In Silico Study and Excito-Repellent Activity of Vitex negundo L. Essential Oil against Anopheles gambiae
, Wafa Ali Eltayb 2, Gideon A. Gyebi 3, Amr R. Ghanam 4, Zakari Ladan 5, Joseph C. Oguegbulu 1 and Mohnad Abdalla 2,6,*
Round 1
Reviewer 1 Report
The paper is really interesting and full of data. I just raised some minor issues that need to be addressed.
Genus and species name must be written always in italics, please read carefully the whole text.
Once written the acronym of OBP for odorant binding protein, please use always the acronym.
ABSTRACT
Line 25 write “this is linked to its”
KEYWORDS
Please delete these keywords as they are already in the title Vitex negundo; Anopheles gambiae; essential oil.
INTRODUCTION
Please add references for these sentences:
- - In hot and humid regions of the world, malaria is a huge health burden. It is an acute fever sickness caused by Plasmodium parasites that are transmitted to humans by the bites of infected mosquitoes.
- - The two primary malaria prevention approaches are use of insecticide-treated nets (ITNs) and indoor residual spraying (IRS). Preventive chemotherapy is the use of medications, either 75 alone or in combination, to prevent infections and their sequelae.
- - Today however, mosquito resistance to pesticides is jeopardising global efforts at controlling malaria.
- - Seventy-eight countries have reported resistance of the anopheles specie to one or more of the four major classes of pesticides over the period, 2010 to 2019 according current World Health Organization, (2019). (Probably authors missed the reference number. Moreover, in this sentence write also “according to”.)
- - The three main types of receptors implicated in mosquito olfaction are gustatory receptors (GRs), odorant receptors (OR) and ionotropic receptors (IRs). ORs and IRs can detect a wide range of odorants, whereas GRs can only detect CO2 and other volatile odorants through a heterotrimeric complex in Anopheles sp. Odorant.
- - OBPs, which are often expressed outside the chemosensory organs, are responsible for this (for example https://doi.org/10.3389/fphys.2018.00777; https://doi.org/10.3390/insects12090814)
- - OBPs are known targets for plant-based anti-mosquito insecticides.
- - Computer-aided molecular design (CAMD) is a rational strategy that combines a variety of theoretical and computational approaches routinely utilised in current drug research.
Line 51 write “morphologically”
Line 96, “According to 96 Wheelwright et al., (2021),” the authors missed the reference number.
Line 111, this sentence is not clear “While it is undeniable that OBPs can bind odorants, their role in the insect olfactory system is less clear [15].”
Line 112 “OBP 1, 7, and 4” did the authors refer to specific insect species?
Line 117 write “sesquiterpenes”
MATERIAL AND METHODS
Lines 167 and 175 “Coetzee, (2020)” the authors missed the reference number.
Lines 183 and 195 “Okoli et al., (2021)” the authors missed the reference number.
Line 196 write “immersed”
Line 236, did the authors mean “interface”
RESULTS AND DISCUSSION
Line 276, write “while other unknown constitutes account for about 10.88%”
Line 294 “selected based on their docking scores for in-vitro repellency activity” please write that these results are reported in Table S1. Perhaps it would be useful to reverse the order of the paragraphs, inserting the in silico analyzes before the in vivo ones.
Line 280 “Gill et al., (2018) and Kumar et al., (1992).” the authors missed the reference numbers.
Line 303, “Hazarika et al., (2012) and Zaidan et 303 al., (2005)” the authors missed the reference numbers.
Line 335 “(Dekel et al., 2019). This inference is in consonance with the stud- 335 ies of Anggraeni et al., (2018) and Nararak et al., (2019, 2020).” the authors missed the reference numbers.
Line 344 “according to Tsitoura et al., (2015) and Degen-344 naro et al., (2013), “the authors missed the reference numbers.
Line 377, write “grooves”
Line 491, write “protein structure but motion due to the absence” or “protein structure, but motion due to the absence”
Line 517, write “in-depth”
Line 577, write “OBP 7 were stable in”
Line 579, write “on these findings”
TABLE
In table 1 when the authors presented the retention time found in literature, they should insert also the references.
FIGURE CAPTION
Figure 2, a final bracket is missing.
Author Response
Once written the acronym of OBP for odorant binding protein, please use always the acronym.
Response: OBP has been adopted throughout the manuscript
ABSTRACT
Line 25 write “this is linked to its”
Response: ‘‘this is linked to its’’ has been added.
KEYWORDS
Please delete these keywords as they are already in the title Vitex negundo; Anopheles gambiae; essential oil.
Response: The new keywords introduced are “repellent; β-caryophellene; β-selinene; sulcatone; α-ylangene; molecular docking studies; Odorant Binding Proteins; mosquito repellent.”
INTRODUCTION
Please add references for these sentences:
- - In hot and humid regions of the world, malaria is a huge health burden. It is an acute fever sickness caused by Plasmodium parasites that are transmitted to humans by the bites of infected mosquitoes.
Response: Reference introduced is” Wickremasinghe, R.; Wickremasinghe, A.R.; Fernando, S.D. Climate change and malaria a complex relationship; 2012; Vol. 47, pp. 21–25.’’
- - The two primary malaria prevention approaches are use of insecticide-treated nets (ITNs) and indoor residual spraying (IRS). Preventive chemotherapy is the use of medications, either 75 alone or in combination, to prevent infections and their sequelae.
Response: Reference introduced is” Pryce, J.; Medley, N.; Choi, L. Indoor residual spraying for preventing malaria in communities using insecticide-treated nets. Cochrane Database Syst. Rev. 2022, 2022, doi:10.1002/14651858.CD012688.pub3.’’
- - Today however, mosquito resistance to pesticides is jeopardising global efforts at controlling malaria.
Response: Reference introduced is” Riveron, J.M.; Tchouakui, M.; Mugenzi, L.; Menze, B.D.; Chiang, M.-C.; Wondji, C.S. Insecticide Resistance in Malaria Vectors: An Update at a Global Scale. In Towards Malaria Elimination - A Leap Forward; 2018.3.’’
- - Seventy-eight countries have reported resistance of the anopheles specie to one or more of the four major classes of pesticides over the period, 2010 to 2019 according current World Health Organization, (2019). (Probably authors missed the reference number. Moreover, in this sentence write also “according to”.)
Response: Reference introduced is” WHO Insecticide resistance-Global Malaria Programme; 2021.’’
- - The three main types of receptors implicated in mosquito olfaction are gustatory receptors (GRs), odorant receptors (OR) and ionotropic receptors (IRs). ORs and IRs can detect a wide range of odorants, whereas GRs can only detect CO2 and other volatile odorants through a heterotrimeric complex in Anopheles sp. Odorant.
Response: Reference introduced is” Wheelwright, M.; Whittle, C.R.; Riabinina, O. Olfactory systems across mosquito species. Cell Tissue Res. 2021, 383, 75–90, doi:10.1007/s00441-020-03407-2.’’
- - OBPs, which are often expressed outside the chemosensory organs, are responsible for this (for example https://doi.org/10.3389/fphys.2018.00777; https://doi.org/10.3390/insects12090814)
Response: Reference introduced is”Scieuzo, C.; Nardiello, M.; Farina, D.; Scala, A.; Cammack, J.A.; Tomberlin, J.K.; Vogel, H.; Salvia, R.; Persaud, K.; Falabella, P. Hermetia illucens (L.) (diptera: Stratiomyidae) odorant binding proteins and their interactions with selected volatile organic compounds: An in silico approach. Insects 2021, 12, doi:10.3390/insects12090814.
Smith, M.B.; March, J. March’s Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 5th Edition; Sixth.; John Wiley & Sons, Inc: Hoboken, New Jersey, 2001; Vol. 6; ISBN 9780471720911.”
- - OBPs are known targets for plant-based anti-mosquito insecticides.
Response: Reference introduced is” Costa*, K.S. da; Costa, K.S. da; Institute of Biodiversity, Federal University of Western Pará, 68035-110 Santarém, Pará, B.; (K.S.D.C)., *E-mail: [email protected]. Phone: +55 93 2101-6771; Costa, M. by K.S. da; Orcidhttp://orcid.org/0000-0002-2735-8016; , João Marcos Galúcio, Clauber Henrique Souza da Costa, Amanda Ruslana Santana, Vitor dos Santos Carvalho, Lidiane Diniz do Nascimento, Anderson Henrique Lima e Lima, Jorddy Neves Cruz, Claudio Nahum Alves, and J.L. Exploring the Potentiality of Natural Products from Essential Oils as Inhibitors of Odorant-Binding Proteins: A Structure- and Ligand-Based Virtual Screening Approach To Find Novel Mosquito Repellents. ACS Omega 4, 27, 224.’’
- - Computer-aided molecular design (CAMD) is a rational strategy that combines a variety of theoretical and computational approaches routinely utilised in current drug research.
Response: Reference introduced is” Kapetanovic1, I.M. COMPUTER-AIDED DRUG DISCOVERY AND DEVELOPMENT (CADDD): in silico-chemico-biological approach. Chem Biol Interact. 2008, Jan 30; 17, 165–176.’’
Line 51 write “morphologically”
Response: “morphologically” written to replace “mophologially”
Line 96, “According to 96 Wheelwright et al., (2021),” the authors missed the reference number.
Response: Reference number inserted.
Line 111, this sentence is not clear “While it is undeniable that OBPs can bind odorants, their role in the insect olfactory system is less clear [15].”
Response: Re-cast as follows, “While it is undeniable that OBPs can bind odorants, their mechanism of interaction with odorant compounds is less clear [15].”
Line 112 “OBP 1, 7, and 4” did the authors refer to specific insect species?
Response: the specific insect species has been included in the sentence
Line 117 write “sesquiterpenes”
Response: “sesquiterpenes” written to replace “sequiterpenes”
MATERIAL AND METHODS
Lines 167 and 175 “Coetzee, (2020)” the authors missed the reference number.
Response: Reference number inserted.
Lines 183 and 195 “Okoli et al., (2021)” the authors missed the reference number.
Response: Reference number inserted.
Line 196 write “immersed”
Response: “immersed” written to replace “immeersed”
Line 236, did the authors mean “interface”
Response: Can’t locate the suggested correction.
RESULTS AND DISCUSSION
Line 276, write “while other unknown constitutes account for about 10.88%”
Response: inserted, ‘‘while other unknown constitutes account for about 10.88%”
Line 294 “selected based on their docking scores for in-vitro repellency activity” please write that these results are reported in Table S1. Perhaps it would be useful to reverse the order of the paragraphs, inserting the in silico analyzes before the in vivo ones.
Response: written as, ‘‘these results are reported in Table S1.” The order of the paragraphs reversed such that the in silico analyzes were presented before the in vivo ones.
Line 280 “Gill et al., (2018) and Kumar et al., (1992).” the authors missed the reference numbers.
Response: Reference number inserted.
Line 303, “Hazarika et al., (2012) and Zaidan et 303 al., (2005)” the authors missed the reference numbers.
Response: Reference number inserted.
Line 335 “(Dekel et al., 2019). This inference is in consonance with the stud- 335 ies of Anggraeni et al., (2018) and Nararak et al., (2019, 2020).” the authors missed the reference numbers.
Response: Reference number inserted.
Line 344 “according to Tsitoura et al., (2015) and Degen-344 naro et al., (2013), “the authors missed the reference numbers.
Response: Reference number inserted.
Line 377, write “grooves”
Response: “grooves” written to replace “pockets”
Line 491, write “protein structure but motion due to the absence” or “protein structure, but motion due to the absence”
Response: Rephrased to ‘‘The high peaks did not necessarily reflect a compromise in the integrity of the protein structure, but motion due to the absence of a structured unit at that time frame.’’
Line 517, write “in-depth”
Response: “in-depth” written to replace “in-dept”
Line 577, write “OBP 7 were stable in”
Response: “OBP 7 were stable in” written to replace “OBP 7 was stable”
Line 579, write “on these findings”
Response: “on these findings” written to replace “Based on this findings”
TABLE
In table 1 when the authors presented the retention time found in literature, they should insert also the references.
Response: References inserted
- Huang, H.C.; Chang, T.Y.; Chang, L.Z.; Wang, H.F.; Yih, K.H.; Hsieh, W.Y.; Chang, T.M. Inhibition of melanogenesis Versus antioxidant properties of essential oil extracted from leaves of vitex negundo linn and chemical composition analysis by GC-MS. Molecules 2012, 17, 3902–3916, doi:10.3390/molecules17043902.
- Khokra, S.; Prakash, O.; Jain, S.; Aneja, K.; Dhingra, Y. Essential oil composition and antibacterial studies of Vitex negundo Linn. extracts. Indian J. Pharm. Sci. 2008, 70, 522–526, doi:10.4103/0250-474X.44610.
- Rana, V.S.. R.D. Seasonal variation of the essential oil of Vitex negundo leaves. Indian For. 2003, 129(5):, 607–610.
FIGURE CAPTION
Figure 2, a final bracket is missing.
Response: final bracket added
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Dear Authors!
We read the article and found it very informative and publishing it would be very useful with perhaps some amendments.
In this work, authors made to delineate the constitution of V. negundo essential oil (VNEO) and their interaction with Odorant Binding Proteins (OBPs) of A. gambiae and hence access its repellent efficiency as cost-effective and safer malaria vector control alternatives. GC-MS analysis of VNEO showed 28 compounds (monoterpenes; 80.16%, sesquiterpenes; 7.63% and unknown constituents; 10.88%). The ligand efficiency metrics of all four ligands against the OBP were within acceptable ranges. β-selinene (-12.2 kcal/mol), β-caryophellene (-9.5 kcal/mol), sulcatone (-10.9 kcal/mol), and α-ylangene (-9.3 kcal/mol) showed the strongest binding affinities for the target proteins. The most stable hydrophobic interactions were observed between β-selinene (Phe111 & Phe120), Sulcatone (Phe54 & Phe120) and α-ylangene (Phe111) while only sulcatone (Tyr49) presented H-bond interactions in the simulated environment. Sulcatone and β-caryophyllene presented the best log P values, 6.45 and 5.20 respectively. VNEO's four major components can be used in their purest form to supplement repellent or as a natural anti-mosquito agent in product formulations.
At the same time , a number of questions arose for the authors. As far as possible, it is necessary to supplement the proposed article with answer.
1. In this article authors reports that GC-MS analysis of V. negundo essential oil was done using a Varian CP 3800 gas chromatograph with a HP5 capillary column. Gc-MS analysis of VNEO shows 28 compounds (...... and unknown constituents; 10.88%). The authors for additional most accurate determination could also use tandem mass spectrometry or HPLC (for determination sesquiterpenes and others biologically active compounds). This technique would significantly enrich this work in terms of active components being determined and would provide an additional opportunity for research.
The article makes a very favorable impression by the completeness of the review and study of issues raised, and after minor amendments it may well be recommended for publication in the Journal.
Sincerely yours
Author Response
- In this article authors reports that GC-MS analysis of V. negundo essential oil was done using a Varian CP 3800 gas chromatograph with a HP5 capillary column. Gc-MS analysis of VNEO shows 28 compounds (...... and unknown constituents; 10.88%). The authors for additional most accurate determination could also use tandem mass spectrometry or HPLC (for determination sesquiterpenes and others biologically active compounds). This technique would significantly enrich this work in terms of active components being determined and would provide an additional opportunity for research.
Response: Given the limited time to respond to the review, it is highly unlikely to meet the deadline of the submission as the GCMS result was done at the University of Strathclyde Glasgow. Notwithstanding, the GCMS study was compared with the latest Adams and Mondello libraries.
