Evaluation of the Antioxidant Activity of Three Formulations of Hair Cosmetic Products Containing the Essential Oil of Clinopodium bolivianum (Benth.) Kuntze “inca muña”

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. How about the sensory experiment using panelist?
2. Do you compare the shampoo product with the commercials?
3. Add some quantity value in conclusion.
4. Emphasize the novelty in the introduction section

Author Response

Reply to reviewer 1

Thank you for reviewing this manuscript in order to improve the quality of our study.

1. How about the sensory experiment using panelist?

R1. Thank you for your suggestion. In this study, a sensory evaluation was not included, as the main focus was on assessing the antioxidant activity and physicochemical stability of the formulations. However, we recognize that sensory analysis is essential for evaluating consumer acceptance and practical application of cosmetic products. Therefore, we have included a note in the Discussion section to recommend future studies involving trained panelists to evaluate quality parameters and user preference. (lines 464-466)

However, we included a sentence as main limitation in the discussion.

2. Do you compare the shampoo product with the commercials?

R2. We appreciate your valuable comment. The present study did not include a comparison with commercial products. The primary objective was to assess the intrinsic antioxidant performance of the formulations containing Clinopodium bolivianum essential oil. However, we acknowledge the importance of benchmarking with commercial shampoos.

3. Add some quantity value in conclusion.

R3. Thank you for this observation. We have revised the conclusion to include quantitative data that highlights the antioxidant potential of the essential oil and the most active formulation.

Lines 468-472.

4. Emphasize the novelty in the introduction section

R4. Thank you for your insightful suggestion. We have updated the Introduction section to emphasize the novelty of this study, particularly the use of Clinopodium bolivianum essential oil in hair care formulations and its antioxidant evaluation in both oil and formulated products.

Lines 90.95.

Reviewer 2 Report

Comments and Suggestions for Authors

Title:       Evaluation of the Antioxidant Activity of Three Formulations of Hair Cosmetic Products Containing the Essential Oil of Clinopodium bolivianum (Benth.) Kunth. “inca muña”   Authors： Raymí Celeste Obispo-Huamani, James Calva, Luis Miguel V. Félix-Veliz, Haydee Chavez, Bertha Josefa PariOlarte, Javier Hernán Chavez-Espinoza, Johnny Aldo Tinco-Jayo, Edwin Carlos Enciso-Roca, Oscar Herrera-Calderon

This paper aimed to determine the volatile components of the essential oil of C. bolivianum and evaluate the antioxidant capacity of the essential oil and hair cosmetic formulations (shampoo, combing cream, and capillary lotion) containing this essential oil using three antioxidant methods in vitro DPPH and ABTS.

 

1. “GC-MS analysis of the volatile components of the essential oil of C. bolivianum”

Please add molecular structure formula of the volatile components of the essential oil of C. bolivianum.

 

2.      “Antioxidant Capacity of the Essential Oil Assessed by DPPH, and ABTS methods” The results above is p<0.0001. It showed the antioxidant capacity of the essential oil Assessed by DPPH, and ABTS is poor compared to Trolox. So it is no significance.   3.      Please provide the pictures of three hair cosmetic formulations: shampoo, combing cream, and capillary lotion.

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

Reply to reviewer 2

This paper aimed to determine the volatile components of the essential oil of C. bolivianum and evaluate the antioxidant capacity of the essential oil and hair cosmetic formulations (shampoo, combing cream, and capillary lotion) containing this essential oil using two antioxidant methods in vitro DPPH and ABTS.

“GC-MS analysis of the volatile components of the essential oil of C. bolivianum”

Please add molecular structure formula of the volatile components of the essential oil of C. bolivianum.

R1. Thank you for your observation, we have included the molecular structure formula in the Table 1 of results and other aspects.

2. “Antioxidant Capacity of the Essential Oil Assessed by DPPH, and ABTS methods”

The results above is p<0.0001.

It showed the antioxidant capacity of the essential oil Assessed by DPPH, and ABTS is poor compared to Trolox.

So it is no significance.

R2.- Thank you for your comment. We agree that the antioxidant capacity of C. bolivianum essential oil, when compared directly with the standard antioxidant Trolox, is lower, as reflected by the significantly higher IC₅₀ values (p < 0.0001, Student Test). However, our intention was not to demonstrate equivalence or superiority to Trolox, but rather to characterize the antioxidant potential of the essential oil in absolute terms and within cosmetic formulations.

Trolox, being a synthetic and pure antioxidant compound, is expected to show greater potency. In contrast, essential oils are complex mixtures, and their antioxidant effects can still be relevant in formulations, especially when considering natural, multifunctional ingredients. Furthermore, the essential oil showed improved antioxidant activity when incorporated into the combing cream formulation, suggesting a synergistic or matrix-enhanced effect. We have clarified this point in the discussion section to avoid misinterpretation.

(Lines 427-436.)

 

3. Please provide the pictures of three hair cosmetic formulations: shampoo, combing cream, and capillary lotion.

Thank you for your recommendations, we have included a figure 2 (pag.7) with the cosmetics preparations

 

Other comments, English was improved in the manuscript.

 

Thank you for your valuable comments in order to improve our manuscript.

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript “Evaluation of the Antioxidant Activity of Three Formulations of Hair
Cosmetic Products Containing the Essential Oil of Clinopodium bolivianum
(Benth.) Kunth. “inca muña” submitted to Special Issue: Fine Chemicals from Natural Sources with Potential Application in the Cosmetic/Pharmaceutical Industry—Volume 2  is interesting. Authors present results of the study on application of Clinopodium bolivianum (Benth.) Kunth, essential oil used to prepare three hair cosmetic formulations: shampoo, combing cream, and capillary lotion. Aim of the study was to determine antioxidant potential of these cosmetic products using DPPH and ABTS methods. Authors also identified the components of Clinopodium bolivianum essential oil using GC-MS. Moreover, the stability of these products during three months was also evaluate. The choice of methods applied in this study is adequate, conclusions are formulated correctly and follow from the results obtained

The paper could be published after some improvements:

Line 82 – probably should be two antioxidant methods

Line 136 -  should be ranging

Line 179 – Table 2: probably should be List of components of combing cream

Line 211-212 the same methodology applied to the essential oil was used for cosmetic formulations: what about combing cream – was it evaluated without additional processing taking into account that it is not a liquid?  

Moreover, authors only listed components of the cosmetic base, but no information is included regarding their content. Did the authors evaluate the effect of base components content on the stability of the products?

List of references should be also corrected

Author Response

Reply to Reviewer 3

The manuscript “Evaluation of the Antioxidant Activity of Three Formulations of Hair

Cosmetic Products Containing the Essential Oil of Clinopodium bolivianum

(Benth.) Kunth. “inca muña” submitted to Special Issue: Fine Chemicals from Natural Sources with Potential Application in the Cosmetic/Pharmaceutical Industry—Volume 2  is interesting. Authors present results of the study on application of Clinopodium bolivianum (Benth.) Kunth, essential oil used to prepare three hair cosmetic formulations: shampoo, combing cream, and capillary lotion. Aim of the study was to determine antioxidant potential of these cosmetic products using DPPH and ABTS methods. Authors also identified the components of Clinopodium bolivianum essential oil using GC-MS. Moreover, the stability of these products during three months was also evaluate. The choice of methods applied in this study is adequate, conclusions are formulated correctly and follow from the results obtained

 

The paper could be published after some improvements:

 

Line 82 – probably should be two antioxidant methods

R1.- Thank you for observation, in effect we have corrected this. We only tested two methods.

Line 91.

Line 136 -  should be ranging

R2.- Thank you for observation, we corrected this word. Line 144.

Line 179 – Table 2: probably should be List of components of combing cream

R3. Thank you for pointing this out. We agree with your observation. The title of Table 2 was labeled as “List of components of shampoo,” when it actually corresponds to the combing cream formulation. This has been corrected in the revised version of the manuscript.

Line 211-212 the same methodology applied to the essential oil was used for cosmetic formulations: what about combing cream – was it evaluated without additional processing taking into account that it is not a liquid? 

R4. Thank you for your comment. You are correct in noting that the combing cream, due to its semi-solid consistency, cannot be directly subjected to antioxidant assays designed for liquid samples. Prior to the DPPH and ABTS assays, the cream formulation was subjected to a pre-treatment involving dilution and homogenization in methanol to extract the antioxidant constituents. The methanolic extract was then centrifuged to separate undissolved residues, and the supernatant was used for the analysis. This step ensured that the antioxidant compounds present in the formulation were appropriately solubilized for accurate assessment. This clarification has now been included in the Materials and Methods section of the revised manuscript. (lines 237-342)

Moreover, authors only listed components of the cosmetic base, but no information is included regarding their content. Did the authors evaluate the effect of base components content on the stability of the products?

R5. Thank you for your comment. We have included the function of each component in the cosmetics formulas (shampoo, combing cream,) but we did not include the percentage of each component because we would like patent the formula later.

Regarding the stability evaluation, the influence of base components was not assessed individually; rather, stability testing was performed on the final formulations, both with and without the essential oil. The differences observed in physicochemical parameters, particularly viscosity and color, were discussed in relation to the presence of the essential oil.

List of references should be also corrected

R6. Thank you for your observation: References were corrected and adapted to MDPI style.

References 26-29.

Reviewer 4 Report

Comments and Suggestions for Authors

The authors of the manuscript entitled "Evaluation of the Antioxidant Activity of Three Formulations of Hair Cosmetic Products Containing the Essential Oil of Clinopodium bolivianum (Benth.) Kunth. "inca muña" present an interesting manuscript in which they evaluated the antioxidant activity of the essential oil of Clinopodium bolivianum in hair cosmetic formulations. The authors also evaluated the stability of the chemical and physical properties of the cosmetic preparations.

The manuscript is generally clearly written and the results are interesting, but there are minor flaws that need improvement.

The following minor issues require attention:

 

Introduction

Lines 77 - 79: This sentence is not part of the aim of the paper and should therefore be in continuity with the previous paragraph.

Line 100: It is essential that the legend and Figure 1 should be well placed. The following requirements must be satisfied:

(a) introduce Figure 1 within the aim of the paper; (b) identify the individual panels within the figure; (c) match the letters of the panels with the text of the legend.

 

Materials and Methods

Section 2.6.1: The rationale behind the 0.5% concentration. Could a higher amount of essential oil be used? The authors respond to this in the discussion. To avoid any expectations of the reader for an answer that may not be there, the authors can anticipate the reason for the chosen concentration in this section. Just a sentence for the rationale.

Lines 217-219: The first part of the sentence is not very straightforward. Authors are requested to rewrite the sentence.

 

Discussion

Lines 313-314: The species name should be written in italics.

Author Response

Reply to reviewer 4

The authors of the manuscript entitled "Evaluation of the Antioxidant Activity of Three Formulations of Hair Cosmetic Products Containing the Essential Oil of Clinopodium bolivianum (Benth.) Kunth. "inca muña" present an interesting manuscript in which they evaluated the antioxidant activity of the essential oil of Clinopodium bolivianum in hair cosmetic formulations. The authors also evaluated the stability of the chemical and physical properties of the cosmetic preparations.

 

The manuscript is generally clearly written and the results are interesting, but there are minor flaws that need improvement.

 

The following minor issues require attention:

 

Introduction

Lines 77 - 79: This sentence is not part of the aim of the paper and should therefore be in continuity with the previous paragraph.

Thank you for the observation. We have revised the sentence to ensure a smoother transition with the preceding paragraph, and clarified that it forms the concluding rationale rather than a new section.

Line 100: It is essential that the legend and Figure 1 should be well placed. The following requirements must be satisfied:

(a) introduce Figure 1 within the aim of the paper; (b) identify the individual panels within the figure; (c) match the letters of the panels with the text of the legend.

 Thank you for this valuable suggestion. We have now introduced Figure 1 appropriately in the main text, clearly identified each panel (A–B), and revised the figure legend to match these identifiers and describe each image accordingly. Furthermore, other reviewer suggested other figures with the cosmetic preparations. (Figure 2).

 

Materials and Methods

Section 2.6.1: The rationale behind the 0.5% concentration. Could a higher amount of essential oil be used? The authors respond to this in the discussion. To avoid any expectations of the reader for an answer that may not be there, the authors can anticipate the reason for the chosen concentration in this section. Just a sentence for the rationale.

We appreciate the reviewer’s suggestion. A sentence was added in Section 2.6.1 to explain the rationale for choosing a 0.5% concentration of the essential oil, based on preliminary optimization for performance and product stability. (Lines -178-180)

 

Lines 217-219: The first part of the sentence is not very straightforward. Authors are requested to rewrite the sentence.

I accept this observation and was corrected (lines 247-249).

 

Discussion

Lines 313-314: The species name should be written in italics.

Thank you, all scientific names were checked and corrected.

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript can be  accepted now.