Green Tea: Antioxidant vs. Pro-Oxidant Activity

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Please provide number of articles studied and journals. Also please display the findings of other authors after the citation. The conclusions are not covered very vell by references.

Author Response

Comment 1:

Please provide number of articles studied and journals. Also please display the findings of other authors after the citation. The conclusions are not covered very vell by references.

Response 1:

The number of articles and journals studied was added.

Response 2:

The Conclusion section was rewritten.

Reviewer 2 Report

Comments and Suggestions for Authors

The article examines the antioxidant and prooxidant properties of catechins contained in green tea, emphasizing both their positive effects on health and the potential risks associated with their excessive consumption. The authors present a literature review on the mechanisms of action of catechins and their effect on oxidative stress and hepatotoxicity. The article is well organized, with a clear division into sections on methodology, antioxidant and prooxidant properties, and health effects in the context of liver damage. The article is based on scientific articles, both experimental and clinical studies, which increases its scientific value. Overall, the topics discussed are very current and fit into current research trends. Despite the high assessment of the article, it emphasizes both positive and negative effects of green tea consumption, the manuscript does not provide specific recommendations on safe doses. In addition, some subsections (e.g. on hepatotoxicity) could be more condensed to avoid repetitive information. In the opinion of the reviewer, the conclusions could be more specific. The cited literature does not raise any objections.

Author Response

Comment 1:

The article examines the antioxidant and prooxidant properties of catechins contained in green tea, emphasizing both their positive effects on health and the potential risks associated with their excessive consumption. The authors present a literature review on the mechanisms of action of catechins and their effect on oxidative stress and hepatotoxicity. The article is well organized, with a clear division into sections on methodology, antioxidant and prooxidant properties, and health effects in the context of liver damage. The article is based on scientific articles, both experimental and clinical studies, which increases its scientific value. Overall, the topics discussed are very current and fit into current research trends. Despite the high assessment of the article, it emphasizes both positive and negative effects of green tea consumption, the manuscript does not provide specific recommendations on safe doses. In addition, some subsections (e.g. on hepatotoxicity) could be more condensed to avoid repetitive information. In the opinion of the reviewer, the conclusions could be more specific. The cited literature does not raise any objections.

Response 1:

The dose-response relationship concerning hepatotoxicity induced by green tea remains the subject of extensive investigation. Nevertheless, certain health regulatory bodies have attempted to issue opinions on the matter, as discussed in the Discussion section. Therein, we emphasize that this effect is primarily attributable to the quantitative presence of the most abundant catechin—epigallocatechin gallate (EGCG). In this context, we consider the European Food Safety Authority’s (EFSA) recommendation particularly valuable, which states that daily EGCG intake should not exceed 800 mg, as higher doses have been associated with increased serum transaminase levels, indicative of liver damage.

Response 2:

The section entitled “Association Between the Pro-Oxidant Activity of Green Tea Catechins and Hepatotoxicity Manifestation” was partially rewritten.

Response 3:

The Conclusion section was rewritten to be more specific and clearer.

Reviewer 3 Report

Comments and Suggestions for Authors

The review (beverages-3534860) deals with currently available scientific data on the antioxidant and pro-oxidant activity of green tea products as well as the relationship between pro-oxidant properties of catechins and liver damage in humans.

In the review titled "Green tea: Antioxidant vs Pro-oxidant Activity" literature reviews provide a comprehensive summary of the existing research on a particular topic, which helps the reader to understand what has already been discovered and what the main directions of research are. Moreover, this helps to identify areas that need to continue to get explored.

The work was structured in a thoughtful, balanced and transparent form. The discussion of the results was kept properly.

The work after corrections have been made in the following areas of the work:

1. Line 72: Authors mentioned that “In the literature hepatotoxicity linked to green tea catechins administration is well described.” but no citations were given. Please, add it.
2. 147 articles were cited. How many are available in the databases mentioned? Please, mentioned about it in methods.
3. Line 557: Instead of “How much antioxidant supplements is too much” please use this form “How much antioxidant supplementation is too much?”
4. In Figure 1, label the rings A, B, C, respectively. The authors mention the B-ring of flavonoids in line 163.
5. Line 355 Repetition of “in the study”.
6. Please complete the abbreviation list. For example, xanthine oxidase, “C” (line 148), EFSA, γX are missing.
7. My suggestion is to compile the literature data from chapters 4 and 5 into tables. This would be more transparent

Author Response

The review (beverages-3534860) deals with currently available scientific data on the antioxidant and pro-oxidant activity of green tea products as well as the relationship between pro-oxidant properties of catechins and liver damage in humans.

In the review titled "Green tea: Antioxidant vs Pro-oxidant Activity" literature reviews provide a comprehensive summary of the existing research on a particular topic, which helps the reader to understand what has already been discovered and what the main directions of research are. Moreover, this helps to identify areas that need to continue to get explored.

The work was structured in a thoughtful, balanced and transparent form. The discussion of the results was kept properly.

The work after corrections have been made in the following areas of the work:

1. Line 72: Authors mentioned that “In the literature hepatotoxicity linked to green tea catechins administration is well described.” but no citations were given. Please, add it.

• Citations were added to support the abovementioned statement.

2. 147 articles were cited. How many are available in the databases mentioned? Please, mentioned about it in methods.

• The number of articles studied was added in the Methods

3. Line 557: Instead of “How much antioxidant supplements is too much” please use this form “How much antioxidant supplementation is too much?”

• The correction was made.

4. In Figure 1, label the rings A, B, C, respectively. The authors mention the B-ring of flavonoids in line 163.

• The rings A, B, C were labeled in Figure 1.

5. Line 355 Repetition of “in the study”.

• The repeated phrase was removed.

6. Please complete the abbreviation list. For example, xanthine oxidase, “C” (line 148), EFSA, γX are missing.

• The abbreviation list was completed.

7. My suggestion is to compile the literature data from chapters 4 and 5 into tables. This would be more transparent

• Some literature data from the section entitled “Association Between the Pro-Oxidant Activity of Green Tea Catechins and Hepatotoxicity Manifestation” are presented in a table to be more transparent.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

When there is a cited article please introduce values of their findings,names and year to be clear the source and short comments about how your findings are corelated. Your article should be readed not all and whole 50 references.

Author Response

Comment 1: When there is a cited article please introduce values of their findings,names and year to be clear the source and short comments about how your findings are corelated. Your article should be readed not all and whole 50 references.

Response 1:

Dear Reviewer, 

Thank you for your comment!

More information was added, according to your recommendation. It should be noted that one of the reviewers recommended the section about hepatotoxicity to be more condensed to avoid repetitive information, while the other suggested to compile the reported literature data about hepatotoxicity into tables to be more transperent.