Novel Approaches for Inhibiting the Indoor Allergen Der f 2 Excreted from House Dust Mites by Todomatsu Oil Produced from Woodland Residues

Abstract

House dust mite (HDM) is a globally ubiquitous domestic cause of allergic diseases. There is a pressing demand to discover efficient, harmless, and eco-friendly natural extracts to inhibit HDM allergens that are more likely to trigger allergies and challenging to be prevented entirely. This study, therefore, is aimed at assessing the inhibition of the allergenicity of major HDM allergen Der f 2 by todomatsu oil extracted from residues of Abies Sachalinensis. The inhibition was investigated experimentally (using enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance (SPR), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)) and in silico using molecular docking. The results showed that todomatsu oil inhibits the allergenicity of Der f 2 by reducing its amount instead of the IgG binding capacity of a single protein. Moreover, the compounds in todomatsu oil bind to Der f 2 via alkyl hydrophobic interactions. Notably, most compounds interact with the hydrophobic amino acids of Der f 2, and seven substances interact with CYS27. Contrarily, the principal compounds fail to attach to the amino acids forming the IgG epitope in Der f 2. Interestingly, chemical components with the lowest relative percentages in todomatsu oil show high-affinity values on Der f 2, especially β-maaliene (−8.0 kcal/mol). In conclusion, todomatsu oil has been proven in vitro as a potential effective public health strategy to inhibit the allergenicity of Der f 2.

Research on Repressing Allergen Cry j 1 Released from Japanese Cedar Pollen Using Todomatsu Oil

“…An automated docking simulation, widely applied during the computer-aided drug design process [55], was achieved with PyRx software 0.8v (San Diego, CA, USA) to disclose the docking modes of todomatsu oil components to the target allergen Cry j 1. The todomatsu oil components (Table A1 in Appendix A), comprising bornyl acetate (25.75%), camphene (20.25%), α-pinene (18.25%), β-phellandrene (12.05%), β-pinene (7.55%), limonene (5.75%), β-myrcene (4.45%), tricyclene (2.25%), β-maaliene (1.25%), borneol (1.00%), α-terpinolene (0.95%), and 3-carene (0.50%), were supplied by Japan Aroma Laboratory Co., Ltd. [45][46][47]. Their structures were obtained in SDF format from the PubChem database (https://pubchem.ncbi.nlm.nih.gov/, accessed on 28 December 2022) and converted to PDBQT format in Open Babel of PyRx [46,47,[55][56][57][58].…”

“…The todomatsu oil components (Table A1 in Appendix A), comprising bornyl acetate (25.75%), camphene (20.25%), α-pinene (18.25%), β-phellandrene (12.05%), β-pinene (7.55%), limonene (5.75%), β-myrcene (4.45%), tricyclene (2.25%), β-maaliene (1.25%), borneol (1.00%), α-terpinolene (0.95%), and 3-carene (0.50%), were supplied by Japan Aroma Laboratory Co., Ltd. [45][46][47]. Their structures were obtained in SDF format from the PubChem database (https://pubchem.ncbi.nlm.nih.gov/, accessed on 28 December 2022) and converted to PDBQT format in Open Babel of PyRx [46,47,[55][56][57][58]. The predicted 3D structure of allergen Cry j 1 (AlphaFold DB: P18632) was retrieved simultaneously from the AlphaFold Protein Structure Database (https://alphafold.ebi.ac.uk/, accessed on 28 December 2022) (Figure 1) and transformed to a macromolecular form in PyRx [46,47,[55][56][57][58].…”

“…Their structures were obtained in SDF format from the PubChem database (https://pubchem.ncbi.nlm.nih.gov/, accessed on 28 December 2022) and converted to PDBQT format in Open Babel of PyRx [46,47,[55][56][57][58]. The predicted 3D structure of allergen Cry j 1 (AlphaFold DB: P18632) was retrieved simultaneously from the AlphaFold Protein Structure Database (https://alphafold.ebi.ac.uk/, accessed on 28 December 2022) (Figure 1) and transformed to a macromolecular form in PyRx [46,47,[55][56][57][58]. Subsequently, the entirely automated docking simulation was performed in AutoDock Vina of PyRx [46,47,55,[59][60][61].…”

“…The predicted 3D structure of allergen Cry j 1 (AlphaFold DB: P18632) was retrieved simultaneously from the AlphaFold Protein Structure Database (https://alphafold.ebi.ac.uk/, accessed on 28 December 2022) (Figure 1) and transformed to a macromolecular form in PyRx [46,47,[55][56][57][58]. Subsequently, the entirely automated docking simulation was performed in AutoDock Vina of PyRx [46,47,55,[59][60][61]. The center grid box was set to the dimensions 64.6450 × 50.9387 × 63.6033 Å.…”

“…Hence, it is a possible prospective nonpharmacological measure for JC pollinosis prevention since it compensates for most drawbacks of other treatments. It has been published as an inhibitor of house dust mite allergens Der f 1, Der p 1, and Der f 2 [46,47]. Nevertheless, its potential to repress the JC pollen allergens has not been validated or published.…”