Antiproliferative, Antimicrobial and Antiviral Activity of β-Aryl-δ-iodo-γ-lactones, Their Effect on Cellular Oxidative Stress Markers and Biological Membranes

Round 1

Reviewer 1 Report

This manuscript is about the biological activities of three lactone analogs, of which the aromatic ring possesses different alkyl groups (isopropyl, methyl, no alkyl group). It is more likely a simple structure-activity relationship study investigating the role of hydrophobic alkyl group in the biological activities: antiproliferative, antimicrobial, etc.
The main concern in this manuscript is the lack of rationale and background. All the activities tested seem to be disconnected from each other. How the authors came up with this idea to evaluate these compounds for a variety of tests? This is an important question for the readers to acquire a take-home message.
Therefore, the reviewer suggests revising this manuscript by adding conceptional background and detailed statements that are based on the information currently available. For the revision, please refer to the attachment.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

please find the attached file with the answers for your review.

 

With kind regards

Aleksandra Włoch

Author Response File: Author Response.pdf

Reviewer 2 Report

see attached file

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

please find the attached file with the answers for your review.

 

With kind regards

Aleksandra Włoch

Author Response File: Author Response.doc

Reviewer 3 Report

Summary:

This manuscript “Antiproliferative, antimicrobial and antiviral activity of β-aryl-δ-iodo-γ-lactones, their effect on cellular oxidative stress markers and biological membranes” by Aleksandra et al., reports the biological activity of three selected racemic cis-β-aryl-δ-iodo-γ-lactones. Author’s has chosen these compounds based on differences in the structure of the aromatic fragment of the molecule, bearing isopropyl, methyl or no substituent on the para position of the benzene ring and tested these compounds for a broad spectrum of biological activity including antimicrobial, antiviral, antitumor, cytotoxic, antioxidant and hemolytic activity. They also studied the interactions of tested iodolactones with the protein-lipid membranes to better understand the mechanism of their biological activity. Though the authors have carried out a series of experiments which all are very much appropriate to achieve their goal for this research work, there are few sections in the manuscript which are still unclear and need to have a substantial modification, justification and clarification.

The following need consideration and correction by the authors:

1. The abstract should have included some results conducted for this research work and provided significant values. The second part of the present abstract is more like describing what are all experiments were conducted for this research work and only on the last sentence a very generalize statement has been given on achieved biological activity.
2. Lines 48-49: …potential alternatives of what and by which means of action?
3. Lactones can serve as signal molecules. Please provide some details about lactones being signalling molecules and references of lactones with their biological activity.
4. Materials and methods are excessively described. For example, section 2.2 and 2.5 can be combined together and present. Similarly, section 2.3 combined with 2.6 and 2.4 can be combined with 2.9.
5. In section 2.3, make sure the bacterial strains should be presented in italics format.
6. Line 95: …were supplied by Pasteur….supplied? or purchased or obtained?
7. Line 236: …in the paragraph 3.4…it should be section, not a paragraph.
8. Section 2.9, did author’s use any positive control in this experiment? Example: Triton X 100.
9. Section 2.10.2, was the RBCMs level kept constant throughout the treatment?  
10. Line 272 – 273: instead of lactone 1; lactone 2 and lactone 3, just mention 1, 2 and 3.
11. Section 3.1, line 279 – 282: Repetition from the methodology. Kindly avoid such way of presentation.
12. Results in section 3.1 are very confusing and presented very badly. In general, as presented by the author’s, concentration of the lactone compounds exhibited MIC and MBC are relatively very high (mg/ml). In between lines 288 – 290, the statement is inconclusive. “The lowest MIC with a value of 0.25 μL/mL was calculated for lactone 1 against P. mirabilis. All the MBC/MIC ratios did not exceed 4, and according to Krishnan et al. [44] we can conclude that the lactones possess a bactericidal activity.” - please add proper justification.
13. In the text MIC value was presented with the following unit μL/mL, but in Table 1 it is mg/mL.  Please clarify.
14. There are two fungal strains Candida albicans ATCC 10231 and Aspergillus brasiliensis ATCC 16404 were used in this study to evaluate the antifungal activity of compound 1, 2 and 3. But presented data in lines 291 – 293, explaining about Fusarium strains that too used in the previous study. Why?
15. Lines 294 – 297: Higher sensitivity …. Kindly reframe this entire sentence.
16. Here author stated that Gram-negative bacteria are generally more resistant against antibiotics because of their cell wall structure and tested compounds are highly active against P. mirabilis, but this did not clarify the mode of action of these tested compounds. Please justify the statement.
17. Why the authors did not use any positive and negative controls (compounds) for MIC and MBC to compare their results?
18. In section 3.6.2, the author mentioned membrane cause a shift to the maximum of the band Amide I and Amide II after the addition of tested compounds to the membrane. But unfortunately, I did not see any significant signal shift in Figure 5 as well as in Table 5 data. The only thing what I have observed is a change in absorbance which might happen due to lysis of RBCMs on different treatment. Please justify.
19. Line 526: obtained

 

1. General questions:

1. Author synthesized these compounds in previous studies along with other compounds (Ref.: 7,25). Then on what basis authors selected these three compounds particularly? If any specific reason behind it? Why did they choose only cis- form of compounds, not trans- form?
2. They obtained RBC from healthy pig directly. Do they need any ethical approval for that? Is there any particular reason for not to purchase commercially available sheep blood but to collect RBC directly from the pig?

 

Author Response

Dear Reviewer,

please find the attached file with the answers for your review.

 

With kind regards

Aleksandra Włoch

Author Response File: Author Response.pdf

Reviewer 4 Report

The work is of good quality  and the activity of synthesized compound is interesting. Nevertheless, there are some major issue that should be considered before publication.

• Why compunds where tested as racemic? The separation of the enantiomers should be performed in order to asses which enantiomer is really responsible for biological activity. This should be clarified for at least one compound.
• Please insert a reference drug for those test where is missing.
• The FT-IR experiments are somehow misleading. How changes of Amide I,II bands of less than 1 cm-1 could be considered significative? Probaly an experiment on membrane fluidity with fluorescent probes could be more significative.
• What about metabolic stability of lactones? Experiment of chemical or microsomial stability should be performed in order to assess the stability due the presence of potentially labile C-I bond and lactone group.

Minor issue, please correct caption of table 1, microgram instead of mg 

 

Author Response

Dear Reviewer,

please find the attached file with the answers for your review.

 

With kind regards

Aleksandra Włoch

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Improved by the revision, and therefore the reviewer recommends it for publication in this journal.

Reviewer 3 Report

The manuscript titled “Antiproliferative, antimicrobial and antiviral activity of β-aryl-δ-iodo-γ-lactones, their effect on cellular oxidative stress markers and biological membranes” by Aleksandra et al., has improved substantially after careful revision by the authors. Authors have also provided point wise response and justification to the questions arose. 

Hence, I recommend the manuscript to be considered for publication in its current form.

Reviewer 4 Report

Authors responded to all points. Please accept.