Vitex negundo L. Essential Oil: Odorant Binding Protein Efficiency Using Molecular Docking Approach and Studies of the Mosquito Repellent

• Published in: Insects (Basel, Switzerland) Vol. 12; no. 12; p. 1061
• Main Authors: Okoli, Bamidele Joseph, Ladan, Zakari, Mtunzi, Fanyana, Hosea, Yayock Chigari
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26.11.2021; MDPI
• Subjects: Adults; Affinity; Anopheles; Anopheles gambiae; Authentication; Blocking; Citronellal; Composition; Constituents; Crystallization; Deviation; Disorientation; Essential oils; Fatalities; Fever; Hydrophobicity; Insecticides; Leaves; ligand efficiency metric; Ligands; Linalool; Malaria; Mathematical analysis; Metabolites; Molecular docking; Monoterpenes; mosquito; Mosquitoes; Myrcene; odorant binding proteins; Odorant receptors; Odorant-binding protein; Oils & fats; Prevention; Proteins; R&D; Receptors; Repellency; repellent; Repellents; Research & development; Screening; Soils; Sustainable development; Toxicity; V. negundo; Vaccines; Vector-borne diseases; Vitex negundo; Womens health; α-Pinene; Nigeria; Sub-Saharan Africa; molecular docking; Anopheles gambiae; ligand efficiency metric; V. negundo; essential oil; odorant binding proteins; repellent; mosquito
• ISSN: 2075-4450; 2075-4450
• DOI: 10.3390/insects12121061

(1) Background: Malaria fever affects millions of people yearly in Africa and Asia's tropical and subtropical areas. Because there is no effective vaccine, malaria prevention is solely dependent on avoiding human-vector interaction. (2) Aim: This study examines the interaction between the constituents of essential oil and Odorant Binding Proteins (OBP) as well as the compositional variation, repellent efficacy, and toxicity profile. (3) Methods: The oils were subjected to GC-MS and mosquito behavioral analysis. OBP-ligand interactions, species authentication, and the toxicity profile were determined by molecular docking, PCR assay and in silico ADME/tox tool. Docking protocol validation was achieved by redocking the co-crystallized ligands into the protein binding pocket and root mean square deviation (RMSD) calculation. (4) Results: The oil yields and compositions are climate-soil dependent with ≈71.39% monoterpenes and ≈16.32% sesquiterpene. Optimal repellency is achieved at 15 min at ED 0.08-0.48% / while the RMSD was estimated to be within 0.24-1.35 Å. Strong affinities were demonstrated by α-pinene (-6.4 kcal/mol), citronellal (-5.5 kcal/mol), linalool (-5.4 kcal/mol), and myrcene (-5.8 kcal/mol) for OBP1, OBP7, OBP4, and OBP; respectively. The hydrophobic interactions involve Leu17 (α-helix 1), Cys35 (α-helix 2), ALA52 (α-helix 3), Leu73, Leu76 (α-helix 4), Ala88, Met91, Lys93, Trp114 (α-helix 5), Phe123 (α-helix 6), and Leu124 (α-helix 7) receptors within the binding cavities, and may cause blocking of the olfactory receptors resulting in disorientation. (5) Conclusion: The ligand efficiency metrics, ADME/tox and repellency screening are within the threshold values; hence, α-pinene, linalool, and myrcene are safe and fit-to-use in the development of a green and novel repellent.