interactions of gama aminobutyric acid receptor were studied through molecular dictioning simulation performed using Auto dock V4.2. The electrostatic energies for every non-bonded atom-atom interactions were estimated. The random number generator seed was set at values 3764 and 1709230133. The grid point spacing was set to 0.481 Angstroms, with an even number of user-specified grid points: 106-x points, 126 y- points and 106 z- points. The coordinates of the central corner point of the map were (154.910, 172.358, 132.697) with the minimum coordinates (-129.417, -142.055, -107.204) and maximum coordinates (180.403, 202.661

3. Micro bacterium saccharophilum - PDB ID: "3VSR"

The processes for discovering a molecular docking by Microbacterium saccharophilum using Autodock Ligand version 4.2 were also derived. In all the non-bonds electrostatic energies were calculated between the atoms that were in action. The combination of 10336 and 1709403080 provided a seed for the random number generator. The grid point spacing was set to 0.603 Angstroms, with an even number of user-specified grid points: x-90, y- 92, z-102. The grid points were embedded in maps at the coordinates of the central grid point (13.975, -0.351, 16.547) with the minimum grid coordinates being at (-13.160, -28.089, -14.206) and the maximum grid points at (41.110, 27.387, 47300).

4. Muscarinic Acetylcholine Receptor - PDB ID: 6ZG4

In the process of molecular docking simulations, Autodock version 4.2 parameter as MGLTools were used. The electromagnetic interaction energies were computed for all of the atoms that were not in the bond. Pseudo-random number generator is initialized with seeds 5468 and 1709231732. The grid point spacing was set to 0.642 Angstroms, with an even number of user-specified grid points: 68 x's, 110 y's, and 126 z's. The coordinates of the highest point of maps maps are (-18.362, 10.899, -16.588), with the minimum coordinates in the grid starting from (-40.190, -24.411, -57.034) to the maximum coordinates (3.466, 46.209, 23).

3. Results and discussion

Molecular docking simulations were carried out to investigate the interactions of menthol with four selected biological targets: GABA Receptor (PDB ID: 7CA3), Muscarinic Acetylcholine Receptor (PDB ID: 6AKZ), Fungal Immunomodulatory Protein (FIP) (PDB ID: 7WDM) and Micro bacterium saccharophilum (PDB ID: 3VSR). The binding energies (kcal/mol) calculated are presented in Table 1:

Figure 1. Binding sites of menthol against:

A (Fungal Immunomodulatory Protein (FIP) - PDB ID: 7WDM), B (Microbacterium saccharophilum PDB ID 3VSR), C (Muscarinic acetylcholine receptor PDB ID 6AKZ) and D (GABA receptor PDB ID 7CA3)

Tabel 1.

Binding energies of menthol with different biological targets

The docking results for menthol showed binding energies ranging from approximately -5.49 to -6.66 kcal/mol for the GABA receptor, -4.63 to -5.61 kcal/mol for the Muscarinic acetylcholine receptor, -4.61 to -4.87 kcal/mol for the Fungal Immunomodulatory Protein (FIP), and -4.84 to -6.02 kcal/mol for Microbacterium saccharophilum. All these values indicate that menthol interacts very well with target proteins, which may implement its possible role in modulating GABAergic neurotransmission, cholinergic signaling pathways, immune response, and microbial growth control. It is to better contextualize these findings by comparing them to previously published results on similar molecular targets. For example, the interactions of FIP-Lrh have been described to have a binding energy of −3.98 kcal/mol with N-acetylglucosamine and N-acetylgalactosamine [11]. The relatively higher observed binding energies for menthol, –4.61 to −4.87 kcal/mol, would suggest that it may form stronger interactions than some glycans. This hints at its possible role as an immunomodulatory agent, although further experimental validation is needed to confirm this hypothesis. Similarly, for Microbacterium saccharophilum, the binding energy of trimethoprim has been reported as -6.236 kcal/mol [12]. The binding energies of menthol (-4.84 to -6.02 kcal/mol) are of the same order, supporting its potential antimicrobial activity. However, the small difference in the binding energy shows the importance of further detailed analysis of binding by menthol and its efficacy relative to already existing antimicrobial drugs such as trimethoprim. As referred to in the docking score studies, Shityakov and Förster suggested that Gibbs free energy values more negative than -6.0 kcal/mol correspond to active drugs, while values less negative than -6.0 kcal/mol correspond to lower activity [13]. In this respect, the binding energy of menthol for the GABA receptor (-5.49 to -6.66 kcal/mol) fits the threshold for active drug molecules, suggesting its effectiveness in modulating GABAergic neurotransmission. Interestingly, the binding energies of menthol to the Muscarinic acetylcholine receptor (-4.63 to -5.61 kcal/mol) and FIP (-4.61 to -4.87 kcal/mol) are less negative than this threshold, indicating moderate interactions. While this may ostensibly limit its standalone therapeutic efficacy, this role of menthol as a complementary modulator in therapeutic strategies deserves further exploration. Such comparisons underline menthol as a pharmacologically active compound but point out areas where its efficacy may vary relative to other molecules. Overall, the results from this study bring a nuanced understanding of menthol's molecular interactions and open the way for experimental studies to validate its therapeutic applications.

Conclusions

The current study used molecular docking simulations to evaluate the possible biological activities of menthol for four different types of biological targets which are GABA receptor, Muscarinic acetylcholine receptor, Fungal Immunomodulatory Protein (FIP), and Microbacterium saccharophilum. The binding energies arrived at in these simulations provide important insights into how menthol interacts with these targets thus providing a basis for understanding its potential pharmacological effects. Results from this study reveal that menthol has positive interactions with all four points suggesting that it could be a multifunctional therapeutic drug. For example, menthol showed strong affinity to GABA receptor and the Muscarinic acetylcholine receptor implying its possibility in modulating cholinergic signaling pathways and neurotransmission respectively. Additionally, there were promising interactions shown by Menthol with FIP; this indicates the fact that it may as well act as an immunomodulator against fungal pathogens. Menthol also exhibited competitive affinity towards Micro bacterium saccharophilum, therefore showing that it can be used as an anti-microbial agent on this micro-organism. The facts highlight the different biological effects of menthol and its diverse uses in relation to neurological science, microbiology and immunology. However, it is worth noting that molecular docking simulations are just a computational method, and more pharmacological studies are needed to validate the effectiveness of menthol in vivo and in vitro. This study therefore adds value to the existing knowledge on the pharmacotherapy with menthol and serves as basis for future research on new Menthol-based therapies for neurodegenerative diseases, infectious disorders and autoimmune conditions.

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