The Extraction of Bioactive Agents from Calophyllum inophyllum L., and Their Pharmacological Properties

Round 1

Reviewer 1 Report

The paper is well thought out, but in my opinion not well organised and conceived. Namely, there is a lack of connection between the information contained in the text and the plant described. Much is written in general terms about the influence of, for example, a part of the plant or a solvent on the chemical profile of the plant, without making the mentioned reference to the plant from the paper (Bulgarian medicinal plants or Humulus lupulus L. are described). If an overview of the research is already given, then this information is important that it refers to C. inophyllum, and the information about the fact that it is difficult to find a universal method of extraction, solvent, etc. should be at the beginning, perhaps in the introductory part (the part referring to plants and phytochemicals in general). The same is repeated in the description of chemical composition and activity. The seed oil is mentioned a little, then the root and suddenly the leaf is mentioned in the text. I suggest that you backtrack and, if the seed oil is already described, give all the information about it in this paragraph and then move on to the other parts of the plant. Table 1 has presented the research well and is a nice start to chapter 3, but the rest of the text is confusing. if you already start with the sentence "The main bioactive compounds and their reported biological activities from different parts (fruits, seeds, leaf, stem, root and flower) of C. inophyllum are presented in Table 1", continue by describing the different parts of the plant and what has been studied on them. If there is no data, highlight it. Also, if the title indicates a chemical profile, you can not talk about the ethanol extract in general without saying what components it contains, etc. All in all, the work is fine, the text just needs to be more readable and clear.

One other comment relates to Table 2, in the table "you list a group of compounds under "yields" but not the percentage yield (it is mentioned in the text, which is fine by me), so I suggest "you write "target compounds" in the table instead of "yields". Also, try to rewrite the data already given in the tables as little as possible in the text. As an example, I give the text from lines 245-251. Instead of the written version, the suggestion is as follows:

"Using the percolation method and optimising the extraction conditions, Hapsari et al [19] extracted the highest total phenolic compounds (289.12 mg GAE/g of leaf residue) and total flavonoid compounds (410.4 mg QE/g) using 80% methanol in water at 30 oC for 48 h. Under these conditions, the leaf extracts of C. inophyllum show antioxidant activity with an IC50 value of 0.054 mg/mL."

To summarise, there is a lot of repetition in the individual chapters, so that sometimes you have to go back to the beginning and look up what the title is, i.e. you lose the sense and purpose of the title of the paper and the individual subtitles while reading.

I think that the paper should be organised a little better and that it is suitable for reading and publishing afterwards.

Author Response

Comments: The paper is well thought out, but in my opinion not well organised and conceived.

Response: Thank you for pointing this out. I have reorganized the manuscript as per the reviewer’s comment.

Comments: Namely, there is a lack of connection between the information contained in the text and the plant described.

Response: To the best of my knowledge, every statement in this manuscript is directly or indirectly relevant to the plant described.

Comments: Much is written in general terms about the influence of, for example, a part of the plant or a solvent on the chemical profile of the plant, without making the mentioned reference to the plant from the paper (Bulgarian medicinal plants or Humulus lupulus L. are described).

Response: Some general statements have been removed from the original manuscript (line numbers: 62–64; 165–167; 187–189; 211-218). Reference has been added for some statements (line numbers 56 and 323). References for Bulgarian medicinal plants, or Humulus lupulus L. were already mentioned in the text (Line numbers: 200, 202, and 211) and in the reference section (Refs. 41 and 42).

Comments: If an overview of the research is already given, then this information is important that it refers to C. inophyllum, and the information about the fact that it is difficult to find a universal method of extraction, solvent, etc. should be at the beginning, perhaps in the introductory part (the part referring to plants and phytochemicals in general). The same is repeated in the description of chemical composition and activity.

Response: Repeated research over view from Section 3 (Chemical composition and activity) has been removed from the original manuscript Line numbers 119–123.

Comments: The seed oil is mentioned a little, then the root and suddenly the leaf is mentioned in the text. I suggest that you backtrack and, if the seed oil is already described, give all the information about it in this paragraph and then move on to the other parts of the plant.

Response: The seed oil paragraph has been elaborated now (Line number 108–131) and separated from the flower (Line 132-134), stem (Line 135–148), root (Line 153–161), leaves (Line 162-172), and fruits (Line 173–178).

Comments: Table 1 has presented the research well and is a nice start to chapter 3, but the rest of the text is confusing. if you already start with the sentence "The main bioactive compounds and their reported biological activities from different parts (fruits, seeds, leaf, stem, root and flower) of C. inophyllum are presented in Table 1", continue by describing the different parts of the plant and what has been studied on them. If there is no data, highlight it.

Response: Agreed and revised as per the reviewer’s comment. Please see revised parts for seed oil (Lines 108–131), flowers (Lines 132-134), stems (Lines 135–148), roots (Lines 153–161), leaves (Line 162-172), and fruits (Lines 173–178).

Comments: Also, if the title indicates a chemical profile, you can not talk about the ethanol extract in general without saying what components it contains, etc. All in all, the work is fine, the text just needs to be more readable and clear.

Response: The term “Ethanol extract” has been removed from Line 140. Since the cited paper did not report any chemical studies, ethanol extracts were used. The reference that I mentioned was about an in vivo antiarthritic activity study (Ref. 17), which properly fits in Section 3 as part of the pharmacological activity study.

Comment: One other comment relates to Table 2, in the table "you list a group of compounds under "yields" but not the percentage yield (it is mentioned in the text, which is fine by me), so I suggest "you write "target compounds" in the table instead of "yields".

Response: “Yields” in Table 2 has been replaced by "Target compounds" as per the reviewers’ comment.

Comment: Also, try to rewrite the data already given in the tables as little as possible in the text. As an example, I give the text from lines 245-251. Instead of the written version, the suggestion is as follows: "Using the percolation method and optimising the extraction conditions, Hapsari et al [19] extracted the highest total phenolic compounds (289.12 mg GAE/g of leaf residue) and total flavonoid compounds (410.4 mg QE/g) using 80% methanol in water at 30 oC for 48 h. Under these conditions, the leaf extracts of C. inophyllum show antioxidant activity with an IC50 value of 0.054 mg/mL."

Response: Table data has been described as per reviewers’ comments. Please see line numbers 109–114, 129–131, and 153–178.

Comment: To summarise, there is a lot of repetition in the individual chapters, so that sometimes you have to go back to the beginning and look up what the title is, i.e. you lose the sense and purpose of the title of the paper and the individual subtitles while reading. I think that the paper should be organised a little better and that it is suitable for reading and publishing afterwards.

Response: Thank you for pointing it. I have deleted the repeated statements from the original manuscript (Line numbers: 20–21; 40–42; 58–60; 81–82; 96–98; 119–123; 344–346) and rearranged the manuscript as per the reviewers’ comments.

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Author,

The author needs to discuss in detail how these two techniques of extraction when it is selected for isolate compounds with special reference 

. The yield of crude extract % or compounds mg

. which methods are suitable to isolate the specific type of compounds such as Tepenids. Etc.

. compare the bioefficacy of these two isolated compounds using these techniques with each other

. The author also searches some literature on how these techniques may influence the biological or pharmacological potency, then concludes which is a better method for extractions for this plan?.

0 provide a detailed table with yield, type of compounds isolated with each technique, also incorporate if any in-vitro studies details and safety profiles in IC50 values

These comments overall improve the manuscript and help the researchers choose the appropriate techniques based on recommendations from this review.

Thanks

Author Response

Comment 1: The author needs to discuss in detail how these two techniques of extraction when it is selected for isolate compounds with special reference

Response: Thank you for your comment. I have discussed several extraction techniques in the manuscript, such as maceration, Soxhlet, percolation, pressured liquid extraction, supercritical fluid extraction (SFE), and ultrasound-assisted extraction. Each method has its own advantages and limitations. This manuscript is focused on extraction, which is crucial for isolation and identification. It’s not clear which two techniques of extraction have been mentioned by the reviewer.

Comment 2: The yield of crude extract % or compounds mg

Response: The term “Yield” has been changed to “Target Compounds” in the Table 2.

Comment: which methods are suitable to isolate the specific type of compounds such as Tepenids. Etc.

Response: This manuscript is focused on extraction techniques, which are crucial for the next steps such as isolation, identification, and characterization. However, there is no compound named “Tepenids” in this manuscript.

Comment: compare the bioefficacy of these two isolated compounds using these techniques with each other

Response: Its not clear to me which “two compounds” are mentioned by the reviewer.

Comment: The author also searches some literature on how these techniques may influence the biological or pharmacological potency, then concludes which is a better method for extractions for this plan?.

Response: Thank you. This topic has already been discussed in sections 4, 6, and 7.

Comment: provide a detailed table with yield, type of compounds isolated with each technique, also incorporate if any in-vitro studies details and safety profiles in IC50 values

Response: Table 2 already describes the extraction technique, extraction conditions, and yield. Some in-vitro studies and iC50 values are given in the text. Please see the line numbers (113-114; 127-129; 137-148; 156-161; 164-165; 177-178).

Comment: These comments overall improve the manuscript and help the researchers choose the appropriate techniques based on recommendations from this review.

Response: Thank you very much.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I am glad that all the comments were useful (and that you agreed with the suggestions) and I think the work is much more readable now. I have to say that this work is acceptable as it is.