Euclasta condylotricha flowers essential oils: A new source of juvenile hormones and its larvicidal activity against Anopheles gambiae s.s. (Diptera: Culicidae)

Roméo Barnabé Bohounton; Oswald Yédjinnavênan Djihinto; Oronce Sedjro-Ludolphe Dedome; Réné Mahudro Yovo; Laurette Djossou; Koffi Koba; Aristide Adomou; Pierre Villeneuve; Luc Salako Djogbénou; Fidèle Paul Tchobo

doi:10.1371/journal.pone.0278834

Peer Review History

Original SubmissionJune 29, 2022
10 Oct 2022 Decision Letter - Guadalupe Virginia Nevárez-Moorillón, Editor PONE-D-22-18507 Euclasta condylotricha flowers essential oils: a new source of juvenile hormones and its larvicidal activity against Anopheles gambiae s.s. (Diptera: Culicidae) PLOS ONE Dear Dr. Tchobo, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Nov 24 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. 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This will take you to the ORCID site and allow you to create a new iD or authenticate a pre-existing iD in Editorial Manager. Please see the following video for instructions on linking an ORCID iD to your Editorial Manager account: https://www.youtube.com/watch?v=_xcclfuvtxQ 5. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. Additional Editor Comments: Please, take in consideration the suggestions done by the reviewers. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Partly Reviewer #2: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: Yes ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: The paper “Euclasta condylotricha flowers essential oils: a new source of juvenile hormones and its larvicidal activity against Anopheles gambiae s.s. (Diptera: Culicidae)”, describes the extraction of essential oils from flowers of a grass and the chemical identification of its components by gas chromatography coupled to mass spectrometry. In addition, the larvicidal activity of essential oil was evaluated in Anopeles gambiae mosquitoes. Authors found JH III as the main compound in the essential oil. The essential oil showed strong larvicidal activity and authors propose the flowers from these grass as a source of juvenile hormone than can be used as mosquito control strategy. The results are interesting, in the light of control of vector-borne diseases. This reviewer have few concerns that should be addressed before accepted for publication. Lines 76-77. “Considering the concerted efforts to develop plant products-based insecticides as an excellent alternative to synthetic insecticides,..” It is an interesting idea that has been proposed long time ago, the question is, how much (or how we evaluate) non-target species could be affected in their habitats by the use of such strategies? Line 169. “…whole plants of Cyperus iria L.”, should say “…whole plants of Cyperus iria L. and C. aromaticus Ridl.” Line 184. “…EOs…” instead “…essential oils” Lines 245-247. Clearly, results show that EOs have a larvicidal effect, but there is not a direct prove that such effect was by JH. It is only an association because our knowledge that JH III interfere with larvae development, but in EOs more components are present and no evaluations separately were performed. Conclusion (and/or discussion) should be clear on those limitations. Reviewer #2: In this paper, the authors present a well-structured work on the characterization and larvicidal effect of Euclasta condylotricha against Anopheles gambiae with promising results against the malaria vector. The results are clear and well represented, I have only minor suggestions to support the publication of the paper. Line 73: Proper spelling of the scientific name "Andropogon condylotrichus" remove the capital letter of the species. Line 195: The value 35.54 does not appear in table 2; correct for the correct data. Line 197-198: It should be: with LC50 of 38.10 ppm and 198 38.46 ppm.... Figure 2. The title should be "Percentage of dead An. gambiae larvae..." instead of "Number of dead An. gambiae larvae...". In the figures, the graphs and text are not clear, I suggest that they be replaced by figures of higher image quality. ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). 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Revision 1
2 Nov 2022 Author Response Dear Editor, Please find below the responses addressing each of the comments of the reviewers assigned to our submitted manuscript entitled: Euclasta condylotricha flowers essential oils: a new source of juvenile hormones and its larvicidal activity against Anopheles gambiae s.s. (Diptera: Culicidae). Editor 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf Reply: We reviewed again the journal formatting guidelines and ensured that the manuscript meets the style requirements. 2. Please describe any permissions and permits you had to collect plant samples. Reply: Please, kindly note that at the University of Abomey-Calavi, there is not yet a policy to deliver permission or permit before plant collection. The general rule at the University is that after plant collection, the author deposits a plant sample at the National Herbarium and gets a voucher number. Furthermore, the plant species used in this study was collected in the field in its natural habitat. The plant is an annual species, very wide distributed that colonizes agricultural lands and vacant fields. In that case, no permission or permit is delivered prior to the plant samples collection. 3. Thank you for stating the following financial disclosure: "RBB received financial support through Wellcome Trust intermediate fellowship in public health and tropical medicine grant (N° 109917/Z/15/Z) awarded to LSD. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript." At this time, please address the following queries: a) Please clarify the sources of funding (financial or material support) for your study. List the grants or organizations that supported your study, including funding received from your institution. Reply: RBB received material support through the grant awarded to LSD. No grants or organizations supported the study. No funding was received from our institution. b) State what role the funders took in the study. If the funders had no role in your study, please state: “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.” Reply: The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. c) If any authors received a salary from any of your funders, please state which authors and which funders. Reply: No author received a salary from the funder. d) If you did not receive any funding for this study, please state: “The authors received no specific funding for this work.” Reply: The authors received no specific funding for this work. Please include your amended statements within your cover letter; we will change the online submission form on your behalf. Reply: Amended statements are provided in the cover letter. 4. PLOS requires an ORCID iD for the corresponding author in Editorial Manager on papers submitted after December 6th, 2016. Please ensure that you have an ORCID iD and that it is validated in Editorial Manager. To do this, go to ‘Update my Information’ (in the upper left-hand corner of the main menu), and click on the Fetch/Validate link next to the ORCID field. This will take you to the ORCID site and allow you to create a new iD or authenticate a pre-existing iD in Editorial Manager. Please see the following video for instructions on linking an ORCID iD to your Editorial Manager account: https://www.youtube.com/watch?v=_xcclfuvtxQ. Reply: ORCID detail of the corresponding author was provided and validated in the Editorial Manager. 5. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. Reply: Done. Reviewer #1 The authors thank the reviewer for his comments on the manuscript. Lines 76-77. “Considering the concerted efforts to develop plant products-based insecticides as an excellent alternative to synthetic insecticides,..” It is an interesting idea that has been proposed long time ago, the question is, how much (or how we evaluate) non-target species could be affected in their habitats by the use of such strategies? Reply: This is a question that needs further investigations before implementing such strategy base on plant products. The final formulation of the plant-based products to be applied to the larval habitats need to be determined. The choice of an appropriate formulation will minimize the non-target impacts. To evaluate the effect of such strategy on non-target species, the final formulation to be delivered in the field should assess the toxicological effects of treating representative, sensitive indicator species, such as an aquatic invertebrates and vertebrates with the plant product. Furthermore, since plant-based products are natural and eco-friendly materials, we assume that these products has no greater toxicological effects than that from the actual chemical larvicides. Line 169. “…whole plants of Cyperus iria L.”, should say “…whole plants of Cyperus iria L. and C. aromaticus Ridl.” Reply: C. aromaticus Ridl was added at the end of the sentence. Done. Line 184. “…EOs…” instead “…essential oils” Reply: Done Lines 245-247. Clearly, results show that EOs have a larvicidal effect, but there is not a direct prove that such effect was by JH. It is only an association because our knowledge that JH III interfere with larvae development, but in EOs more components are present and no evaluations separately were performed. Conclusion (and/or discussion) should be clear on those limitations. Reply: Please, notice that in Lines 245-247, we did not mean that the larvicidal effect of the EOs is due to the Juvenile Hormone. As conclusion, we were reporting the major phytochemical compound found in all EOs. In the discussion session, lines 225-241, we stated that the larvicidal effect could be due to the secondary metabolites present in the EOs (Juvenile hormone and sesquiterpenes). However, we added a statement in the conclusion. Please see line 249 to 252 as follow: “…Before the translation of these research findings into operational interventions, further investigations on mechanisms by which EOs mediate their bioinsecticidal activity may require evaluations of the major EOs’ constituents separately…” Reviewer #2: We are grateful to the reviewer for his comments on the manuscript. Line 73: Proper spelling of the scientific name "Andropogon condylotrichus" remove the capital letter of the species. Reply: Done. Line 195: The value 35.54 does not appear in table 2; correct for the correct data. Reply: Done. Line 197-198: It should be: with LC50 of 38.10 ppm and 198 38.46 ppm.... Reply: Done. Figure 2. The title should be "Percentage of dead An. gambiae larvae..." instead of "Number of dead An. gambiae larvae...". In the figures, the graphs and text are not clear, I suggest that they be replaced by figures of higher image quality. Reply: The Title of Figure 2 was changed accordingly. The low quality of the Figure 2 may be due to the PDF generation system in the Editorial Manager. Otherwise, the figure 2 was submitted to PACE platform according to PLOS One recommendation for Figures. After figure correction using PACE (https://pacev2.apexcovantage.com/), the generated file was submitted with the manuscript. Therefore, we assume that, if accepted for publication, the figure will be more clear on the online version of the paper. A new version of Figure 2 was submitted. Attachments Attachment Submitted filename: Response to reviewers.pdf https://doi.org/10.1371/journal.pone.0278834.r002
24 Nov 2022 Decision Letter - Guadalupe Virginia Nevárez-Moorillón, Editor Euclasta condylotricha flowers essential oils: a new source of juvenile hormones and its larvicidal activity against Anopheles gambiae s.s. (Diptera: Culicidae) PONE-D-22-18507R1 Dear Dr. Tchobo, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Guadalupe Virginia Nevárez-Moorillón, Ph.D. Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0278834.r003
Formally Accepted
13 Jan 2023 Acceptance Letter - Guadalupe Virginia Nevárez-Moorillón, Editor PONE-D-22-18507R1 Euclasta condylotricha flowers essential oils: a new source of juvenile hormones and its larvicidal activity against Anopheles gambiae s.s. (Diptera: Culicidae) Dear Dr. Tchobo: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. If we can help with anything else, please email us at plosone@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Guadalupe Virginia Nevárez-Moorillón Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0278834.r004

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